Creatine: what it is, what it does and how to use it safely

Creatine is one of the best-known supplements among people who do strength training or high-intensity sports, yet it is still surrounded by myths. Here we explain what it is, what it can really do and what precautions to take.

What creatine is and where it is found

Creatine is a substance produced naturally by the body, mainly in the liver and kidneys, from three amino acids: arginine, glycine and methionine. Around 95% of the body's creatine is stored in the muscles, mostly in the form of phosphocreatine, and a small amount is found in the brain.

Besides what the body makes, creatine also comes from food. The main sources are:

• Beef and pork: roughly 4 to 5 g of creatine per kilo of raw meat.
• Fish: herring, salmon and tuna are among the richest.
• Chicken and other poultry: in smaller amounts.

Because cooking destroys part of the creatine and the amounts needed to fill muscle stores are high, it is hard to reach those levels through diet alone. That is why people looking for a performance effect usually turn to a supplement. Vegetarians, who get little creatine from their diet, tend to have lower stores and often notice a clearer response.

How it works in the muscle

During very short, intense efforts, such as a sprint, a jump or a set of heavy squats, the muscle uses ATP, the cell's energy molecule, as its immediate fuel. ATP stores run out within a few seconds, and this is where phosphocreatine comes in: it donates a phosphate to regenerate ATP quickly.

With more phosphocreatine available, the muscle can sustain intensity for a little longer and recovers faster between efforts. In practice, this may mean one or two extra repetitions per set, or repeated sprints with less drop in performance. Over several weeks, this small increase in training volume can contribute to gains in strength and muscle mass.

Realistic benefits

It is important to separate what is well established from what is still a promise. The most consistent effects are:

• Better performance in short, repeated efforts: weight training, sprints and stop-and-go sports such as football, tennis or basketball.
• Gains in strength and lean mass when supplementation goes hand in hand with a well-structured strength programme. Without training, creatine alone does not build muscle.
• Slightly faster recovery between sets and between sessions in some people.

Other areas, such as possible effects on cognitive function, during sleep deprivation or in age-related muscle loss, are being researched, but the results do not yet allow firm conclusions. Nor is there any basis for claiming that creatine treats cardiovascular disease or lowers blood pressure. For long endurance events, such as the marathon, the benefit is small.

It is also worth knowing that a weight gain of 1 to 2 kg in the first weeks is normal, because creatine draws water into the muscle cells. This is neither fat nor puffiness under the skin.

How it is usually taken

The most researched and most affordable form is creatine monohydrate. Other, more expensive versions have not shown clear advantages. The most common approaches in healthy adults are:

• Constant daily dose: about 3 to 5 g per day, every day. Muscle stores fill up after three to four weeks.
• Loading phase (optional): higher doses for five to seven days, split throughout the day, followed by the maintenance dose. It fills stores faster but causes more digestive discomfort in some people.

Some practical tips:

• The time of day matters little; what counts is consistency. Many people take it after training or with a meal.
• Mixing it with water, juice or a shake containing carbohydrates may improve tolerance.
• Drink enough water throughout the day, especially on training days and in hot weather.

Precautions and who should avoid it

In healthy adults, creatine in the usual amounts is considered safe. The most common unwanted effects are abdominal discomfort, nausea or diarrhoea, usually linked to large doses taken all at once. Even so, some situations call for caution:

• People with kidney or liver disease, or with abnormal kidney function tests, should only take it on medical advice.
• Pregnant or breastfeeding women and minors should seek advice before taking any supplement.
• Anyone on regular medication should check possible interactions with their doctor or pharmacist.

Creatine can slightly raise blood creatinine values, which may be mistaken for a kidney problem. If you have blood tests, it is worth telling your doctor that you are taking the supplement.

In summary

Creatine is a supplement with proven effectiveness for improving performance in short, intense efforts and for boosting the gains from strength training, but it does not work miracles: without consistent training, a balanced diet and adequate rest, the results are minimal. The monohydrate form, taken regularly, is the simplest option. This article is for information only and does not replace the advice of a doctor, dietitian or other health professional.