Research has demonstrated that biotin hair growth supplements do not seem to improve hair growth except in extreme cases including:

  • Severe deficiency from malnutrition
  • Removal of portions of the intestines
  • Malabsorption caused by gastrointestinal disease
  • Neurological diseases
  • Enzyme deficiency
  • Treatment with antiepileptic medication or broad-spectrum antibiotics

Overconsumption of raw egg whites can also cause biotin deficiency.

In short, if you are healthy with a varied diet and not biotin-deficient, adding extra biotin will not alter your hair’s growth.