What Does Creatine Do? Benefits, Side Effects & Evidence

By Alex Lawrence, qualified nutritionist · Fact-checked against sources on 30 October 2026 · Updated 30 October 2026

Creatine helps your muscles make energy faster during short, hard efforts like lifting or sprinting. Taken daily (3–5 g), it tops up your muscle stores, which in most studies leads to a little more strength and muscle when you train, with water weight as the main side effect.

It’s one of the most researched supplements there is. Below is what it is, how it works, what the evidence actually supports, and what it doesn’t.

What is creatine?

Creatine is a natural compound your body makes and also gets from food. According to the ISSN position stand, it’s made mainly in your liver and kidneys from the amino acids arginine and glycine, and it’s found mostly in red meat and seafood.

A few key facts from that position stand:

About 95% of your creatine is stored in skeletal muscle. Roughly two thirds of it is held as phosphocreatine.
You use about 1–3 g a day, and about half of that is normally replaced from your diet.
A typical diet leaves muscle stores only partly full. Vegetarians tend to have lower stores, because creatine comes mainly from meat and fish.

Supplements are usually sold as creatine monohydrate, a white, tasteless powder. It’s the same molecule your body makes, not a steroid or a hormone.

How does creatine work?

Creatine works by storing a quick back-up supply of energy in your muscles as phosphocreatine. Your muscles run on a molecule called ATP, but they only hold enough for a few seconds of all-out effort. Phosphocreatine hands its phosphate back to rebuild ATP almost instantly, using an enzyme called creatine kinase. Biochemists describe this as the “phosphocreatine circuit”, an energy buffer for tissues whose demand jumps suddenly, like muscle.

Taking creatine raises muscle creatine and phosphocreatine by about 20–40%, according to the ISSN. With fuller stores, you can usually squeeze out an extra rep or two, or recover slightly faster between sets. Over weeks of training, those extra reps add up to more strength and muscle.

That’s also why creatine helps most with short, repeated bursts (a set of squats, a sprint) and much less with long, steady exercise.

What are the benefits of creatine?

The best-supported benefit is a modest boost to strength and lean mass when you combine creatine with resistance training. Here’s how the main claims stack up.

Claim	What the evidence says	Source
More strength in the gym	Small but consistent gains, e.g. bench press, across 53 trials	Lanhers 2017
Better short, high-intensity efforts	Small benefit for repeated efforts of 30 seconds or less	Branch 2003
More lean mass with training	About 1.1 kg (2.4 lb) more on average with resistance training	Delpino 2022
Better running or swimming	Not supported: no clear effect	Branch 2003
Burns fat	Not supported: no change in absolute fat mass	Candow 2023

Strength and power

Creatine gives a small, reliable strength boost. A meta-analysis of 53 trials found it improved upper-body strength (such as bench and chest press) in efforts under 3 minutes, whatever people’s age, sex or training level. An earlier meta-analysis of 100 studies found the biggest effects for repeated, short lab-type efforts like resistance exercise, and no difference between men and women or trained and untrained people.

“Small” is the honest word here. Creatine won’t replace a good programme. If you need one, our beginner workout plan is a sensible place to start.

Muscle mass

Creatine helps you gain a little more lean mass, but only when you train. A 2022 meta-analysis of 35 trials found creatine plus resistance training added about 1.1 kg (2.4 lb) more lean mass than training alone. With no exercise, there was no meaningful effect. Gains were larger in men than in women in that analysis. Part of early “lean mass” is water held in the muscle (more on that below). Eating enough protein matters too: the protein calculator gives you a daily target.

Older adults and the brain

These are promising but less settled areas. The ISSN reports that creatine with resistance training may help older adults hold on to muscle and strength, and that it can raise brain creatine levels, with possible benefits for mental fatigue. Treat these as “being studied”, not as reasons on their own to take it.

What creatine doesn’t do

Creatine doesn’t help much with endurance and isn’t a fat burner. The Branch meta-analysis found it doesn’t appear to improve running or swimming performance. And in adults under 50 who lift, it made no difference to absolute fat mass, only a very small drop in body-fat percentage.

How much creatine should you take?

Most people should take 3–5 g of creatine monohydrate a day, every day. That’s the dose the ISSN gives for maintenance, and the 2021 ISSN review says that at 3–5 g a day your muscles reach similar levels to loading after at least 4 weeks.

Loading is optional. The fastest way to fill your stores is about 0.3 g per kg of body weight a day (around 20 g, in 4 doses) for 5–7 days, then back to 3–5 g. It gets you to the same place, just sooner.

Timing doesn’t matter much; taking it every day does. Use our creatine calculator to get your daily dose and an optional loading plan based on your weight.

Does creatine make you gain weight?

Yes, most people gain a little weight on creatine, and it’s mostly water stored in your muscles, not fat. The 2021 ISSN review notes that a loading phase typically adds 1–3 kg (2–7 lb) of body mass, mostly water. Without loading, the change is usually smaller and slower. Read the full answer in does creatine make you gain weight?

Does creatine cause hair loss?

There’s no good evidence that creatine causes hair loss. The worry comes from one small 2009 study that saw a rise in the hormone DHT but didn’t measure hair. A 2025 randomised trial that did measure hair found no difference between creatine and placebo over 12 weeks. See does creatine cause hair loss? for the full picture.

Which type of creatine is best?

Creatine monohydrate is the best choice for most people: it’s the most studied, it works, and it’s usually the cheapest. Newer forms such as creatine HCl dissolve more easily, but a review of novel creatine forms found little to no evidence that any of them work better or are safer. We compare the two in creatine HCl vs monohydrate.

Is creatine safe? Side effects

At recommended doses, creatine appears safe for healthy adults. The ISSN says studies of up to 30 g a day for 5 years found it safe and well tolerated in healthy people, and that the only consistently reported side effect is weight gain.

Stomach upset: more likely with big single doses, such as during loading. Splitting the dose helps.
Kidneys: the 2021 ISSN review found no kidney damage in healthy people at recommended doses.
Blood tests: creatine can raise blood creatinine, a marker doctors use to check kidney function, without your kidneys being harmed. Tell your doctor you take it before a kidney blood test.
Who should check first: speak to a GP or pharmacist if you’re pregnant, breastfeeding, under 18, have kidney disease or take medication.

This guide is general information, not medical advice (see our terms).

How to make creatine work for you

Creatine only works if you take it every day, so consistency beats everything else. In practice:

Take 3–5 g of creatine monohydrate daily, at whatever time you’ll remember.
Train with weights; that’s where the benefit shows up.
Expect a small, early jump on the scales and don’t panic about it.
Give it at least 4 weeks before judging it.

If you tend to forget, Get Gains has supplement tracking with reminders on its free tier, so you can tick off your daily dose and log your training and body weight in the same app.

How we wrote this: drafted with AI assistance, then fact-checked against the sources below and edited by Alex Lawrence. Read our editorial policy.