In healthy men over 65, doing resistance exercises without any HMB-free acid supplements leads to measurable increases in muscle strength, muscle size, and lean tissue in the thighs after six weeks.

For older men doing strength training, taking HMB-free acid supplements does not lead to greater increases in muscle strength, muscle size, or maximum force production than taking a placebo over six weeks.

In older men doing strength training, taking HMB-free acid supplements for six weeks did not lead to measurable improvements in strength, muscle size, or maximum force production compared to a placebo, even if there was a slight increase in lean mass.

In older men, doing resistance exercises such as weightlifting increased muscle strength, muscle size, and lean tissue in the thighs, even without taking HMB supplements, indicating that the exercise itself was the main factor driving these changes.

In healthy men aged 67 to 69, taking 3 grams of HMB-free acid daily while doing strength training led to a slightly greater increase in thigh muscle mass compared to a placebo, though the difference was not large enough to be considered statistically certain.

In healthy men aged 67 to 69 who are doing progressive strength training for six weeks, taking 3 grams of HMB-free acid daily might be linked to a small increase in thigh muscle mass compared to a placebo, but this effect was not seen consistently in other muscle measurements or function tests.