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Botox Explained: How a Neurotoxin Became a Beauty Staple

In 2022, over 9 million Botox injections were given worldwide, making it one of the most popular cosmetic treatments today. Known for its ability to reduce wrinkles and give skin a smoother, younger appearance, Botox is particularly popular among celebrities looking to maintain a youthful appearance. But what exactly is Botox, and how does it work?

What is Botox?

Botulinum toxin, or Botox, is a neurotoxic protein derived from a bacteria known as bacterium Clostridium botulinum. Neurotoxic proteins are substances that disrupt the function of the nervous system. Botulinum toxin works by blocking the release of acetylcholine, a neurotransmitter that plays a critical role in muscle contraction, by interfering with the vesicles responsible for releasing acetylcholine. Located in neurons, vesicles are small sacs that store neurotransmitters, like acetylcholine. Botox targets and breaks down the proteins that help these vesicles release acetylcholine, preventing it from being released into the space between the nerve and the muscle.

This prevention of muscle contraction ultimately leads to reduced wrinkles, fine lines, improved skin texture, and overall a more youthful appearance.

While Botox is best known for its cosmetic benefits, it also provides several other medical benefits. This versatile procedure can also mitigate neck spasms and chronic migraines under the same mechanism. Additionally, Botox is effective in treating excessive sweating (hyperhidrosis). Not only is acetylcholine responsible for muscle contraction, but it also plays a key role in triggering sweat production in sweat glands. Botox can be injected in the affected areas, preventing them from producing excess sweat. Botox injections can also treat lazy eye by relaxing the overactive muscle in the eye—specifically, the extraocular muscle, which controls eye movement.

Different muscles vary in size and strength, so they require varying amounts of Botox to effectively relax the target muscle. Botox injections are administered in units, with 1 unit being a standardized measure of biological potency.

Where is Botox injected?

Botox can be used wherever facial muscles are creating lines. Here are the most common injection sites:

Forehead – to relax those horizontal lines that show up when you raise your eyebrows. 10-30 units of Botox.

Between eyebrows (glabella) – to soften the vertical lines caused by frowning. 5-15 units of Botox on each side.

Outer corners of eyes (crow’s feet) – to soften the orbicularis oculi muscles at the outer corners of the eyes. 10-15 units of Botox per side.

Around the mouth – to reduce smile lines (nasalabial folds) by pulling the corners of the mouth down. 3-6 units of Botox on each side.

How long does Botox last?

Botox injections generally last 3 to 4 months, depending on the dosage and site of injection. In areas with more muscle activity, like around the eyes or mouth, the effects of Botox will wear off faster compared to areas with less movement, like the forehead.

Side effects of Botox

As we’ve learned, Botox prevents the release of acetylcholine and ultimately muscle contraction. After injection, the targeted muscle remains entirely inactive for the treatment’s duration—typically 3 to 4 months. This prolonged inactivity can cause muscle atrophy, meaning that the muscle will reduce in mass, size, and strength. Some studies have shown that if a patient continues to undergo Botox injections in the long term, their skin might experience increased susceptibility to sun damage, premature aging, and dehydration. Granted, the current research on the long-term effects of Botox remains inconclusive.

Takeaway:

Known for its effective ability to smooth wrinkles by temporarily paralyzing facial muscles, Botox continues to reign as one of the most popular cosmetic treatments. Beyond aesthetics, Botox also treats medical conditions like migraines, excessive sweating, and muscle spasms. However, while generally safe, long-term use may lead to muscle atrophy and potential skin changes. As with any procedure, it’s important to weigh the benefits against possible risks and consult a healthcare provider for personalized care.

Bibliography

“Botox.” MedlinePlus, U.S. National Library of Medicine, 2 Aug. 2023, https://medlineplus.gov/botox.html.

“Vesicle.” NCI Dictionary of Cancer Terms, National Cancer Institute, https://www.cancer.gov/publications/dictionaries/cancer-terms/def/vesicle.

“What Areas Can Be Treated with Botox?” Westlake Dermatology & Cosmetic Surgery, https://www.westlakedermatology.com/blog/what-areas-can-be-treated-with-botox/.

“The Long-Term Effects of Botox: What Research Says.” Your Laser Skin Care, https://www.yourlaserskincare.com/blog/the-long-term-effects-of-botox-what-research-says.

Featured

Why Skin of Color Still Gets Misdiagnosed — and How We Can Fix It

13,400+ Black Man At Doctors Office Stock Photos, Pictures & Royalty-Free Images - iStock

In 2012, Lauryn Taylor—a Black woman—was misdiagnosed with eczema. Another doctor thought it might be vitiligo. Then came guesses like pityriasis alba or macular hypomelanosis. But none of them were right. In reality, Lauryn had skin cancer—and it took nearly 10 years to get the correct diagnosis.

I'm a Black Woman and My Skin Cancer Was Misdiagnosed for Years — Lauryn Taylor

Let that sink in — for nearly a decade, Lauryn lived with a misdiagnosis while her skin cancer went untreated, simply because her condition wasn’t recognized on darker skin.

Misdiagnosis isn’t just a medical error—it’s a public health crisis with endangering consequences. Diagnosis of the wrong condition can delay the proper treatment, allowing the condition to worsen over time. Dermatologists may prescribe particular creams or medications that can cause irreversible damage.

It’s also emotionally draining. Patients may feel frustrated or anxious when their ‘treatments’ are not working, leaving them feeling hopeless and dismayed. In desperation, patients will keep paying and returning for medical consultations and buying the wrong products/treatments. This becomes a heavy financial burden.

These are licensed physicians, right? Why are so many of them misdiagnosing patients?

“Probably no doctor is intending to do worse on any type of person, but it might be the fact that you don’t have all the knowledge and the experience, and therefore on certain groups of people, you might do worse,” says Northwestern University professor Matt Groh. In fact, it’s not the dermatologists’ fault — it’s the education system.

“A large part of dermatology education involves visual recognition,” states dermatologist Jasmine Onyeka Obioha, MD. “Physicians must identify conditions from photos of skin in textbooks or shared in the classroom. But most of the patients in those images are white and only 4.5% of the images show dark skin.” As a result, most medical students don’t know how to identify the skin conditions of patients of color, leading to a disparity in misdiagnosis among racially and ethnically diverse populations.

