Clin Interv Aging.2006;1:121
Possibilities for prevention or reversal of hair loss during aging
....minoxidil stimulates hair growth, yet its mechanism of action on the hair follicle is still poorly understood. A number of in vitro effects of minoxidil have been described in monocultures of various hair follicle cell types including stimulation of cell proliferation, inhibition of collagen synthesis, and stimulation of vascular endothelial growth factor (VEGF) and prostaglandin synthesis. In animal studies, topical minoxidil shortens the resting phase (telogen) of the hair cycle, causing premature entry of resting hair follicles into the growing phase (anagen), and it probably has a similar action in humans. Minoxidil may also cause prolongation of anagen and increases hair follicle size. Clinical trials of topical 2% and 5% minoxidil in male and female hair loss have all shown remarkably rapid increase in hair growth, measured by hair counts or hair weight (Olsen et al 1985, 1987, 1990; Price and Menefee 1990; De Villez et al 1994; Olsen, Dunlap, et al 2002; Lucky et al 2004). The increase is evident within 6–8 weeks of treatment and has generally peaked by 12–16 weeks. However, topical minoxidil has not been studied in the specific perspective of aging and senescent alopecia. In an recent analysis of clinical trial data in 636 males and 630 females, a therapeutic benefit of topical 2 and 5% minoxidil solution was compared with age, duration of balding, and diameter of balding vertex area in males, and age and duration of hair loss in females (Rundegren 2004). Males showed an inverse relationship between effect and duration of balding. Males with duration of balding <5 years showed a significantly better effect than those with duration of balding >21 years. Females, in contrast, showed no correlation with duration of balding. The diameter of vertex balding in men showed an inverse relationship with efficacy of minoxidil. Males with <5 cm diameter vertex balding area showed a better effect of treatment than subjects with diameters >15 cm. Finally, duration of hair loss less than one year compared with more than 10 years at onset of treatment resulted in a significantly more effective treatment with respect to stabilization of alopecia and new hair growth.
Labels: hair, loss, regrowth, treatment
