"In fact, when I first received the product, I reviewed the list of ingredients and did not see any prohibited substances.

"I am absolutely shocked that deer antler spray may contain a banned substance and am angry that I have put myself in this position.

"I have been in contact with the PGA Tour and am cooperating fully with their review of this matter. I will not be commenting further at this time."

Two years ago, 1999 British Open champion Mark Calcavecchia was advised by golf officials to stop using the spray.

It is manufactured by an Alabama-based company Sports With Alternatives to Steroids (SWATS), who have links to other major sports in the United States.

Deer velvet

CNN Senior Managing Editor of Medical News Tim Langmaid says the spray, which is also known as deer velvet, is purportedly used to boost strength and endurance, while it also improves immune system function.

He said: "It contains small amounts of deer IGF-1, or Insulin-like Growth Factor-1, which mediates the level of HGH in the body.

"It comes from the deer velvet that covers the growing bone and cartilage that develop into deer antlers.

"It's the IGF-1 that is on WADA's banned substance list. Excessive use in humans can lead to metabolic dysfunction, including glucose intolerance."