Does creatine harm you? What the evidence says about safety

For most healthy people, at the doses usually studied, creatine does not harm you. It is one of the most researched supplements in the world, and safety reviews in healthy people have found no clinically significant deviations from normal kidney, liver, heart or muscle function values ¹. That does not mean it is harmless for everyone, in any amount: there are uncomfortable but benign side effects, there are groups who should speak to a healthcare professional first, and there are situations where the most sensible thing is to stop.

This article answers the question directly and then goes deeper: what the studies measured, what is myth, what is known about the kidneys, what changes (and what does not change) when creatine comes as a gummy, and when to seek help.

What the studies say about creatine safety

Creatine monohydrate is the most studied form and the reference standard. A literature analysis concluded that no clinically significant side effects have been reported and that almost 99% of orally ingested creatine monohydrate is taken up by muscle or excreted in urine ². Another review, focused specifically on adverse effects, found no clinically significant deviations from normal kidney, liver, heart or muscle function values, although the authors note that data on the consequences of very prolonged use are lacking ¹.

There is also specific evidence in women. In a systematic review with meta-analysis that included 29 studies and 951 female participants, there were no deaths and no serious adverse events; no significant differences were found in total adverse events, gastrointestinal events or weight gain, and there was no statistically significant difference in measures of kidney or liver function ³.

An important note on context: most of these data come from short- and medium-term studies, with doses typically ranging from 3 to 5 g per day, or from shorter loading protocols. The doses used in studies are not dosing instructions.

Creatine and the kidneys: what is known today

This is the most common concern, and it is worth being precise. Creatine can slightly raise serum creatinine — the marker used to estimate kidney function — without this meaning kidney injury. A 2025 meta-analysis, which included 21 studies in the systematic review and 12 studies (177 participants in the creatine group and 263 in the control group) in the quantitative analysis, found a small but statistically significant increase in serum creatinine; this effect was significant mainly in studies with follow-up of one week or less and was not observed in follow-ups of 1 to 12 weeks ⁴.

An earlier meta-analysis, with 15 studies in the qualitative analysis and 6 in the quantitative analysis, found no significant changes in serum creatinine or plasma urea, concluding that supplementation did not induce kidney damage at the doses and durations studied ⁵.

What this means in practice: in people with healthy kidneys, the available evidence does not show kidney injury. What creatine does is raise a marker that doctors use to assess the kidney — which can cause confusion in a blood test. If you have blood tests and your doctor does not know you take creatine, tell them.

Common side effects (and usually temporary)

The effects most frequently reported in healthy people are gastrointestinal and muscle cramps, described as occasional and anecdotal in nature in the safety reviews ⁶. In the meta-analysis in women, gastrointestinal events were no more frequent with creatine than with placebo ³.

• Digestive discomfort — nausea, feeling of fullness or diarrhoea, especially when the dose is taken all at once or on an empty stomach. It usually improves by splitting the dose or taking it with a meal.
• Weight gain — partly due to intracellular water retention in muscle. In the meta-analysis in women, the weight difference was not statistically significant ³.
• Cramps — occasionally reported, but with no clear relationship demonstrated in studies ⁶.

These effects are uncomfortable, not dangerous. If they persist or bother you, reduce the dose or speak to a healthcare professional.

Who should speak to a professional before taking it

The question "does creatine harm you?" has different answers depending on the person. The safety evidence is robust in healthy adults; it is much more limited in some groups.

• Diagnosed kidney or liver disease — most safety studies were carried out in healthy people. If you have kidney disease, liver disease or diabetes, only a doctor can assess whether creatine is suitable for you.
• Pregnancy and breastfeeding — there is not enough data to confirm safety at these stages; speak to your doctor before taking it.
• Children and adolescents — long-term safety in this age group is not established. Do not give creatine to children without a healthcare professional's recommendation.
• Chronic medication — if you take medicines that affect the kidneys, such as non-steroidal anti-inflammatories used continuously or some diuretics, ask your doctor or pharmacist first. We have a dedicated article on creatine and medicines.

If you take caffeine, be aware that the evidence on a possible interaction with creatine is mixed: some studies suggest caffeine may reduce the effect of creatine and others show no difference. It is not a dangerous interaction, but it may be worth separating the times you take them. There are no known serious interactions with food or other common supplements; even so, if you take chronic medication, ask your doctor or pharmacist before adding creatine.

If you have risk factors for kidney disease (high blood pressure, diabetes, family history), a blood test before starting helps you decide with information.

Warning signs: when to stop and seek help

There are symptoms that are not normal effects and that justify stopping and contacting a healthcare professional:

• Persistent lower back pain or pain when urinating;
• Marked decrease in urine volume, frothy or bloody urine;
• Swelling in the legs, ankles or eyelids;
• Unexplained fatigue or shortness of breath;
• Allergic reaction — rash, itching, difficulty breathing (rare).

