What supplements should not be taken with creatine?

Open the register and find it nearly empty: why creatine interacts with almost nothing, the one disputed entry for caffeine and what the trials actually found, and the fix

What supplements should not be taken with creatine is a question that expects a list and gets a register with almost nothing in it, and the emptiness is the answer. Interactions between supplements happen through a small number of mechanisms: two minerals competing for the same absorption route, a compound binding another in the gut, two products with the same pharmacological action stacking into an excess, or a herb altering the enzymes that clear a medicine. Creatine does none of these. It is an amino acid derivative the body makes in the liver and kidneys and eats in meat and fish, it is absorbed by its own transporter rather than by the mineral routes, it binds nothing in the gut, it has no pharmacological action to stack with anything, and it does not touch the liver enzymes that herb-drug interactions run through. A person who opens the interaction register for creatine finds one disputed entry, one caution that is about the person rather than about any supplement, and zero bans, and the rest of this page is about those three things and then about the shorter, more useful list of what to take alongside it.

The disputed entry is caffeine. An early study found that volunteers who took caffeine daily alongside a creatine loading phase did not show the improvement in repeated high-intensity performance that the creatine-only group showed, and that finding has been repeated in gyms for thirty years as the rule that caffeine cancels creatine. The later work did not consistently reproduce it. Several trials found that caffeine taken before a session improved performance in people who were already saturated with creatine, that the two together improved performance more than either alone in some protocols, and that the one reliable effect of taking both in a single large dose was stomach discomfort in some people. The reviews conclude that if the interaction is real it is small, that it may have depended on the daily caffeine habit during loading rather than on a pre-session dose, and that it remains unresolved. The practical reading for a lifter is not to choose between them, since both have authorised claims and both work, but to separate them: creatine with a meal, caffeine before the session, a few hours apart, which removes the stomach problem and any plausible version of the blunting without giving either up. A lifter who has been told to drop their morning coffee for the sake of their creatine has been given a rule the evidence does not support.

The one thing the caffeine entry does illustrate is how the register should be read. A single early study, not reproduced, becomes a gym rule because it is memorable and because the mechanism sounded plausible, and the rule outlives the evidence. The same pattern produced the belief that creatine and protein should not be taken together, for which there was never a study at all, and the belief that creatine should not be taken with acidic drinks, which is a stability question about the glass rather than an interaction question about the body and is covered on the page on what to mix it with. The register is read from the trials, not from the changing room.

One disputed entry resolved by a few hours, and the one caution, the zero bans, and the list worth having, which is the next section.

The one caution, which is about the person and not any supplement; the zero bans and why; the creatinine artefact to warn a doctor about; the shorter list of what to take alongside creatine; the worked example; and the verdict

The one caution in the register is not an interaction with a supplement but a note about the organ. Creatine is cleared by the kidneys, and the long-term trials measuring kidney filtration directly in healthy adults at the recommended doses found no impairment, which settles the question for the healthy. For a person whose kidney function is already reduced, who has a kidney condition, or who takes medicines that affect the kidney, the question is different, not because creatine interacts with their medicine but because adding any load to a compromised organ is a decision made with the doctor who knows the organ, and the same caution applies to combining creatine with high-dose anti-inflammatory medicine over long periods, or with aggressive dehydration for a weight cut, both of which load the kidney independently. A healthy lifter has nothing in this entry; a lifter with a kidney history has a conversation before the first dose.

The zero bans deserve a sentence each for the pairings a lifter is most likely to have been warned about. Protein: no interaction, and taking them together is the recommendation, since the amino acids and the insulin response of a protein and carbohydrate meal help the muscle take creatine up. Beta-alanine: no interaction, both have evidence in high-intensity work and are commonly trialled together. Magnesium, zinc and other minerals: no interaction, creatine does not use the mineral absorption routes, and this site's worked example sits in the same cupboard without a note. Omega-3, vitamin D, a multivitamin: no interaction. Pre-workout blends: the only question is the caffeine content, which is the disputed entry already covered, and the stomach, which is settled by not taking a large dose of everything at once. Diuretic herbs sold for water loss: no interaction with creatine, but the dehydration they aim for is the kidney caution in another form, and a lifter who is cutting water should not be adding kidney load from any direction.

One artefact is worth knowing before a blood test. Creatine is broken down to creatinine, and creatinine in the blood is the marker doctors use to estimate kidney function, so a lifter taking creatine will often show a creatinine reading slightly above the reference range with kidneys that are working perfectly, because the supplement has raised the marker rather than impaired the organ. A lifter tells the doctor ordering the test that they take creatine, so that the reading is interpreted correctly or a different measure is used, and does not stop taking it secretly before the test, which hides the context rather than the problem.

