Washington, Oct 21 : Laser hair removal therapy can be effective only when used separately than when used as a combination treatment, according to a new study.

During the past decade, laser hair removal has become a popular and accepted method used to reduce the growth of unwanted hair that have profound psychological effects and also appear to be safer.

The research team led by Dr Seyyed Masoud Davoudi, of the Baqiyatallah University of Medical Sciences, Tehran, Iran, analysed the results of the participants who underwent treatment at a private laser skin centre and received a total of four treatment sessions at eight-week intervals.

They found that the average hair reductions 18 months after final treatment were 75.9 percent for the 12-millimeter spot size alexandrite laser, 84.3 percent for the 18-millimeter spot size alexandrite laser, 73.6 percent for the Nd: YAG laser and 77.8 percent for the combination therapy.

Moreover, the average pain severity was higher in areas that received the alexandrite laser treatments than in those treated with the Nd: YAG laser.

However, the highest incidence of pain was reported in areas that received the combination treatment.

The areas treated with combination treatment were also more likely to experience hyperpigmentation or dark spots on the skin.

"Despite other studies showing more efficacy of the alexandrite rather than the Nd: YAG laser, our trial results showed no significant difference between them," the authors said.

"The use of alexandrite or Nd: YAG laser systems alone for at least four treatments sessions and with eight-week intervals have long-term persistent efficacy in hair reduction with acceptable and transient adverse effects," they added.

The study appears in Archives of Dermatology, one of the JAMA/Archives journals. (ANI)