Have any supplements been studied for hair loss?

Several RCTs have tested the effect of individual supplements on hair loss, given either orally (including vitamin E and saw palmetto) or applied topically to the scalp (including pumpkin seed oil, melatonin, and procyanidin from apples).^[1] A number of studies have also examined the effect of oral supplements containing a mixture of compounds, typically a combination of nutrients (e.g., amino acids and vitamins).