The Healthspan Map · Nutrient

Biotin (B7)

Compiled by Aamir Malik, PhD, Professor of Neuroengineering at Brno University of Technology, from published studies. He is a researcher, not a physician. Last updated 21 August 2026.

Linked to getting too little

Where a shortfall of Biotin (B7) is linked: 3 sources.In the order the Map holds them: strongest evidence first. That is a statement about the evidence, not about what matters most.
Condition or system	Direction	Strength	Evidence type	What was found	Source
Depression / low mood	Eat enough of	Moderate	Established clinical	Adult deficiency causes neurological findings including depression, lethargy and hallucinations.	NIH ODS – Biotin (opens in a new tab)
Skin, hair, nails & wound healing	Eat enough of	Moderate	Review / narrative	Biotin deficiency causes brittle nails, alopecia and scaly dermatitis (but supplements only help if truly deficient).	Biotin & hair/nails (opens in a new tab)
Stress	Eat enough of	Emerging	Systematic review	Higher dietary B-vitamin intake, especially biotin, is associated with lower stress symptoms.	B-vitamins/EFA/mineral stress review (McCabe et al. 2017) (opens in a new tab)

Linked to getting too much

Where an excess of Biotin (B7) is linked: 1 source.In the order the Map holds them: strongest evidence first. That is a statement about the evidence, not about what matters most.
Condition or system	Direction	Strength	Evidence type	What was found	Source
Cardiovascular	Don't overdo	Moderate	Established clinical	High supplemental biotin caused a falsely LOW troponin result and a missed heart attack — the FDA reported one death; also distorts NT-proBNP and many hormone assays.	FDA Safety Communication (2017) – Biotin (opens in a new tab)

The Healthspan Map is part of Fix the Floor, a book by Aamir Malik. About the book