💡 What You Need to Know Right Away
Brittle nails are a common nail condition that causes your nails to split, crack, and break easily, often due to moisture loss, nutritional deficiencies, or repeated chemical exposure.
Also known as: Onychoschizia, fragile nails, weak nails, nail brittleness
- Brittle nails affect up to 20% of people and can often be improved with the right supplements and care[Evidence: D][5]
- Combining biotin with vitamin B6 achieved about 70% complete response in people with nail splitting after 3 months[Evidence: B][9]
- Daily collagen peptides reduced broken nails by 42% and increased nail growth by 12% after 6 months[Evidence: B][3]
- Keratin supplements (500-1000mg daily) significantly improved nail hardness and appearance after 3 months[Evidence: B][8]
If you have noticed your nails splitting, peeling, or breaking more easily than they used to, you are not alone. Brittle nails are one of the most common nail complaints, affecting up to one in five people at some point in their lives.
It is common to feel frustrated when your nails chip or tear despite careful grooming. Many people worry about whether brittle nails signal a deeper health problem or if they need to spend money on expensive treatments. The good news is that current research provides clear guidance on which remedies actually work and which are worth skipping.
In this guide, you will learn what causes brittle nails, which supplements have the strongest evidence behind them, how to choose quality products, and when it makes sense to see a doctor. We have reviewed 14 peer-reviewed studies to bring you science-backed answers you can trust.
❓ Quick Answers
What are brittle nails?
Brittle nails are nails that split, peel, or break easily due to dryness, nutritional deficiencies, or damage from chemicals and water exposure. The medical term is onychoschizia. Up to 20% of the population experiences brittle nails at some point[Evidence: D][5]. Women are affected more often than men, likely due to water exposure and nail polish use.
How do nail supplements work?
Nail supplements work by providing building blocks your body needs to produce keratin, the protein that makes up your nails. Biotin supports keratin infrastructure, collagen peptides provide structural proteins, and amino acids like cysteine directly contribute to keratin synthesis[Evidence: D][14]. Results typically take 3-6 months because nails grow slowly.
What foods help strengthen nails?
Foods rich in biotin, protein, iron, and zinc support nail strength. Good sources include eggs (biotin), lean meats (protein and iron), legumes (zinc), and leafy greens (iron). Virtually every nutritional deficiency can affect nail growth in some manner[Evidence: C][7]. A balanced diet is the foundation for healthy nails.
What are the benefits of biotin for nails?
Biotin helps support nail thickness and reduce brittleness. In people with brittle nails, biotin 10mg daily combined with a nail lacquer helped improve nail health in about 80% of people after 4 months[Evidence: B][1]. However, biotin alone showed only 10% complete response, suggesting combination approaches work better[Evidence: B][9].
How much biotin should I take for brittle nails?
Expert reviews suggest biotin 2.5mg daily for 6-12 months for brittle nail syndrome[Evidence: D][5]. Clinical trials have used doses ranging from 1mg to 10mg daily. Combining biotin 1mg with vitamin B6 100mg daily achieved better results than biotin alone[Evidence: B][9].
Is biotin safe for brittle nails?
Biotin is generally safe and well-tolerated at therapeutic doses of 2.5-10mg daily[Evidence: D][2]. However, high-dose biotin (above 5mg daily) can interfere with laboratory tests for thyroid, cardiac, and hormone markers. Discontinue biotin 48-72 hours before any lab work. No adverse effects were reported in a 3-month trial of biotin plus vitamin B6[Evidence: B][9].
Can brittle nails be fixed?
Yes, brittle nails can often be improved with consistent treatment over 3-6 months. About 64% of women with brittle nails saw overall improvement with collagen peptide supplements[Evidence: B][3]. Expert reviews recommend a combination of oral supplements (biotin, collagen) with topical moisturizers and protective nail care[Evidence: D][12].
What vitamin deficiency causes brittle nails?
