British wrestler Vahid Hosseinpoor has been banned for two years after testing positive for drugs during his country's Senior Wrestling Championships.
An in-competition test on May 11 found he had tamoxifen in his system.
It is a drugs that binds to the oestrogen receptor and used most commonly in the treatment of breast cancer due to its anti-oestrogenic effect in mammary tissue.
"This effect is also responsible for athlete use in treating/preventing gynaecomastia (breast tissue enlargement in men) which can occur as a result of anabolic steroid use," said UK Anti-Doping (UKAD)
Tamoxifen is a prescription-only medicine in the UK.
Hosseinpoor, 29, was provisionally suspended from all competition on June 3.
UKAD has now banned him from all sport until June 2, 2016.
Under the 2015 Code, he would have had an automatic four-year ban.
"Vahid Hosseinpoor failed to make the necessary checks before using a product which was not prescribed by his consultant, he did not have a Therapeutic Use Exemption, nor did he disclose his use of this product on the doping control form," said UKAD legal director Graham Arthur.
"He therefore receives a mandatory two-year ban."