Effect of topical application of raspberry ketone on dermal production of insulin-like growth factor-I in mice and on hair growth and skin elasticity in humans

Growth Horm IGF Res. 2008 Aug;18(4):335-44. doi: 10.1016/j.ghir.2008.01.005. Epub 2008 Mar 5.

Abstract

Sensory neurons release calcitonin gene-related peptide (CGRP) on activation. We recently reported that topical application of capsaicin increases facial skin elasticity and promotes hair growth by increasing dermal insulin-like growth factor-I (IGF-I) production through activation of sensory neurons in mice and humans. Raspberry ketone (RK), a major aromatic compound contained in red raspberries (Rubus idaeus), has a structure similar to that of capsaicin. Thus, it is possible that RK activates sensory neurons, thereby increasing skin elasticity and promoting hair growth by increasing dermal IGF-I production. In the present study, we examined this possibility in mice and humans. RK, at concentrations higher than 1 microM, significantly increased CGRP release from dorsal root ganglion neurons (DRG) isolated from wild-type (WT) mice and this increase was completely reversed by capsazepine, an inhibitor of vanilloid receptor-1 activation. Topical application of 0.01% RK increased dermal IGF-I levels at 30 min after application in WT mice, but not in CGRP-knockout mice. Topical application of 0.01% RK increased immunohistochemical expression of IGF-I at dermal papillae in hair follicles and promoted hair re-growth in WT mice at 4 weeks after the application. When applied topically to the scalp and facial skin, 0.01% RK promoted hair growth in 50.0% of humans with alopecia (n=10) at 5 months after application and increased cheek skin elasticity at 2 weeks after application in 5 females (p<0.04). These observations strongly suggest that RK might increase dermal IGF-I production through sensory neuron activation, thereby promoting hair growth and increasing skin elasticity.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Administration, Topical
  • Adolescent
  • Adult
  • Alopecia / drug therapy*
  • Alopecia / metabolism
  • Animals
  • Butanones / administration & dosage*
  • Calcitonin Gene-Related Peptide / genetics
  • Cells, Cultured
  • Dermis / drug effects*
  • Dermis / metabolism
  • Drug Evaluation, Preclinical
  • Elasticity / drug effects
  • Female
  • Hair / drug effects*
  • Hair / growth & development
  • Humans
  • Insulin-Like Growth Factor I / metabolism*
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Middle Aged
  • Models, Biological
  • Rats
  • Skin Physiological Phenomena / drug effects*

Substances

  • Butanones
  • Insulin-Like Growth Factor I
  • raspberry ketone
  • Calcitonin Gene-Related Peptide