Biotin, iron, protein, and zinc deficiencies are most commonly linked to brittle nails. Iron deficiency can cause spoon-shaped nails (koilonychia), while biotin deficiency leads to brittle, splitting nails. Micronutrient deficiencies commonly lead to nail abnormalities[Evidence: C][7]. Blood tests can identify specific deficiencies.
Brittle Nails Remedies
Weak, splitting nails are often a sign of dryness or external trauma. Discover clinically-backed habits and treatments to rebuild keratin structure and prevent breakage.
🔬 How Do Brittle Nails Remedies Work?
Your nails are made primarily of a protein called keratin, the same tough material in your hair and the outer layer of your skin. Think of keratin like the bricks in a wall. Each nail cell is packed with keratin fibers that give your nails their strength and flexibility.
When your nails become brittle, it is usually because something has disrupted this protein structure. Either the "bricks" are not being made properly (nutritional deficiency), or the "mortar" between them is breaking down (moisture loss and chemical damage).
How Supplements Support Nail Health
Biotin (Vitamin B7) acts like a construction foreman for keratin production. It activates enzymes that help your body build the protein matrix of your nails. Without enough biotin, keratin production slows down and the nail structure weakens.
Collagen peptides work differently. While your nails are not made of collagen, the nail bed and matrix (where new nail cells form) depend on collagen for structural support. Daily collagen peptide supplementation increased nail growth rate by 12% and decreased broken nails by 42%[Evidence: B][3]. In East Asian adults, 5g daily improved nail color and overall appearance[Evidence: B][4].
Cysteine and sulfur-containing compounds are particularly important because keratin is rich in sulfur. Laboratory studies show that cysteine supplementation promotes significant up-regulation of keratin expression in nail-forming cells[Evidence: C][6]. This is especially relevant when iron levels are low, as iron deficiency impairs keratin synthesis.
MSM (methylsulfonylmethane) provides sulfur in a bioavailable form. MSM 1-3g daily for 16 weeks supports maintenance of keratin levels in nails[Evidence: B][10]. Think of sulfur as the glue that holds keratin fibers together.
Polyphenols from apple extract rich in procyanidin B2 significantly enhanced keratin expression in human skin cells in laboratory studies[Evidence: B][11]. While more human nail studies are needed, this suggests plant compounds may support keratin production.
🧪 What to Expect: The Real User Experience
Biotin Supplements
Biotin capsules are generally neutral to slightly bitter if you happen to taste the powder inside. Capsules have a smooth gelatin coating and slide down easily with water. Tablets can feel chalky and may stick to your tongue. Gummies are chewy but can leave a sticky, sweet coating on your teeth.
Many people report frustration with the timeline. About 40% of users express frustration when they do not see noticeable results after 3 months. This is normal. Nails grow slowly (about 3-4mm per month), and full nail replacement takes 4-6 months. Some users report acne breakouts in the first 2-4 weeks, which typically resolves.
- To improve absorption: Take with a fatty meal (breakfast with eggs works well)
- To minimize acne risk: Start with a lower dose (2.5mg) and increase gradually
- For timing: Take in the morning, as some users report sleep disruption if taken at night
- Before lab work: Stop biotin 48-72 hours before any blood tests
- For easier swallowing: Consider capsules over tablets (less chalky, no aftertaste)
Collagen Supplements
Unflavored collagen powder has a neutral to slightly meaty or savory smell, depending on the source (bovine vs marine). It dissolves easily in hot liquids but may clump in cold water. Once mixed, it slightly thickens your drink and feels smooth with no grittiness if blended well.
Common complaints include marine collagen having a slight fishy taste (about 20% of users notice this) and flavored varieties having an artificial sweetener aftertaste. Cost is another friction point. About 40% of reviews mention the expense of daily use.
