the effect of one session low level laser therapy of extracted follicular units on the outcome of hair transplantation

introduction: photobiostimulation with low level laser (lll) has been used in medicine for a long time and its effects have been shown in many diseases. some studies have evaluated the effect of lll on androgenic alopecia. one of the most important limitations of the use of lll in the treatment of alopecia is the requirement for multiple sessions, which is hardly accepted by patients. this study was conducted to evaluate the effect of the irradiation of extracted follicular hair units by lll on the outcome of hair transplantation. methods: we enrolled 10 patients with androgenic alopecia and after screening tests for infections and other diseases, we extracted hair follicular units. the hair units were divided in two groups. one group was irradiated by lll 20 minutes before transplantation (660 nm, 80 hz, 100 mw) and the other one was used as control. the containing plates were labeled as a and b and sent to the operation room. the surgeon was unaware of the therapy assigned to the plates and transplanted them randomly on the right or left side of the head. one hundred follicular units on each sides of the scalp were transplanted symmetrically. the follicles on both sides were evaluated at 3 and 6 months of transplantation for hair growth rate by another physician, blinded to the treatment assigned to each side. results: ten patient with androgenic alopecia and mean (sd) age of 31.5 (6.6) years (range 25-45 years) completed the study. all patients had 100% hair growth at 3 and 6 months follow-up except one who had hair growth of 20% at three months of transplantation, which changed to 100% at sixth months. there was no significant difference between the groups regarding hair growth ( p > 0.8). conclusion: one session of lll irradiation has no significant effect on the outcome of transplanted hair follicles. studies with larger sample size are needed to draw a definite conclusion.