Creatine and Training: What Studies Measured

Quick answer

Creatine has been tested mostly alongside resistance training, at 3 to 5 g a day after a loading week or about 3 to 6 g a day without one. For endurance, a pooled analysis of 13 placebo-controlled trials in trained people found no significant difference in performance, and another of 19 trials found VO2max rose slightly less.^1,2,3

Key facts

NIH lists 3 to 5 g of creatine a day after a loading week, or about 3 to 6 g a day with no loading.¹
Trials that gave creatine just before or just after weight training found similar strength results.^4,5
A pooled analysis of 13 placebo-controlled trials in trained people found no significant change in endurance performance.²
In 19 randomized trials with 424 people, VO2max rose in both groups but slightly less with creatine than with placebo.³
Weight often rises by 1 to 2 kg in the first month, largely water held in muscle.¹
A review of 10 controlled trials found no evidence that creatine at recommended amounts hinders heat tolerance.⁶

Creatine and strength training: what the trials looked at

Most creatine research sits alongside resistance training, which is also called strength training or weight training. Trials usually gave creatine to people doing resistance training for several weeks and compared them with people taking a placebo, then measured strength and lean mass. What those trials found, and how strong the evidence is, is set out with grades on our creatine guide, alongside the position stand of the International Society of Sports Nutrition (ISSN). This page is about how creatine fits around training.^1,7

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.^1,7

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.^1,8

Only 58 of 656 creatine studies, about 9 percent, enrolled women alone.⁹

When to take creatine around training

Trials that gave creatine just before or just after weight training found similar gains in strength. In one 32-week trial in adults aged 50 to 71, strength rose about equally with either timing, and the group taking it after training gained more lean tissue than the placebo group.^4,5,10,11

A review of timing studies found no consensus, with some evidence leaning toward taking it after exercise and study limitations ruling out firm conclusions. Taken together, the timing studies did not show that one hour is better than another.¹²

Muscle stores drift back to their starting level about 4 to 6 weeks after stopping.⁷

Creatine and endurance training: two pooled analyses

Creatine does little for steady exercise lasting more than about two and a half minutes, which relies on a different energy system.¹

Two systematic reviews looked at endurance outcomes. One pooled 13 placebo-controlled trials in trained people and found no significant change in endurance performance after creatine monohydrate (standardized mean difference -0.07, with a confidence range from -0.32 to 0.18). The other pooled 19 randomized trials with 424 people and found that VO2max, the top rate at which the body uses oxygen, rose in both groups but rose slightly less with creatine than with placebo.^2,3

What each kind of training was measured on^2,3
Kind of training	Outcomes the trials measured	Source for what was found
Resistance training	Strength and lean mass	Graded entries on the creatine guide
Endurance training in trained people	Time trials and tests of endurance performance	13 trials: no significant change
Aerobic fitness	VO2max	19 trials: rose slightly less than with placebo

Creatine and marathon, triathlon or Ironman training

The pooled analyses were not limited to one event, so they speak to endurance performance in trained people generally, not to any single marathon, triathlon or Ironman result. If your week mixes lifting with long sessions, the lifting is where the creatine research sits. The long sessions are where it has not shown a difference.^2,3

Three practical points come from the safety entries. Body weight often rises by 1 to 2 kg in the first month, mostly water held in muscle, which is worth weighing for events where you carry your own weight over a distance. A single large serving was linked with more stomach trouble than two smaller ones. And creatine at recommended amounts did not hinder heat tolerance in a review of 10 controlled trials.^1,6,13

Weight gain of about 1 to 2 kg in the first month, largely water held in muscle; it comes on faster with loading¹

Diarrhea was more common with one 10 g serving a day (56 percent of players) than with two 5 g servings (29 percent) or placebo (35 percent) in a 28-day trial of 59 soccer players.¹³

Who should ask a doctor first

Ask your doctor before taking creatine if you have kidney disease or reduced kidney function, take medicines that affect the kidneys, are pregnant or nursing, or are under 18. Tell them before a kidney blood test, because creatine raises creatinine, the marker that test measures.^1,14

A small rise in blood creatinine on lab tests, without a change in estimated kidney filtration¹⁴

A review of 10 controlled trials found no evidence that creatine at recommended amounts hinders heat tolerance or fluid balance in athletes exercising in the heat.⁶

Nausea, diarrhea or stomach upset have been reported by some users.¹

Questions people ask

Can you take creatine during marathon training?

The pooled analyses found no significant difference in endurance performance from creatine in 13 trials, and weight often rises by 1 to 2 kg in the first month. Ask a doctor first if you have kidney problems or take medicines that affect the kidneys.^1,2

What does creatine do for triathlon or Ironman training?

Two pooled analyses of endurance outcomes, covering 13 and 19 trials, found no significant change in endurance performance and a slightly smaller rise in VO2max with creatine than with placebo. Neither was limited to one event.^2,3

How much creatine for strength training?

NIH lists 3 to 5 g a day after a loading week of about 20 g a day, or about 3 to 6 g a day with no loading. The ISSN notes that larger athletes may need 5 to 10 g.^1,7

Should creatine be taken before or after weight training?

Trials giving creatine just before or just after weight training found similar strength results, and a review found no consensus on timing, so the studies do not show that either timing is better.^4,5,12

Does creatine hurt heat tolerance on long runs?

A review of 10 controlled trials found no evidence that creatine at recommended amounts hinders heat tolerance or fluid balance in athletes exercising in the heat.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

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