Be Ready to Answer Common Questions About Biotin
As a community pharmacist, you will hear biotin touted for a beauty “glow-up” to support hair, nail, and skin health. It’s an essential vitamin (B7) with key roles in nutrient metabolism and cellular signaling. And signs of biotin deficiency include thinning hair, brittle nails, and skin rashes.
Explain that biotin is effective to prevent or treat true deficiency due to alcohol use disorder, malnutrition, or certain meds (carbamazepine, phenytoin, phenobarbital, etc). But clarify that deficiency is rare in people eating a mixed diet. And evidence for biotin, outside of deficiency, is generally limited.
For example, a small study in patients with alopecia areata suggests that biotin 5 mg IM weekly, in combo with other vitamins, may improve hair density or hair loss. But this study didn’t include a placebo group. And small, low-quality studies suggest that taking biotin 2.5 mg by mouth daily can increase nail thickness and reduce splitting.
Be aware, there’s interest in high-dose biotin, such as 300 mg daily, for progressive multiple sclerosis, but it does not improve outcomes, such as disability or walking time. And there isn’t good evidence that biotin is effective for other conditions including depression, diabetes, or neuropathy.
If patients try biotin, explain that it’s generally well tolerated. But caution that biotin can interfere with some lab tests, especially at higher doses.
- For example, biotin can lead to falsely high results for estradiol and testosterone levels and falsely low results for prostate-specific antigen (PSA) and thyroid-stimulating hormone (TSH) levels.
- Recommend confirming with the lab which tests are affected and the washout time; labs may use different assays and the impact can vary.
- Often, a washout of at least 8 hours is needed for biotin doses of 5 mg or more, or about 72 hours for doses of 100 mg or more.
References
- TRC Healthcare. “NatMed pro - Biotin.” Therapeuticresearch.com, 2026, naturalmedicines.therapeuticresearch.com/Data/ProMonographs/Biotin. Accessed 8 Mar. 2026.
- WebMD (2010). Biotin: Uses, Side Effects, Interactions, Dosage, and Warning. [online] Available at: https://www.webmd.com/vitamins/ai/ingredientmono-313/biotin.
