Increasing blood circulation in the scalp is considered to be a good method for increasing hair growth. One of the only FDA approved treatments for hair loss — Minoxidil — works by increasing scalp blood circulation, by increasing the growth factor VEGF.
Citrulline is an ingredient used in many pre-workout supplements and drinks and is marketed as an ingredient that increases blood nitric oxide levels.
I showed in a previous article that increasing nitric oxide levels can increase hair growth. So, can citrulline increase hair growth?
Work in rodent models of reduced l-arginine bioavailability has demonstrated that l-citrulline, but not l-arginine supplementation, increased NO synthesis and microcirculatory (gut villi) blood flow
Could topical citrulline stimulate hair growth?
Although there’s evidence to suggest high levels of oral citrulline may help reduce blood pressure and improve blood flow, can topical citrulline increase scalp blood circulation in a similar way to Minoxidil?
Unfortunately there are no studies suggesting topical citrulline can increase blood circulation locally.