Creatine

Creatine: what is it?

Creatine occupies an unusual position: it is one of the most studied sports supplements there is, and it is also one of the most misunderstood by clients, who typically arrive believing it is a steroid, that it damages kidneys, or that it makes you fat. A coach's job here is mostly correction and clear expectations, not persuasion. It is also worth being straight about scope: recommending supplements to a client with a medical condition or on medication is not a personal trainer's call.

What it does in the body

Short, maximal efforts run on ATP, and the store of ATP in a muscle lasts a few seconds. Phosphocreatine regenerates it. More creatine in the muscle means more phosphocreatine available, which means the muscle can sustain high output slightly longer before it has to slow down.

In practice that shows up as an extra rep or a little more weight on heavy sets, and better quality on repeated sprints. Over a training block, more accumulated quality work is what produces the adaptation. Creatine does not build muscle directly; it lets a client train slightly harder, repeatedly.

Forms and dosing in standard practice

Creatine monohydrate is the form used in most of the research and the one coaches default to. It is also the cheapest. Other forms are marketed as superior in absorption or effectiveness, and none has displaced monohydrate as the standard recommendation.

What to tell a client to expect

The first thing they will notice is bodyweight, not strength. Creatine draws water into muscle cells, so a small rise on the scale in the first weeks is expected and is not fat. A client who has not been warned about this, especially one in a fat-loss phase, will conclude the supplement is making them gain and stop taking it.

The second thing is that the effect is modest and cumulative. It is not a pre-workout feeling. Anyone expecting to notice something in the first session will be disappointed, and honest expectation-setting up front prevents that.

• Monohydrate, 3-5 g a day, taken consistently, is the standard practice.
• Expect a small early rise in bodyweight from intracellular water.
• Not all clients respond equally; some already have high muscle stores from diet.
• It is a supplement to a good programme, not a substitute for one.

The kidney question and coaching scope

The concern that creatine damages kidneys largely comes from a misread: creatine supplementation raises blood creatinine, which is a marker used to assess kidney function. A raised marker in this context reflects more creatine in the system, not damage. In people with healthy kidneys, creatine at standard doses has a long track record of use.

That said, a personal trainer is not a dietitian or a doctor. A client with kidney disease, on medication, pregnant, or under 18 should be discussing supplements with a medical professional. Recommending a supplement is easy; recommending it to the wrong client is a professional problem.