Supplements for Strength Training, Graded

Quick answer

Creatine has the strongest evidence for strength training. Both of its entries are graded strong, at 3 to 8 g a day or a loading week of about 20 g. Protein is graded moderate, and in trials it added no more once total intake passed about 1.6 g per kg of body weight a day.^1,2,3

Key facts

Creatine's strength entry rests on a 2025 meta-analysis of 69 randomized trials with 1,937 people.¹
The strength gains were clearest in younger adults, men and people who already train.¹
Creatine does little for steady exercise lasting more than about two and a half minutes.²
In pooled trials, protein supplements added no more once total protein passed about 1.6 g per kg of body weight a day, and that estimate is uncertain.³
Neither creatine nor protein has a tolerable upper intake level, but both have groups who should ask a doctor first.^2,4

What the evidence shows

Three graded entries on this site qualify for strength, two for creatine and one for protein. An entry qualifies only if it is graded moderate or strong. The grade, what the studies did and the amount they used are shown with each one.

Supports muscle strength during resistance training*^1,2,5

Strong evidence

A 2025 meta-analysis of 69 randomized trials (1,937 people) found that creatine plus resistance training added about 1.4 kg to bench or chest press and 5.6 kg to squat strength over placebo. Strength gains were seen at maintenance doses of 8 g a day or less and were clearest in younger adults, men and people who already train.

Amount studied: 3 to 8 g a day, with or without a loading phase

Supports performance in repeated short bursts of high-intensity exercise, such as sets of lifts or sprints*^2,5

Strong evidence

The NIH Office of Dietary Supplements and the International Society of Sports Nutrition (ISSN) both conclude that creatine improves repeated short, intense efforts; the ISSN puts the typical improvement after a loading phase at 10 to 20 percent in such tests. Most of these studies used about 20 g a day for 5 to 7 days, which matches the label's loading phase. It is of little value for endurance events.

Amount studied: About 20 g a day for 5 to 7 days, then 3 to 5 g a day

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*³

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

Other products sold for strength are not shown here, because no graded entry for them reached the moderate grade for this goal.

How much the studies used

The two ingredients are counted differently. Creatine is a fixed daily amount that fills muscle stores over days or weeks. Protein is a share of everything you eat in a day, so the figure depends on your body weight.^2,4

About 20 g a day, split into four 5 g portions, for 5 to 7 days. Some studies set the loading amount by body weight, at 0.3 g per kg a day.^2,5

About 3 to 6 g a day, or 0.03 to 0.1 g per kg of body weight, for 3 to 4 weeks reaches the same muscle stores without a loading phase.^2,6

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.^4,7

In a pooled analysis of 49 training trials, protein supplements added no more lean mass once total protein intake passed about 1.6 g per kg of body weight a day. The estimate was uncertain, with a likely range of about 1.0 to 2.2 g per kg.³

The protein per day calculator turns the per-kilogram amounts into grams for your weight, and the creatine dose calculator does the same for creatine.

Food first

Both ingredients are in ordinary food, so look at your plate before you add a powder.⁸

Animal foods contain creatine: beef has about 2 g per pound, pork about 2.3 g and salmon about 2 g.²

Creatine in food comes only from animal foods, mainly muscle meat and fish. Vegans get none from their diet.⁹

One ounce of meat, fish or poultry, 1 large egg, a quarter cup of tofu, or half a cup of cooked beans or lentils each gives about 7 g of protein.¹⁰

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.⁸

Upper limits and who should ask first

No tolerable upper intake level is set for creatine. NIH reports few safety concerns at 20 g a day for up to 7 days followed by 3 to 5 g a day, and says use for several years appears safe in healthy adults. The ISSN reports no harm in studies using up to 30 g a day for up to 5 years.^2,5

No tolerable upper intake level has been set for protein, because the risk of harm from protein in food is very low. NIH still advises caution with high intakes from foods and supplements combined, since data are limited, and reports no safety concerns up to about 2.0 g per kg a day.⁴

You have kidney disease or reduced kidney function, or you take medicines that affect the kidneys. Ask before using creatine or raising protein.
You have a kidney blood test coming up. Creatine raises creatinine, the marker that test measures.¹¹
You are pregnant, nursing or under 18.
You are allergic to milk, soy, peanuts, peas, lentils or other legumes, or to yeast, and your protein powder is made from them.
You already use one creatine product. A second one on the same day only doubles the dose.

Questions people ask

Is creatine or protein better for getting stronger?

They answer different questions. Creatine's strength entries are graded strong and protein's is graded moderate. Protein only adds when your usual intake is low, because trials found no further gain once total intake passed about 1.6 g per kg of body weight a day.^1,3

Does it matter when I take creatine?

Trials that gave creatine just before or just after weight training found similar strength gains, so taking it regularly mattered more than the clock.^12,13,14,15

Do I need a loading week for creatine?

No. The loading amount of about 20 g a day for 5 to 7 days is optional, because about 3 to 6 g a day reaches the same muscle stores in 3 to 4 weeks.^2,5,6

Is creatine safe for my kidneys?

NIH reports few safety concerns in healthy adults. Creatine raises creatinine on a blood test without changing estimated kidney filtration. Ask your doctor first if you have kidney disease or a kidney test coming up.^2,11

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*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.