Creatine Side Effects: Weight Gain, Bloating, Acne and Is It Safe?

Creatine can make the number on the scale go up, usually by about 1 to 3 kg (2 to 6 pounds) in the first week if you start with a high loading amount, and less if you start at 3 to 5 g a day. That early gain is mostly water drawn into your muscles, not fat. Beyond that, creatine monohydrate is one of the most studied supplements there is, and its side effects are usually mild: water weight, bloating and an upset stomach, mostly with large single servings. This guide covers what the research says about weight gain, bloating, acne, hair loss and kidneys, whether creatine expires, and who should check with a clinician first.

It is educational, not medical advice.

Key Takeaways

• Weight gain is mostly water: a loading phase of 20 g a day for 5 to 7 days typically adds 1 to 3 kg of body weight, mostly water held in muscle. Trials lasting a week to two years did not find that creatine adds fat.
• Bloating and stomach upset are dose related: in one trial, a single 10 g serving caused diarrhea more often than two 5 g servings.
• Kidneys: a 2019 review of the studies found creatine did not harm kidney function at the amounts and durations studied, but it can raise creatinine on a blood test.
• Hair and acne: a 2025 12-week trial found no change in DHT or hair with 5 g a day. We found no controlled trials linking creatine to acne.
• Creatine powder rarely expires in practice: stored dry, creatine monohydrate showed no breakdown after more than 3 years, even at 40°C (104°F). Once mixed into liquid, it breaks down within days.
• Check first if: you have kidney disease, take medicine that affects the kidneys, are pregnant or breastfeeding, or are under 18.

Does Creatine Make You Gain Weight?

Yes, often a little, and mostly in the first week. Creatine is stored in your muscles, and it pulls water in with it. That water is inside the muscle cells, not under the skin, so it shows up on the scale more than in the mirror.

A 2021 review by an international team of creatine researchers in the Journal of the International Society of Sports Nutrition put numbers on it: a loading phase of 20 g a day for 5 to 7 days typically adds 1 to 3 kg of body mass, mostly from water. The same review noted that several training studies of 5 to 10 weeks found no long-term rise in total body water (Antonio, 2021).

You can see the short-term effect in small trials too. Young soccer players who took 0.3 g per kg of body weight a day for 7 days held about 2.3 liters more body water and weighed about 1 kg more than the placebo group (Deminice, 2016).

Is It Fat?

No. The 2021 review looked at randomized trials lasting from one week to two years and found they did not support the idea that creatine increases fat mass. Across those studies, fat mass did not change, while fat-free mass often went up (Antonio, 2021). If you train while taking creatine, part of any later gain can be muscle, since creatine helps you do more work in each session (Kreider, 2017).

Does It Happen to Everyone?

No. The gain is larger with a loading phase and smaller or absent at 3 to 5 g a day. A review of 29 studies in women found no significant difference in weight gain between creatine monohydrate and placebo (de Guingand, 2020). For more on how women respond, see our guide to creatine for women.

Situation	What to expect on the scale
Loading phase (about 20 g a day for 5 to 7 days)	Often 1 to 3 kg in the first week, mostly water in muscle
Steady 3 to 5 g a day, no loading	A smaller rise that builds more slowly, or none you notice
Weeks to months of training	Any further gain is more likely muscle than water; trials did not find more fat
Stopping creatine	Muscle creatine falls back over several weeks, and the extra water goes with it

For a week by week look at what changes on the scale and in the gym, see our guide to creatine before and after.

For how much water weight studies measured, how long it lasts and how to keep it low, see creatine water retention.

Does Creatine Make You Bloated?

It can, mainly with large single servings. In a 28-day trial in 59 male soccer players, diarrhea was reported by 55.6 percent of those taking one 10 g serving a day, compared with 28.6 percent of those taking two 5 g servings and 35 percent on placebo. The two 5 g servings were no different from placebo for digestive complaints (Ostojic, 2008).

• Keep servings to about 5 g. If you take more, split it across the day.
• Skip loading if your stomach is sensitive. 3 to 5 g a day fills your muscles more slowly, over about 3 to 4 weeks, with less water and fewer stomach complaints.
• Mix it well and take it with food or a drink. Undissolved powder is harder on the stomach.

