Hair Loss News

Researchers in Japan have found that chemical compounds found in cayenne peppers and soy beans stimulate hair growth.

Capsaicin - a chemical component in cayenne peppers – has been shown to increase IGF-I production in previous studies. Insulin-like growth factor-I (IGF-I) plays an important role in hair growth.  In another separate study isoflavone - a phytoestrogen found in soy beans - was also found to increase IGF-1 production.

In the study below the researchers decided to test a combination of capsaicin and isoflavone as a hair growth stimulant.
   
They first tested it on mice and gave the mice oral doses of capsaicin and isoflavone for a period of 4 weeks.   After the 4 weeks they found that the mice that had been given these chemical compounds had increased IGF-I levels in their dermal papillae of their hair follicles.

The researchers then gave it to human volunteers suffering with hair loss.   Volunteers with alopecia (hair loss) were given oral doses of capsaicin (6mg/day) and isoflavone (75mg/day) for 5 months.

After 5 months the plasma (blood) levels of IGF-I were significantly increased from baseline levels in the 31 volunteers who had taken the active ingredients, compared to the 17 volunteers who just got a placebo.

In addition, the number of volunteers with alopecia who showed promotion of hair growth at 5 months was significantly higher among volunteers administered capsaicin and isoflavone than the placebo group.

Based on this outcome the researchers concluded that combined administration of capsaicin and isoflavone might increase IGF-I production in hair follicles in the skin, thereby promoting hair growth.
 

Administration of capsaicin and isoflavone promotes hair growth by increasing insulin-like growth factor-I production in mice and in humans with alopecia.

Growth Horm IGF Res. 2007 Jun 12
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.

PMID: 17569567