The guide

How much protein do you need to build muscle?

By GyroscopeUpdated November 15, 202616 sources

Aim for the typical 1.2 to 1.6 g of protein per kg a day, about 100 to 130 g at 180 lb. If you lift hard and want every last bit of muscle, going up toward 2.2 g per kg, about 180 g at 180 lb, covers the top of what the trials could measure. They didn’t find more muscle past that. Lifting does most of the building, and enough protein keeps it from being held back.

Why the gym says 1 g per pound

The classic gym rule is a gram of protein per pound of body weight, which is 2.2 g per kg. A 180 lb lifter would eat 180 g a day. The food label world says 0.8 g per kg, the RDA, which is 65 g for the same person. Both numbers get quoted with total confidence, and they’re almost three times apart.

The RDA covers basic needs for nearly everyone, and it was never meant as a number for building muscle. The gym rule turns out to sit at the top end of what the research supports, which is why it keeps working for people. It’s more food than most lifters need, but healthy kidneys showed no harm in the short trials, and it gives a margin. Our gram per pound myth covers it in more detail.

What the trials found

Put together, the trials point at 1.6 as the place most of the benefit is in, with 2.2 as a margin for people who want to cover the top of the uncertainty. These reviews found no extra muscle past that.

Protein without lifting

Protein supplies the amino acids that muscle is rebuilt from every day, and lifting is the signal that tells the muscle to build more than it breaks down. How protein works walks through it.

Think of a workshop where lifting is the work order and protein is the wood. A shop that’s short of wood builds more as soon as wood arrives. A shop that already has enough mostly needs more work orders. You can see both in the Tagawa numbers. Below 1.3 g per kg, each extra 0.1 g per kg went with 0.39 kg more lean mass, and most of that came from trials where people didn’t lift, so it looks like protein filling a gap. In people who lifted, extra protein added only a little, because the lifting was already doing most of the building.

The US activity guidelines ask every adult for at least 2 days a week of muscle work. strength.guide covers how many days to lift and how to start. The 2025 GLP-1 advisory notes that higher targets “have been proposed during strength training of 1.2–1.7 g/kg body weight/day”, close to the same range.

Your numbers

These are the network’s typical ranges, the same on bodyfat.guide and tdee.guide, plus the top of the uncertainty in the 49-trial review. The meal line is 0.4 g per kg, rounded to 5.

The top of the typical range is 1.6 g per kg, which is where gains leveled off. The 2.2 column is the margin for people who want to cover the top of the uncertainty, and most lifters won’t need to reach it. To check any number someone gave you, use is my number enough?

How to split it

In 2018, Brad Schoenfeld and Alan Aragon reviewed how much protein a meal can use for muscle building, and suggested “a target intake of 0.4 g/kg/meal across a minimum of four meals”. That’s the meal line on this site, about 35 g at 180 lb.

The best test of splitting is a 2013 study by José Areta and colleagues. 24 trained young men did a leg workout, then drank 80 g of whey over 12 hours, split three ways. Four doses of 20 g built 31% more muscle protein than eight doses of 10 g, and 48% more than two doses of 40 g. It only measured one leg workout and one day.

Bigger meals aren’t wasted. In 2023, Jorn Trommelen and colleagues gave 36 young men 0, 25 or 100 g of milk protein after a whole-body workout. The 100 g dose kept muscle building going for more than 12 hours, longer than 25 g. It was one session in men, and it measured muscle building, not growth over months, but it means a big dinner still counts. Our myth on 30 g per meal has the rest.

Does timing matter?

Timing does less than the supplement aisle says. In 2013, Schoenfeld, Aragon and Krieger pooled 23 studies with 525 people. Once total protein was counted, eating it right around the workout made no difference, and the day’s total was the strongest predictor of growth. Only 3 of the studies matched totals, so the evidence is thin, but it points one way. The anabolic window myth covers it.

Bedtime protein got popular from a 2015 trial where 44 young men drank 27.5 g of protein each night for 12 weeks and gained more strength and size than a group given no protein. But the protein group also ate more protein overall, about 1.9 against 1.3 g per kg, so the trial showed that more protein helped. In 2018, a smaller trial in 13 men gave 35 g of casein either at night or during the day, with the same daily total. The results were the same.

A lifter’s day at 180 lb

Grams and calories from USDA FoodData Central, before cooking oil and vegetables. Every meal clears the 35 g meal line, and the day comes to about 2.0 g per kg, past the top of the typical range and under the 2.2 mark. Drop the shake and the three meals still come to 120.3 g, inside the typical range of 100 to 130 g.

Lean, lifting and dieting

Lean lifters cutting to get leaner are the one group where the evidence points higher. A 2014 review by Eric Helms and colleagues looked at 6 studies of trained lifters on a diet and suggested 2.3 to 3.1 g per kg of lean mass. For a 180 lb lifter at 12% bodyfat, that’s about 165 to 225 g a day. The daily range calculator shows this range when you add your bodyfat.

In a 2016 trial by Thomas Longland and colleagues, 40 young men cut calories by 40% for 4 weeks and lifted and did intervals 6 days a week. On 2.4 g per kg, they gained 1.2 kg (2.6 lb) of lean mass and lost 4.8 kg (10.6 lb) of fat. On 1.2 g per kg, lean mass rose 0.1 kg and fat fell 3.5 kg. That’s a hard diet with hard training, so it doesn’t stand for most people losing weight. Our guide to keeping muscle while you lose weight covers the rest.

Plants build muscle too

In a 2023 trial, 22 young adults lifted hard for 10 weeks on about 2 g of protein per kg a day, half on a vegan diet and half eating meat. Lean mass rose 3.1 kg vegan and 2.6 kg with meat, and thigh muscle grew 8.3% in both groups. Soy and blends close the gap best, and plant protein has the details.

Creatine is the other supplement with real evidence for lifting, and creatine.guide covers it. strength.guide answers the same question from the training side in how much protein do I need to build muscle?