Enhancing hair growth with phytoactives
SabihAkram, Gabriela Daniels, SlobodankaTamburic
Cosmetic Science Research Group, London College of Fashion, University of the Arts London
Both reduction of hair growth rate and follicle miniaturisation occur with ageing, two natural processes which many consumers wish to counteract. In addition to ageing, consumers find the effects of stress, illness, diet and seasonal variations of the rate of hair loss quite distressing and often resort to manage them by over-the-counter drug treatments. Cosmetic products aimed at improving the scalp health and the condition of the hair fibres are also in great demand.
Amongst those, products containing naturally derived actives have gained popularity due to widely available scientific data on their chemical composition and the mechanisms of action. Several of these actives will be reviewed in this presentation.
Caffeine is a naturally occurring purine-based methylxanthine alkaloid, derived from coffee, tea and cocoa. As a hydrophilic molecule, caffeine is able to penetrate thehair follicle ostium within two minutes, creating a reservoir at the site-of-action. As a phosphodiesterase inhibitor, caffeine indirectly increases the intercellular concentration of cyclic adenosine monophosphate (cAMP), stimulating cellular proliferation. It is also a proven muscle relaxer, which increases blood flow and nutrients to the follicle.
Green-tea polyphenols are believed to stimulate hair growth via their proliferative effect on the dermal papilla cells. Epigallocatechin-3-gallate (EGCG) has been identified as an integral polyphenolic catechin of green-tea, which could mediate a multitude of its proposed benefits, including inhibition of 5α-reductase. EGCG is a potent antioxidant, which exerts its biological effect by eliminating reactive oxygen species (ROS), thus protecting the fibre and scalp from the adverse effects of UV-radiationand free-radicals.
Castor oil contains high amounts of ricinoleic acid (RA), ω-9 fatty acid with anti-inflammatory, anti-microbialand antioxidant properties. RA is also believed to inhibit the enzyme prostaglandin D2 synthase, which indirectly impairs PGD2 synthesis (a contributing factor in androgenic alopecia).
Red clover isoflavones, andaloe veraare actives commonly usedto treat skin conditions associated withinflammation such as eczema. They can be applied to scalps sufferingfrom inflammation and related hair growth issues.
In addition to these topically applied phytoactives, natural oral supplementshave been shown to enhance hair growth in vivo. Amongst those Korean red ginseng, especiallywhen used with minoxidilas combined therapy, and sources of Vitamin C which improve iron absorption, are best documented.