However, the misrepresentation of racially/ethnically diverse populations extends beyond dermatology textbooks, reflecting a broader, systemic issue within clinical education and diagnostic training. “Women and racial and ethnic minorities are 20% to 30% more likely than white men to experience a misdiagnosis,” said Johns Hopkins professor of neurology David Newman-Toker. This astounding statistic reveals the racial/ethnic disparities embedded in the foundations of medical training.

It’s no wonder why physicians often struggle to diagnose conditions in patients whose appearances and symptoms fall outside of the narrow standards they were taught.

What can we do?
In order for us to promote racial equality in dermatology/health care and prevent misdiagnoses, we must:

Reform medical education:
As only ~4.5% of dermatology images feature darker skin, we need to bring that number up to at least 30%. This number ensures equitable inclusion and representation of racially and ethnically diverse populations.

We need to incorporate modules tailored to diagnosing and treating conditions presented by racially and ethnically diverse populations into the medical curriculum.

Advocate for change:
Acknowledging the issue and the devastating statistics is the first step. Now, to turn awareness into action, we must collectively raise our voices, educate others, and advocate for meaningful change. People of color deserve to be treated with dignity and equity in the healthcare system.

Available resources:
https://guides.ucsf.edu/c.php?g=1081119&p=9159811

https://skinofcolorsociety.org/

https://www.aad.org/member/career/diversity

Bibliography:

1. UCSF Library. Health Disparities and Skin of Color in Dermatology. University of California San Francisco, 2022, https://guides.ucsf.edu/c.php?g=1081119&p=9159811.

2 Skin of Color Society. Home. https://skinofcolorsociety.org/.

3. American Academy of Dermatology. Diversity, Equity, and Inclusion in Dermatology. https://www.aad.org/member/career/diversity.

4. Miller, Korin. “Doctors Told Me My Skin Cancer Was Eczema for Almost a Decade.” Prevention, 28 May 2021, https://www.prevention.com/health/health-conditions/a36230501/mycosis-fungoides-misdiagnosis/.

5. Kim, Sophia, et al. “Diagnostic Performance of Dermatologists and General Practitioners in Skin Diseases on Diverse Skin Tones.” Nature Medicine, vol. 29, 2023, pp. 1941–1948. https://www.nature.com/articles/s41591-023-02728-3.

6. Loftus, Peter. “Misdiagnosed: Women and Minorities Face Higher Risk of Harm from Medical Errors.” KFF Health News, 15 Dec. 2023, https://kffhealthnews.org/news/article/medical-misdiagnosis-women-minorities-health-care-bias/.

7. Cedars-Sinai. “Why Skin Issues in Patients of Color Are Neglected, Mistreated.” Cedars-Sinai Newsroom, https://www.cedars-sinai.org/newsroom/why-skin-issues-in-patients-of-color-are-neglected-mistreated/.

8. Pew Research Center. Facts About the U.S. Black Population. 9 Feb. 2023, https://www.pewresearch.org/race-and-ethnicity/fact-sheet/facts-about-the-us-black-population/.

9. Massachusetts General Hospital. Skin Assessment in Patients with Dark Skin Tone. Munn Center, Apr. 2023, https://www.mghpcs.org/MunnCenter/Documents/weekly/apr-23/Skin-Assessment-in-Patients-with-Dark-Skin-Tone.pdf.

10. Trafton, Anne. “Doctors Struggle to Diagnose Diseases in Patients with Darker Skin.” MIT News, 5 Feb. 2024, https://news.mit.edu/2024/doctors-more-difficulty-diagnosing-diseases-images-darker-skin-0205.

11. TEDx Talks. “Why Doctors Misdiagnose Skin Conditions on Darker Skin.” YouTube, uploaded by TEDx, 7 Oct. 2022, https://www.youtube.com/watch?v=2JUQo-PnY2g.

Featured

Laser Resurfacing vs. Pigmentation Lasers: Which Treatment Suits Your Skin?

Which is better? Erbium YAG Laser vs CO2 Laser | The Ferguson Clinic

Providing a diverse plethora of skin benefits, laser treatments have revolutionized dermatology and have skyrocketed in popularity, with roughly 4 million laser skin treatments being performed annually. This surge in demand can be attributed to their ability to effectively address a variety of skin concerns: acne scars, wrinkles, hyperpigmentation, and unwanted hair. Offering precision and long-lasting results, laser treatments work in a very fascinating and non-invasive manner.

The significance of collagen

Before exploring the various types of laser treatments for the skin, it’s essential to understand why they’re effective: they stimulate collagen production — a key factor in maintaining youthful, healthy skin. Collagen is the most abundant protein in the human body and forms the structural framework of the skin. It interacts with other molecules like hyaluronic acid to provide firmness, elasticity, and hydration. As we age, natural collagen production declines, leading to wrinkles, sagging, and thinning skin. To combat this, laser treatments can be used to trigger fibroblasts to produce more collagen, consequently rebuilding smoother skin.

Laser resurfacing:

One of the more popular laser treatments, laser resurfacing is a technique that uses ablative lasers, non-ablative lasers, or fractional lasers. Ablative lasers (eg: CO₂) cast a beam of light that destroys the protective keratin on the epidermis—the outer layer of the skin—and heats the underlying skin—dermis. Ablative lasers emit energy at a wavelength of around 10,600 nm. In response, the body stimulates collagen growth to regrow the targeted wound. Once fully healed, the treated area returns smoother—free of sun damage and wrinkles. Ablative lasers are the most effective/intense laser option, requiring longer recovery time while providing the most drastic results.

Types of ablative lasers

CO₂ and Er:YAG lasers are the most commonly used ablative lasers, each with distinct advantages and applications. CO₂ lasers, operating at a high wavelength of ~10,600 nm, penetrate deeply into the skin, making them highly effective for severe sun damage, deep wrinkles, acne scars, and skin tightening. In contrast, Er:YAG lasers, with a moderate wavelength of ~2940 nm, offer more precise and controlled resurfacing, making them ideal for treating mild to moderate wrinkles, fine lines, and sun damage while minimizing heat damage.