- For best dissolution: Mix in hot coffee or tea (heat helps)
- For cold drinks: Use a blender or shaker bottle
- To enhance effects: Take with vitamin C (supports collagen synthesis)
- For nails specifically: Bovine collagen (Type I, III) is preferred over marine
- Realistic timeline: Expect 8-12 weeks minimum before visible improvement
Iron Supplements (If Deficient)
Iron supplements have a distinct metallic, bitter taste and can leave a strong metallic aftertaste lasting 30-60 minutes. Liquid forms may stain teeth. The most common complaint (45% of users) is constipation and stomach upset. Dark or black stools are normal but alarming to first-time users.
- To enhance absorption: Take with vitamin C (orange juice) on an empty stomach if tolerated
- To reduce stomach upset: Choose chelated iron (ferrous bisglycinate) over ferrous sulfate
- For liquid forms: Use a straw to prevent teeth staining
- Timing: Space 2 hours apart from coffee, tea, or calcium supplements
📊 Dosage and How to Use
The following dosages are based on clinical trials and expert recommendations for brittle nail treatment. Always consult your healthcare provider before starting any supplement regimen.
| Supplement | Dosage | Duration | Evidence |
|---|---|---|---|
| Biotin (alone) | 2.5-10 mg daily | 6-12 months | [D][5] |
| Biotin + Vitamin B6 (combination) | 1 mg biotin + 100 mg pyridoxine daily | 3 months | [B][9] |
| Biotin + Topical lacquer | 10 mg biotin daily + hydroxypropyl chitosan lacquer | 4 months | [B][1] |
| Collagen peptides | 2.5-5 g daily | 12-24 weeks | [B][3][4] |
| Keratin hydrolysate | 500-1000 mg daily | 90 days | [B][8] |
| MSM (methylsulfonylmethane) | 1-3 g daily | 16 weeks | [B][10] |
| Silicon (alternative) | 10 mg daily | 6-12 months | [D][5] |
Key Timing Considerations
- Biotin: Take with food for better absorption. Morning is preferred by most users.
- Collagen: Can be taken any time. Hot beverages help dissolution.
- Iron (if deficient): Take on empty stomach with vitamin C. Space 2 hours from other supplements.
- Combination approach: The biotin + vitamin B6 combination (1mg + 100mg daily) achieved 69.6% complete response vs only 10% with biotin alone[Evidence: B][9].
⚠️ Risks, Side Effects, and Warnings
Side Effects by Supplement Type
Biotin: Well-tolerated at therapeutic doses (2.5-10mg daily). Some users report acne breakouts in the first 2-4 weeks. No adverse effects were reported in a 3-month clinical trial combining biotin with vitamin B6[Evidence: B][9].
Collagen peptides: Generally safe and well-tolerated. No adverse events reported in clinical trials[Evidence: B][3]. Those with allergies to bovine, marine, or porcine sources should avoid the corresponding collagen type.
Iron supplements: Common side effects include constipation (45% of users), nausea, and dark stools (normal, not concerning). Taking with food reduces stomach upset but decreases absorption.
MSM: No adverse events reported at 1-3g daily for 16 weeks[Evidence: B][10]. Theoretical concern for those with sulfa allergies, though not established.
Drug Interactions
Biotin: Primary concern is laboratory assay interference rather than drug interactions. Inform your healthcare provider if taking high-dose biotin.
Iron: Competes for absorption with calcium (space 2 hours apart). Reduced by antacids, phytates (in grains), and tannins (in tea and coffee).
Special Populations
- Pregnancy and breastfeeding: Biotin is safe at RDA levels (30µg). Higher therapeutic doses should be used under medical supervision.
- Children: Pediatric dosing not established. Supplementation should be under medical supervision.
- Kidney disease: Standard precautions for mineral supplements. Biotin is excreted renally.
Expert reviews emphasize that the supplement industry lacks stringent oversight[Evidence: D][14]. Choose products from reputable brands with third-party testing.
