L14.    The use of placebo or untreated controls in male pattern hair loss studies leads to a significant and permanent loss of hair.
Hugh Rushton, Ian Ramsay*, Jeremy Gilkes*; School of Pharmacy & Biomedical Sciences, University of Portsmouth, Portsmouth, *Lister Hospital, London, UK.

Objective: Do men with male pattern hair loss (MPHL) irreversibly lose hair if they are assigned to a placebo or untreated group? Methods: Monozygotic twins with MPHL, who were clinically indistinguishable for extent of hair loss and medical history, were followed for four years. During the first year twin #1(OW) was treated with an effective topical type I 5-alpha reductase inhibitor in combination with minoxidil and oral finasteride; a type II 5-alpha reductase inhibitor. Twin #2(RW) remained untreated for 12 months following which he received the same treatment as his brother. After 36 months on treatment a unit area trichogram was undertaken in the same frontal area in each twin. Result: Comparing both twins after 36 months treatment, a significant decrease (P<0.05) in Total Hair Density (THD: 247 hair/cm2 versus 212) and (P<0.01) in Useful Hair Density (UHD: 140 hair >30mm in length/cm2 versus 104) was found in twin #2(RW). A significant (P<0.05, one tail) decrease in mean hair diameter (79µm[OW] versus 73µm[RW]) of hair longer than 30mm in length and an increase in hair unable to grow beyond 30mm was also found in twin #2(RW), who started treatment one year later than his brother(OW). Conclusion: On initial presentation these identical twins were clinically indistinguishable and we believe had no difference in baseline hair status. A chance event resulted in twin #2(RW) remaining untreated for 12 months. In our experience we would not expect to see any further improvement after three years treatment. Consequently, these data indicate that hair loss progressed in the untreated twin #2(RW) and that these changes were irreversible despite receiving a known efficacious regimen. Delaying treatment, such as employing placebo or untreated controls in clinical trials where an active control is available, appears unethical and needs reviewing.