Non-ablative lasers

If you seek a more gentle procedure with a shorter recovery time, non-ablative lasers would be a more suitable option. Unlike ablative lasers that both vaporize the epidermis and heat the dermis, non-ablative lasers do not create a wound on the surface, only heating the dermis. Non-ablative lasers operate at a marginally lower wavelength, typically between 1320 nm – 1927 nm. This still stimulates collagen production, but more gradually/gently.

Both ablative and non-ablative lasers can alternatively be offered fractionally instead of full-field. Fractional ablative/non-ablative lasers create microscopic wounds on the skin, leaving the surrounding skin intact. It should be noted that this fractional approach maintains the same wavelength as its full-field counterpart, but the delivery of the laser energy is different. Fractional lasers allow for reduced downtime and faster healing. It still effectively stimulates collagen production, though the results tend to be more gradual compared to full-field treatments.

Pigmentation & spot removal lasers

Similarly to laser resurfacing, pigmentation lasers also target and treat sun spots and pigmentation; however, they are a targeted treatment specifically designed to break down melanin without affecting the surrounding skin. The significantly low wavelength of pigmentation lasers—between 532 nm and 1064 nm—enables pinpoint accuracy for melanin to more effectively absorb laser energy. Unlike resurfacing lasers, which also improve skin texture, wrinkles, and scars, pigmentation lasers focus solely on degrading pigmentation, making them ideal for treating sunspots, freckles, melasma, and hyperpigmentation. It’s important to note that pigmentation lasers do not strongly stimulate collagen production, as they do not heat the dermis and trigger fibroblasts to produce new collagen.

Laser Pigmentation Removal in Portland, Oregon — Process of Laser Pigmentation Removal

Takeaway:

Ultimately, if your skin concern is solely moderate pigmentation and sun damage, pigmentation & spot removal lasers would be a better choice. These lasers operate at a low wavelength, ensuring minimal downtime, targeted melanin degradation, and reducing damage to surrounding tissue. If you wish to also treat scarring/texture or severe sun damage, resurfacing lasers (ablative/non-ablative) would be more suitable, as their potency stimulates collagen production and promotes new and smoother skin.

Bibliography

Cambridge Laser Clinic. “Detailed Explanation of Pigment Laser Treatments.” Cambridge Laser Clinic, https://cambridgelaserclinic.com/laser-treatments/pigment/detailed-explanation/#:~:text=Several%20different%20laser%20wavelengths%20can,(Nd%20Yag%201064nm%20laser). Accessed 2024.

“Laser Resurfacing.” Mayo Clinic, https://www.mayoclinic.org/tests-procedures/laser-resurfacing/about/pac-20385114#:~:text=Results%20after%20nonablative%20laser%20resurfacing,treatments%20to%20get%20noticeable%20results. Accessed 2024.

“Laser Light Energy-Based Procedures in the U.S. by Type.” Statista, https://www.statista.com/statistics/319224/distribution-of-laser-light-energy-based-procedures-in-the-us-by-type/. Accessed 2024.

RCSB Protein Data Bank. “Collagen Structure.” Protein Data Bank, https://pdb101.rcsb.org/motm/4. Accessed 2024.

“Lasers in Dermatology and Medicine.” National Center for Biotechnology Information, https://www.ncbi.nlm.nih.gov/books/NBK557474/. Accessed 2024.

Rokhsar, C. K., and Fitzpatrick, R. E. “The Treatment of Wrinkles and Skin Laxity Using a Fractional Ablative CO₂ Laser: A Retrospective Study.” National Center for Biotechnology Information, https://pmc.ncbi.nlm.nih.gov/articles/PMC3580982/. Accessed 2024.

The Ferguson Clinic. “Which Is Better? Erbium YAG Laser vs. CO₂ Laser.” The Ferguson Clinic, https://www.thefergusonclinic.com/which-is-better-erbium-yag-laser-vs-co2-laser/. Accessed 2024.

Full Potential Men. “Laser Pigmentation Removal.” Full Potential Men, https://www.fullpotentialmen.com/laser-pigmentation-removal/. Accessed 2024.

Featured

What Happens During an Eczema Flare-Up? A Scientific Breakdown

What is eczema?
Eczema is a common skin condition characterized by inflamed, itchy patches of dry and scaly skin. This chronic condition affects roughly 10% of the US population. These patches result from a combination of environmental triggers and immune system reactions, often with a genetic predisposition. There are several types of eczema, including atopic dermatitis—the most common type—and contact dermatitis, among others. The key difference between atopic dermatitis and contact dermatitis comes down to the underlying cause and immune response. Atopic dermatitis is a chronic condition that can be triggered by both external factors and internal influences, such as stress, but is ultimately caused by genetic and immune system factors. In contrast, contact dermatitis is an acute condition that is directly caused by irritants like soaps or chemicals and can easily be prevented by avoiding said irritants.

Who suffers from atopic dermatitis?
The integration of genetic mutations and a hyperactive immune response in individuals with atopic dermatitis leads to persistent eczema flare-ups. In particular, these individuals have a loss-of-function genetic mutation in their filaggrin gene—one of 70 genes comprising the Epidermal Differentiation Complex—which is crucial for maintaining the epidermis and protecting it from allergens and irritants. This genetic mutation causes the affected individual to produce less filaggrin protein, ultimately resulting in a compromised skin barrier and increased susceptibility to environmental triggers. This single filaggrin defect leads to a cascade of dysfunctions in the body, including reduced natural moisturizing factor levels and a hyperactive immune system.

Filaggrin and eczema – Nursem Skincare — (https://www.nursem.co.uk/pages/filaggrin-and-eczema)

What happens during a flare-up?
An atopic dermatitis flare-up is a multi-step process that begins with a trigger—environmental factors, irritants, allergens, etc. Because the skin barrier of these individuals is compromised and more susceptible to infiltration, allergens and irritants can penetrate more easily. Once the trigger reaches the compromised skin barrier, antigen-presenting cells capture the trigger and carry it over to the local lymph nodes. Lymph nodes are organs that house various immune cells that help coordinate the immune response. T cells – a key type of immune cell – activate and then identify the trigger to initiate the release of cytokines—signaling proteins that—when overproduced—are primarily responsible for the redness and inflammation associated with atopic dermatitis.

