I've noticed several topical hair loss products (ex: minoxidilmax) add caffeine to their recipes with the claim that "caffeine stimulates blood flow to the scalp" thereby improving hair quality/hair growth.
I find this strange because I had read elsewhere that stimulants such as caffeine and nictoine constrict blood vessels when drank/smoked.
So the question:
Is it that being applied topically is different than being consumed as a liquid? What would be the biochemical explanation behind this? Or is there no basis at all for the claims that caffeine stimulate hair growth
If caffeine indeed does stimulate hair growth, could it be possible that other stimulants such as nicotine if applied topically, would help as well?