Supplements for Muscle Growth, Graded

Quick answer

Protein and creatine have the most evidence for muscle growth, both graded moderate, and the trial results come from people doing resistance training. For protein, trials found no added gain once total intake passed about 1.6 g per kg of body weight a day. Magnesium has a graded entry for normal muscle function, not growth.^1,2

Key facts

The creatine entry rests on a meta-analysis of 35 randomized trials with 1,192 people. The gain was clear in men and not statistically significant in women.²
Part of creatine's early gain is water held in muscle, which is why its lean mass entry is graded moderate and not strong.²
Total daily protein predicted muscle gain better than timing: protein taken within an hour before or after exercise made no significant difference.^3,4
People who exercise regularly are advised 1.4 to 2.0 g of protein per kg of body weight a day, and adults over 65 at least 1.0 to 1.2 g.^5,6
A meta-analysis of 14 trials found no significant gains in muscle strength or power from magnesium, except in groups likely to be short of it.⁷

What the evidence shows

Four graded entries qualify for muscle: two for protein, one for creatine and one for magnesium. They are different kinds of evidence. Protein's first entry and magnesium's are well-established nutrient functions, while creatine's entry and protein's second come from pooled trials of people lifting weights.

Protein contributes to the growth and maintenance of muscle*⁴

Moderate evidence

This is a well-established nutrient function: the NIH describes protein as necessary to build, maintain and repair muscle, and the essential amino acids it supplies must come from the diet. One serving of our Plant Protein provides 20 g (vanilla) or 21 g (chocolate) of protein.

Amount studied: The RDA of 0.8 g per kg of body weight a day from all foods, and more for people who train

Extra protein supports small added gains in strength and lean mass from resistance training when your usual intake is below about 1.6 g per kg of body weight a day*¹

Moderate evidence

A meta-analysis of 49 randomized trials (1,863 people) found protein supplements added about 2.5 kg to one-rep-max strength and 0.3 kg of fat-free mass over training alone, with no further gain above about 1.6 g of protein per kg a day in total. The trials averaged 36 g of supplement a day (range 4 to 106 g) and mostly used whey or milk protein, so 20 or 21 g of a fava and yeast blend is only a partial match; hence moderate, not strong.

Amount studied: 4 to 106 g of supplemental protein a day (36 g on average) during 6 to 52 weeks of resistance training

Supports gains in lean body mass when combined with resistance training*^2,8,9

Moderate evidence

A meta-analysis of 35 randomized trials (1,192 people) found that creatine added about 1.1 kg of lean body mass when combined with resistance training, and nothing measurable without exercise. Men gained about 1.5 kg; the gain in women (about 0.3 kg) was not statistically significant, and part of the early gain is water held in muscle, so the grade is moderate.

Amount studied: 3 to 5 g a day with resistance training, often after a loading phase

Contributes to normal muscle and nerve function*^7,10,11

Moderate evidence

A long-established role of the mineral, described by NIH and included in the EU list of permitted nutrient-function statements. It does not mean extra magnesium improves performance in people who already get enough: a meta-analysis of 14 trials found no significant gains in muscle strength or power, with benefits appearing only in groups likely to be short of magnesium, such as older adults.

Amount studied: Recommended daily intake from food and supplements

How much protein, creatine and magnesium

Protein is counted in grams per kilogram of body weight, so the amount depends on you. Creatine is a flat daily amount, and magnesium has a recommended range from all sources.^5,8,12

The International Society of Sports Nutrition says 1.4 to 2.0 g of protein per kg of body weight a day is enough for most people who exercise to build and keep muscle. NIH gives a similar range for athletes, 1.2 to 2.0 g per kg.^4,5

An international expert group on protein in older people (PROT-AGE) recommends at least 1.0 to 1.2 g per kg of body weight a day for adults over 65, and 1.2 g or more for those who exercise.⁶

For people who train, the ISSN suggests about 0.25 g of high-quality protein per kg of body weight per serving, or 20 to 40 g, containing 0.7 to 3 g of leucine.⁵

3 to 5 g a day keeps muscle stores full for most people after a loading phase. The ISSN notes that larger athletes may need 5 to 10 g.^8,9

Men need 400 to 420 mg of magnesium a day from all sources.¹²

Women need 310 to 320 mg a day, and 350 to 360 mg during pregnancy.¹²

Food first

NIH says most athletes can probably get enough protein from food, so a powder fills a gap rather than starting a routine.

NIH says most athletes can probably get enough protein from food, and that protein powders and protein-fortified foods can help when they cannot. It sees no benefit in eating more than the recommended amounts.¹³

Plant foods with protein include beans such as pinto, black and kidney beans, lentils, split peas and chickpeas, tofu, tempeh and other soy foods, nuts, seeds and nut butters, and some grains such as quinoa and wheat germ.¹⁴

Essential amino acids do not have to be eaten at every meal; the balance over the whole day matters more. You do not need animal foods to get all the protein you need.¹⁴

Legumes, nuts, seeds, whole grains and green leafy vegetables such as spinach provide magnesium, as do fortified breakfast cereals, milk and yogurt.¹²

Upper limits and who should ask first

The upper limit for magnesium from supplements and medicines is 350 mg a day for adults. It does not count magnesium in food and drinks.^10,12

High-protein diets of two to three times the RDA do not appear to harm kidney function, bone health or hydration in healthy people, and trained adults eating up to about 3.3 g per kg a day for up to a year showed no change in kidney or liver markers. People with severely reduced kidney function may need to limit protein.^4,5,6

You have kidney disease or reduced kidney function. People with severely reduced kidney function may need to limit protein, and the kidneys clear magnesium.^4,10
You take an antibiotic, a bisphosphonate, a diuretic or a medicine for acid reflux, which magnesium can interact with.
You have been told to limit protein, or you take levodopa or an MAO inhibitor.
You are pregnant, nursing or under 18.

Questions people ask

How much protein do I need to build muscle?

People who exercise regularly are advised 1.4 to 2.0 g of protein per kg of body weight a day from all foods. In pooled trials, supplements added no more once total intake passed about 1.6 g per kg.^1,5

Does creatine work without lifting?

In the meta-analysis behind the lean mass entry, creatine added about 1.1 kg of lean body mass alongside resistance training and nothing measurable without exercise.²

Does it matter when I eat protein?

Total daily protein was the strongest predictor of muscle gain. Protein taken within an hour of a workout made no significant difference once other factors were controlled, and the ISSN suggests spreading servings through the day.^3,5

Can a high-protein diet harm my kidneys?

In healthy people, diets of two to three times the RDA do not appear to harm kidney function. People with severely reduced kidney function may need to limit protein, so ask your doctor first if you have kidney disease.^4,5,6

See what we make

Every product shows its whole label and what its lab report covers. The store opens soon.

See the Full Measure line

Sources

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.