waynakyo
Experienced Member
- Reaction score
- 464
Administration of capsaicin and isoflavone promotes hair growth
by increasing insulin-like growth factor-I production in mice
and in humans with alopecia
Abstract
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 5 months.
Results: Subcutaneous administration of capsaicin significantly increased dermal IGF-I levels at 30 min 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 4 wks than in those administered capsaicin alone for 4 wks (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 4 wks. Hair regrowth was clearly more accelerated in
WT mice administered capsaicin and isoflavone for 4 wks than in those administered capsaicin alone for 4 wks and in those administered
neither of them. Plasma levels of IGF-I were significantly increased from baseline levels in 31 volunteers with alopecia at
5 months after oral administration of capsaicin (6 mg/day) and isoflavone (75 mg/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 5 months 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://home.arcor.de/gekkehenk/HW/I...es hair growth by increasing insulin-like growth%20factor-I%20production%20in%20mice%20and%20in%20humans%20with%20alopecia.pdf
But how do we know this is not the effect of Isoflavones alone, and isn't this latter supposed to be really bad for guys ?
by increasing insulin-like growth factor-I production in mice
and in humans with alopecia
Abstract
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 5 months.
Results: Subcutaneous administration of capsaicin significantly increased dermal IGF-I levels at 30 min 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 4 wks than in those administered capsaicin alone for 4 wks (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 4 wks. Hair regrowth was clearly more accelerated in
WT mice administered capsaicin and isoflavone for 4 wks than in those administered capsaicin alone for 4 wks and in those administered
neither of them. Plasma levels of IGF-I were significantly increased from baseline levels in 31 volunteers with alopecia at
5 months after oral administration of capsaicin (6 mg/day) and isoflavone (75 mg/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 5 months 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://home.arcor.de/gekkehenk/HW/I...es hair growth by increasing insulin-like growth%20factor-I%20production%20in%20mice%20and%20in%20humans%20with%20alopecia.pdf
But how do we know this is not the effect of Isoflavones alone, and isn't this latter supposed to be really bad for guys ?