How do topical medications alleviate flare-ups?

The complex combination of genetics, environmental triggers, and the immune system makes eczema uncurable, although its symptoms can be mitigated. Topical steroids and inhibitors are commonly used to manage inflammation in conditions like atopic dermatitis. Topical steroids are applied directly to the skin, where they enter cells and bind to receptors in the cytoplasm. This binding triggers the formation of a steroid-receptor complex, which then migrates to the nucleus. In the nucleus, the complex binds to and modifies specific DNA sequences, including the one to reduce the production of inflammatory cytokines. This process helps alleviate redness, swelling, and other symptoms of inflammation.
On the other hand, topical inhibitors reduce inflammation by binding to a protein in T cells, creating a complex that inhibits calcineurin, an enzyme responsible for promoting cytokine transcription and T cell activation. Although these topical treatments yield similar results, their function is very different, so prescription of either should be done by a healthcare professional.

Bibliography

National Center for Biotechnology Information. “Chemical Bonding and Molecular Structure.” NCBI Bookshelf, 2019, https://www.ncbi.nlm.nih.gov/books/NBK538209/.

Wang, Y., et al. “Molecular Insights into Chemical Interactions.” PLOS Computational Biology, vol. 17, no. 2, 2021, e1008623. https://pmc.ncbi.nlm.nih.gov/articles/PMC7880084/.

“—.” American Cancer Society, www.cancer.org/cancer/diagnosis-staging/lymph-nodes-and-cancer.html#:~:text=Lymph%20vessels%20send%20lymph%20fluid,filter%20fluid%20in%20those%20areas.

National Eczema Association. “Eczema Topical Treatments | National Eczema Association.” National Eczema Association, 4 Mar. 2022, nationaleczema.org/eczema/treatment/topicals.

Biochemical Markers of Psoriasis: What’s Happening Beneath the Skin?

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Often confused with atopic dermatitis, psoriasis is also an incurable chronic skin condition that is characterized by itchy/inflamed and scaly patches of skin. As psoriasis affects ~2% of the United States population, the demand for treatment continues to soar. Unfortunately, psoriasis is a complex autoimmune condition that entails various factors. In this post, we’ll learn about the causes of psoriasis, the role of the immune system in psoriasis, remedies, as well as how it differs from other inflammatory skin conditions like eczema.

What causes psoriasis?

The root causes of psoriasis start with genetics and environmental triggers. This combination is integral for psoriasis, with genetic predispositions endangering the host to an overreactive immune response, which can be provoked by an environmental trigger. Triggers include skin injuries, infections, stress, alcohol, and more.

What happens during a psoriasis flare-up?

Once triggered, the immune system begins to malfunction. Crucial immune cells known as t cells—responsible for fighting off pathogens—become overactive. They begin to mistakenly orchestrate an attack on skin cells, assuming them to be pathogens. First, T cells release cytokines (typically IL-17 and IL-23)—proteins that regulate immune responses and contribute to inflammation. These cytokines then stimulate the overproduction of keratinocytes (skin cells) to try to repair the damage. The basal layer of the epidermis (where keratinocytes are produced) then goes overdrive, resulting in rapid cell division. This manifests as flaky, inflamed, and itchy lesions of the skin of psoriasis.

Here is a flowchart to help demonstrate the process:

Genetic predisposition and environmental triggers

T cells become overactive

T cells release cytokines

Cytokines stimulate keratinocyte overproduction

Visible symptoms of psoriasis (Scaly, itchy plaques)

Psoriasis vs. atopic dermatitis

Psoriasis and atopic dermatitis are both chronic skin conditions that manifest as flaky, inflamed, and itchy patches of skin. However, the difference between these two comes down to their underlying cause. As we’ve learned, psoriasis is an autoimmune condition that involves the immune system mistakenly attacking the body. In contrast, atopic dermatitis is an inflammatory condition involving a defective/hypersensitive skin barrier due to genetic mutation. Although psoriasis can also be triggered by environmental triggers, think of atopic dermatitis as being the direct, inflammatory response to a trigger. Psoriasis, on the other hand, happens because the immune system is already defective and attacking the body’s own skin cells, and outside triggers just make it worse.

Types of psoriasis

Psoriasis can take on several forms, depending on the types of cytokines involved. Accounting for 80-90% of psoriasis cases, plaque psoriasis is the most common form. Primary cytokines involved: IL-17 and IL-23. Manifests as raised, silver-colored, scaly patches of skin. Most commonly forms on the elbows and knees. Psoriasis can also take several other forms, affecting different parts of the body. These include: guttate psoriasis (torso, upper arms, and legs), pustular psoriasis (palms of hands or soles of feet), inverse psoriasis (skin folds), and many more.

Plaque psoriasis

Treatments:

Luckily, scientists have developed various treatment options for psoriasis that work by reducing inflammation and slowing the overproduction of skin cells. Treatments include topical therapies (creams and ointments), light therapy, and oral or injected medications. The best option for each patient depends on the severity of the condition, medical history, and lifestyle.

Conclusion:

Understanding the biochemistry and immunology behind psoriasis reveals the complexity of this abstract, chronic, autoimmune condition. Although there isn’t currently a direct cure for psoriasis, several treatments have been developed to mitigate symptoms, reduce inflammation, and prevent flare-ups. The more we understand the underlying cause of psoriasis, the closer we get to hopefully curing this chronic condition.

Bibliography

American Academy of Dermatology Association. “What Causes Psoriasis?” AAD, https://www.aad.org/public/diseases/psoriasis/what/causes. Accessed 13 Apr. 2025.

Rendon, Adriana, and Benjamin Schäkel. “Psoriasis Pathogenesis and Treatment.” International Journal of Molecular Sciences, vol. 19, no. 5, 2019, p. 1475, https://pmc.ncbi.nlm.nih.gov/articles/PMC5751129/. Accessed 13 Apr. 2025.

National Institute of Arthritis and Musculoskeletal and Skin Diseases. “Psoriasis.” NIAMS, U.S. Department of Health and Human Services, https://www.niams.nih.gov/health-topics/psoriasis. Accessed 13 Apr. 2025.

