How Much Protein You Need to Build Muscle

The direct answer

If you are lifting weights to build muscle, the target to use today is 1.6 grams of protein per kilogram of body weight per day, or about 0.7 grams per pound. If you weigh 180 pounds, that is about 126 grams per day. If you weigh 70 kilograms, it is about 112 grams per day. You do not need to default to 1 gram per pound unless you prefer the simplicity, are dieting hard, or have a reason to bias upward.

The useful range is 1.6 to 2.2 g/kg/day. The lower end is enough for many people who are training consistently and eating enough calories. The higher end is a safety margin for people in a calorie deficit, older lifters, people with high training volume, or people whose protein quality is lower. The point is not to chase the highest number. It is to reach the amount where protein stops being the limiting factor.

What the trials actually show

The most useful single estimate comes from a large systematic review and meta-analysis by Morton and colleagues. It included randomized trials of adults doing resistance exercise programs lasting at least 6 weeks. Protein supplementation increased gains in fat-free mass and strength, but the dose-response analysis showed a plateau around 1.6 g/kg/day. The confidence interval extended up to about 2.2 g/kg/day, which is why that upper number is often used as a practical ceiling rather than a magic threshold.1

That finding matters because it separates two questions people often merge. Protein can help you gain muscle while lifting. But more protein does not keep adding muscle indefinitely. Once daily intake is high enough, your program, effort, sleep, calories, and genetics matter more than adding another shake.

The International Society of Sports Nutrition position stand lands in a similar place. It states that 1.4 to 2.0 g/kg/day is sufficient for most exercising people to build and maintain muscle, while higher intakes, roughly 2.3 to 3.1 g/kg/day, may be useful for retaining lean mass during hypocaloric periods in resistance-trained people.2 That distinction is important. Cutting fat while trying to keep muscle is not the same problem as gaining muscle while eating at maintenance or in a surplus.

Older consensus work by Phillips and Van Loon also argued that athletes usually need more than the general adult RDA, and placed common athlete targets around 1.3 to 1.8 g/kg/day, with higher intakes during energy restriction or intense training blocks.4 Different expert groups use slightly different ranges, but they converge on the same practical message: the RDA is too low for muscle building, and 1 g/lb is usually above the minimum effective target.

What changes the answer

The first condition is body composition. If you have a higher body-fat percentage, calculating protein from total body weight can overshoot. A 260-pound beginner and a 260-pound lean bodybuilder do not have the same protein need. In that case, use goal body weight or lean body mass as the anchor. Aiming for 0.7 to 1.0 grams per pound of goal body weight is often more realistic than using current body weight.

The second condition is calorie intake. In a surplus or at maintenance, 1.6 g/kg/day is a strong target. During fat loss, especially if you are already lean, pushing closer to 2.2 g/kg/day is more defensible. The reason is not that higher protein builds more new muscle during a cut. It is that energy restriction increases the need to protect lean mass while you train.2

The third condition is age. Older adults often need a stronger protein dose per meal to maximize muscle protein synthesis, partly because muscle becomes less responsive to smaller amino acid doses with age. This does not mean older lifters need extreme daily protein. It means the daily target should be distributed in meals that are actually large enough to matter, often around 25 to 40 grams of high-quality protein per meal depending on body size and food source.2

The fourth condition is protein quality. Whey, dairy, eggs, meat, fish, and soy are rich in essential amino acids and leucine. Plant-forward diets can absolutely support muscle gain, but they may require a little more total protein or more attention to food combinations because some plant proteins are lower in one or more essential amino acids. This is a reason to aim toward the higher end of the range, not a reason to abandon plant-based eating.2

The thing you heard that matters less

The big confound is timing. Many lifters worry more about the post-workout window than the daily total. Timing is not irrelevant, but it is smaller than people think. A trial by Areta and colleagues found that, after resistance exercise, spreading 80 grams of whey as 20 grams every 3 hours stimulated muscle protein synthesis more effectively over 12 hours than very small frequent doses or two large boluses.3 That supports distribution, not panic.

A reasonable plan is simple: eat 3 to 5 protein-containing meals per day, with roughly 25 to 40 grams per meal for most adults. If you train between meals, have protein within a few hours before or after. You do not need to drink a shake in the locker room unless it helps you hit your daily target.

The other confound is the general adult RDA. The RDA is 0.8 g/kg/day, but it was designed to cover basic needs for most adults, not to optimize muscle gain in people progressively overloading squats, presses, rows, and deadlifts.⁵ Using the RDA to plan hypertrophy nutrition is asking the wrong standard to answer the wrong question.

The decision to make today

Set your protein target at 1.6 g/kg/day. If you prefer pounds, multiply body weight by 0.7. If you are dieting, older, very lean, or training hard, move toward 2.2 g/kg/day, or about 1.0 g/lb/day. Then stop optimizing the number and make it repeatable.

For a 180-pound lifter, that means a daily target of about 125 to 180 grams, with most people doing well near the lower to middle of that range. Put it into meals you can sustain: Greek yogurt and eggs, tofu and rice, chicken and potatoes, lentils plus a protein-rich side, fish tacos, a shake when food is inconvenient. The best protein target is not the highest one. It is the one that removes protein as a bottleneck while you train hard enough to give your body a reason to build muscle.