What's the evidence for hair removal?
BMJ Group Medical Reference
There are very few studies looking at ways of removing hair for women with polycystic ovary syndrome (PCOS).
We found one summary of the research (a systematic review) on removing unwanted hair with lasers. It found that women had about 50 percent less hair in areas treated after six months. But these results may not be entirely reliable, as most of the studies in the summary weren't very good quality. Also, the results apply to two specific types of lasers, called alexandrite and diode lasers.
One good study (a randomised controlled trial) in the summary compared laser treatment with a dummy treatment (a placebo) using a low-powered laser. It showed that the women with PCOS who had four or five laser treatments on their faces over six months had much less unwanted hair at the end of the study than women who had the placebo treatment.
A placebo is a 'pretend' or dummy treatment that contains no active substances. A placebo is often given to half the people taking part in medical research trials, for comparison with the 'real' treatment. It is made to look and taste identical to the drug treatment being tested, so that people in the studies do not know if they are getting the placebo or the 'real' treatment. Researchers often talk about the 'placebo effect'. This is where patients feel better after having a placebo treatment because they expect to feel better. Tests may indicate that they actually are better. In the same way, people can also get side effects after having a placebo treatment. Drug treatments can also have a 'placebo effect'. This is why, to get a true picture of how well a drug works, it is important to compare it against a placebo treatment.
randomised controlled trials
Randomised controlled trials are medical studies designed to test whether a treatment works. Patients are split into groups. One group is given the treatment being tested (for example, an antidepressant drug) while another group (called the comparison or control group) is given an alternative treatment. This could be a different type of drug or a dummy treatment (a placebo). Researchers then compare the effects of the different treatments.
A systematic review is a thorough look through published research on a particular topic. Only studies that have been carried out to a high standard are included. A systematic review may or may not include a meta-analysis, which is when the results from individual studies are put together.
- 1. Haedersdal M, Gotzsche PC. Laser and photoepilation for unwanted hair growth (Cochrane review). In: The Cochrane Library. Wiley, Chichester, UK.
- 2. Clayton WJ, Lipton M, Elford J, et al. A randomized controlled trial of laser treatment among hirsute women with polycystic ovary syndrome. British Journal of Dermatology. 2005; 152: 986-992.