It is 2015, so finally a good time to write about Bimatoprost. The main reason for this is that at the end of January 2015, Allergan will end its phase II clinical trials for the use of Bimatoprost for hair loss in humans. It is expected that results will be announced shortly thereafter.
What is Bimatoprost?
Bimatoprost is a synthetic prostamide (= prostaglandin-ethanolamide) analog. It is sometimes mistakenly called a prostaglandin analog, since prostaglandins and prostamides are structurally similar to each other. Bimatoprost is increasingly being used in dermatological applications, including off-label for hair growth and pigment related skin issues.
Prostaglandins were originally named due to the mistaken assumption that they were derived from the prostate gland and its secretions. I have written a number of posts on this blog regarding prostaglandin D2 (PGD2) and prostaglandin E2 (PGE2). PGD2 is especially important when it comes to hair loss. Bimatoprost is a prostamide F2α analog. Latanoprost and Travoprost are examples of prostaglandin F2α analogs.
Current Uses
While approval for use to grow scalp hair will depend on the upcoming phase 2 clinical trial results (and hopefully Allergan will decide to fund further phase 3 clinical trials), Bimatoprost has already been FDA approved for use in humans for:
- Glaucoma and ocular hypertension treatment, approval in 2001 (brand name Lumigan). Dosage = 1 drop of Lumigan 0.01 percent or Lumigan 0.03 percent depending on source, once daily.
- Eyelash growth (lengthening) treatment, approval in 2008 (brand name Latisse). Dosage = 1 drop of Latisse 0.03 percent, once daily.
Bimatoprost Side Effects
Although there are some significant side effects (e.g., darkening of iris, undereye, eyelash and eyelid), that can occur when using Bimatoprost for the above applications, most seem to be reversible.
It is also great to know that people have been using this product in such a sensitive areas as the eye for over a decade now without any large-scale reports of major injuries, nor any class action lawsuits against Allergan.
Will Bimatoprost be a Miracle Treatment for Hair Loss?
Initially when I first read about Bimatoprost a few years ago, I felt that it was going to be inferior to Minoxidil and not worth researching. For one, eyelash growth type results on scalp hair would be a joke in my opinion. More significantly, I thought that all Bimatoprost was doing was keeping scalp hair in anagen (growth) phase for a longer duration.
So once the androgens and dihydrotestosterone (DHT) killed the scalp hair, Bimatoprost would no longer have any positive effect. So my feeling was that all you were getting was a temporary spike in the amount of your hair that was in anagen phase. Also implying lengthier hair for a short time.
However, I have started to doubt my initial skepticism about this product. In 2013 Dr. Valerie Randall and a number of other co-authors published a great study on the successful use of Bimatoprost to grow human hair (in organ culture) and mouse hair (in vivo). The most interesting aspect of the study was that it seems like Bimatoprost stimulates intercellular signaling pathways and causes keratinocytes to produce increased hair growth as well as melanocytes to produce increased pigmentation. The whole process seems to start in the dermal papilla (which ties in to my recent posts on the University of Calgary’s and Replicel’s work related to dermal sheath cup cells).
It seems like Bimatoprost is not just temporarily keeping scalp hair in anagen phase longer. It is actually altering scalp biology at the cellular level and changing paracrine signaling (cell to cell communication) that may end up increasing protection against the ravages of DHT. According to the study:
Bimatoprost caused individual isolated scalp hair follicles from 10 different people to stay in anagen longer in organ culture, and about one-third more new hair was synthesized over 9 d with 100 and 1000 nM.
Note that the 100nM and 1000nM are dose measures, and much higher than the 0.03% present in Latisse and Lumigan. Another part of the study concludes that results from 100nM were better than from 10nM, but results from 1000nM were essentially the same as from 100nM. This is kind of the same phenomenon that we see in studies that show the negligible gains from higher and higher doses of Finasteride or Dutasteride.
My feeling is that Bimatoprost may result in slightly superior results to Minoxidil, but nothing extraordinary. Will this be sufficient for Allergan to fund final stage 3 clinical trials? I would hope so, considering how well the company has done recently.