The International Tennis Federation says it has banned a Ukrainian doctor from sports for four years for giving a banned substance to WTA Tour player Kateryna Kozlova.

The ITF said in a statement Monday that Elena Dorofeyeva gave a supplement containing the banned stimulant DMBA to Kozlova, the current world No. 98, in 2014.

Kozlova tested positive and served a six-month ban last year, when the ITF ruled she had not intentionally doped. Kozlova said she had taken what she thought to be vitamins provided by Dorofeyeva.

The ITF dismissed an appeal by Dorofeyeva and ruled that she deserved a four-year ban because "a doctor setting him/herself up as a sports medicine specialist...bears an extremely heavy responsibility", particularly when working with young athletes. Kozlova was 20 when she tested positive.