New research suggests healthy estrogen levels are just as important for men as regular levels of testosterone are, NBC News reported.

Researchers from Massachusetts General Hospital in Boston found a lack of estrogen in men who also had low testosterone levels caused accumulation of body fat. The increased body, of course, leads to a higher risk of cardiovascular disease and diabetes.

The researchers also found that low estrogen contributes to decreased libido and a lack of a sex drive, which was solely blamed on low testosterone, or "low T."

Brad Anawalt, an endocrinologist at the University of Washington's Department of Medicine, who was not involved with the study, told NBC News the study is "mind bender." If the research can further solidified, it could change the way doctors prescribe hormones for men.

"When you lose estrogen, it's all bad," endocrinologist and lead author of the study Joel Finkelstein said. "With estrogen loss you get fat accumulation, loss of libido, bone loss."

For the study, the researchers tracked 400 healthy men over 16 weeks using intermediary scans, surveys and strength tests. The participants were all aged 20 to 50 years old and were split into two groups.

One group was given an increasing dosage of a drug to lower estrogen and testosterone levels, while the other was given the same drug, only with a placebo testosterone replacement.

The men whose testosterone was unaffected by the placebo and whose estrogen was still lowered experienced body fat accumulation and erectile dysfunction.

While the study gave the researchers evidence for younger and middle-aged men, they were left wondering about older men. They plan to repeat the study for men aged 60 years and up.

"What do we do about men as they age into their 60s, 70s, 80s? Is it helpful or harmful? Both? Neither? We don't know," Finkelstein said.

Men make most of their body's estrogen by converting testosterone using an enzyme called aromatase. When a man's testosterone drops, so does his estrogen. As it does in post-menopausal women, a lack of estrogen weakens a man's bones, but testosterone loss can also decrease in lean muscle mass, muscle size and strength.

In some cases, Anawalt said, a man's loss of muscle size and strength is just related to aging. Despite the study, doctors may still be wary of prescribing testosterone to older men because the effects they are experience may just be natural.

"If we cannot prove harm, and the potential benefit is sex function, perhaps lower fat accumulation, a number of doctors and patients are going to glom onto that and say it sounds like a good plan," Anawalt said. "I predict a number of us would be leery about it."