How creatine works: what it does in your body

Creatine works as a fast-access energy reserve for your cells: it increases the phosphocreatine stored in muscle, which donates a phosphate to ADP to regenerate ATP in milliseconds. It is this mechanism that lets you sustain short, very intense efforts — lifting weights, sprints, jumps — for a few more reps or seconds before fatigue sets in ¹.

It is not a stimulant or a fat burner: without a training stimulus there is no performance to improve. This article explains what happens in the muscle, what the research shows (and where it has limits), who benefits most, what the label of Creatine Gummies says and when it makes sense to talk to a health professional.

What happens in the muscle when you take creatine

Muscle cells use ATP as their energy currency. When the muscle contracts, ATP loses a phosphate and becomes ADP, which can no longer directly fuel a new contraction. Creatine exists in muscle as phosphocreatine and donates its phosphate to ADP, regenerating ATP in milliseconds. It is a reserve system, not the main energy production line ².

What supplementation does is increase the amount of phosphocreatine stored in muscle. With a bigger reserve, you can sustain high-intensity efforts for longer before fatigue appears. In practice, this translates into more reps in a set, more power in a sprint or more total training volume. It is not a magic effect, but it is measurable.

There is also a secondary effect that matters to people who train: creatine pulls water into muscle cells, which can give a fuller look and, in some cases, stimulate pathways related to muscle growth. But do not confuse this with immediate lean mass gain — it is cellular hydration, not new tissue.

What the evidence shows — and where it has limits

Creatine is probably the supplement with the most consistent research in strength training. The effect on strength, power and lean mass is consistent, especially in high-intensity, short-duration exercise, and it is one of the few in sports nutrition that repeats reliably: the average effect is real, though modest ³⁴⁵.

But there are limits worth knowing. First, individual response varies. Some people respond very well and others notice no difference — genetics, diet and type of training all play a part. Second, creatine does not help with prolonged aerobic efforts, such as long runs or endurance cycling; in those cases, the energy system is different. Third, the evidence is strongest in young trained men; in women, older adults or endurance athletes, the data are less robust, although they do not indicate an absence of effect.

There is also a question science has not yet settled: the optimal dose and timing. There is no clear consensus on whether taking it before or after training makes a relevant difference. What is known is that daily consistency matters more than the exact moment. And note: creatine does not work if you do not train. It is not a stimulant or a fat burner. If there is no training stimulus, there is nothing to improve.

What the trials show in numbers

In healthy adults, the research on creatine and resistance training is relatively consistent. A meta-analysis of 23 studies in adults under 50 showed that creatine combined with resistance training increased upper-body strength by about 4.4 kg and lower-body strength by about 11.4 kg, compared with placebo ³. The sample was mostly men (20 studies with men, 2 with women and 1 mixed), and the authors noted a trend towards greater upper-body strength gains in men than in women, but the female sample was small.

In another meta-analysis, which looked at 10 studies of at least 6 weeks' duration with direct measures of hypertrophy (MRI, CT or ultrasound), the combination of creatine with resistance training showed a very small but favourable effect on muscle thickness in the upper and lower body (about 0.10 to 0.16 cm) ⁴. However, the credibility interval includes zero, so the evidence is not conclusive. In other words: the effect on muscle mass is modest and depends on training.

A meta-analysis of 12 studies in adults under 50 assessed body composition and concluded that creatine added to resistance training has a small but measurable effect on lean mass ⁵. In footballers, a 2019 meta-analysis showed that creatine may improve performance in high-intensity actions, but results vary according to the energy system involved ¹.

There is also research outside sport. A meta-analysis of 10 randomised trials in healthy people found an overall improvement in memory with creatine, but the effect was mainly in older adults (66–76 years); in younger people (11–31 years) the same was not observed ⁶. This does not mean that creatine is a "brain supplement" for everyone — it means there is a signal in specific populations.

Who it is really useful for — and who can ignore it

If you train strength, power or sports with short, intense bursts — football, basketball, martial arts, bodybuilding — creatine is probably one of the most justifiable supplements you can take. The effect is small but consistent, and the cost-benefit is usually good.

If your training is mostly aerobic, such as distance running or long-distance swimming, creatine probably will not help your performance. It may even cause a slight weight gain from water retention, which is not ideal if you need to stay light. But note: many sports are mixed, and even endurance athletes can benefit from final sprints or changes of pace.

If you are vegetarian or vegan, there is an extra point. Creatine occurs naturally in meat and fish, and people who do not eat these sources tend to have lower muscle stores. Supplementation can, in those cases, have a more noticeable effect than in someone who already eats meat regularly.

If you never train, creatine is not for you. There is no reason to take a performance supplement if there is no performance to improve. And if you have kidney or liver disease, you should talk to a doctor before any supplement — safety in people with compromised kidney function is not established.

How to use this information in practice

If you decide to try it, the simplest step is to choose a daily dose and be consistent. The typical dose is 3 to 5 grams per day. You do not need a loading phase (that 20-gram week) — the evidence shows that low doses over a few weeks reach the same result, only more slowly.

The time of day is not critical. What matters is taking it every day, even on rest days, to keep muscle levels high. You can take it with water, juice or a meal; there is no strong evidence that carbohydrates enhance absorption, despite some older studies suggesting it.