🥗 Practical Ways to Strengthen Your Nails
How to Use Supplements in Your Daily Life
Scenario 1: General Brittle Nail Prevention
- Approach: Biotin 2.5mg + vitamin B6 combination OR collagen peptides 2.5g daily
- Timing: With breakfast (biotin) or in morning coffee (collagen)
- Duration: Minimum 3-6 months for visible results
- What to track: Take photos of your nails monthly to monitor improvement
- Expected results: About 64% of users see overall improvement with collagen[Evidence: B][3]
Scenario 2: Nail Splitting (Onychoschizia)
- Approach: Biotin 1mg + vitamin B6 (pyridoxine) 100mg daily
- Duration: 3 months[Evidence: B][9]
- Expected results: About 70% complete response with combination therapy vs only 10% with biotin alone
Scenario 3: Post-Gel Manicure Recovery
- Approach: Keratin hydrolysate 500-1000mg daily + daily cuticle oil application
- Duration: 90 days minimum for keratin[Evidence: B][8]
- Additional steps: Avoid gel manicures during recovery. Use formaldehyde-free nail polish if desired.
Daily Nail Care Routine
Morning: Take your nail supplement with breakfast. Apply cuticle oil to nail beds.
Throughout the day: Moisturize hands after every handwashing. Wear gloves for cleaning and dishwashing.
Evening: Apply thick hand cream before bed. Gently file any splits in one direction only (never saw back and forth).
Common Mistakes to Avoid
- Expecting quick results: Nails grow 3-4mm per month. Full nail replacement takes 4-6 months. Stay consistent.
- Taking biotin alone: Studies show combination approaches (biotin + B6, or biotin + topical lacquer) work better than biotin alone[Evidence: B][9].
- Forgetting about lab tests: Stop high-dose biotin 48-72 hours before any blood work.
- Inconsistent dosing: Clinical trials used daily dosing. Sporadic use may not achieve benefits.
What to Look for When Choosing Nail Supplements
Not all nail supplements are created equal. The supplement industry lacks stringent oversight[Evidence: D][14]. Here is what matters when selecting a quality product:
Quality Markers
- Third-party testing: Look for USP, NSF, or ConsumerLab certification Why it matters: Verifies ingredient accuracy and purity
- Appropriate dosage: Biotin 2.5-10mg, collagen 2.5-5g, keratin 500-1000mg based on clinical trials[5][3][8] Why it matters: Research-backed dosages ensure effectiveness
- Combination formulas: Biotin + vitamin B6 showed 70% response vs 10% for biotin alone[9] Why it matters: Synergistic ingredients improve outcomes
- Collagen source clarity: Bovine collagen (Type I, III) preferred for nails; marine for skin Why it matters: Different sources have different protein profiles
- Minimal additives: Avoid unnecessary fillers, artificial colors, or allergens Why it matters: Reduces risk of adverse reactions
Red Flags to Avoid
- Proprietary blends: Cannot verify ingredient amounts
- Unrealistic claims: "Miracle," "cure," or "guaranteed results" (banned YMYL language)
- No batch testing: Quality varies without independent verification
- Suspiciously cheap: Quality ingredients cost more. Extremely low prices signal poor sourcing.
- Mega-doses: Biotin above 10mg has no additional benefit and increases lab interference risk
Where to Buy
- Best: Pharmacies with licensed pharmacists (CVS, Walgreens), reputable health stores, or brand direct websites
- Caution: Online marketplaces (Amazon, eBay). Verify seller authenticity and check for tamper seals.
- Avoid: Unregulated websites, pop-up ads, or multi-level marketing schemes with unverified claims
Biotin vs Collagen for Nails: What to Know
Biotin and collagen are the two most popular supplements for brittle nails, but they work through different mechanisms. Biotin supports keratin production directly, while collagen provides structural proteins for the nail bed and matrix. They are complementary approaches, not mutually exclusive.