The shorter list is what to take alongside creatine. Protein at the intake the lifting guidance recommends, around 1.6g per kilogram a day, because the adaptation creatine supports is built from it. A meal, because the carbohydrate and protein response increases uptake into the muscle and the question of a special sugar drink is answered by the plate. The daily dose itself, 3 to 5g every day including rest days, because the effect comes from saturated muscle stores rather than from timing. And the training, which is the thing creatine makes slightly more productive and without which it does nothing measurable. The worked example sits in the same cupboard as all of this: {FL}, 1500mg magnesium bisglycinate stated as 300mg elemental at 80% NRV, two capsules with the evening meal, authorised for normal muscle function, normal protein synthesis and electrolyte balance, batch tested for lead, mercury, arsenic and cadmium, UK made, 180 capsules for £19.99 at 22p a day, taken for a short plate alongside creatine with no interaction between them. The full label breakdown is here.

The verdict: almost no supplement should not be taken with creatine. Separate it from caffeine by a few hours to settle a disputed and probably small interaction and to spare the stomach, ask a doctor first if the kidneys are compromised or medicated, tell any doctor ordering a blood test that creatine is being taken, and otherwise take it with a meal, with protein, every day, and train.

What to check on the label

Questions people also ask

Does caffeine cancel out creatine?

The rule comes from one early study in which volunteers taking caffeine daily alongside a creatine loading phase did not show the performance improvement the creatine-only group showed, and later trials did not consistently reproduce it, several finding that caffeine before a session improved performance in people already saturated with creatine and that the two together improved it more than either alone; the one reliable effect of taking both in a single large dose was stomach discomfort, so the fix is to take creatine with a meal and caffeine before the session, a few hours apart, rather than to give either up.

Can I take creatine with protein powder?

Yes, and it is the recommendation rather than a risk: there was never a study showing a problem, and the amino acids and insulin response of a protein and carbohydrate meal increase the muscle's uptake of creatine, so the daily 3 to 5g goes with a meal or a shake, with protein kept at around 1.6g per kilogram a day because the adaptation creatine supports is built from it; the belief that the two should be separated is a changing-room rule with no trial behind it.

Is creatine bad for your kidneys?

In healthy adults at the recommended doses the long-term trials measuring kidney filtration directly found no impairment, which settles the question for the healthy; a person whose kidney function is already reduced, who has a kidney condition or who takes medicines affecting the kidney asks a doctor before starting, not because creatine interacts with a supplement but because adding any load to a compromised organ is a decision made with the doctor who knows it, and the same caution applies to long-term high-dose anti-inflammatories and to aggressive water cuts.

Will creatine affect my blood test?

It raises creatinine, the marker doctors use to estimate kidney function, because creatine is broken down to creatinine, so a lifter taking it will often show a reading slightly above the reference range with kidneys working perfectly; the right move is to tell the doctor ordering the test that creatine is being taken so the reading is interpreted correctly or a different measure is used, rather than to stop secretly before the test, which hides the context rather than any problem.

Can I take magnesium and creatine together?

Yes, with no interaction: creatine is absorbed by its own transporter rather than by the mineral routes, binds nothing in the gut and has no action to stack with a mineral, so magnesium, zinc, iron and the rest sit in the same cupboard without a note; this site's worked example is 300mg elemental at 80% NRV in two capsules with the evening meal for 22p a day, batch tested for four metals and UK made, taken for a short plate alongside creatine with a meal, with protein, every day.

Sources

1. The creatine and caffeine interaction question: one early study found that caffeine taken daily alongside creatine loading blunted the performance effect, later work did not consistently reproduce it, some trials found gastrointestinal discomfort when both were taken in a single large dose, and the reviews conclude the interaction is unresolved and small if real. PubMed record
2. The creatine and kidney function literature: long-term creatine supplementation at recommended doses does not impair kidney function in healthy adults in trials measuring filtration directly, serum creatinine rises as a laboratory artefact of the supplement, and people with existing kidney disease or taking medicines affecting the kidney are the group who ask a doctor first. PubMed record
3. Kreider RB, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Journal of the International Society of Sports Nutrition 2017;14:18. PubMed record
4. EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on the substantiation of health claims related to creatine and increase in physical performance during short-term, high intensity, repeated exercise bouts. EFSA Journal 2011;9(7):2303. https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2011.2303

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