Biotin (Vitamin B7): Practical Guide for Hair, Skin, Nails and Health

Biotin — also called vitamin B7 — gets a lot of buzz for hair and nails. People take it hoping for thicker hair, stronger nails, or better skin. The reality is simple: biotin helps your body turn food into energy and supports tissues that grow fast, like hair and nails. It’s useful in some clear-cut medical cases, but for many people the benefits are modest.

How much biotin should you take?

The recommended daily intake for most adults is about 30 micrograms (mcg) a day. Foods normally cover that: egg yolks, liver, nuts, seeds, salmon, avocados, and sweet potato are good sources. Over-the-counter supplements often contain 1,000–10,000 mcg — far more than the daily need. Higher doses are used in specific conditions (for example, genetic biotinidase deficiency) and sometimes for hair trials, but the evidence for routine high-dose use is mixed.

If you’re thinking about a high-dose product, ask why you need it. Expect to wait: hair and nail changes usually show after 3–6 months of steady use if they’re going to happen. If you have symptoms of deficiency — thinning hair, brittle nails, red scaly rash around the eyes or nose, or unusual tiredness — see a clinician. They can test levels and check for causes like long-term anticonvulsant use or very poor diet.

Tips for choosing and using biotin

Want practical tips? First, try to get biotin from food before grabbing a big supplement bottle. If you take supplements, pick a reputable brand and a dose that matches your goal. For general wellness, a low-dose formula (30–300 mcg) is usually enough. If you use high-dose biotin, tell your doctor or lab technician before blood tests — high biotin can disrupt common lab tests, including thyroid panels and troponin, and cause false results. Stopping biotin 48–72 hours before testing often solves this.

Beware of raw egg whites. They contain avidin, a protein that binds biotin and can cause a deficiency if you eat lots of raw egg whites over time. Cooked eggs don’t have this problem. Also, some medications (certain anticonvulsants and long-term antibiotics) can lower biotin levels, so mention any prescription meds when you talk to your provider.

Finally, don’t expect magic. If your hair loss is from hormonal changes, thyroid issues, or genetics, biotin alone won’t fix it. Use it as one part of a plan: balanced diet, correct any medical causes, manage stress, and be patient. If you’re unsure, a short clinic visit can help decide whether a supplement makes sense and what dose is safe for you.