Creatine’s Surprising Second Life In Endurance

For most of the past three decades, creatine has belonged to one tribe. Lifters. The supplement aisle reflected that.

So did the marketing. So did the research focus from the early 1990s onward. If you ran, cycled or swam for a living or a hobby, the prevailing wisdom was that creatine was not for you.

Watch the conversation in serious endurance sport over the last few years and you can see that wisdom getting quietly retired.

A coach I know who works with masters runners in California told me she has been adding creatine to the stacks of about a third of her older athletes over the last twelve months.

None of them are chasing PRs. All of them are trying to keep their bodies together for another decade in the sport.

The reasoning is research-based and not particularly controversial anymore. It just took the endurance community fifteen years to catch up.

A quick refresher on what creatine does

Creatine helps muscle cells regenerate ATP. ATP is the molecule the body burns for short bursts of effort. The first ten or fifteen seconds of a sprint. The last reps of a heavy set. The sudden surge required to chase down a breakaway in a race.

The body produces a small amount of creatine on its own. Meat and fish add some more. Supplementation closes the gap between dietary intake and what muscle tissue can store.

Three to five grams a day, taken consistently, saturates muscle stores within three to four weeks.

For pure aerobic work, ATP is not the rate-limiting energy system. That is why creatine looked irrelevant to endurance for so long. The trouble with that framing is that almost no serious endurance training is purely aerobic in structure.

Why endurance was overlooked for so long

Most endurance training is built around aerobic conditioning. Long steady efforts at lower intensities. The phosphocreatine system creatine supports is a minor contributor to those sessions.

The original studies focused on those sessions. They found nothing exciting. The conclusion drawn from that work was that creatine did not help endurance athletes, and the supplement was effectively shelved by the endurance community for about twenty years.

What the studies did not account for was the rest of the training week. Intervals. Strength work. Hill repeats. The repeated short surges that come up in racing.

All of those efforts pull on the phosphocreatine system, and the assumption that endurance training was 100 per cent aerobic turned out to be wrong by a significant margin.

The form and the dose, if you want to try it

Creatine monohydrate is the form with the deepest evidence base. The newer formulations on the shelf, things like ethyl ester or hydrochloride or buffered creatine, have not earned the price premium they ask for.

For athletes wanting to compare options without the marketing noise, a range like the EliteSupps catalogue of creatine supplements is a useful reference for what the current Australian market actually carries.

The dose is unromantic. Three to five grams a day, taken with anything. Saturation takes three to four weeks at a steady dose.

A loading phase of 20 grams a day for the first week shaves a few days off saturation but tends to come with stomach upset, which is not what any athlete needs heading into a hard block.

Timing within the day does not appear to matter much. Whatever fits a routine you will actually maintain for months is the right answer.

What the newer evidence actually says

Several lines of research have pulled creatine back into the endurance picture.

Repeated sprint performance is the most settled. Trials in cyclists and runners have shown improved performance on short, repeated maximal efforts when creatine is supplemented.

The effect on a single time trial is small. The effect across a session of six by 30-second efforts is meaningful.

Glycogen synthesis is the second area. Combining creatine with carbohydrate after exhaustive exercise appears to enhance muscle glycogen replenishment compared to carbohydrate alone. For athletes stacking sessions across consecutive days, that matters.

The third area is recovery markers. Several studies have measured indicators of muscle damage following hard endurance sessions and found smaller increases in supplemented subjects. Less damage means less degradation in performance across a high-volume block.

The fourth, and most recent, is brain performance under fatigue. Endurance athletes routinely train and race in mentally fatigued states.

Creatine’s apparent effect on cognitive performance under stress is relevant to anyone making race-day decisions in the last hour of a marathon or the late stages of a long ride.

None of these effects on their own would justify dropping a five-figure shoe rotation budget. Together, across a training year, they accumulate.

What the formal sports nutrition bodies actually say

For anyone who wants to read past the marketing claims and into what the formal sports nutrition literature has concluded, the International Society of Sports Nutrition position stand on creatine is the most thorough single document available.

The full text is open access. It covers safety, efficacy, dosing, contraindications and the population groups where the evidence is strongest.

The position stand has been the reference document for sports dietitians and coaches for the last decade, and it has held up against newer studies more cleanly than most position papers on the supplement category.

If you find yourself sceptical of the case for creatine in endurance, that paper is the place to start checking it.

A reasonable trial

For an endurance athlete who has skipped creatine and is curious whether the newer research applies to them, the experiment is unflashy.

Three to five grams daily for eight weeks. Continue training as normal. Track sessions the way most serious athletes already do.

What to look for is not a dramatic time-trial improvement. Look at recovery between key sessions, perceived effort during repeated short efforts and how well the body holds together across a high-volume block. Those are where the effect, if it shows up, will show up.

The athletes who have made this trial in the last few years have mostly stayed on it. The ones who have dropped it did so because they were not training hard enough for the effects to matter. Which is itself useful information.