Vitamin D2000–4000 IU · morning
Hair follicles carry vitamin D receptors and need them to start a new growth phase.
Evidence · 1 study, positiveResearch →
skin hair nails · symptom
Hair Thinning
More hair in the brush, less on your head.
Might help
Real research, but thin or split. Worth knowing, not worth counting on.3Real research, but thin or split. Worth knowing, not worth counting on.
Saw Palmetto160–320 mg · with_food
Blocks the conversion of testosterone into DHT, the hormone behind pattern hair loss.
Evidence · 1 study, positiveResearch →
Zinc15–30 mg · empty_stomach
Hair follicles divide fast and need zinc to do it, and zinc also damps the hormone behind hair loss.
Evidence · 2 of 2 studies agreeResearch →
Tested — didn’t work
Measured properly against placebo. Nothing found.2Measured properly against placebo. Nothing found.
Biotin2500–5000 mcg · morning
Biotin helps build keratin, the protein hair is made of.
No benefit foundResearch →
Selenium50–100 mcg · with_food
Your thyroid needs selenium, and thyroid trouble is a known cause of hair loss.
No benefit foundResearch →
No research yet
People take these for it. We haven’t found trials we would stand behind.3People take these for it. We haven’t found trials we would stand behind.
Calcium1000 mg · split
No trials we can vouch forResearch →
Copper1–2 mg · any
Copper helps cross-link the structural proteins in hair, and is needed for pigment.
No trials we can vouch forResearch →
Iron18–36 mg · empty_stomach
Hair follicles are among the fastest-dividing cells you have, and they need iron.
No trials we can vouch forResearch →