If you lift weights to build muscle, protein is the nutrient everyone talks about. And for good reason: muscle is largely made of protein, and every training session starts a repair and growth process that needs a steady supply of amino acids.
But more is not always better. Here is how much you actually need, and what else matters.
Key points
- Aim for 1.6 g of protein per kg of body weight a day (0.7 g per lb).
- Up to 2.2 g/kg (1 g per lb) covers people who respond best to more.
- Spread protein across 3–5 meals of about 0.4 g/kg each.
- Training is the signal to grow. Protein supplies the materials.
What the research says
The strongest evidence comes from a 2018 meta-analysis that pooled 49 studies and nearly 1,900 people doing resistance training. Adding protein increased gains in muscle and strength, but the benefit leveled off at around 1.6 g/kg of body weight per day. The upper end of the statistical range was 2.2 g/kg.
In practice, that gives a clear target:
| Body weight | 1.6 g/kg | 2.2 g/kg |
|---|---|---|
| 60 kg (132 lb) | 96 g | 132 g |
| 70 kg (154 lb) | 112 g | 154 g |
| 80 kg (176 lb) | 128 g | 176 g |
| 90 kg (198 lb) | 144 g | 198 g |
| 100 kg (220 lb) | 160 g | 220 g |
Use the protein calculator to get your own range, adjusted for your activity, age and body composition.
Beginners vs experienced lifters
Beginners build muscle quickly almost regardless of diet, as long as they train and eat reasonably. Protein still helps, and 1.6 g/kg is a good target from day one.
Experienced lifters gain muscle more slowly, so every factor counts for more. Aiming toward the upper half of the range is a reasonable insurance policy, especially during a diet.
Protein alone does not build muscle
Protein is the raw material. The signal to build muscle comes from resistance training that challenges your muscles and gets harder over time. Without that signal, extra protein is mostly burned for energy.
Muscle growth also needs:
- Enough calories. A small surplus makes it easier to build muscle. See how many calories to eat to gain muscle.
- Enough sleep. Seven hours or more supports recovery and muscle protein synthesis.
- Time. Measurable muscle growth takes weeks to months of consistent training.
Protein quality
Not all protein sources are equal. Animal proteins such as dairy, eggs, meat and fish contain all essential amino acids and plenty of leucine, the amino acid that switches on muscle building. About 2–3 g of leucine per meal is a useful benchmark, which most people get from 25–40 g of high-quality protein.
Plant-based diets
You can build muscle on plants. Plant proteins tend to contain less leucine and are slightly less digestible, so:
- Aim for the upper half of the range.
- Combine sources such as soy, lentils, beans, grains and seeds.
- Consider soy or pea protein powder to make targets easier.
Does timing matter?
Less than you might think. Total daily intake matters most. That said, a few habits help:
- Spread it out. Three to five protein-rich meals keep muscle building active across the day. Read how much protein per meal.
- Eat around training. Have a protein-rich meal within a few hours before or after your workout.
- Consider protein before bed. In a 12-week study, young men who had about 27.5 g of casein protein before sleep gained more muscle and strength than those who did not.
Summary
For muscle growth, eat about 1.6–2.2 g of protein per kg of body weight a day, spread across your meals, and pair it with progressive resistance training, enough calories and good sleep. Beyond that range, your training and consistency will move the needle more than extra protein.