Capsaican & isoflavone promote hair growth via raising i

[harold]

1: Growth Horm IGF Res. 2007 Jun 12; [Epub ahead of print]
Administration of capsaicin and isoflavone promotes hair growth by increasing insulin-like growth factor-I production in mice and in humans with alopecia.
Harada N, Okajima K, Arai M, Kurihara H, Nakagata N.

Department of Translational Medical Science Research, Nagoya City University, Graduate School of Medical Sciences, Kawasumi 1, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.

OBJECTIVE: Insulin-like growth factor-I (IGF-I) plays an important role in hair growth. Capsaicin activates vanilloid receptor-1, thereby increasing the release of calcitonin gene-related peptide (CGRP) from sensory neurons, and CGRP has been shown to increase IGF-I production. We recently reported that isoflavone, a phytoestrogen, increases production of CGRP by increasing its transcription in sensory neurons. These observations raise the possibility that administration of capsaicin and isoflavone might promote hair growth by increasing IGF-I production. In the present study, we examined this possibility in mice and humans with alopecia. DESIGN: Dermal IGF-I levels, immunohistochemical expression of IGF-I in the skin and hair regrowth were examined after capsaicin and isoflavone administration to wild-type (WT) mice and CGRP-knockout mice. Plasma levels of IGF-I and promotion of hair growth were evaluated in 48 volunteers with alopecia after administration of capsaicin and isoflavone for 5months. RESULTS: Subcutaneous administration of capsaicin significantly increased dermal IGF-I levels at 30min after administration in WT mice (p<0.01), but not in CGRP-knockout mice. Dermal levels of IGF-I were significantly higher in WT mice administered capsaicin and isoflavone for 4wks than in those administered capsaicin alone for 4wks (p<0.01) and in those administered neither of them (p<0.01). Immunohistochemical expression of IGF-I at dermal papillae in hair follicles was increased in WT mice administered capsaicin and isoflavone and in those administered capsaicin alone at 4wks. Hair regrowth was clearly more accelerated in WT mice administered capsaicin and isoflavone for 4wks than in those administered capsaicin alone for 4wks and in those administered neither of them. Plasma levels of IGF-I were significantly increased from baseline levels in 31 volunteers with alopecia at 5months after oral administration of capsaicin (6mg/day) and isoflavone (75mg/day) (p<0.01), while they were not increased in 17 volunteers with alopecia administered placebo. The number of volunteers with alopecia who showed promotion of hair growth at 5months after administration was significantly higher among volunteers administered capsaicin and isoflavone (20/31: 64.5%) than among those administered placebo (2/17: 11.8%) (p<0.01). CONCLUSIONS: These observations strongly suggested that combined administration of capsaicin and isoflavone might increase IGF-I production in hair follicles in the skin, thereby promoting hair growth. Such effects of capsaicin and isoflavone might be mediated by sensory neuron activation in the skin.

http://www.ncbi.nlm.nih.gov/sites/entre ... d_RVDocSum

 

[harold]

"Transforming growth factor-β (TGF-β) plays a critical role in androgenetic alopecia (Androgenetic Alopecia) by inducing apoptosis of keratinocytes in hair follicles [32]. IGF-I has been shown to antagonize TGF-β-induced apoptosis by activating the phosphatidylinositol 3-kinase/Akt pathway [33], suggesting that an increase in IGF-I production induced by administration of capsaicin and isoflavone might promote hair growth in patients with Androgenetic Alopecia. Twenty-five people with Androgenetic Alopecia were included in the volunteers with alopecia who were administered capsaicin and isoflavone in the present study and promotion of hair growth was observed in 88.0% of the 25 patients with Androgenetic Alopecia. This observation is consistent with the hypothesis described above."

 

[docj077]

There is something funny about IGF-1. Increased IGF-1 levels in the scalp is also associated with vertex baldness.

 

[Jkkezh]

Makes sense to me. I've noticed that 'bigger' stronger people/bodybuilders (high IGF-1) most of the time have vertex balding. And thinner people are more likely to have temple hair loss.

 

[eddy_simpson]

Jkkezh its strange that you should say this, because I have observed precisely the opposite - that stronger, fitter men often have receding hairlines and skinny unhealthy looking men diffuse/vertex loss.

 

[flimflam]

maybe it's both!

or neither!

 

[eddy_simpson]

i think your spot on there flimflam.


ps. whos that chick in your avatar? shes quite cute in a GI Jane / britney spears kind of way.

 

[oyo]

this study didn't have the in vivo testing the other one did. still its interesting it looks like it contradicts it.

A hot new twist to hair biology: involvement of vanilloid receptor-1 (VR1/TRPV1) signaling in human hair growth control.
Bodó E, Bíró T, Telek A, Czifra G, Griger Z, Tóth BI, Mescalchin A, Ito T, Bettermann A, Kovács L, Paus R.

The vanilloid receptor-1 (VR1, or transient receptor potential vanilloid-1 receptor, TRPV1) is activated by capsaicin, the key ingredient of hot peppers. TRPV1 was originally described on sensory neurons as a central integrator of various nociceptive stimuli. However, several human skin cell populations are also now recognized to express TRPV1, but with unknown function. Exploiting the human hair follicle (HF) as a prototypic epithelial-mesenchymal interaction system, we have characterized the HF expression of TRPV1 in situ and have examined TRPV1 signaling in organ-cultured human scalp HF and outer root sheath (ORS) keratinocytes in vitro. TRPV1 immunoreactivity was confined to distinct epithelial compartments of the human HF, mainly to the ORS and hair matrix. In organ culture, TRPV1 activation by capsaicin resulted in a dose-dependent and TRPV1-specific inhibition of hair shaft elongation, suppression of proliferation, induction of apoptosis, premature HF regression (catagen), and up-regulation of intrafollicular transforming growth factor-beta(2). Cultured human ORS keratinocytes also expressed functional TRPV1, whose stimulation inhibited proliferation, induced apoptosis, elevated intracellular calcium concentration, up-regulated known endogenous hair growth inhibitors (interleukin-1beta, transforming growth factor-beta(2)), and down-regulated known hair growth promoters (hepatocyte growth factor, insulin-like growth factor-I, stem cell factor). These findings strongly support TRPV1 as a significant novel player in human hair growth control, underscore the physiological importance of TRPV1 in human skin beyond nociception, and identify TRPV1 as a promising, novel target for pharmacological manipulations of epithelial growth disorders.
http://www.ncbi.nlm.nih.gov/pubmed/1579 ... stractPlus

 

[Prevent99]

Isoflavone is a phytoestrogen. Wouldn't its consumption reduce endogenous test and DHT levels? How do we know that the results aren't from an androgenic response?