Creatine: the most studied supplement you're still explaining wrong

Chances are you've already recommended creatine to a client. Or you've avoided it because "it's bad for your kidneys" or "it's only for people trying to get huge." Either way, if you're a personal trainer who can't explain what creatine does, who it works for, and what the real evidence says, you're giving incomplete advice about the most studied supplement in sports nutrition history.

Creatine doesn't build muscle on its own. It increases phosphocreatine stores in muscle tissue, allowing cells to regenerate ATP faster during high-intensity efforts. In practical terms: more reps before fatigue, more total work capacity, and over time, more accumulated stimulus for growth.

A 2024 meta-analysis in Nutrients evaluated effects on strength in adults under 50. Creatine combined with resistance training produced a significant increase in upper-body strength (weighted mean difference of 4.43 kg on bench press). But the key finding for programming was that significant effects only appeared in interventions lasting 8 weeks or more.

This isn't a quick-fix supplement — tell your client that results show up at 3 to 4 weeks on maintenance dosing, and the real advantage compounds over the medium term.

It's the most persistent myth and the easiest to dismantle. A 2023 narrative review in Nutrients concluded that controlled clinical trials do not support the claim that creatine impairs kidney function in healthy individuals. A 2025 meta-analysis in Frontiers in Nutrition reinforced the same: no significant change in serum creatinine or plasma urea.

Where the myth comes from: creatine spontaneously converts into creatinine, the standard marker of kidney function. If you supplement, your creatinine may rise — but that doesn't indicate kidney damage, just greater substrate availability. It's like assuming a car with a full tank has a fuel leak.

Reasonable precaution: people with pre-existing kidney disease should consult their doctor before supplementing. For everyone else, the evidence is clear.

This is where the conversation gets interesting for coaches working with diverse populations. A 2024 meta-analysis in Frontiers in Nutrition found significant improvements in memory and processing speed with creatine. The mechanism is coherent: the brain consumes roughly 20% of total body ATP, and creatine directly participates in neuronal ATP regeneration.

For vegetarians and vegans, the data is particularly relevant. A 2020 systematic review in Nutrients confirmed that these populations start with lower baseline muscle creatine stores — dietary creatine comes almost exclusively from meat and fish. The response to supplementation tends to be more pronounced for both physical performance and cognitive markers.

If you have plant-based clients, creatine stops being a "gym supplement" and becomes a nutritional recommendation with solid backing.

The loading phase — 20 g/day split into 4 doses for 5 to 7 days — is still an option if you want rapid saturation. But 3 to 5 g daily without prior loading reaches the same muscle saturation levels in 3 to 4 weeks.

For most clients, a maintenance dose of 3 to 5 g/day is enough. Time of day doesn't appear to matter significantly. The only form with solid evidence is creatine monohydrate — variants with aggressive marketing (HCl, ethyl ester, buffered) haven't shown superiority in any comparative trial.

Summary for your client: one teaspoon of creatine monohydrate per day, with water, at any time. No cycling, no mandatory loading, no complications.

When you're managing a roster of fifteen or twenty clients and several ask about supplements in the same week, the difference between a coach who gives a generic answer and one who gives a personalized recommendation isn't knowledge — it's systems.

Being able to see in one place who's supplementing what, whether performance improved since they started, whether adherence to the nutrition plan is consistent. Centralizing planning, progress tracking, and routine updates in a single platform changes the equation: it's not just knowing what to recommend, but being able to evaluate whether the recommendation is working for each client without losing the thread.

You don't need to be a nutritionist to explain creatine. You need to be clear about what the evidence says:

Creatine monohydrate is the supplement with the most clinical trials in history, and the 2024–2025 evidence left it in an even more solid position: significant effects on strength starting at 8 weeks, no kidney damage in healthy people, and emerging benefits in cognition and in vegetarian populations.

If you're going to recommend it, recommend it with data. If you decide not to, make sure the reason is real — not a 2012 myth.