The Real Reason Men Build Muscle Faster Than Women

Walk into any gym, and one thing becomes obvious right away — the men are generally larger, stronger, and more muscular than the women. Sure, there are some unusually large and strong women, and some men that land on the smaller side of the spectrum. But even when a man and woman are the exact same height and weight, the man will normally have more muscle mass (via DrElist). What gives?

We can give the sex hormone testosterone most of the credit for the difference. The hormone contributes in a major way to (among other things), growth in both muscle mass and bone mass (via WebMD). Although women's bodies do produce some testosterone, their levels of the hormone are far lower — 90 percent lower on average — than men's. The hormonal difference accounts for men's ability to both build more muscle than women, and to build it faster.

Sean Fortune, a personal trainer and running coach in New York City, explains "As a trainer, I know some very strong females. But it's safe to say that, generally speaking, it's easier for men to develop not just upper-body strength, but strength in any body part, simply because of the hormonal advantage of having more testosterone."

While testosterone plays a major role in muscle mass, there's more to the structural and physiological differences between men and women than just a single hormone. Women have (and need) a higher percentage of body fat than men, to maintain optimum health. And their muscle mass tends to be more concentrated in the lower body, while for men it's greater in the upper body. Also, scientists have found more than 3000 unique genes that behave differently in women's muscles than in men's (via Livestrong).

In spite of the differences, both women and men can benefit greatly from strength training exercises. Fortune adds, "Strength training is so important in terms of building bone density and strength ... women are going to get the same results as men, just to somewhat of a lesser degree" (via WebMD).