How Much Protein You Actually Need To Build Muscle, Explained

Whether you're hoping to lose weight, 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.

Many experts agree that a large majority of Americans are still not eating enough protein to build and maintain muscle. So in the name of leveling the score, we spoke with nutrition experts to answer the question: Just how much protein do you actually need to build muscle?

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."

Dietary protein is also highly satiating2, which means it keeps you feeling fuller longer. This is one reason why getting enough protein every day (while eating at a caloric deficit and doing resistance training3) can help you lose fat while gaining muscle4.

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. 

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.

However, we still have a lot to learn about the role that protein plays in the aging process12, so it's best to talk to your doctor to determine the amount that is right for you.

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."

Ideally, you're completing multiple resistance workouts a week and increasing the stress you're putting on your muscles—either by doing more reps, more total sets, or using a heavier weight—every few weeks.

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 day14, and aiming to get approximately 25 to 30 grams of high-quality protein at each meal, is optimal for the stimulation of MPS in healthy adults.

But the range may be even greater: A study published in the Journal of the International Society of Sports Nutrition15 found that ingesting 20 to 40 grams of protein from a high-quality source every three to four hours appears to have the greatest effect on MPS rates and is associated with improved body composition and performance outcomes.

Complete proteins contain adequate amounts of all nine essential amino acids.

"This is important because we cannot create these amino acids within the body, so they must come from our diet," says Frutchey.

One amino acid—leucine—is particularly important: Layman and his colleagues found that 2.5 grams of leucine stimulate MPS after exercise16 or an overnight fast.

It's totally possible to get adequate protein on a plant-based diet, but it's important to keep in mind that it will require more diligent monitoring of your amino acids (as most plant-based foods are incomplete proteins) and total calorie intake (it often requires higher quantities of plant-based foods to fulfill protein needs). 

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. 

Here's a sample meal plan to show you what that might look like: 

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 protein24. 

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.

It's important to monitor both your sources of protein as well as how your protein intake fits into your overall calorie intake each day. 

The current research suggests that most active people could benefit from eating roughly 100 grams of protein a day from high-quality protein sources. To spur muscle growth, spread your daily protein intake evenly throughout the day—starting with a protein-rich breakfast.