Substance P (SP) is a neuropeptide that is released from specific sensory nerves in response to pain and stress, and plays a central role in the pathogenesis of MPB. SP is directly implicated in the inflammation, catagen induction and growth inhibition that characterizes both Androgenetic and stress related hair loss. If you are treating hair loss it makes sense to counteract Substance P, which can be accomplished a couple of ways, using Substance P antagonists.
Cayenne Pepper, (Capsaicin), is a well documented Substance P antagonist which also causes a rapid and pronounced increase in localized cutaneous IGF-1 (Which antagonizes TGF-b, an inflammatory mediator) resulting in pronounced and sustainable stimulation of hair growth.
In a previous update we featured an Italian patent that detailed the hair growth effects of an oral combo of Resveratrol and Curcumin. The mechanism of action behind this effect that they proposed was that this combination, amongst other things, functioned as a SP antagonist.
Harada et al. tested the hair growth response to oral capsaicin and isoflavone supplementation in humans, with various types of alopecia. In all of the subjects receiving the capsaicin + isoflavone, serum IGF-I was increased after 5 months. 64.5% overall showed regrowth, while it was effective in 88% of subjects with androgenic alopecia. The following photos are results from 4 subjects, subjects A (male) and C (female) have Androgenetic Alopecia.
Effect of oral administration of capsaicin and isoflavone on hair growth in 4 volunteers with alopecia. Hair growth was observed at 5 months after administration of capsaicin and isoflavone in a male volunteer with AGA (54 y.o.) (a), in a male volunteer with AT (29 y.o.) (b), in a female volunteer with AGA (39 y.o.) (c), and in a female volunteer with AA (40 y.o.) (d).
The Resveratrol /Curcumin combination studied by Gigli, Marliani, and Campo was potent enough to induce hair growth in older men with prostate disorders, a typically nonresponsive group with regards to hair loss intervention. This same research team posits that this combo will ameliorate stress related hair loss due to its effects on SP and neurogenic inflammation.
Exposure to full spectrum sunlight evidently antagonizes SP to some degree, and facilitates Vitamin D production, providing a possible theoretical basis for its role in hair loss prevention.