“Psoriasis.” TeachMe Paediatrics, https://teachmepaediatrics.com/dermatology/dermatology/psoriasis/. Accessed 13 Apr. 2025.

Greb, Jennifer E., et al. “Psoriasis.” International Journal of Molecular Sciences, vol. 20, no. 10, 2019, p. 2558, https://www.mdpi.com/1422-0067/20/10/2558. Accessed 13 Apr. 2025.

Radiant Dermatology. “Psoriasis.” Radiant Dermatology & Skin Cancer Center, https://www.radiantdermtx.com/view-medical-dermatology/psoriasis. Accessed 13 Apr. 2025.

Thomas, Liji. “What Are T Cells?” News Medical, 27 Feb. 2019, https://www.news-medical.net/health/What-are-T-Cells.aspx. Accessed 13 Apr. 2025.

Di Meglio, Paola, et al. “The Role of APCs in Psoriasis Pathogenesis.” Frontiers in Immunology, vol. 6, 2015, https://pmc.ncbi.nlm.nih.gov/articles/PMC4437803/. Accessed 13 Apr. 2025.

WebMD. “Cytokines and Psoriasis.” WebMD, https://www.webmd.com/skin-problems-and-treatments/psoriasis/cytokines-psoriasis. Accessed 13 Apr. 2025.

Parisi, Rosalind, et al. “Psoriasis Vulgaris: A Comprehensive Overview.” Dermatology and Therapy, vol. 10, no. 2, 2020, pp. 261–273, https://pmc.ncbi.nlm.nih.gov/articles/PMC7122924/. Accessed 13 Apr. 2025.

Tyrosinase Inhibitors vs. Melanogenesis Inhibitors: Which is Better for Treating Pigmentation?

What causes pigmentation?

Responsible for providing color to our skin, hair, and eyes, melanin is an essential, naturally produced pigment that our body–and most organisms— is constantly producing. Our natural skin tone is largely accredited to our genetically determined melanin production rate, which vastly varies across ethnicities. Inhabitants of regions with more intense UV radiation have evolved to develop genetic mutations that increase their melanin production and thus have darker skin tones, whereas people in lower UV regions have lighter skin tones. The process of melanin production—otherwise known as melanogenesis—entails the conversion of tyrosinase—a natural enzyme—into melanin.

Simplified pathways of tyrosine-derived melanin synthesis showing... | Download Scientific Diagram — Process of Melanin Synthesis
(ResearchGate)

How does UV radiation influence melanin production?

As a defense mechanism against UV radiation, the skin initiates melanogenesis. Melanin then transfers to keratinocytes—the cell that produces keratin, an essential protein in the epidermis—where the melanin internally absorbs UV rays and reduces DNA damage. However, if the skin receives excessive exposure to UV radiation—without sun protection—the melanin will eventually fail to provide skin protection, leading to sun damage and, soon enough, hyperpigmentation. Although tyrosinase production is also largely influenced by genetics and exposure to UV radiation, tyrosinase, and melanin production can be reduced by tyrosinase inhibitors.

What are tyrosinase inhibitors?

Whether found synthetically in ingredients like azelaic acid or naturally in ingredients like aloe vera, tyrosinase inhibitors are widely used to even out skin tone by blocking tyrosinase activity during catalytic reaction, thereby reducing melanin production and, in some cases, breaking down and degrading pre-existing melanin. Their versatility makes them a key component in the treatment of hyperpigmentation, melasma, and age spots. While different tyrosinase inhibitors function differently, they ultimately yield the same results—reduced melanin synthesis and a more even complexion. Here are some examples of tyrosinase inhibitors with varying potency.

Niacinamide: Although not technically a tyrosinase inhibitor, niacinamide Inhibits melanosome transfer—the process of turning melanin into a visible pigment. Niacinamide does not alter tyrosinase production, making it a more gentle alternative to typical tyrosinase inhibitors. It can be applied up to twice daily.

Azelaic acid: Inhibits tyrosinase and gently reduces pigmentation by targeting hyperactive melanocytes—cells that produce melanin. Azelaic acid is slightly more potent than niacinamide. It can be applied up to twice daily.

Hydroquinone: Directly inhibits tyrosinase and melanin synthesis. It can be used up to twice a day for 3-6 months as treatment for intense hyperpigmentation or melasma; to avoid irritation, it should not be used any longer, as it is highly potent.

Melanogenesis inhibitors are often confused with tyrosinase inhibitors, and although they yield similar results—reducing pigmentation—tyrosinase inhibitors are a subset of melanogenesis inhibitors, which differ in that they affect melanin synthesis as a whole rather than directly targeting tyrosinase. Alongside just targeting tyrosinase production, melanogenesis inhibitors also promote melanin degradation and target melanogenesis pathways, blocking melanin from transferring to keratinocytes.

Which inhibitor is better?

Although melanogenesis inhibitors target several steps in melanogenesis as opposed to directly targeting tyrosinase activity—as seen with tyrosinase inhibitors—that doesn’t necessarily mean that one is stronger or more effective than the other. In general, melanogenesis inhibitors are preferred for more gradual and long-term treatment for pigmentation, whereas tyrosinase inhibitors are stronger for more rapid pigmentation treatment and results. While both are effective in their own ways, combining these treatments with sun protection, exfoliants, and antioxidants ensures the best results for maintaining an even skin tone and treating hyperpigmentation.

Bibliography

Boissy, R. E. “Melanosome Transfer to and Translocation in the Keratinocyte.” Experimental Dermatology, vol. 7, no. 3, 1998, pp. 143-150. PubMed.

National Cancer Institute. “Melanocyte.” NCI Dictionary of Cancer Terms, n.d., [https://www.cancer.gov/publications/dictionaries/cancer-terms/def/melanocyte](https://www.cancer.gov/publications/dictionaries/cancer-terms/def/melanocyte#:~:text=(meh%2DLAN%2Doh%2D,contains%20the%20pigment%20called%20melanin.).

University of Rochester Medical Center. “What Is Skin Pigmentation?” Health Encyclopedia, n.d., https://www.urmc.rochester.edu/encyclopedia/content?contenttypeid=85&contentid=p01359.