If you want to go deeper into the timing of the dose, see the guide creatine: when to take it for best results.

As for the form, creatine monohydrate is the most studied and the cheapest. Other forms, such as creatine ethyl ester or hydrochloride, have not shown clear advantages over monohydrate — they are more expensive and less researched. If you prefer gummies, check the label to confirm the dose per serving.

What the label of Creatine Gummies says

TuttiBear's Creatine Gummies provide 5000 mg (5 g) of creatine monohydrate per serving of 3 gummies, plus 50 µg of vitamin B12 (2000% of the reference intake). The directions for use state to chew 3 gummies per day, preferably after a meal, without exceeding the recommended daily dose. The product contains polyols, and excessive consumption may have laxative effects.

Comparing with the trials: many studies use doses between 3 and 5 g per day, so the dose per serving on the label is in line with that range. However, study doses are not instructions for use — you should always follow the label information. If you take other sources of creatine, add up the amounts so you do not exceed what is reasonable.

Vitamin B12 contributes to the normal functioning of the nervous system and to normal red blood cell formation ⁷. This is an authorised claim for vitamin B12, not for creatine.

Where popular claims overreach

There are three common claims that science does not support. The first is that creatine is an anabolic agent or that it builds muscle on its own. It is not. Muscle gain comes from training; creatine only lets you train a little more and, indirectly, handle more stimulus.

The second is that creatine causes visible water retention or bloating. The retention is intracellular, not subcutaneous — that is, you do not look puffy, just have more hydrated muscles. The initial weight gain of 1 to 2 kg is common and is water, not fat.

The third is that creatine damages the kidneys or liver. In healthy people, recommended doses over months have not shown relevant adverse effects. A 2019 meta-analysis, which included 15 studies in the qualitative analysis and 6 in the quantitative analysis, concluded that creatine supplementation did not induce kidney damage at the doses and durations studied, although serum creatinine and plasma urea levels showed statistically significant changes in the studies analysed ⁸. A more recent meta-analysis, from 2025, which included 12 studies (177 participants in the creatine group and 263 in the control group), found a small but statistically significant increase in serum creatinine (mean difference of 0.07 µmol/L), mainly in studies with follow-up of less than 1 week; no significant effect was observed in longer studies ⁹. This suggests that creatine may slightly increase serum creatinine without indicating kidney damage, but it is important that a doctor knows you take creatine if you have blood tests.

Long-term safety in healthy populations is reasonably established, but not absolute — so if you have any health condition, talk to a professional.

What the gummy form changes

Creatine in gummies is a practical option for those who do not like the taste or texture of powder. Bioavailability is probably similar, provided the dose is equivalent. What changes is convenience and, sometimes, the price per gram. There is no evidence that gummies are superior to powder — they are just an alternative.

If you choose gummies, pay attention to sugar and other ingredients. Some brands add flavours and sweeteners, which may be irrelevant for most people but relevant for those who control calorie intake. Always check the label for the amount of creatine per serving and the number of gummies you need to take.

In the case of TuttiBear's Creatine Gummies, the product is designed to fit into your daily routine without complications. But, as with any supplement, the effect depends on training and consistency — not on the form.

When to talk to a health professional

If you have kidney or liver disease, diabetes, uncontrolled hypertension, or if you are pregnant or breastfeeding, you should talk to a doctor before taking creatine. The same applies if you take medicines, especially those that affect kidney function. Creatine is generally well tolerated in healthy people, but safety in specific conditions is not established.

If you take medicines, talk to your doctor before starting — especially if they are drugs that affect kidney function. You can read more about creatine and medicines: interactions and safety.

If you have blood tests, tell your doctor that you take creatine, because it may slightly increase serum creatinine and be interpreted as a change in kidney function ⁹.

Creatine is one of the most honest supplements there is: it does what it promises, but within clear limits. If you train with intensity, it can be a useful addition. If you do not train, it is not for you. And if you decide to try it, choose a form that fits your routine and stay consistent. The rest is training.

Frequently asked questions

Does creatine really work?

Yes, for short, intense efforts. It increases phosphocreatine in muscle, which helps regenerate ATP more quickly. The effect is modest but consistent in strength and power training.

Do I need a loading phase?

It is not obligatory. Doses of 3 to 5 g per day over a few weeks reach the same muscle levels, only more slowly. Loading only speeds up the process.

Is creatine bad for the kidneys?

In healthy people, the evidence does not show kidney damage at the doses and durations studied. It may slightly increase serum creatinine, which does not indicate disease, but you should tell your doctor if you have blood tests.

Can I take creatine if I do not train?

You can, but you will not get performance benefits. Creatine supports training; without a stimulus, there is nothing to improve. It may still have effects in other contexts, but the evidence is strongest for performance.

Are creatine gummies as effective as powder?

There are no studies directly comparing the two forms. What matters is the total dose of creatine per day. If the gummy provides the same amount, effectiveness should be similar.

How long does it take to work?

With daily doses of 3 to 5 g, muscle levels usually stabilise after 3 to 4 weeks. With loading, it can be faster, but the final result is the same.