Does Creatine Make You Gain Weight? Creatine Side Effects and Myths for Runners
Creatine is one of the most researched supplements in sport, yet runners are still wary of it. Most of that wariness comes from its reputation as a bodybuilding product. This article takes the common worries one at a time, starting with the one we are asked about most: weight gain. It combines our two earlier creatine myths articles.
1. “It will make me gain weight”
This one is partly true, and it is worth understanding why. Creatine draws water into muscle cells. When people start taking it, especially with a high-dose loading phase, the scale often rises by around a kilogram in the first week or two, occasionally more. That is water stored inside the muscle, not fat, and not bloating under the skin.
Why the bulking image does not apply to runners
The muscle gain associated with creatine comes from the heavy lifting and surplus calories that bodybuilders pair with it. Creatine on its own, alongside endurance training, does not turn a runner into a sprinter. If you skip the loading phase and take a steady daily dose, any change on the scale tends to be smaller and more gradual.
Does the extra water slow you down?
For most runners the change is small relative to body weight. Whether it matters depends on your goals, so trial it in a training block rather than in race week. If you stop taking creatine, the stored water returns to baseline over a few weeks.
2. “It damages your kidneys”
Creatine supplementation raises creatinine, a marker used in kidney blood tests, which can make results look worse than they are. In healthy people, research at recommended doses has not shown kidney harm. If you have kidney disease or take medication that affects the kidneys, speak to your GP first, and tell them you take creatine before any blood test.
3. “It causes hair loss”
This comes from a single small study in rugby players that reported a rise in the hormone DHT. It did not measure hair loss, and the finding has not been consistently replicated. There is currently no good evidence that creatine causes hair loss.
4. “It dehydrates you and causes cramp”
Studies have not found that creatine increases cramp or dehydration. Hydration during running still matters, so read electrolytes for UK runners for the basics.
5. “It is basically a steroid”
No. Creatine is a compound your body makes itself and that you get from meat and fish. It is not a hormone and is not on the WADA prohibited list. If you are a tested athlete, the real risk is contamination in poorly made products, which is why batch testing matters; see Cologne List vs Informed Sport.
6. “It does nothing for endurance”
The authorised claim for creatine is that it increases physical performance in successive bursts of short-term, high-intensity exercise (with a daily intake of 3g). That is relevant to runners doing strength work, hill reps and interval sessions rather than steady easy miles. We look at the wider research in creatine for runners: does it work? and how to fit it into a block in creatine and marathon training.
7. “It is only for men”
Creatine works the same way in women. See creatine for women runners.
The side effects that are actually common
- Mild stomach discomfort, usually from taking a large dose at once. Split it or take it with food.
- The initial water-weight increase described above.
Who should not take it
Anyone with kidney disease, anyone who is pregnant or breastfeeding, and under-18s should not take creatine without medical advice.
Where that leaves you
If you want to try creatine, a steady 3–5g daily with no loading phase is the simplest approach. Daily Hydrate & Perform provides 5g creatine monohydrate alongside L-glutamine and sodium in one daily drink. Comparing options? Read our best creatine for runners UK buyer’s guide.
Food supplements should not be used as a substitute for a varied, balanced diet and healthy lifestyle. Speak to your GP before taking supplements if you are pregnant, breastfeeding, on medication or have a medical condition.