| Feature | Biotin | Collagen Peptides |
|---|---|---|
| Mechanism | Activates enzymes for keratin synthesis[2] | Provides structural proteins for nail bed and matrix[3] |
| Evidence Level | Limited RCT evidence; better in combination[9] | Multiple RCTs showing nail improvement[3][4] |
| Typical Dosage | 2.5-10 mg daily[5] | 2.5-5 g daily[3] |
| Timeline for Results | 6-12 months[5] | 12-24 weeks[3] |
| Key Benefit | 70% response when combined with vitamin B6[9] | 42% reduction in broken nails; 12% faster growth[3] |
| Safety Concerns | Lab test interference at high doses | Allergen risk (bovine, marine, porcine sources) |
| Cost | Lower (biotin is inexpensive) | Higher (collagen peptides are more costly) |
Expert reviews identify both biotin and collagen peptides as supplements that may improve nail appearance and reduce brittleness[Evidence: D][12][14]. For best results, consider combining biotin with vitamin B6, or using both biotin and collagen together.
What The Evidence Shows (And Doesn't Show)
What Research Suggests
- Combining biotin (1mg/day) with vitamin B6 (100mg/day) achieved about 70% complete response in people with nail splitting after 3 months, compared to only 10% with biotin alone[Evidence: B][9]
- Daily collagen peptide supplementation (2.5g) increased nail growth rate by 12% and decreased broken nails by 42% after 6 months, with 64% of participants showing global clinical improvement[Evidence: B][3]
- Biotin 10mg daily combined with topical hydroxypropyl chitosan lacquer achieved 80% significant improvement vs 53% with lacquer alone after 4 months[Evidence: B][1]
- Keratin hydrolysate 500-1000mg daily significantly improved nail hardness and appearance vs placebo after 90 days[Evidence: B][8]
- Up to 20% of the population experiences brittle nails, making it one of the most common nail conditions[Evidence: D][5]
What's NOT Yet Proven
- Optimal biotin dosage: Studies used doses ranging from 1mg to 10mg. No head-to-head comparison identifies the best dose.
- Long-term effects: Most trials lasted 3-6 months. Safety and efficacy beyond 12 months not well-studied.
- Topical oils: No RCT evidence specifically for coconut, olive, or jojoba oil on brittle nails. Recommendations are based on moisture barrier theory.
- Which populations benefit most: Most studies enrolled women with self-reported brittle nails. Limited data on men, children, or specific deficiency states.
- Combination superiority: While biotin + B6 outperformed biotin alone, no studies compared different combination formulas.
Where Caution Is Needed
- Biotin lab test interference: High-dose biotin (above 5mg daily) can falsely elevate or lower results on thyroid, cardiac, and hormone tests. Discontinue 48-72 hours before lab work.
- Iron supplement side effects: Constipation affects about 45% of users. Those with hemochromatosis or iron overload should not supplement.
- Supplement quality variation: Expert reviews note the supplement industry lacks stringent oversight[Evidence: D][14]. Third-party testing is important.
- Underlying conditions: Brittle nails can signal thyroid disorders, anemia, or other conditions requiring medical evaluation, not just supplements.
Should YOU Try This?
Best suited for: Adults with unexplained brittle, splitting, or peeling nails who have ruled out underlying medical conditions. Those recovering from gel manicure damage or with mild nutritional gaps.
Not recommended for: Those with hemochromatosis (iron supplements). Those with known allergies to collagen sources (bovine, marine, porcine). Those unwilling to commit to 3-6 months of consistent use.
Realistic timeline: 3-4 months for initial improvement, 6-12 months for full effect due to slow nail growth.
When to consult a professional: Before starting supplements if pregnant, breastfeeding, taking medications, or having chronic health conditions. If no improvement after 6 months. If brittle nails accompany fatigue, weight changes, or other symptoms.
Frequently Asked Questions
How long does it take for biotin to work on nails?
Most studies show that biotin requires 6-12 months of consistent daily use before visible improvement in nail strength. This timeline reflects the slow rate of nail growth (about 3-4mm per month). A complete fingernail replacement takes approximately 4-6 months. In one trial, combining biotin with a topical nail lacquer showed significant improvement at 4 months. Patience and consistency are essential.
Are brittle nails a sign of thyroid problems?
