The IOC medical commission will make a final ruling in April, he said.
"It's still in a gray area,'' Schamasch told The Associated Press in a telephone interview. "For the moment, if we want to go by a very strict definition, it may be banned. But we don't want to accuse anyone without having more information.''
The IOC announced categorically in December that Actovegin, an extract of calf's blood, was banned under the classification of blood-doping agents.
But the IOC, at an executive board meeting last week in Dakar, Senegal, signaled a softening of its stance.
Actovegin, manufactured by a Norwegian company, Nycomed, contains deproteinized extracts of calf's blood. It has been suspected of improving the circulation of oxygen in the blood in a manner similar to the banned drug EPO, or erythropoietin.
But Schamasch said Tuesday that Actovegin apparently does not transport oxygen.
"The explanation of the manufacturers is very vague,'' he said. "We have asked for more investigation to find out why athletes are taking a product which cannot transport oxygen, to find out if it has any other special effect.''
The IOC said a number of teams brought Actovegin with them to last year's Sydney Olympics, thus raising suspicions that the product could be used for unethical reasons.
The IOC is working with the world governing body of cycling, the UCI, to make a definitive ruling on Actovegin.
"According to the IOC medical code, we are entitled to ban a product either if it is performance enhancing and/or harmful to the health of the athletes,'' Schamasch said.
Armstrong and the U.S. Postal Service team have repeatedly denied using banned drugs.