A mineral involved in muscle development, muscle is essential for reproductive function in men of every age and activity level. One study that compared athletes to non-active individuals found that supplementing with 22 mg magnesium per pound of body weight of the course of four weeks raised testosterone levels in both groups. And two separate studies, one on a group of men over the age of 65 and a second on a younger 18-30 year old cohort, present the same conclusion: levels of testosterone (and muscle strength) are directly correlated to the levels of magnesium in the body. These are the 9 Foods That Are Best For Magnesium!