Creatine: what it is for, how to take it and who may benefit

What is creatine and which foods contain it?

Creatine is a substance your body makes from three amino acids and that you also get from food. Almost all of it is stored in muscle. There, it serves as a rapid energy reserve for efforts lasting a few seconds, such as a sprint or a heavy set [2].

It is found mainly in meat and fish. About 450 g of raw beef or salmon provides 1 to 2 g of creatine [2]. With an omnivorous diet, some of what the body uses each day comes from food and it makes the rest itself [2].

That is why vegetarians and vegans tend to have less creatine in their muscles. When they supplement, their stores increase, often to levels above those of people who eat meat [4]. Studies do not agree on whether their performance improves more than other people’s [4].

What does the evidence say about performance?

Creatine is one of the best-supported sports supplements. In the European Union, an authorised claim states that it increases physical performance during successive bouts of short, high-intensity exercise [1]. The authorisation requires an intake of 3 g per day and applies to adults who do this type of exercise [1].

In sport, this means repeated efforts with short breaks. Sprints in football or basketball, long points in padel or tennis, sets of weight training or combat rounds. In these efforts, with stores full, performance usually improves by 10 to 20% [2]. Alongside strength training, it also helps increase strength and muscle mass [2]. See “Vegan diet for athletes”.

For long, continuous events such as a marathon, the authorised claim says nothing, and the benefit is much less clear. Energy intake, carbohydrates and hydration matter more there.

Creatine helps when everything else is already in place. If you eat too little or train without a plan, it will not fix that.

For the basics of what to eat to train, compete and recover, see the sports nutrition guide.

How do you take creatine, and do you need a loading phase?

The usual dose for adults is 3 to 5 g of monohydrate per day, every day [2] [6]. The Spanish food safety agency considers up to 3 g per day safe as a supplement for healthy adults [5]. The European performance claim sets conditions for use [1].

The loading phase involves taking about 20 g per day, divided into four servings, for five to seven days [2]. This fills stores within a week. With 3 g per day, you reach the same point in about four weeks [2] [3].

Both approaches lead to the same result; only the timing differs. That is why we almost never recommend loading. It exceeds the amount considered safe as a supplement [5] and brings forward the water-related weight increase [3]. It may make sense if a competition is coming up, and your dietitian decides whether it is appropriate.

Does creatine cause water retention and weight gain?

Yes, at first. Creatine draws water into the muscle, and the scales may show an increase of up to 1 or 2 kg [3]. This water retention is water inside the muscle, not fat.

In longer studies, total body water does not end up higher than without creatine [6]. If you stop taking it, that extra weight goes away over four to six weeks [3].

This matters especially in sports with a weight category. If you have a weigh-in coming up, those kilos count. For guidance on planning weight for competition, see the martial arts diet.

Is it safe for the kidneys?

In healthy people following an appropriate plan, creatine does not damage the kidneys [6]. An analysis that brought together the available trials found no changes in blood creatinine or urea, two markers of how the kidneys filter blood [7]. There is also no evidence that it causes hair loss, another question that often comes up in consultations [6].

Kidney disease is different. If you have kidney problems, do not take creatine [5]. Your nephrologist or dietitian will tell you how much protein, potassium, phosphorus and other ions or minerals are suitable for you, depending on your stage. We can adjust your diet for training according to their instructions. You can request this assessment from our sports nutrition team.

If you have a blood test, tell them you take it. That way, the person reviewing the results has all the relevant information.

What about older adults and women?

For older adults who do strength training, creatine adds somewhat more lean mass and strength than training alone. On average, just over 1 kg more lean mass than with placebo [8]. All the research studied creatine alongside strength training, which remains the main factor.

Research involving women is more recent. It points to improvements in strength and performance before menopause, and possible benefits for muscle and bone after menopause, always alongside training [9]. Research is ongoing, and its findings should be read with caution.

Do not take it on your own during pregnancy or while breastfeeding. And if an older adult takes several medicines or has kidney disease, they should discuss it with their doctor first.

Can children and teenagers take creatine?

We do not recommend it for anyone under 18. There is insufficient information about its safety in minors [5]. At that age, the scope for improvement lies in eating enough, sleeping well and training sensibly.

If your child competes and someone at the club has mentioned creatine, the useful conversation is about their meals and rest. There is plenty that can be adjusted there.

How do you choose a creatine product?

If your doctor or dietitian prescribes it, there are three things to check on the label.

• It should be creatine monohydrate, the most studied form [2].
• It should clearly state the amount of creatine per serving.
• It should carry a batch-testing seal from an independent anti-doping programme [3].

The seal matters especially if you compete in events with anti-doping controls. Unflavoured powder is the simplest option and dissolves in water, juice or yogurt.

The Australian Institute of Sport creatine fact sheet explains how competitive athletes use it.

What mistakes do we see in consultations?

• Starting with the tub. People come in with creatine already bought while eating less than they expend.
• Taking it only on training days. Daily intake maintains stores, including on rest days.
• Getting worried by the scales. The kilo gained in the first few weeks is water, but some people interpret it as fat.
• Expecting results without strength training. Creatine supports training; it does not replace it.

It is a conversation we have almost every week in consultations. And almost always, it ends up being about food before supplements.