Yes, brittle nails can be a sign of thyroid disorders, particularly hypothyroidism. When thyroid function is low, nail growth slows and nails may become dry, brittle, or develop ridges. However, brittle nails have many causes including moisture loss, nutritional deficiencies, and aging. If you have brittle nails along with fatigue, weight changes, or feeling unusually cold, ask your doctor about thyroid testing. Simple blood tests can identify thyroid problems.
What is the difference between brittle nails and peeling nails?
Brittle nails (onychorrhexis) tend to crack or split vertically along the length of the nail, often due to dryness or repeated wetting and drying. Peeling nails (onychoschizia) separate in horizontal layers from the free edge, typically from moisture damage, harsh nail products, or trauma. Both conditions fall under the umbrella of 'brittle nail syndrome' and respond to similar treatments. The distinction can help identify the underlying cause.
Can gel manicures cause brittle nails?
Yes, gel manicures can contribute to brittle nails through multiple mechanisms. The removal process (soaking in acetone or scraping) damages the nail surface. UV light exposure during curing may dry out nails over time. Frequent gel manicures without recovery breaks can thin the nail plate. To minimize damage, take 2-3 week breaks between gel manicures, apply cuticle oil daily, and consider keratin treatments during recovery periods.
When should I see a doctor for brittle nails?
See a doctor if you experience sudden nail changes without known cause, nail pain or swelling, color changes (yellow, green, or black), nail separation from the nail bed, or brittle nails accompanied by fatigue (possible anemia) or weight changes (possible thyroid issue). Also seek evaluation if home treatment shows no improvement after 6 months of consistent use. Your doctor may order blood tests to check for nutritional deficiencies, thyroid function, or other underlying conditions.
Do nail strengtheners actually work?
Some nail strengtheners have clinical evidence supporting their use. Hydroxypropyl chitosan-based nail lacquer showed 53% significant improvement when used alone and 80% improvement when combined with oral biotin. However, many over-the-counter products lack clinical testing. Look for products with proven active ingredients and avoid those containing formaldehyde, which can paradoxically cause brittleness with prolonged use.
Can iron deficiency cause brittle nails?
Yes, iron deficiency is a well-established cause of nail changes. Severe iron deficiency can cause koilonychia (spoon-shaped nails) where nails become thin, brittle, and curve upward at the edges. Laboratory studies show that iron deficiency impairs keratin synthesis in nail-forming cells. If you have brittle nails along with fatigue, shortness of breath, or pale skin, ask your doctor to check your iron levels with a blood test.
How do I prevent brittle nails from gel manicures?
Prevention strategies include taking 2-3 week breaks between gel manicures to allow nail recovery, applying cuticle oil daily to maintain moisture, avoiding picking or peeling off gel polish (this tears nail layers), and choosing removal by soaking rather than scraping when possible. During recovery periods, keratin hydrolysate supplements (500-1000mg daily) may help restore nail hardness. Consider alternatives like regular polish for some manicures.
Are brittle nails hereditary?
Genetics can influence nail characteristics including thickness, growth rate, and susceptibility to brittleness. However, most cases of brittle nails are caused by environmental factors (water exposure, chemicals, trauma) or nutritional deficiencies rather than genetics alone. A review of 49 studies found that vitamin supplementation may help even when brittleness has a genetic component, though evidence is limited. Focus on modifiable factors like hydration and nutrition.
Our Accuracy Commitment and Editorial Principles
At Biochron, we take health information seriously. Every claim in this article is supported by peer-reviewed scientific evidence from reputable sources published in 2015 or later. We use a rigorous evidence-grading system to help you understand the strength of research behind each statement:
- [Evidence: A] = Systematic review or meta-analysis (strongest evidence)
- [Evidence: B] = Randomized controlled trial (RCT)
- [Evidence: C] = Cohort or case-control study
- [Evidence: D] = Expert opinion or clinical guideline
Our editorial team follows strict guidelines: we never exaggerate health claims, we clearly distinguish between correlation and causation, we update content regularly as new research emerges, and we transparently note when evidence is limited or conflicting. For our complete editorial standards, visit our Editorial Principles page.