Costin, G. E., and V. J. Hearing. “Human Skin Pigmentation: Melanocytes Modulate Skin Color in Response to Stress.” The FASEB Journal, vol. 21, no. 4, 2007, pp. 976-994. PMC.

Burkhart, C. G., and H. R. Burkhart. “Hydroquinone.” StatPearls, StatPearls Publishing, 2019. NCBI.

Pillaiyar, T., M. Manickam, and V. Namasivayam. “Skin Whitening Agents: Medicinal Chemistry Perspective of Tyrosinase Inhibitors.” Journal of Enzyme Inhibition and Medicinal Chemistry, vol. 32, no. 1, 2017, pp. 403-425. PMC.

Chang, T. S. “Natural Melanogenesis Inhibitors Acting Through the Down-Regulation of Tyrosinase Activity.” International Journal of Molecular Sciences, vol. 10, no. 6, 2009, pp. 2440-2475. PMC.

Sasaki, M., K. Hasegawa, and Y. Takahashi. “Recent Advances in Skin Lightening Agents: A Comprehensive Review.” Journal of Dermatological Science, vol. 110, no. 1, 2023, pp. 12-24. PMC.

Protease vs. PHAs: Which is Better for Sensitive Skin?

Protease vs. PHAs: Which is Better for Sensitive Skin?

Both protease enzymes and polyhydroxy acids (PHAs) are widely known for their gentle exfoliating properties, making them excellent choices for individuals with sensitive skin who may not tolerate stronger exfoliants like AHAs and BHAs. While both options help remove dead skin cells without excessive irritation, they differ significantly in how they work, how frequently they can be used, and their overall impact on the skin barrier.

What is protease?

Proteases, also known as proteolytic enzymes, are natural enzymes that our bodies continuously produce to facilitate various biochemical processes. Enzymes act as biological catalysts, meaning they speed up specific chemical reactions. Proteases, in particular, function by breaking peptide bonds between amino acids in proteins, playing a crucial role in digestion, wound healing, protein turnover, immune responses, and hormone regulation.

These enzymes are not only essential within the body but are also beneficial in skincare. When derived from plant-based sources like papaya, protease enzymes provide enzymatic exfoliation, helping the skin naturally shed dead cells in a non-abrasive and barrier-friendly way.

How does protease work on the skin?

Since protease enzymes naturally break down proteins, they can also target keratin, a structural protein that forms the outermost layer of the skin. This natural exfoliation process is known as desquamation, where the skin uses its own proteases to degrade the corneodesmosomes—the protein structures that hold dead keratinocytes together in the stratum corneum.

Desquamation is a slow, multi-step process that usually occurs over 28 days as the skin renews itself. However, various factors—such as aging and environmental stressors—can slow down this natural shedding process, leading to dullness, clogged pores, and rough texture. This is where protease-based exfoliants can help.

In skincare, protease enzymes mimic and enhance this natural desquamation process by gently breaking down corneodesmosomes – structures that bind skin cells -, allowing dead skin cells to detach and shed naturally. Unlike acids, which rely on low pH levels to weaken cell adhesion, protease exfoliants work without significantly altering the skin’s pH balance. Their mildly acidic pH (~4.5–5.5) closely matches the skin’s natural acidity, ensuring minimal barrier disruption. Additionally, proteases are hydrophilic, meaning they attract moisture, helping to keep the skin hydrated and smooth. Due to their surface-level action, protease enzymes can be used daily without the risk of over-exfoliation or excessive irritation.

11 Corneodesmosomes Royalty-Free Photos and Stock Images | Shutterstock — Anatomy of Epidermis

How do PHAs work on the skin?

PHAs (polyhydroxy acids) belong to the hydroxy acid family and are considered the gentlest type of chemical exfoliant. Compared to AHAs (glycolic, lactic acid) and BHAs (salicylic acid), PHAs have the largest molecular structure, which prevents deep penetration into the skin. Instead, they work at a minimal depth, making them less irritating than their smaller-molecule counterparts.

Unlike proteases, which exfoliate exclusively on the skin’s surface, PHAs function by weakening the corneodesmosome bonds that hold dead skin cells together. This process allows for gradual shedding while simultaneously providing hydration due to their humectant properties. PHAs are hydrophilic, meaning they attract water molecules, helping to reinforce the skin barrier and improve moisture retention.

For most circumstances, PHAs are best to be used 2-4 times per week. PHAs are very gentle in that they minimally penetrate the skin, although their low pH can likely disrupt the skin barrier if used too frequently. Proteases, on the other hand, can be used daily because of their surface-level exfoliation and seamless pH level.

Which one is better for sensitive skin?

Both proteases and PHAs are excellent choices for sensitive skin, but understanding their key differences can help you determine which one is better suited to specific needs: Ultimately, if you have super sensitive skin and may find irritation from a PHA, protease enzymes will ensure no skin barrier disruption/irritation, whilst also drawing moisture to the skin. It’s important to consider that proteases provide surface-level exfoliation, whereas PHAs minimally penetrate the skin to weaken the corneodesmosome bonds holding dead skin cells together. For this reason, it will take longer to notice results from proteases, so PHAs would likely be the preferable option if your skin can handle it.

Bibliography

Trevisol, Thalles Canton, et al. “An Overview of the Use of Proteolytic Enzymes as Exfoliating Agents.” Journal of Cosmetic Dermatology, vol. 21, no. 8, Dec. 2021, pp. 3300–07. https://doi.org/10.1111/jocd.14673.

“Topical Skin Care and the Cosmetic Patient.” ScienceDirect, 2018, www.sciencedirect.com/topics/neuroscience/hydroxy-acids#:~:text=Hydroxy%20acids%2C%20also%20known%20as,%2C%20glycolic%20acid%2C%20oxalic%20acid. Accessed 4 Feb. 2025.

“Intramembrane Proteases.” ScienceDirect, www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/protease. Accessed 4 Feb. 2025.

Hoshikawa, Karina. “A Guide to Polyhydroxy Acids (PHA) in Skin Care.” Allure, 24 Jan. 2019, www.allure.com/story/what-are-phas-polyhydroxy-acids.

