Excess in women can lead to facial hair and less feminine features. In men it can lead to too high a sex drive and increased aggression.

The balance of evidence is that meat increases testosterone, although the mechanism is not fully understood. It may have little to do with the protein, and more to do with the cholesterol content. Perhaps this is why there are conflicting views on the effects of protein on testosterone. Hormones, including testosterone, are made from cholesterol; so increasing one' s intake of cholesterol may increase one' s production of testosterone. A low cholesterol, vegetarian diet is known to lower testosterone.