Biotin -

Most researchers conclude that the widespread use of biotin for general hair growth is not supported by robust clinical trials.

The FDA has warned that high biotin doses can interfere with critical blood tests, including those for heart attacks (troponin), thyroid function, and pregnancy. User Experience Summary A Review of the Use of Biotin for Hair Loss - PMC biotin

Biotin (Vitamin B7) is a popular supplement primarily marketed for strengthening hair and nails. While many users report positive aesthetic changes, scientific evidence suggests its benefits are mostly limited to individuals with an actual biotin deficiency. Most researchers conclude that the widespread use of

It is effective for treating rare biotinidase deficiencies or conditions like "uncombable hair syndrome". including those for heart attacks (troponin)

Scientific reviews indicate that biotin is highly effective for those with a deficiency, but there is little clinical proof that it improves hair or nail health in healthy individuals.