“Industrial Biotechnology and Commodity Products.” ScienceDirect, 2011, www.sciencedirect.com/topics/earth-and-planetary-sciences/protease#:~:text=The%20proteases%20with%20pH%20optima,from%20Bacillus%20and%20Streptomyces%20species. Accessed 4 Feb. 2025.“Implications of normal and disordered remodeling dynamics of corneodesmosomes in stratum corneum.” ScienceDIrect, www.sciencedirect.com/science/article/pii/S102781171500035X#:~:text=The%20principal%20functions%20of%20desmosomes,cells%2C%20i.e.%2C%20the%20epidermis. Accessed 4 Feb. 2025.

Debunked: Are Beef Tallow Moisturizers Better than Traditional Moisturizers?

Applying beef tallow – rendered fat of a cow – on the skin has an extensive historical background, dating back centuries ago, and has recently regained popularity on social media, particularly in the form of a moisturizer. Unlike traditional moisturizers that use glycerin or hyaluronic acid to moisturize the skin, beef tallow-based moisturizers use solely beef tallow and oftentimes, oil. I decided to look into beef tallow-based moisturizers to determine whether or not they are effective/safe, and how they compare to traditional moisturizers.

The skin benefits of beef tallow

Beef tallow moisturizers are promoted to deeply moisturize the skin and soothe acne, however, there’s insufficient research to support this claim. As stated by the NCBI, more research is still needed for beef tallow to be used as a cosmetic product for humans. The potential benefits of beef tallow for the skin are as follows: beef tallow’s rich content of fatty acids is assumed to protect the skin barrier from pollutants/inflammation, thus promoting a stronger lipid barrier. Fatty acids also help retain water/moisture in the skin, preventing a process known as transepidermal water loss, which occurs when water evaporates from the skin, drying it out. Beef tallow advocates claim that the fatty acids replicate the skin’s natural sebum, making it a “better” alternative than traditional moisturizers.

The drawbacks of beef tallow

Despite the moisturizing benefits of fatty acids, the chemical construction of fatty acids makes them comedogenic and not fungal acne-safe; the rich content of fatty acids and the thick nature of beef tallow may feel thick and heavy on the skin. Moreover, beef tallow moisturizers typically contain oil – often olive oil – alongside beef tallow. This makes beef tallow moisturizers comedogenic, alongside feeling heavy and greasy, with a rating of 2 out of 5 on the comedogenic scale. For this reason, beef tallow moisturizers are not advised for individuals with acne-prone skin despite companies claiming that they’re suitable for all skin types. However, for individuals with dry skin or eczema, beef tallow moisturizers may be tolerable.

What do reviews say about beef tallow moisturizers?

Due to the lack of research regarding beef tallow for the skin, I looked into reviews from customers. One customer experimented with a beef tallow moisturizer for one week and found that the product was heavy and left a greasy finish. By day five, her face started breaking out – this likely alludes to the comedogenic formulations of beef tallow moisturizers. While this customer had a poor experience with beef tallow, it should be noted that her skin type may not be compatible with these thick moisturizers, as she doesn’t have super dry or eczema-prone skin.

For some reason, social media has tried to label traditional moisturizers as having “dangerous chemicals,” scaring the public into buying these natural, beef tallow-based moisturizers. Although some customers may have a pleasant experience with these products, there’s still insufficient scientific evidence/research to back up using beef tallow for the skin, so it would be safe to use traditional moisturizers instead. The ingredients and nature of beef tallow moisturizers make them likely heavy and comedogenic for acne-prone individuals, as proven by customer reviews. As long as you invest in a quality product that doesn’t have parabens, sulfates, etc., traditional moisturizers are completely safe and effective.

Works Cited

“Does Tallow Clog Pores? The Comedogenic Scale Explained.” Sun & Moo, sunandmoo.com/blogs/sun-moo/does-tallow-clog-pores-the-comedogenic-scale-explained. Accessed 16 Jan. 2025.

Holender, Samantha. “So, People Are Slathering Their Faces In Beef Tallow Now?” Vogue, www.vogue.com/article/beef-tallow-for-skin. Accessed 16 Jan. 2025.

Medaris, Anna. “Beef Tallow for Skin: What Dermatologists Think About the Trend.” Edited by Ross Radusky. Everyday Health, 29 Feb. 2024, www.everydayhealth.com/healthy-skin/beef-tallow-for-skin-what-dermatologists-think-about-the-trend/#:~:text=The%20Takeaway,irritation%20rather%20than%20any%20benefits. Accessed 16 Jan. 2025.

“Relative irritancy of free fatty acids of different chain length.” National Library of Medicine, pubmed.ncbi.nlm.nih.gov/233889/. Accessed 16 Jan. 2025.”Tallow, Rendered Animal Fat, and Its Biocompatibility With Skin: A Scoping Review.” National Library of Medicine, pubmed.ncbi.nlm.nih.gov/38910727/. Accessed 16 Jan. 2025.

The Role of the Gut Microbiome in Healthy Skin

On social media, you may have heard influencers promote the idea that having a healthy gut is the most crucial factor for healthy skin, more so than a skincare routine. I decided to investigate the gut microbiome’s correlation with the skin, measure the impact of the microbiota on skin conditions, and how to improve your gut health.

What is the gut microbiota?

The gut microbiota is the collection of microorganisms – bacteria, viruses, fungi – located in the gastrointestinal tract. This means that the intestines are strongly connected with the health of the gut microbiome. The gut microbiota facilitates several of the body’s functions, including protection against pathogens – disease-inducing agents -, strengthening the immune system, metabolism, the health of the gut barrier, etc.

Will Gut Microbiome Transplants Lead to New Treatments for Ulcerative Colitis? - ENCORE Research Group

How does the gut microbiota relate to the skin?

The skin’s health is largely determined by the immune system, as it provides the skin protection from the external environment. The skin contains various immune cells that are populated with microorganisms. The community of these microorganisms inhabiting the skin’s cells is referred to as the skin microbiome, which is interconnected with the gut microbiome. These immune cells rely on the gut microbiome for regulation, enabling them to protect the skin from pathogens and inflammation. An unhealthy gut microbiome – otherwise referred to as dysbiosis – can lead to various skin conditions including eczema, psoriasis, acne, rosacea, skin cancer, etc.. The relationship between the gut and the skin is often called the gut-skin axis.

