Hair Growth: Evidence-Based Supplement Guide

Hair loss and thinning are deeply personal concerns, and the supplement industry is happy to capitalize on that anxiety with products making aggressive claims about hair regrowth. The evidence reality is more modest: supplements can help hair growth primarily when a nutrient deficiency is the underlying cause of the hair loss. For the most common type of hair loss - androgenetic alopecia (male and female pattern baldness) - supplements are not effective because the cause is hormonal and genetic, not nutritional.

The supplements with the best evidence for hair health all work through the same basic mechanism: correcting deficiencies that impair the hair growth cycle. Iron deficiency is the most common nutritional cause of hair loss in women, and multiple studies have linked low ferritin levels to telogen effluvium (excessive shedding). Zinc deficiency disrupts the hair growth cycle and can cause diffuse hair loss. Vitamin B12 deficiency, while less directly linked, can contribute to hair thinning as part of its broader effects on cell division. Collagen peptides provide amino acids (particularly glycine and proline) that the body uses to build keratin, the protein hair is made of.

The critical first step for hair loss is a dermatologist visit and blood work. Thyroid disorders, iron deficiency, autoimmune conditions, and hormonal changes are common treatable causes. Buying a hair supplement without investigating the cause is likely wasting money.