These signs can have several causes and creatine may not be any of them, but it is prudent to rule it out and be assessed.

Common myths about creatine

"Creatine damages the kidneys"

In healthy people, the evidence does not show kidney damage at the doses and durations studied ⁵⁴. What exists is a rise in the creatinine marker, which can be misinterpreted as a kidney problem.

"Creatine is a steroid"

It is not. It is a natural compound present in meat and fish and produced by the body itself. The literature analysis on creatine monohydrate reported no clinically significant side effects ².

"It only works with a loading phase of 20 g per day"

The loading phase speeds up muscle saturation, but it is not obligatory. The usual daily dose studied is 3 to 5 g. To understand the logic of dosing, see creatine daily dose.

"Creatine causes hair loss"

There is no solid evidence to support this idea; safety reviews do not identify it as an adverse effect ¹.

What changes when creatine comes as a gummy

The active substance is the same; the pharmaceutical form does not change the safety of creatine itself. What changes are the excipients and the presentation. TuttiBear Creatine Gummies provide 5000 mg of creatine monohydrate and 50 µg of vitamin B12 (2000% NRV) per 3-gummy serving, in a jar of 90 gummies. The directions on the label are to chew 3 gummies per day, preferably after a meal, without exceeding the recommended daily dose.

For comparison: trials usually use 3 to 5 g per day; Creatine Gummies provide 5000 mg (5 g) per 3-gummy serving. Remember that study doses are not dosing instructions — always follow the label.

There are specific aspects of gummies to consider:

• Polyols — the label warns that it contains polyols and that excessive consumption may have laxative effects. If you have a sensitive digestion, this can add to gastrointestinal discomfort.
• Teeth and children — the sticky texture adheres to teeth and the format can be mistaken for sweets. Keep the jar out of reach of younger children, as indicated in the product warning. In case of accidental ingestion by a child, contact a healthcare professional immediately.

If a child accidentally swallows gummies, do not wait and see: contact your doctor, pharmacist or poison information centre immediately. Keep the jar out of reach of little ones, preferably in a high cupboard.

• Vitamin B12 — vitamin B12 contributes to normal functioning of the nervous system and to normal energy-yielding metabolism ⁷.

For a more detailed comparison between formats, see creatine gummies or tablets.

What is still not known

There are honest gaps in the evidence. The safety of continuous use over decades is not established: most studies last weeks or months, and safety reviews point to the lack of long-term data ¹. There is also not enough data in people with mild undiagnosed kidney disease, nor in children and adolescents in the long term. And there are no studies directly comparing the safety of gummies with that of tablets or powder — what is known is about creatine monohydrate itself, regardless of form.

How to decide with peace of mind

If you are a healthy adult, the available evidence is reassuring: at the doses studied, creatine monohydrate has not been shown to cause kidney damage in healthy people ⁵⁴. Choose a trusted product, follow the dose on the label, drink enough water and pay attention to how you feel. If you have a health condition, take chronic medication, are pregnant or breastfeeding, or if it concerns a child, speak to a doctor or pharmacist first. If you already take creatine and have symptoms that worry you, stop and seek professional advice — your health is worth more than a supplement. To go deeper into what creatine does in the body, see how creatine works and the benefits of creatine.

Frequently asked questions

Does creatine harm your kidneys?

In healthy people, the available evidence does not show kidney damage at the doses and durations studied. Creatine can slightly raise serum creatinine, which is the marker used to estimate kidney function, without this meaning kidney injury. If you have diagnosed kidney disease or risk factors, speak to your doctor before taking it.

What are the most common side effects of creatine?

The most frequent are gastrointestinal discomfort (nausea, fullness or diarrhoea) and occasional muscle cramps. You may also notice weight gain from water retention in muscle. These effects are uncomfortable but usually temporary and tend to improve with adjustments to how you take it.

Are creatine gummies as safe as powder?

The active substance is the same, so the safety of creatine itself does not change with the format. What changes are the excipients: gummies may contain polyols, whose excessive consumption may have laxative effects, and the sticky texture adheres to teeth. There are no studies directly comparing the safety of gummies with that of tablets or powder.

Can I take creatine if I am pregnant or breastfeeding?

There is not enough data to confirm safety at these stages. The most prudent approach is not to take it without a healthcare professional's recommendation. Speak to your doctor or pharmacist before starting any supplement during pregnancy or breastfeeding.

Does creatine cause hair loss?

There is no solid evidence to support this idea. Safety reviews of creatine do not identify hair loss as an adverse effect. It is a myth that circulates mainly from interpretations of older studies that have not been confirmed.

When should I stop taking creatine and seek help?

You should stop and contact a healthcare professional if you have persistent lower back pain, decreased urine volume, frothy or bloody urine, swelling in the legs or ankles, unexplained fatigue or signs of an allergic reaction. These symptoms can have several causes, but it is prudent to be assessed.