Niacin Flush Increases PGD2?
Hi Dr….Great blog.
Dr.Cotsarelis’s recent discovery about PGD2 and hair loss raises some interesting questions. Niacin (or Niaspan which is a prescription drug) increases pgd2 in the skin which I found doing some searching. (See here)
I’m very interested in the fact that the niacin flush significantly increases pgd2 levels in the skin. I would really think if high levels of pgd2 cause (possible) hair loss than how can Niapsan not show high degrees of hair loss as a side effect? It actually doesn’t list it as a rare event. The amount of studies and people taking Niaspan prescription should give doctors a massive pool of people to research regarding hair loss from PGD2 increase at the skin level. And one would think if increase PGD2 causes hair loss then we would be hearing this a lot regarding the drug Niaspan. I also couldn’t find any cases of hair loss related to Niacin toxicity…..can you?
Oddly we know that Niacin increases blood flow to capillaries, which one would think could help hair loss even though blood flow isn’t a major contributor to hair loss.
My second question is regarding high cholesterol and tryglecerides in general. If one has very high blood fats in theory could that drastically decrease blood flow at the scalp capillaries and veins by clogging them up… leading to diffuse hair loss over the entire scalp as seen some times with FPB and DUPA. If so wouldn’t reducing the blood fats to normal levels re-establish blood flow to these areas and possibly restoring lost hair.( I understand this would do nothing to pattern loss, I’m speaking mostly of diffuse.)
Thanks
These sound like bits of information and theories… not really questions for me to address. I don’t fully understand the role PGD2 plays in hair loss or the possible cause(s) of DUPA. I did find your info interesting, but they are nothing that I can act upon in my practice at this time. Perhaps someone that has researched this more would like to theorize with you in the comments…
While niacin increases plasma PGD2, there is no evidence that any vasodilator increasing plasma levels of PDG2 (and there ate many) increases hair loss. This may seem inconsistent with the recent report that prostaglandin D2 synthase is locally elevated at the mRNA and protein levels in bald scalp compared to haired scalp of men with androgenic alopecia. But, the real answer is that one does not know how these two observations relate. As blood flow per se is unrelated to hair loss, one would not expect an atherosclerotic process – which affect arteries more than capillaries – to impact hair growth. At the end of the day, men with significant atherosclerosis (as evidenced by a history of heart attacks and strokes)still have adequate blood flow and oxygenation to a hair follicle – which is why a transplanted hair in these men can still grow (the blood supply remains the same locally). In these men, any badness is related to other factors.
I think this whole Prostaglandin D2 causes hairloss is a crock.
The drug Bimatoprost is a Prostaglandin Analog and it is being tested as a hair regrowth agent.
So unless their are types of Prostaglandin that inhibit hair growth and some that promote hair growth I just can’t see how this recent research holds water.
Just got an answer to my question on another forum:
Bimatoprost causes hair growth because it deals with prostaglandin F2 alpha which is known to increase hair growth.
Bimatoprost, which is a prostaglandin analogue, is used topically for eyelash growth off-label). To avoid confusion, the blog poster asks about niacin, which is one of hundreds of *systemically used* drugs that act through the prostaglandin pathway either as a synthetic prostaglandin or an analogue. None of these drugs promote hair growth. This has no bearing on the PGD2 baldness hypothesis; it just answers the posters question about whether a systemic drug (eg niacin) can increase hair growth.