April 17, 2009 --
Young women who use oral contraceptives may not get as much out of their weight lifting routine as women who are not on the pill.Scientist's presented the study at the American Physiological Society meeting and said they were surprised at the magnitude of differences in muscle gains between the two groups.
The women who weren't on the pill gained more than 60 percent greater muscle.
Women on the pill had lower levels of muscle building hormones such as testosterone and far higher levels of muscle breaking hormones such as cortisol.
Researchers aren't sure why this happens and say future studies are needed.