- Reaction score
- 1,400
Hey everyone, long time lurker here. I've been following this forum for a few months now, and would like to thank some of you for all the information you've gathered. I've been scouring the internet and educating myself on the science of hair loss for the past few months, and would like to revisit the famous (or infamous) study done by Dr. George Cotsarelis "Prostaglandin D2 inhibits hair growth and is elevated in bald scalp of men with androgenetic alopecia."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3319975/
As I'm sure many of you are aware, PGD2 and PGE2 play a significant role in androgenic alopecia. People with this disease have highly elevated PGD2 levels and significantly lower PGE2 levels. Interestingly enough, one mechanism in which minoxidil works is to increase PGE2 (Nieves, 2014). Just like minoxidil, niacin is also a vasodilator (widens blood vessels and improves circulation).
When taking niacin, you will most likely experience a "flush". This is the itchy, hot sensation in your skin caused by a release of PGD2 from mast cells. Now in the human body, there are 2 types of PGD2 receptors - DP1 and DP2. Cotsarelis showed that the DP2 receptor (and not DP1) is involved in hair growth downregulation. DP1 is not shown to be involved with hair loss. Now this is where niacin comes into play - it flushes PGD2 through the DP1 receptor, the one that has nothing to do with hair loss. This action makes PGD2 less available for the "bad" receptor (DP2) to use, theoretically having a positive affect on hair loss.
I have not tested this theory personally. All I have done is read scientific studies to try to understand the process of prostaglandins in hair loss. I'm posting this to have a mature, scientific conversation about how niacin flushing may or may not help our situation. I am aware that this has been discussed on other forums, but in light of new information on the link between PGD2 and hair loss I figured this could be a worthy discussion. Sorry about this lengthy post but I believe this might be a piece of the puzzle. Please let me know your thoughts!
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3319975/
As I'm sure many of you are aware, PGD2 and PGE2 play a significant role in androgenic alopecia. People with this disease have highly elevated PGD2 levels and significantly lower PGE2 levels. Interestingly enough, one mechanism in which minoxidil works is to increase PGE2 (Nieves, 2014). Just like minoxidil, niacin is also a vasodilator (widens blood vessels and improves circulation).
When taking niacin, you will most likely experience a "flush". This is the itchy, hot sensation in your skin caused by a release of PGD2 from mast cells. Now in the human body, there are 2 types of PGD2 receptors - DP1 and DP2. Cotsarelis showed that the DP2 receptor (and not DP1) is involved in hair growth downregulation. DP1 is not shown to be involved with hair loss. Now this is where niacin comes into play - it flushes PGD2 through the DP1 receptor, the one that has nothing to do with hair loss. This action makes PGD2 less available for the "bad" receptor (DP2) to use, theoretically having a positive affect on hair loss.
I have not tested this theory personally. All I have done is read scientific studies to try to understand the process of prostaglandins in hair loss. I'm posting this to have a mature, scientific conversation about how niacin flushing may or may not help our situation. I am aware that this has been discussed on other forums, but in light of new information on the link between PGD2 and hair loss I figured this could be a worthy discussion. Sorry about this lengthy post but I believe this might be a piece of the puzzle. Please let me know your thoughts!