• A lot of time and financial resources are spent by the patients for hair removal.
  • It is often believed by the public that hair removal can be complete aften multiple treatment sessions. However this is wrong for many reasons:
  1. -different lasers achieve different long term results on hair growth
  2. -even the best lasers can only achieve lasting hair reduction, but not complete removal. They act by reducing progressively the size of the hair.
  3. -response to treatment may also vary from one individual to another.


  • Based on a review of 30 control trials (CT) (see bibliography) 9 of which were randomized (RCT), different lasers were studied:
  1. -alexandrite laser: 3 RCTs, 8 CTs= Good scientific evidence
  2. -diode laser: 3 RCTs, 4 CTs= Good scientific evidence
  3. -ruby laser: 2 RCTs, 6 CTs) = Good scientific evidence
  4. -Nd:YAG (two RCTs, four CTs) = Good scientific evidence
  5. -IPL (intense pulsed light, flash lamp) sources (1 RCT, 1CT)=Limited scientific evidence


  • The authors came to the following conclusions:
  1. -Hair removal with lasers and light sources induces a partial short-term hair reduction up to 6 months postoperatively. In practice, maintenance treatment therefore is advised every 6months to a year.
  2. -efficacy is improved when repeated treatments are given
  3. -efficacy is superior to conventional treatments (shaving, wax epilation, electrolysis)
  4. -evidence exists for a partial long-term hair removal efficacy beyond 6 months postoperatively after repetitive treatments with alexandrite and diode lasers and probably after treatment with ruby and Nd:YAG lasers, whereas evidence is lacking for long-term hair removal after IPL treatment
  5. -There is no evidence for a complete and persistent hair removal
  6. -the occurrence of postoperative side-effects is reported low for all the laser systems


  • Regarding permanent hair loss, the FDA hass given a definition* which has led to unrealistic expectations bacause of mistaken perceptions in the media.


*”Permanent hair reduction refers to a significant reduction in the number of terminal hairs after a given treatment, which is stable for a period of time longer than the complete growth cycle of hair follicles at the given body site.”


To conclude, we agree with the authors that an honest explanation of treatment outcome is mandatory after assessing the patient’s expectations. Anything other than that will lead ultimately to dissatisfaction and frustration.




Evidence-based review of hair removal using lasers and light sources; Haedersdal M, Wulf HC.; J Eur Acad Dermatol Venereol. 2006 Jan;20(1):9-20.

This advice is for informational purposes  only and does not replace therapeutic judgement done by a skin doctor.