Testosterone is an androgen hormone which regulates the development of the male reproductive system and male secondary sex characteristics.
Testosterone regulation involves using a drug - such as leuprolide - to reduce the amount of testosterone in the body. This is sometimes done to treat medical conditions such as prostate cancer or to help reduce sexually inappropriate behaviour.
Some people think that reducing testosterone can also have beneficial effects in people on the autism spectrum. This is because they think that some of the symptoms of autism are caused by toxins from heavy metals such as mercury.
They also think that since androgens increase the toxicity of mercury, reducing the amount of testosterone will reduce the effects of that toxicity.
The National Institute of Health and Clinical Excellence (NICE) made the following recommendation.
'Do not use testosterone regulation for the management of core symptoms of autism in adults.' (NICE, 2012)