What should you preferably not combine with creatine?
Combining creatine with caffeine produces no additional athletic performance benefits and can cause mild gastrointestinal complaints. If you want to use both, it is better to take them separately.
Caffeine is the combination that has been studied most together with creatine, and the outcome is fairly unambiguous: the combination adds little. In a randomised crossover study with trained cyclists, creatine plus caffeine did not improve cycling performance, peak speed or total work any more than placebo. After six weeks of resistance training in 28 young adults, the combination likewise produced no additional gains in muscle mass, strength or endurance beyond either supplement on its own. In fact, creatine alone showed a small increase in muscle thickness.
Beyond the absence of benefit, there is also a concrete drawback: gastrointestinal complaints. In a randomised study in which participants loaded creatine for five days while also taking caffeine powder, four of the thirteen participants in that group reported mild stomach complaints. Nobody experienced problems with creatine alone or with creatine plus coffee. The complaints remained mild, but they provide a reason to avoid the combination if you already have stomach issues with creatine.
On the topic of cognition, there is a smaller study examining creatine nitrate and caffeine together. It found a slightly positive effect on a colour-naming test, but no improvement in athletic performance. The study included twelve participants and therefore lacks sufficient power to draw firm conclusions.
A broader risk factor is stacking multiple supplements at the same time. A review warns that the simultaneous use of various sports supplements can produce unpredictable interactions and overdose risks. In addition, a large portion of the sports supplement market is contaminated with substances that do not belong there, such as hormone-disrupting compounds, stimulants or diuretics. These do not appear on the label but can still affect your health.
Evidence based on multiple randomised studies (n=7 to n=28), a crossover study, a small cognitive study (n=12) and a systematic review of 36 cycling studies, plus a review on supplement safety. The study groups are small; for athletic performance the picture is fairly consistent, but for cognition the evidence is too limited to draw conclusions.
Which supplements are best avoided in combination with blood thinners?
Several supplements can strengthen or weaken the effect of blood thinners; always mention them to your pharmacist or doctor before you start using them.
Which supplements or medications are best not combined with NAD+?
The combination of NAD+ supplements (particularly nicotinamide) with platinum-based chemotherapy is the most concrete reason for caution; for other interactions the indications are preliminary but worth discussing with your doctor if you are using multiple substances.
Why don't doctors always recommend creatine?
Creatine monohydrate is well supported for strength sports and its safety profile in healthy adults is reassuring, but safety data for children and teenagers are lacking and some proven applications are more limited than the marketing suggests.
Do you need to do a loading phase with creatine?
A loading phase is not necessary, but it does speed up the build-up of creatine in your muscles. Choose a loading phase if you want quick results, or simply take 3-5 grams daily if you have more patience.
Does creatine work better with carbohydrates?
Carbohydrates likely increase the uptake of creatine into the muscles, but whether this also leads to better performance is not demonstrated by randomised research. Add carbohydrates if you want to load, but do not automatically count on extra training results.
Does creatine do anything to your immune system?
Creatine affects immune cells, but whether that turns out well or badly depends strongly on the situation. For healthy older adults who also do strength training there is a cautiously positive signal; if you have endometriosis or a certain type of cancer, the context is more complex and consulting your doctor is advisable.