Most people benefit from 20 to 40 grams of protein after a workout, depending on body size. A more precise target is about 0.31 grams per kilogram of body weight, which works out to roughly 25 grams for a 175-pound person. That’s enough to maximize the muscle repair process without wasting excess protein through oxidation.
The Weight-Based Formula
Flat recommendations like “eat 30 grams” don’t account for the difference between a 130-pound runner and a 220-pound lifter. Research published in Frontiers in Nutrition found that muscle protein synthesis after resistance exercise peaks at about 0.31 g of protein per kilogram of body weight. To build in a safety margin for individual variation, the upper useful limit lands around 0.39 g/kg.
Here’s what that looks like in practice:
- 130 lbs (59 kg): 18–23 g protein
- 155 lbs (70 kg): 22–27 g protein
- 180 lbs (82 kg): 25–32 g protein
- 210 lbs (95 kg): 29–37 g protein
These numbers assume a high-quality, fast-digesting protein source like whey, eggs, or lean meat. If you’re using a plant-based protein, you may need to aim toward the higher end or slightly above it (more on that below).
Why More Isn’t Always Better
There’s a ceiling to how much protein your muscles can use from a single meal. Studies consistently show a graded increase in muscle repair as protein intake rises, but only up to a point. One well-known study found that 30 grams of beef protein was enough to fully stimulate muscle protein synthesis, and doubling the portion to 60 grams didn’t improve the response at all. The extra amino acids are simply oxidized for energy, essentially burned as fuel rather than built into muscle.
That said, there’s a practical wrinkle. Some data suggests the response can plateau at different thresholds depending on how your overall diet is structured. People who spread their protein across multiple meals saw the benefit cap out around 30 grams per meal, while those eating fewer high-protein meals saw it stretch closer to 45 grams. So if you only eat two or three meals a day, a slightly larger post-workout serving makes sense.
Timing Matters Less Than You Think
The idea of a strict 30-minute “anabolic window” after exercise is one of the most persistent myths in fitness nutrition. A 2013 meta-analysis of 43 studies found no strong link between immediate post-workout protein intake and greater muscle growth or strength gains. Other research showed that people who consumed protein just before exercise had similar muscle protein synthesis to those who ate it an hour after.
What does matter is getting protein somewhere in the few hours surrounding your workout, whether that’s a meal beforehand, a shake right after, or lunch an hour later. If you train fasted first thing in the morning, eating sooner after your session is more important because your body hasn’t had amino acids available for several hours. If you had a protein-rich meal an hour or two before training, there’s less urgency.
The biggest factor isn’t timing at all. Total daily protein intake has a larger effect on muscle growth and recovery than when exactly you eat it. For active people, that daily target falls between 1.2 and 1.7 grams per kilogram of body weight, spread across your meals.
Older Adults Need More Per Serving
If you’re over 60, the standard 20-gram post-workout target probably isn’t enough. Aging muscles develop what researchers call anabolic resistance: they become less responsive to the signals that dietary protein sends to trigger repair. In younger adults, muscle protein synthesis maxes out at about 20 grams after exercise. In older adults, muscles continue responding to higher doses, with 40 grams producing a meaningfully greater effect than 20.
This means older exercisers should aim for the higher end of the range, roughly 35 to 40 grams of high-quality protein after resistance training, and prioritize protein sources rich in leucine, the amino acid that acts as the primary trigger for muscle building. Getting at least 2.5 to 3 grams of leucine per meal appears to be especially important for overcoming that age-related resistance.
Protein Source Makes a Difference
Not all protein sources stimulate muscle repair equally, and leucine content is a big reason why. Whey protein contains about 13.6% leucine by weight, nearly double the 7.8–8.0% found in pea and soy protein. Because leucine is the key amino acid that kicks off the muscle-building process, plant-based proteins tend to produce a weaker post-exercise response gram for gram.
That doesn’t mean plant protein can’t work. It means you likely need a larger serving to hit the same leucine threshold. If 25 grams of whey gets the job done, you might need 35 to 40 grams of pea or soy protein to match the effect. Blending plant sources (combining rice and pea protein, for instance) can also help fill in amino acid gaps.
Whole Foods vs. Protein Powder
Protein powder is convenient, but whole foods offer something supplements can’t replicate. Research from the Gatorade Sports Science Institute found that whole food sources like eggs, milk, and meat produce a slower, more sustained release of amino acids into the bloodstream, lasting over five hours compared to the sharp spike from an isolated powder. That prolonged availability may actually support muscle repair more effectively over time.
One striking example: whole eggs stimulate significantly more post-exercise muscle protein synthesis than an equivalent amount of protein from egg whites alone, even though the protein content is matched. The fats, vitamins, and other nutrients in the yolk appear to enhance how the body uses those amino acids. Whole milk shows a similar advantage over skim milk.
Protein powders aren’t required to get a strong post-workout response. A chicken breast, a few eggs, Greek yogurt, or a glass of milk will do the job. Powders are useful when whole food isn’t practical, like when you’re rushing from the gym to work, but they’re a convenience tool, not a superior one.