A cardiologist has panned Maria Sharapova’s justification for taking a prohibited substance.

Sharapova has been taking a drug, meldonium, since 2006.

It became illegal this year.

Sharapova claims to have taken the substance for health issues including a magnesium deficiency, irregular EKG results, and a family history of diabetes.

But Dr Ross Walker told Neil Mitchell her explanation doesn’t make sense.

He said meldonium is only available on the internet, and there’s no proof that it works against Sharapova’s symptoms.

‘It all sounds extremely dodgy to me,’ he said.

‘There’s no evidence that it improves an irregular ECG.

‘Would you take a pharmaceutical drug just because you have a family history?’

Dr Walker said we don’t know the effects of the drug in the long term.

‘I’d be very concerned about this drug, especially giving it to young women in their reproductive years,’ he said.

Click play to hear Dr Walker’s interview