Most people looking to build muscle need between 1.4 and 2.0 grams of protein per kilogram of body weight per day. For a 180-pound (82 kg) person, that works out to roughly 115 to 164 grams daily. The exact number depends on your training experience, age, and whether you’re eating in a caloric deficit.
The Daily Target That Actually Matters
The International Society of Sports Nutrition recommends 1.4 to 2.0 g/kg/day for most people who exercise regularly. A large meta-analysis published in the British Journal of Sports Medicine found that protein supplementation stops producing additional muscle gains at around 1.6 g/kg/day for younger adults. That’s a useful middle target: enough to maximize growth for most people without overthinking it.
To put that in practical terms:
- 150 lb (68 kg) person: 95 to 136 g of protein per day
- 180 lb (82 kg) person: 115 to 164 g of protein per day
- 220 lb (100 kg) person: 140 to 200 g of protein per day
Competitive bodybuilders often go higher. Research using advanced measurement techniques found that male bodybuilders needed about 2.2 g/kg/day even on non-training days. If you’re not competing, that level of intake is unlikely to provide meaningful additional muscle growth, though very high intakes (above 3.0 g/kg/day) may help with fat loss in resistance-trained individuals.
How to Spread Protein Across Meals
Your body can only use so much protein at once to build muscle. The muscle-building response to a meal ramps up as protein intake increases, then plateaus. Research shows that 30 to 45 grams of protein per meal produces the strongest association with lean mass and strength. A general guideline is about 0.25 g/kg of body weight per serving, which lands most people in that 20 to 40 gram range.
Spacing these doses every three to four hours across the day keeps the muscle-building signal elevated more consistently than loading all your protein into one or two meals. For someone aiming for 160 grams daily, that could look like four meals of 40 grams each. A protein-rich snack before bed (30 to 40 grams, ideally from a slow-digesting source like casein) has been shown to increase overnight muscle protein synthesis and metabolic rate.
Timing Around Workouts Is Overrated
The idea that you need a protein shake within 30 minutes of your last set is one of the most persistent gym beliefs, and the evidence doesn’t support it. When researchers tested whether post-exercise protein dose influenced muscle gain over weeks of training, it had no significant effect. What mattered was hitting total daily protein and distributing it reasonably across meals.
The muscle-building effect of a single workout lasts at least 24 hours, gradually tapering off. So whether you have your protein an hour before or two hours after training, the difference is negligible. Eat when it’s convenient for you.
Why Protein Source Matters
Not all protein is created equal for muscle growth. Animal proteins (meat, dairy, eggs) generally have a higher digestibility score and a more complete profile of essential amino acids than plant proteins. A key driver is leucine, an amino acid that acts as a trigger for the muscle-building process. You need roughly 2 to 3 grams of leucine in a meal to fully activate that signal, and animal proteins deliver that more easily per serving.
A 2024 meta-analysis in Nutrition Reviews pooling data from randomized controlled trials found that animal protein produced modestly greater muscle mass gains than plant protein overall. The gap was most pronounced when comparing animal protein to non-soy plant sources like rice, oat, or potato protein. Soy protein, however, performed nearly identically to milk protein for muscle mass across 17 trials.
Interestingly, there was no difference in muscle strength between plant and animal protein groups in younger adults. The practical takeaway: if you eat a plant-based diet, prioritize soy-based proteins and aim for slightly higher total intake to compensate for lower digestibility. Blending multiple plant sources can also help fill amino acid gaps.
Cutting Weight Without Losing Muscle
When you’re eating fewer calories than you burn, your body is more likely to break down muscle for energy. Higher protein intake counteracts this. During a caloric deficit, resistance-trained athletes benefit from 1.8 to 2.7 g/kg/day, well above the standard recommendation. Even for recreational lifters, staying at the upper end of the 1.4 to 2.0 range helps preserve the muscle you’ve already built.
This is one of the few situations where going above 2.0 g/kg/day has clear justification. The caloric deficit itself creates a hormonal environment that favors muscle breakdown, and extra protein provides both the raw materials and the metabolic signals to protect lean tissue.
Adjustments for Age
Adults over 65 face a double challenge: muscle mass naturally declines with age, and older muscles respond less efficiently to protein. While the official RDA remains 0.8 g/kg/day for all adults, researchers consistently recommend that older adults consume at least 1.0 to 1.2 g/kg/day just to maintain existing muscle. For active older adults trying to build muscle, aiming for the higher end of the 1.4 to 2.0 range makes sense.
Older adults also appear to need a higher leucine threshold per meal, around 3 grams, to trigger the same muscle-building response that younger people achieve with less. This means choosing leucine-rich protein sources (whey, eggs, chicken, beef) and keeping per-meal protein at 35 to 40 grams becomes more important with age.
Putting It All Together
For most people lifting weights and trying to grow muscle, the formula is straightforward. Aim for 1.6 to 2.0 g/kg of body weight per day, split across three to five meals of 30 to 45 grams each, spaced roughly every three to four hours. Prioritize high-quality protein sources rich in essential amino acids. If you’re over 65, push toward the higher end. If you’re dieting, push even higher, up to 2.2 to 2.7 g/kg/day.
Total daily intake matters far more than precise timing or the specific protein powder you choose. Get the total right, spread it reasonably across the day, and the details will take care of themselves.