What makes a man?

Testosterone plays a vital role in both men’s and women’s bodies. Its dominion over muscle function and a healthy sex drive are often marketed as the gauge of a guy’s essential “manliness.” Men’s fitness articles and ads for combatting “Low-T” stress the importance of avoiding testosterone “bombs” and tout many foods and supplements as T-“boosters.” But in clamoring to help readers squeeze more manpower out of maca root and egg yolks, this “bombs versus boosters” mentality can sometimes miss the point.

Dr. Daniel Caruso is a graduate of the University of Nevada medical school and a practicing endocrinologist in Reno. Endocrinologists specialize in hormone conditions and treatments, and many male patients come to him when they, or sometimes a wife or girlfriend, notice something “off.”

“Decreased stamina, decreased muscle strength, muscle mass, change in libido, sex drive—that isn’t otherwise attributable to anything else,” Caruso said. “When it’s part of the bigger picture, then it’s a pretty big indicator that there’s something wrong.”

In an effort to stave off sexual frustration or aid in their fitness goals, many men will subscribe to the newest T-boosting super-foods and avoid certain products and habits purported to sap testosterone.

For example, soy products have long been blacklisted in men’s health forums as estrogen powerhouses, but Dr. Caruso believes there is little cause for concern. “There isn’t enough estrogen in soy to make a difference,” Caruso said. “They’ve actually done formal studies looking at that, comparing testosterone levels to soy intake and didn’t see any appreciable change.”

Caruso says that many of these products rumored to increase or decrease T levels offer more of a clinical connection as opposed to hard and fast lifestyle rules. Even physical behaviors like masturbation don’t seem to have any discernible effect.

“It’s a theoretical difference,” said Caruso. “You can show it in a test-tube, you can show it in a receptor analysis, but practically speaking you can’t measure a person’s blood-level change.”

Diet and lifestyle choices are crucial in maintaining overall health, but those looking for quick hormonal fixes should focus on what Caruso considers to be the greatest threats to testosterone production: obesity and stress.

“Anything raising stress levels is going to decrease reproductive hormones,” Caruso said. “There’s always stress in life, but in terms of how you respond to it, that makes a big difference. Going out for a run instead of drinking a six-pack might be a better way to deal with the stress.”

While obesity quickens the transformation of testosterone to estrogen, chronic stress suppresses the release of hormones not immediately useful for the “fight or flight” reflex. Basically, if your body believes you are in immediate peril (even if you aren’t), you have little need for sex.

Testosterone is crucial for normal bodily functions and its absence is readily noticed in men of any age. Rather than turning to lists of do’s and do-not’s, however, men might have better luck focusing on the basics: normalizing sleep patterns, regular exercise, and avoiding unhealthy stress or coping mechanisms. And as always, consult your doctor before you take a magazine’s prescription.