How Much Protein You Actually Need To Build Muscle, Explained

Whether you're hoping to build strength, improve your performance at the gym, or simply age more gracefully, protein can help. This macronutrient is a critical building block for your body that promotes muscle growth—but only if you get enough of it, and the type you get is high-quality.

There's one thing to know right off the bat: No matter how much time you spend in the gym, you won't be able to build muscle if you don't eat protein. 

"One of the main issues I see is clients working out daily and not seeing results because they do not prioritize protein intake," says registered dietitian and certified personal trainer Brianna Frutchey, R.D., CPT.

This is because dietary protein is essential for muscle protein synthesis (MPS)—a metabolic process that involves the incorporation of amino acids into skeletal muscle to help produce new muscle proteins. "This is why we must consume adequate daily dietary protein to promote muscle growth," Frutchey says. "Without adequate protein intake, muscle protein synthesis cannot occur1 effectively and muscle growth will be limited." In order to promote MPS and build muscle, your protein needs to contain an adequate amount of leucine—more on that below.

The current Recommended Dietary Allowance (RDA) for protein is 0.8 grams of protein per kilogram of body weight per day (g/kg). For a 130-pound individual, that would be approximately 47 grams of protein per day.

But it's important to understand that the RDA is defined as the minimum allowance to prevent deficiencies in nearly all healthy people. 

​​"Nobody I know is after minimum health. We're after optimum health," Don Layman, Ph.D., one of the world's leading protein researchers, previously told mindbodygreen.

The exact amount of protein you need depends on many factors, including activity level, age, muscle mass, and overall health. Layman, like many experts in his field, recommends most individuals aim to get at least 100 grams of protein per day.

"We find from a metabolic standpoint, working predominantly with women, that if they get below 100 grams per day, they lose most of the benefits of protein: fatty acid metabolism, insulin sensitivity, weight loss, satiety," Layman says.

If your goal is building muscle, researchers recommend5 aiming for a target intake of 0.4 gram per kilogram body weight per meal (across a minimum of four meals) in order to reach a minimum of 1.6 grams per kilogram body weight per day. According to their research, this can be safely scaled to a daily intake of 2.2 grams per kilogram of body weight.

By this logic, the same 130-pound individual actually needs a range of 94 to 130 grams of protein per day to build muscle. This protein should have at least 2.5 grams of leucine per serving.

Over the decades, our body's ability to efficiently convert dietary protein into muscle6 begins to decline. This can lead to a decrease in muscle mass, strength, and function—a condition known as sarcopenia7. Muscle loss can greatly impact quality of life8, and it's a major risk factor for increased frailty, falls, and fractures9 among older adults. This makes staying on top of protein consumption10 even more important as we age.

According to a study published in Nutrients11, a protein intake of 1.0 to 1.2 grams per kilogram body weight per day has been recommended for the preservation of healthy aging muscles, while 1.2 to 1.5 grams per kilogram body weight per day may be necessary for older patients with acute or chronic diseases.

Earlier we said that you can't build muscle without dietary protein. Well, you can't build it without exercise, either. The two go hand in hand.

Resistance training serves to stress and break down your muscle fibers, and it's through the body's recovery process that muscles become stronger.

"This is done through a cellular process where muscle fibers become fused together in order to form new muscle protein strands that are called myofibrils," Frutchey explains. "These repaired myofibrils increase in thickness and number to create growth—known as muscle hypertrophy13."

It's important to keep in mind that this growth can only happen when sufficient tension is put on your muscles, says Frutchey. "If we are continuously lifting the same amount of weight at the same amount of reps each week, muscle growth will plateau."

Complete proteins contain adequate amounts of all nine essential amino acids. One amino acid—leucine—is particularly important: Layman and his colleagues found that 2.5 grams of leucine stimulate MPS after exercise14 or an overnight fast. If you don’t hit this leucine threshold, your protein isn't helping you put on muscle.

OK, now you get that eating ample protein is important, especially if you're trying to build muscle. But it's not just your total daily intake that matters—frequency and timing play an important role, too. 

It has been shown that splitting up your protein intake throughout the day17, and aiming to get approximately 25 to 30 grams of high-quality protein at each meal with 2.5 grams of leucine, is optimal for the stimulation of MPS in healthy adults.

Remember, spreading your protein more evenly throughout the day (aiming for ~30 grams of protein per meal or snack) is not only an easier way to hit your daily goals—it's also a more effective way to build muscle. 

Eating up to 2.2 grams per kilogram body weight of protein per day has limited risks for healthy individuals, but check with your doctor about any concerns you have before starting a higher protein diet. They can help identify any risks and cater daily protein recommendations for your individual needs. 

While the risk of side effects from eating more protein is low in otherwise healthy people, researchers advise patients with renal dysfunction and gout to avoid excessive amounts of protein19. 

It's also important to keep in mind that if your goal is weight loss, eating too much protein might work against your efforts. Calories from protein are still calories, after all. If you're consuming an excess of calories per day, no matter their source, it will be harder for you to lose weight.