The common rule of thumb is that a natural male lifter can gain about 20 pounds of muscle in his first year, 10 pounds in his second, 5 in his third, and gradually less after that.
Women build muscle just as easily as men do. However, they’re usually smaller, so their average rate of muscle growth is proportionally slower. For example, if the average woman’s frame holds 2/3rds as much muscle as the average man’s, she might expect to gain 14 pounds of muscle in her first year, 7 in her second, and 3 in her third.
More controversially, you can expect to build muscle faster if you’re starting off skinny (full explanation). If you have an athletic background, you might start off more muscular, but future growth might be slower.
Perhaps most of all, your rate of muscle growth depends on how well you train and how much food you eat.
Quite a few studies have tracked muscle growth over several months. Most of those studies show guys gaining 5–10 pounds of muscle within 3–5 months. That means the average guy can expect to gain about 1–2 pounds per month, adding up to 10–20 pounds of muscle per year.
Most of those studies don’t have the participants intentionally eating in a calorie surplus. When they do, we often see much faster rates of muscle growth. For example, in a study by Ribeiro and colleagues, the participants bulking aggressively gained over 5 pounds of lean mass in a month (full explanation). Rozenek and colleagues found similar results, with the participants gaining 8 pounds of muscle in 2 months (study).
Still, on average, it’s reasonable to think that the average man could gain about 20 pounds of muscle in his first year.
This chart assumes you’re a 5’10 man with an average bone structure. If you’re shorter or have a narrower frame, you should expect to build muscle slower. If you’re taller or have a broader frame, you can expect to build muscle faster.
That initial period of rapid muscle growth is called “newbie gains.” What’s interesting, though, is that most studies on intermediate lifters see fairly impressive rates of muscle growth, too. When people double down on their efforts, stepping up their training and nutrition, they often see a new wave of muscle growth.
Also, if you’ve never trained a muscle properly, you can probably still make newbie gains in that muscle. For example, your neck muscles might grow as quickly as your biceps once did.
I think what’s happening is that the more room you have on your frame, the faster you can build muscle. That means if you’re of average height and have a normal bone structure, but you’re thinner than the average man, then you can expect to build muscle faster—sometimes much faster.
I asked the top bulking researcher, Dr. Eric Helms, about this, and I showed him my graph (above). He suspects my hunch is correct, but it’s hard to say for sure. There’s some evidence showing that underweight people build muscle faster and more leanly than average, but these weren’t lifting studies, just overfeeding studies (study).
Women Build Muscle Slightly Slower
Women build muscle just as effectively as men do, kind of (study, study). As we covered above, the more room you have on your frame, the faster you can build muscle. On average, women have proportionally smaller frames, so they tend to build muscle more slowly.
If you’re a 5’10 woman with a large frame, you can expect to build muscle as quickly as the average man. If you’re bigger, you can expect to build muscle even faster. But if you’re the average 5’4 woman, you might gain muscle at about 2/3 of the pace.
On the bright side, the smaller your frame is, the more of an effect each pound of muscle will have. Many of the best bodybuilders and strength athletes, male and female, are quite short. It tends to be an advantage.
How to Maximize Your Rate of Muscle Growth
Most people build muscle quite a bit slower than they theoretically could. Some people don’t train hard enough or eat enough food to gain more than a couple of pounds of muscle per year. It’s common to find people who’ve been lifting for 5–10 years who can still gain 10–20 pounds of muscle in a year.
If you want to maximize your rate of muscle growth, you have to do a few things:
Stimulate as much muscle growth as you can with your workouts: You can stimulate a little bit of muscle growth indirectly by doing things like cardio, callisthenics, strength training, or CrossFit. You’ll build muscle much faster if you train for it directly with hypertrophy training (aka bodybuilding).
Eat enough food: Thinner people need to gain weight to build muscle, but almost everyone builds muscle faster when they eat in a calorie surplus. You also need to eat plenty of protein, carbs, and healthy fats, all of which offer different benefits. Here’s how to set up your bulking diet.*
Get enough sleep: Once you’ve done your workouts and eaten your meals, try to get to bed early. Try to sleep reasonably well. You’ll have more energy and willpower, and you’ll build muscle faster and more leanly.
*If you’re overweight, you already have plenty of extra energy stored as body fat, so you don’t need to get as much from your diet. It often makes more sense to start with body recomposition, where you focus on burning fat to fuel muscle growth.
Shane Duquette is the co-founder of Outlift, Bony to Beastly, and Bony to Bombshell. He's a certified conditioning coach with a degree in design from York University in Toronto, Canada. He's personally gained 70 pounds and has over a decade of experience helping over 10,000 skinny people bulk up.
