Biotin and Keratin: What the Science Says About Hair, Skin and Nails

Hair and nails are made mostly of keratin, and biotin is the vitamin that helps your body build it. That is why this pair appears in so many hair, skin and nail supplements. Here is what international research supports, and what it doesn't.

What is keratin?

Keratin is a family of tough, fibrous structural proteins that form the main building material of hair, nails and the outer layer of skin (Moll et al., 2008; Bragulla & Homberger, 2009). It is rich in cystine, whose sulfur bonds give hair and nails strength and resilience (Wang et al., 2016).

The roles of keratin

1. Hair structure. Keratin makes up about 90% of the hair shaft's dry weight and gives it strength and elasticity.
2. Nail plate. Hard keratin gives nails their rigidity and protects the nail bed.
3. Skin barrier. Epidermal keratins help skin resist mechanical stress and water loss.
4. Cell integrity. Keratin filaments hold epithelial cells together. Mutations cause fragility and blistering disorders.
5. Biomaterials and repair. Keratin is studied for wound dressings and tissue scaffolds because it is biocompatible and biodegradable (Rouse & Van Dyke, 2010; Hill et al., 2010).
6. Hair care. Hydrolysed keratin peptides can bind damaged hair and improve its properties in lab studies (Barba et al., 2017). Explore BIOMED's Hair Care range.

What is biotin?

Biotin (vitamin B7) is a coenzyme for enzymes involved in fatty-acid, glucose and amino-acid metabolism (Mock, 2017). The European Food Safety Authority sets an adequate intake of 40 µg/day for adults (EFSA, 2014).

The evidence for biotin

• Deficiency clearly causes hair thinning, skin rash and brittle nails (Zempleni & Mock, 1999; Patel et al., 2017).
• Brittle nails: small studies using about 2.5 mg/day reported thicker, less split nails (Floersheim, 1989; Colombo et al., 1990; Hochman et al., 1993). These were small and mostly uncontrolled.
• Hair loss without deficiency: evidence is limited (Soleymani et al., 2017; Trüeb, 2016).

The evidence for oral keratin

Evidence is thinner than for biotin. Keratin is well supported as a topical and biomaterial ingredient, but large, controlled human trials of oral hydrolysed keratin are scarce. Digestion breaks it into amino acids and peptides, so it is best described as providing building blocks, not as a proven treatment.

Safety: biotin and lab tests

High-dose biotin can interfere with biotin-based immunoassays, including thyroid and cardiac troponin tests, giving falsely high or low results (Li et al., 2017; Kummer et al., 2016). Tell your doctor you take biotin before any blood test.

Where TEENUR fits in

TEENUR (Biotin + Keratin) Stronger Hair, Skin & Nails from BIOMED Innovation Pharmaceuticals combines Biotin 2500 mcg with Hydrolysed Keratin 250 mg in a once-daily, 30-tablet pack. It is a dietary supplement meant to support hair, skin and nail nutrition alongside a balanced diet, not a medicine. It is made in a GMP-certified facility, and you can read more on BIOMED's Quality & Safety page. Pregnant or nursing individuals and people on medication should consult a healthcare provider first. You can also consult a doctor or pharmacist before starting.

Practical tips:

• Take one tablet daily with a meal.
• Allow 3 to 6 months, since hair and nails grow slowly.
• Support results with enough protein, iron, zinc and vitamin D.
• See a doctor for sudden or patchy hair loss. More articles are on the BIOMED Health Blog.

Conclusion

Keratin is the structural protein of hair, nails and skin, and biotin is a key nutrient for making it. Evidence is strongest for correcting deficiency and for brittle nails, and weaker for extra hair growth in healthy people. A biotin plus keratin supplement like TEENUR is nutritional support, not a cure.

References

• BIOMED Innovation Pharmaceuticals. (2026). TEENUR (Biotin + Keratin) Stronger Hair, Skin & Nails.
• EFSA NDA Panel (2014). Dietary reference values for biotin. EFSA Journal, 12(2), 3580.
• Patel DP et al. (2017). A review of the use of biotin for hair loss. Skin Appendage Disord, 3(3), 166–169.
• Soleymani T et al. (2017). The infatuation with biotin supplementation. J Clin Aesthet Dermatol, 10(8), 28–35.
• Trüeb RM. (2016). Serum biotin levels in women complaining of hair loss. Int J Trichology, 8(2), 73–77.
• Mock DM. (2017). Biotin: from nutrition to therapeutics. J Nutr, 147(8), 1487–1492.
• Zempleni J, Mock DM. (1999). Biotin biochemistry and human requirements. J Nutr Biochem, 10, 128–138.
• Floersheim GL. (1989). Treatment of brittle fingernails with biotin. Z Hautkr, 64(1), 41–48.
• Colombo VE et al. (1990). Brittle fingernails and onychoschizia with biotin. Cutis, 46(2), 141–144.
• Hochman LG et al. (1993). Brittle nails: response to daily biotin. Cutis, 51(4), 303–305.
• Li D et al. (2017). Biotin ingestion and assay performance. JAMA, 318(12), 1150–1160.
• Kummer S et al. (2016). Biotin treatment mimicking Graves' disease. N Engl J Med, 375, 704–706.
• Moll R et al. (2008). The human keratins. Histochem Cell Biol, 129, 705–733.
• Bragulla HH, Homberger DG. (2009). Structure and functions of keratin proteins. J Anat, 214(4), 516–559.
• Rouse JG, Van Dyke ME. (2010). Keratin-based biomaterials. Materials, 3(2), 999–1014.
• Hill P et al. (2010). Some properties of keratin biomaterials: kerateines. Biomaterials, 31(4), 585–593.
• Wang B et al. (2016). Keratin: structure, mechanical properties. Prog Mater Sci, 76, 229–318.
• Barba C et al. (2017). Restoring hair properties with wool keratin proteins and peptides. Fibers Polym, 18, 1085–1094.