Our guide to creatine powder vs pills vs gummies covers how form and serving size affect bloating.

How to load with less stomach upset, or skip it, is covered in our guide to the creatine loading phase.

Does Creatine Cause Acne or Hair Loss?

These two worries share one source. A small 2009 study in 20 college rugby players found that DHT, a hormone linked to hair loss and oily skin, rose by 56 percent after a week of 25 g a day of creatine and stayed 40 percent above baseline at 5 g a day (van der Merwe, 2009). It did not measure hair or skin.

A 2025 randomized trial tested the question directly. Thirty-eight resistance-trained men aged 18 to 40 took 5 g of creatine monohydrate or placebo daily for 12 weeks. There were no differences between groups in DHT, the DHT to testosterone ratio, hair density, hair count or hair thickness (Lak, 2025).

We found no controlled trials that measured acne with creatine. If you notice breakouts after starting it, it is reasonable to look at other changes made at the same time, such as a new protein powder, pre-workout or diet.

The full research on hair, including the 2025 trial, is in our guide does creatine cause hair loss?

Is Creatine Bad for Your Kidneys?

In healthy people, the research says no at usual doses. A 2019 systematic review and meta-analysis concluded that creatine supplementation did not cause kidney damage in the amounts and durations studied (de Souza e Silva, 2019). The 2017 position stand of the International Society of Sports Nutrition described short- and long-term use, up to 30 g a day for 5 years, as safe and well tolerated in healthy people (Kreider, 2017).

The confusion comes from a lab test. Your body turns creatine into creatinine, and doctors use blood creatinine to estimate kidney function. Taking creatine can raise creatinine without any change in how well your kidneys work (Antonio, 2021). If you have blood work coming up, tell your doctor you take creatine.

If you have kidney disease, reduced kidney function, or take medicine that affects the kidneys, do not start creatine without your doctor's approval.

Other Creatine Side Effects People Ask About

• Dehydration and cramps. Some athlete surveys report cramping, but those users often took far more than 5 g a day. In a season-long trial in college football players training in heat and humidity, creatine users had less cramping and fewer cases of heat illness and dehydration than non-users (Antonio, 2021). Drinking water through the day is still sensible, especially in heat.
• Peeing more. A 2025 follow-up review found no evidence that creatine itself increases urine output; the extra fluid people drink with it is the likely reason (Antonio, 2025).
• Is it a steroid? No. Creatine is made from amino acids, and your body makes about half of what it uses each day in the liver and kidneys.
• Taking too much. Large single servings mainly cause stomach upset and diarrhea. There is no benefit to going above 3 to 5 g a day once your muscles are full.

For a dosage chart by body weight and goal, see how much creatine per day.

Does Creatine Expire?

Creatine monohydrate powder is very stable when kept dry. A 2011 review in Amino Acids reported that it showed no signs of breaking down into creatinine after more than 3 years, even when stored at 40°C (104°F) (Jäger, 2011). In practice, a sealed tub kept cool and dry often stays usable well past its best-by date.

Liquid is different. The same review explains that creatine breaks down in water within days, faster in acidic drinks and warm temperatures. Mix it just before you drink it, and do not buy ready-to-drink creatine beverages that sit on a shelf. If you like to stir it into your morning coffee, see creatine and caffeine.

• Signs to throw it out: hard clumps that will not break up, an odd smell, color change, or any sign of moisture getting in.
• Storage: keep the lid closed, use a dry scoop, and store it away from humidity and heat.

Who Should Check With a Clinician First

• Kidney disease or reduced kidney function, or medicine that affects the kidneys.
• Pregnancy or breastfeeding. Research is still limited.
• Anyone under 18. Talk with a pediatrician first.
• Upcoming blood work, since creatine can raise creatinine.
• Prescription medicines or a chronic health condition.

