Strength training boosts bone mass in older men with muscle loss, but adding collagen supplements doesn't make it better than just training alone.

Older men with muscle loss who do strength training and take collagen supplements gain more muscle mass (4.2 kg) than those taking a placebo (2.9 kg).

When older men with muscle loss take collagen supplements during strength training, gaining muscle is more closely linked to losing fat compared to those taking a placebo.

Older men with muscle loss who take collagen supplements during strength training lose more body fat (5.4 kg) than those taking a placebo (3.5 kg).

Middle-aged men doing strength training and taking this collagen supplement build 1.6 kg more muscle than those taking a placebo.

Doing strength training alone helps middle-aged men build stronger bones, but adding this collagen supplement doesn't make a bigger difference than a placebo or whey protein.