How does dysbiosis cause skin conditions?

As the gut microbiome is strongly correlated with the skin, dysbiosis can lead to various conditions. Inflammation from dysbiosis can trigger the body to excessively release cytokines – proteins that regulate inflammation. When cytokines are excessively released into the bloodstream, they start to irritate the skin, causing skin conditions like rosacea. Atopic dermatitis – or eczema – can be caused by dysbiosis as well, as an imbalance in the gut is linked with a weakened immune system, thus making the skin more sensitive to environmental factors. When the skin is more vulnerable and sensitive, it’s more susceptible to developing inflamed, itchy rashes – a common symptom of eczema. In general, an imbalanced gut microbiome is detrimental to the proper physiological functioning of the body, ultimately leading to skin conditions.

Improving gut health with diet

Several dietary modifications are linked with improved gut health, including probiotics, lemon, ginger, and an increased intake of dietary fiber. These modifications all are linked with the production of butyrate – a short-chain fatty acid produced in the gut. Butyrate serves a valuable role in the gut microbiome, an essential component for a healthy gut. supporting its function and regulation, providing energy for gut cells, and reducing inflammation. The large intestine relies on butyrate as an energy source for its colonocytes – cells that support the large intestine’s function – and thus, a healthy gut. In general, it’s best to avoid excessively processed foods and refined sugars, as these foods can inflame the gut microbiota.

In brief, the gut microbiome is strongly correlated with skin health. An imbalance in the gut microbiome – dysbiosis – hinders the proper functioning of the body, particularly the immune system. When the body fails to function and support the skin barrier properly, the skin barrier deteriorates. For this reason, following a healthy diet is essential to a healthy gut and ultimately, healthy skin.

Works Cited

“Gut–Skin Axis: Current Knowledge of the Interrelationship between Microbial Dysbiosis and Skin Conditions.” National Library of Medicine, pmc.ncbi.nlm.nih.gov/articles/PMC7916842/#:~:text=The%20microbiome%20plays%20an%20important,by%20an%20altered%20gut%20microbiome. Accessed 13 Dec. 2024.

“Introduction to the human gut microbiota.” National Library of Medicine, 16 May 2017, pmc.ncbi.nlm.nih.gov/articles/PMC5433529/. Accessed 4 Dec. 2024.

“Signs of an Unhealthy Gut and What to Do About It.” Healthline, www.healthline.com/health/gut-health. Accessed 13 Dec. 2024.

The Significant Role of Keratin in the Body

Keratin is a crucial protein that your body constantly produces; keratin is essential for the function and maintenance of the skin, hair, and nails. Neglecting keratin can lead to several skin/hair issues, so it’s important to properly understand the role of keratin and how you can manage it.

What is keratin?

Keratin is a protein, meaning that it’s composed of a chain of amino acids. Keratin can be categorized as either hard or soft keratin. There are over 50 types of keratin, hard keratin and soft keratin are just to name a few. Hard keratin tends to be sturdier and less elastic, which can be found on the hair and nails. Soft keratin is more elastic, which is found on the skin, preventing the skin from sagging (the skin loses elasticity with age). Keratin is an essential protein in the structure of the skin, hair, and nails, but how exactly does it support them?

Keratin in the skin

The skin consists of three layers: hypodermis, dermis, and epidermis. The epidermis is the top layer of the skin, responsible for forming a protective barrier, protecting the skin from pollutants and irritants. The function of the epidermis is accredited to soft keratin, which is created by keratinocytes in the stratum basale – the deepest layer of the epidermis.

Keratin in the hair

Similarly to the skin, the scalp has a dermis and epidermis, with the dermis containing hair follicles. Hair follicles store keratinocytes, which distribute hard keratin from the hair follicle to the hair shaft – the hair that extends beyond the scalp. The hair shaft is almost entirely composed of keratin, which provides the hair with protection, strength, elasticity, etc.

Keratin hair treatments

Although keratin is constantly produced by hair follicles, keratin production decreases with age. Not only do keratinocytes experience lowered cell turnover, but keratin on the surface of the hair starts to break down in response to UV rays from the sun. For this reason, keratin treatments are offered by hair stylists, which is a process that takes a couple of hours. Keratin treatments are enriched with artificial keratin protein to straighten hair and reduce frizz.

Keratin in nails

Similarly to the hair, nails are primarily composed of hard keratin. Keratin is being constantly produced by the matrix of the nail, which gets pushed out to grow the nail and provide its protective surface.

(https://my.clevelandclinic.org/health/body/24734-nail-matrix)

As we’ve established, keratin is an essential protein in the structure of the skin, hair, and nails, providing protection and strength. Unfortunately, as we age, keratinocytes produce less keratin, and keratin breaks down/gets damaged. However, you can combat this with a proper diet and lifestyle habits.

Boosting keratin production with diet:

In order for a nutrient to boost keratin production, it has to be associated with protein synthesis. Biotin is a B vitamin that has been shown to boost the metabolism of amino acids, and thus keratin synthesis. Protein and vitamin A have also been shown to stimulate protein synthesis. Incorporating foods rich in nutrients like biotin, protein, and vitamin A can boost keratin production in the body.

As we’ve learned, keratin serves the common purpose of protection and elasticity in the skin, hair, and nails. Although keratin is naturally produced by the body, keratin levels decline over time. For this reason, you can modify your diet to boost keratin synthesis in the body, or maybe consider a keratin treatment to replenish keratin in the hair.

Bibliography

https://www.cancer.gov/publications/dictionaries/cancer-terms/def/keratin

https://health.clevelandclinic.org/keratin-treatments

https://www.ncbi.nlm.nih.gov/books/NBK513133/#:~:text=The%20part%20that%20we%20call,the%20nail%20bed%20beneath%20it.

https://www.healthline.com/nutrition/keratin-rich-foods#:~:text=Keratin%20is%20a%20type%20of%20protein%20that%20boosts%20the%20health,keratin%20production%20in%20your%20body.

https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/keratin#:~:text=Keratin%20can%20be%20divided%20into,and%20contains%20approximately%2014%25%20cystine.