If you're a healthy man between 18 and 40 years old, doing strength training will help you build muscle at about the same rate no matter your exact age in that range.

If you're a guy between 18 and 40 and you start lifting weights, whether you're new to it or have been doing it for years, you probably won't gain much more muscle just because you're experienced—but the people who’ve trained the longest (4+ years) still tend to gain the most muscle, so experience doesn’t always make a clear difference.

Doing full-body strength training three times a week for three months helps older adults, even those over 85, gain about 2% more muscle — and it works just as well for the very elderly as it does for the 'younger' elderly.

If healthy guys between 18 and 40 lift weights regularly for at least two weeks up to a year, they typically gain about 1.5 kilograms of muscle—no matter what kind of weight routine they follow.

Even people in their 50s and 70s can get much stronger and activate their muscles better after 12 weeks of heavy weight training — age doesn’t stop them from improving.

When men and women in their late teens to mid-40s do strength training, they both gain muscle at about the same rate—men might gain a tiny bit more, but it’s so small it doesn’t really mean one sex builds muscle better than the other.