A friend recently asked me whether I would recommend caffeine shampoos for his hair loss. I was totally surprised and it even necessitated a subtle upward drift to my gaze to check out what the problem was.
A particular brand of caffeine shampoo was already in mind and I was told that it was the best selling shampoo for men in Germany and that therefore proved its effectiveness. I confess, I had never heard of such a product and therefore had to do my own bit of research.
What research is there?
The research is fairly limited. There is a study from 2007 which showed a significant stimulation of hair growth with 0.005% and 0.001% caffeine applied to hair follicle biopsies. Stronger concentrations of caffeine were shown to be suppressive to hair growth. However, this was a laboratory experiment on scalp skin biopsies and not on real live men’s scalps.
[Fischer TW, Hipler UC, Elsner P. Effect of caffeine and testosterone on the proliferation of human hair follicles in vitro. Int J Dermatol 2007; 46: 27-35.]
Is that all the research there is?
There are other studies.
One paper found that caffeine improves skin barrier function, ie prevents water loss from the skin of men compared to women.
[Brandner JM, Behne MJ, Huesing B et al. Caffeine improves barrier function in male skin. Int J Cosmet Sci. 2006;28:343–7.]
Another group found that the hair follicle is a fast route for absorption of certain substances such as caffeine with caffeine levels being detectable in the blood within 5 minutes of application.
[Otberg N, Patzelt A, Rasulev U et al. The role of hair follicles in the percutaneous absorption of caffeine. Br J Clin Pharmacol. 2007; 65: 488–92.]
The same group found that caffeine in a shampoo formulation left on the scalp for 2 minutes was absorbed far faster via the hair follicles than the skin between the follicles.
[ Otberg N, Teichmann A, Rasuljev U et al. Follicular penetration of topically applied caffeine via a shampoo formulation. Skin Pharmacol Physiol. 2007; 20: 195–8.]
The group that have formulated and marketed the leading brand of caffeine shampoo also published some research in 2010 in the Journal of Applied Cosmetology.
This study involved 30 male subjects aged between 18-55y who applied the caffeine shampoo for 2 minutes every day for 6 months. This study showed that hair loss decreased when assessed at 3 months and 6 months by 7.17% and 13.45% respectively.
[Bussoletti C, Mastropietro F, Tolaini MV et al. Use of a Caffeine Shampoo for the Treatment of Male Androgenetic Alopecia. Int J Cosmetol 2010; 28: 153-162.]
But how does caffeine stimulate hair growth?
Well, that is still not known or there are no studies available that can give us the answer yet.
It is thought that caffeine inhibits an enzyme called phosphodiesterase within cells. Inhibition of phosphodiesterase leads to elevation of another cellular entity called cyclic AMP (cAMP). Raised levels of cAMP generally lead to increased metabolism within the cell and thereby cell proliferation.
[Bansal M, Manchanda K, Pandey SS. Role of Caffeine in the Management of Androgenetic Alopecia. Int J Trichol 2012; 4(3): 185-186.]
However, this is all postulation and none of the studies aforementioned discussed this area.
So where do we go from here?
It seems as if there is insufficient evidence to recommend the use of caffeine shampoos to curtail hair loss in men. The only currently available evidence of any benefit is by the group who make the leading brand of caffeine shampoo. Until more robust trial evidence is available from those not directly involved in its manufacture, I’m afraid, I will not be able to recommend caffeine shampoos.
Dr Sandy Flann, Consultant Dermatologist