We’ll be honest with you: this is a difficult topic. Hair growth and health are affected by many factors, both internal and external. With this in mind, many people swear by hair vitamins and supplements to help support overall hair health.*

Now the theory behind hair supplements really comes down to internal structural support. Let’s explain: Hair consists of keratin1a type of protein that consists of about 18 amino acids2 including cysteine, proline, threonine, leucine and arginine. Like most processes in the body, keratin production is greatly affected by free radical damage and oxidative stress—both of which can be alleviated or neutralized by antioxidants.*

OK, but do supplements work? Well, while key nutrients and bioactives may support hair synthesis and protection*, clinical studies using supplements in healthy populations are hard to find. (You’ll find some research on people with various nutrient deficiencies, but not a lot of published research on hair supplements for the average person.)

And given that their mechanisms are aimed more at creating optimal conditions for hair health, it is difficult to track how much they affect hair growth.

Not to mention: As with any supplement, it comes down to ingredients. But that doesn’t mean there isn’t solid anecdotal support for hair supplements: While peer-reviewed publications are ideal, many anecdotal reports in aggregate also have merit.