Creatine: Benefits, How It Works, Side Effects and Safety
Updated: 2 days ago
Written and medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: November 2026 · How we review
Quick Answer
Creatine is a natural substance that gives the muscles quick energy, especially during short, intense exercise such as sprinting or weightlifting. About half comes from food, and the body makes the rest. As a supplement taken with regular exercise, it can help build strength and muscle. It's considered relatively safe. Talk to a provider before you start.
What the research says
Creatine boosts upper-body strength: pooling 53 placebo-controlled trials, creatine improved bench press and other upper-body strength regardless of age, sex, training level or dose (Lanhers C et al., Sports Med, 2017) [2]
It helps leg strength too: in 60 placebo-controlled trials, creatine improved squat and leg press strength for short, intense efforts lasting under 3 minutes (Lanhers C et al., Sports Med, 2015) [3]
Key takeaways
Creatine helps muscles make quick energy during intense exercise.
Your body makes about half; the rest comes from meat, seafood and milk.
Creatine monohydrate is the most common supplement.
With exercise, it can add strength and muscle mass.
Water weight gain is the most common side effect.
What is creatine?
Creatine is an amino acid compound stored mainly in your skeletal muscles. A small amount goes to your heart, brain and other tissues. Your diet usually provides about 1 to 2 grams a day. Creatine is allowed by professional sports organizations, the International Olympic Committee and the NCAA. Sources: [1]
How creatine works
Creatine supports short bursts of energy and strength.
Your muscles turn creatine into phosphocreatine.
Phosphocreatine helps make ATP, the main energy source your cells use during exercise.
Creatine may help repair small tears in muscle fibers after workouts.
It may draw water into muscle cells, which may support growth and reduce cramps. Sources: [1]
Creatine helps with quick bursts of power, but it doesn't improve aerobic endurance, such as long-distance running. Sources: [1, 3]
Possible benefits
Most research is in active adults aged 18 to 30.
Better exercise performance and faster recovery.
More muscle mass and strength when combined with weightlifting.
Fewer or less severe muscle injuries, strains and pulls.
Less dehydration and fewer muscle cramps.
Possible benefits for short-term memory and reasoning in people 60 and older.
Under study for conditions such as muscular dystrophy, Parkinson's disease, Huntington's disease, diabetes and fibromyalgia. Sources: [1]
Most muscle research is in people aged 18 to 30. There isn't enough research yet in people over 65 or with diseases that affect muscles, such as muscle atrophy. Vegetarians and vegans, who get less creatine from food, may see bigger gains. Sources: [1]
Food sources and supplements
Source | Examples |
Food | Red meat such as beef, pork and veal; fish and shellfish; milk from cows, goats or sheep |
Your body | Made in the liver, kidneys and pancreas |
Supplements | Powders, tablets, capsules, liquids and energy bars; creatine monohydrate is the most common |
Other forms of creatine don't appear to have the same benefits as creatine monohydrate. Your provider can recommend a dose and product. Sources: [1]
Side effects and safety
Side effect | Notes |
Weight gain | From water held in the muscles |
Nausea, vomiting or diarrhea | Splitting the daily amount into smaller doses may help |
Dizziness | Stop and talk to your provider |
Heavy sweating | Called hyperhidrosis |
There isn't enough safety research in pregnancy, breastfeeding, diabetes, kidney disease or liver disease, so talk to your provider first. People with bipolar disorder may have a higher risk of mania. Sources: [1]
Creatine can raise levels of creatinine, a waste product your provider uses in kidney function tests, so tell your provider you take it before any blood work.
Results and stopping
Women may gain less strength or muscle than men.
Some studies show 2 to 4 extra pounds of muscle over 4 to 12 weeks of regular exercise.
Women may gain less strength or muscle than men.
After you stop, creatine levels fall slowly over a few weeks.
You may feel tired or lose some muscle and weight at first.
Regular exercise usually keeps the strength you gained. Sources: [1]
Conclusion
Creatine is one of the most studied supplements for strength and muscle. Used with regular exercise and good nutrition, it's relatively safe for most healthy adults, but check with your provider first.
Keep learning: read about the creatine kinase test and muscle atrophy.
Frequently asked questions
What is creatine?
A natural compound that gives your muscles quick energy.
What does creatine do?
It helps muscles make energy during short, intense exercise.
What foods contain creatine?
Red meat, fish, shellfish and milk.
What is the best form of creatine?
Creatine monohydrate is the most common and best studied.
Does creatine build muscle?
With exercise, some studies show 2 to 4 extra pounds over 4 to 12 weeks.
Does creatine cause weight gain?
Yes, mainly from water held in the muscles.
Is creatine safe?
It's considered relatively safe for healthy adults.
Who should avoid creatine?
Talk to a provider first if you're pregnant or have kidney, liver or bipolar disorder.
Does creatine help endurance?
No. It helps short bursts of power, not aerobic endurance.
What happens when I stop?
Levels fall over a few weeks, but exercise helps keep your strength.
Related Reading
Muscle Atrophy: Causes, Symptoms, Testing and Treatment loss of muscle mass and strength.
Creatine Kinase (CK) Test: What It Is, Normal Levels and High CK Causes a blood test for muscle damage.
Kidney Function Tests: Types, Normal eGFR by Age and What Results Mean tests that measure creatinine.
Probiotics: Benefits, Types, Foods and Side Effects another popular supplement and how it works.
References
Cleveland Clinic. Creatine: What It Does, Benefits, Supplements & Safety. Cleveland Clinic. Last updated April 26, 2023. https://my.clevelandclinic.org/health/treatments/17674-creatine
Lanhers C, Pereira B, Naughton G, et al. Creatine supplementation and upper limb strength performance: a systematic review and meta-analysis. Sports Med. 2017;47(1):163-173. PMID 27328852. https://doi.org/10.1007/s40279-016-0571-4
Lanhers C, Pereira B, Naughton G, et al. Creatine supplementation and lower limb strength performance: a systematic review and meta-analyses. Sports Med. 2015;45(9):1285-1294. PMID 25946994. https://doi.org/10.1007/s40279-015-0337-4
Medical disclaimer
This article is for general education only and does not replace advice from a qualified healthcare professional. Talk to your doctor about your own diagnosis and treatment, and seek emergency care right away for severe or sudden symptoms.
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