How to Take Creatine With the Fewest Side Effects

• Use creatine monohydrate. It is the form with the most safety research, and newer forms have not been shown to be safer or more effective (Jäger, 2011).
• Take 3 to 5 g a day. This is the amount the research calls well tolerated (Antonio, 2021).
• Skip loading if you want to keep water weight and stomach upset to a minimum.
• Split anything over 5 g into smaller servings.
• Be consistent. Timing matters much less than taking it every day.

If you eat little or no meat, you may notice creatine more, since your starting levels tend to be lower; see is creatine vegan. For the brain side of creatine research, see creatine for brain health, and for the wider picture on daily energy, cellular energy and mitochondrial health. To judge any supplement's quality, our guide to reading a supplement label walks through what to check.

Coming soon from Synchronicity: our Creatine Monohydrate powder, with 5 g of creatine monohydrate in every scoop. Join the list on the product page to hear first when it launches.

Thinking about a different form, such as HCl? See creatine HCl vs monohydrate.

Frequently Asked Questions

Can creatine make you gain belly fat?

No. Randomized trials lasting from a week to two years did not find that creatine increases fat mass. Any early weight gain is mostly water stored in your muscles, not fat around your stomach.

How much weight will I gain on creatine?

With a loading phase of about 20 g a day, many people gain 1 to 3 kg in the first week, mostly water. At 3 to 5 g a day without loading, the gain is smaller and slower, and some people notice none.

Should I take creatine if I am trying to lose weight?

Creatine is not a weight loss supplement, and the scale may go up slightly from water at first. If you are tracking progress, body measurements and how your clothes fit tell you more than the scale in the first few weeks.

What happens after 1 month of creatine?

At 3 to 5 g a day, your muscle creatine stores are usually full after about 3 to 4 weeks. Any water weight has usually settled by then, and people who train often notice they can do a little more work in each session.

Does creatine bloating go away?

Usually, yes. It is most common during loading or with single servings over about 5 g. Dropping the loading phase and splitting servings often helps within days.

Is creatine safe to take every day?

For healthy adults, research supports daily use. The International Society of Sports Nutrition describes long-term use as safe and well tolerated in healthy people. Check with your doctor first if you have kidney problems.

Does creatine expire?

Dry creatine monohydrate powder is very stable and showed no breakdown after more than 3 years in testing. Once mixed into liquid it breaks down within days, so mix it right before you drink it.

Can creatine cause hair loss?

A 2025 trial of 5 g a day for 12 weeks found no change in DHT or hair measures compared with placebo. The worry comes from a small 2009 study that measured DHT but not hair.

Sources

• Antonio J, et al. Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show? J Int Soc Sports Nutr. 2021. PubMed 33557850
• Antonio J, et al. Part II. Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show? J Int Soc Sports Nutr. 2025. PubMed 39720835
• Kreider RB, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr. 2017. PubMed 28615996
• Deminice R, et al. Creatine supplementation increases total body water in soccer players: a deuterium oxide dilution study. Int J Sports Med. 2016. PubMed 26509366
• de Guingand DL, et al. Risk of adverse outcomes in females taking oral creatine monohydrate: a systematic review and meta-analysis. Nutrients. 2020. PubMed 32549301
• Ostojic SM, Ahmetovic Z. Gastrointestinal distress after creatine supplementation in athletes: are side effects dose dependent? Res Sports Med. 2008. PubMed 18373286
• van der Merwe J, et al. Three weeks of creatine monohydrate supplementation affects dihydrotestosterone to testosterone ratio in college-aged rugby players. Clin J Sport Med. 2009. PubMed 19741313
• Lak M, et al. Does creatine cause hair loss? A 12-week randomized controlled trial. J Int Soc Sports Nutr. 2025. PubMed 40265319
• de Souza e Silva A, et al. Effects of creatine supplementation on renal function: a systematic review and meta-analysis. J Ren Nutr. 2019. PubMed 31375416
• Jäger R, et al. Analysis of the efficacy, safety, and regulatory status of novel forms of creatine. Amino Acids. 2011. PubMed 21424716

These statements have not been evaluated by the Food and Drug Administration. This content is for education and is not medical advice. Our products are not intended to diagnose, treat, cure or prevent any disease. Talk with a healthcare provider before starting a new supplement if you are pregnant, breastfeeding or taking medication.