This manuscript may provide some useful ideas, especially in terms of design and measurement. Also, some good preliminary data perhaps to help you with sample size estimates and expected effect estimates.
Control of hair growth and follicle size by VEGF-mediated angiogenesis
Kiichiro Yano1, Lawrence F. Brown2 and Michael Detmar1
1Cutaneous Biology Research Center, Department of Dermatology, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts, USA
2Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
http://www.jci.org/articles/view/11317/version/1