6-Gingerol inhibits hair shaft growth in cultured human hair follicles and modulates hair growth in mice.

Ginger (Zingiber officinale) has been traditionally used to check hair loss and stimulate hair growth in East Asia. Several companies produce shampoo containing an extract of ginger claimed to have anti-hair loss and hair growth promotion properties. However, there is no scientific evidence to back up these claims. This study was undertaken to measure 6-gingerol, the main active component of ginger, on hair shaft elongation in vitro and hair growth in vivo, and to investigate its effect on human dermal papilla cells (DPCs) in vivo and in vitro. 6-Gingerol suppressed hair growth in hair follicles in culture and the proliferation of cultured DPCs. The growth inhibition of DPCs by 6-gingerol in vitro may reflect a decrease in the Bcl-2/Bax ratio. Similar results were obtained in vivo. The results of this study showed that 6-gingerol does not have the ability to promote hair growth, on the contrary, can suppress human hair growth via its inhibitory and pro-apoptotic effects on DPCs in vitro, and can cause prolongation of telogen phase in vivo. Thus, 6-gingerol rather than being a hair growth stimulating drug, it is a potential hair growth suppressive drug; i.e. for hair removal.

[Experimental research of hair follicle reconstruction with the aid of embryonic mice dermal cells].

OBJECTIVE: To investigate the effect of embryonic dermal signal on the hair-inductive capacity of neonatal mice dermal cells which have been amplified in vitro. METHODS: Embryonic mice dermal cells of embryonic day 14 were added to a chamber on the back of nude mice with neonatal mice dermal cells which had been amplified in vitro for 3 days and freshly isolated neonatal mice epidermal cells. The hair regeneration was compared between the groups with or without embryonic mice dermal cells. Meanwhile, chambers with following cells respectively were constructed as controls: embryonic mice dermal cells + neonatal mice epidermal cells; freshly isolated neonatal mice dermal cells + neonatal mice epidermal cells; amplified neonatal mice dermal cells only; embryonic mice dermal cells only; freshly isolated neonatal mice dermal cells only; neonatal mice epidermal cells only. RESULTS: The number of regenerated hairs with the aid of embryonic mice dermal cells (207 +/- 15. 948) was significantly higher than that (67 +/- 8.963) in the group without embryonic mice dermal cells (n = 3, t = 7.653, P = 0.002). CONCLUSION: Embryonic dermal signal can enhance the hair-inductive capacity of neonatal mice dermal cells which have been amplified in vitro.