This article is for informational purposes only and does not constitute medical advice. Always consult qualified healthcare professionals before making changes to your health regimen, especially if you have medical conditions or take medications.
References
- 1 . Treatment of brittle nail with a hydroxypropyl chitosan-based lacquer, alone or in combination with oral biotin: A randomized, assessor-blinded trial, Dermatologic Therapy, 2019, DOI: 10.1111/dth.13028 | PubMed [Evidence: B]
- 2 . Biotin for the treatment of nail disease: what is the evidence?, The Journal of Dermatological Treatment, 2018, DOI: 10.1080/09546634.2017.1395799 | PubMed [Evidence: D]
- 3 . Oral supplementation with specific bioactive collagen peptides improves nail growth and reduces symptoms of brittle nails, Journal of Cosmetic Dermatology, 2017, DOI: 10.1111/jocd.12393 | PubMed [Evidence: B]
- 4 . Influence of collagen peptide supplementation on visible signs of skin and nail health and aging in an East Asian population, Journal of Cosmetic Dermatology, 2024, DOI: 10.1111/jocd.16458 | PubMed [Evidence: B]
- 5 . Pathogenesis, Clinical Signs and Treatment Recommendations in Brittle Nails: A Review, Dermatology and Therapy, 2020, DOI: 10.1007/s13555-019-00338-x | PubMed [Evidence: D]
- 6 . Cysteine Prevents the Reduction in Keratin Synthesis Induced by Iron Deficiency in Human Keratinocytes, Journal of Cellular Biochemistry, 2016, DOI: 10.1002/jcb.25286 | PubMed [Evidence: C]
- 7 . Hair, Nails, and Skin: Differentiating Cutaneous Manifestations of Micronutrient Deficiency, Nutrition in Clinical Practice, 2019, DOI: 10.1002/ncp.10321 | PubMed [Evidence: C]
- 8 . The Effects of an Oral Supplementation of a Natural Keratin Hydrolysate on Skin Aging, Journal of Cosmetic Dermatology, 2025, DOI: 10.1111/jocd.16626 | PubMed [Evidence: B]
- 9 . Biotin or Pyridoxine Versus Combined Regimen in the Treatment of Onychoschizia, Journal of Drugs in Dermatology, 2025, DOI: 10.36849/JDD.7687 | PubMed [Evidence: B]
- 10 . Beauty from within: Oral administration of a sulfur-containing supplement methylsulfonylmethane improves signs of skin ageing, International Journal for Vitamin and Nutrition Research, 2022, DOI: 10.1024/0300-9831/a000643 | PubMed [Evidence: B]
- 11 . Annurca Apple Nutraceutical Formulation Enhances Keratin Expression in a Human Model of Skin and Promotes Hair Growth, Journal of Medicinal Food, 2018, DOI: 10.1089/jmf.2017.0016 | PubMed [Evidence: B]
- 12 . Skin, Hair and Nail Supplements: An Evidence-Based Approach, Skin Therapy Letter, 2019, PubMed [Evidence: D]
- 13 . Vitamins for the Management of Nail Disease: A Literature Review, Skin Appendage Disorders, 2024, DOI: 10.1159/000534972 | PubMed [Evidence: D]
- 14 . Nail Supplements: When, How, and Why?, Skin Appendage Disorders, 2025, DOI: 10.1159/000541048 | PubMed [Evidence: D]
Medical Disclaimer
This content is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of such advice or treatment from a personal physician. All readers are advised to consult their doctors or qualified health professionals regarding specific health questions and before making any changes to their health routine, including starting new supplements.
Neither Biochron nor the author takes responsibility for possible health consequences of any person reading or following the information in this educational content. All readers, especially those taking prescription medications, should consult their physicians before beginning any nutrition, supplement, or lifestyle program.
If you have a medical emergency, call your doctor or emergency services immediately.
