Maybe Endurance Athletes Should Take Creatine After All

When the International Olympic Committee published a consensus statement on dietary supplements in 2018, it identified a grand total of four substances whose performance-boosting effects were backed by a reasonable body of evidence. Three of those substances are very familiar to endurance athletes: caffeine, nitrate (as found in beet juice), and baking soda (possibly along with beta alanine, which does roughly the same thing). The fourth one, which is far better known to sprint and power athletes, is creatine. There’s ample evidence that creatine can help build strength and power, primarily by boosting your performance in the gym.

Over time, squeezing out an extra rep or two in every set of every workout can lead to substantial gains. Could it be useful for endurance athletes too?

Researchers have been considering this idea since at least the early 1990s, with mixed results at best. But 2023 review in the Journal of the International Society of Sports Nutrition argues that it’s time for the endurance world to take another look at creatine.

Understanding Your Body’s Energy Systems

We normally think of two energy systems: aerobic and anaerobic. While this terminology is oversimplified, it makes a useful distinction: aerobic energy is slow but sustainable, while anaerobic energy is fast but easily depleted. But there’s also a third energy system, which is even faster and more rapidly depleted than the anaerobic system. It’s sometimes called the anaerobic alactic system, and it relies on creatine phosphate stored right in the muscle cells to fuel sudden, explosive movements for up to about ten seconds.

Our bodies make their own creatine out of amino acids, and we also get some from food sources like seafood, red meat, and poultry. But the key point is that even in meat-eaters, the creatine stores in our muscles are typically about 80 percent full. With creatine supplements, you can boost that up to 100 percent, which will give you a little more energy for each burst from the anaerobic alactic system.

Creatine Can Give Runners a Boost When They Need It Most

Marathoners understandably don’t spend much time worrying about a fuel tank that lasts for ten seconds. And in general, creatine hasn’t helped in tests of even-paced endurance time trials.

But the new review, co-authored by a large group of sports nutrition researchers led by Scott Forbes of Brandon University in Canada, suggests that many real-life endurance events have “key race-defining moments” where a little extra creatine could make a difference: surges, hill-climbs, and finishing sprints. A few studies have tested this idea. For example, a 2018 study from Australian Catholic University put cyclists through 120K time trials punctuated by a series of 1K and 4K sprints. Creatine didn’t improve their overall time, but it did boost their power in the final sprints.

The biggest objection to creatine for endurance athletes is that it’s associated with immediate weight gain, typically on the order of about 1 percent or more of your total weight. That’s a result of water retention, independent of any additional muscle you pack on over time with creatine-fueled workouts. That makes creatine an easier sell for non-weight-bearing sports like cycling and swimming than for running. Still, the Australian cycling study mentioned above finished with an uphill ride to exhaustion to see if the negative effects of weight gain would outweigh the positive effects of creatine, and found that it was a wash.

Creatine Has a Number of Additional Benefits

If that’s all the review discussed, it would be a pretty short paper. But it turns out that creatine has a huge range of other possible benefits, perhaps not surprisingly given that it plays such an important role in the energy supply of cells throughout the body. Taking creatine along with carbohydrate seems to enhance glycogen storage in the muscles. The extra water retention, despite its added weight, may help performance in heat.

Oh, and it may also help buffer rising blood pH, reduce neuromuscular fatigue, counteract inflammation, and speed up recovery. And did I mention the potential health benefits for bone strength, concussion, degenerative brain conditions, heart disease, and more?

At this point, your alarm bells may be ringing. Scroll down to the bottom of the article, and you see a long list of ethics disclosures for various authors ranging from “received research grants and performed industry sponsored research involving creatine supplementation” to “owns a company that sells creatine products.” The International Society of Sports Nutrition, which publishes the journal the review appears in, was explicitly founded in response to the perceived anti-supplement bias of more mainstream organizations like the American College of Sports Medicine. “When you eat fish, you are consuming creatine,” ISSN founder Jose Antonio, who is also the corresponding author of the new creatine review, pointed out in an interview a few years ago. “But god forbid you put creatine powder in a glass of grape juice and give it to a teenage wrestler or football player!”

It’s not surprising, in other words, that the review has a bit of a boosterish quality. The authors are avowed fans of supplements in general and creatine in particular. Forbes, the lead author, goes by the handle of Dr. Creatine on Instagram and Twitter, and is the co-author of many articles with titles like “Do Pregnant Women Consume Enough Creatine?” But that doesn’t mean he’s crazy. Forbes gave a nice interview recently on Jason Koop’s ultrarunning podcast, and one of the points he emphasized was that he’s not taking any money from creatine companies. He was introduced to creatine research because one of his undergraduate professors was studying it, and he’s been hooked ever since.

My own take is that, at least for now, we should ignore most of the secondary claims about heat stress and inflammation and brain health and so on. If researchers come up with solid evidence about them, we’ll hear about it. As for the primary benefits—topped-up creatine stores to fuel surges, and perhaps a little extra glycogen stored in the muscles—they’re certainly intriguing. Whether they’re worth pursuing likely depends on the nature of your competition: how hard are the surges, how important are they to the final outcome, and how much of a price would you pay for carrying an extra pound or two?

If you’re interested, check out the review (which is free to read online), and consider the following practical points:

• There are plenty of fancy creatine variants on the market. None have been shown to outperform the cheapest and most basic version, creatine monohydrate.
• You can max out your creatine levels in a week by taking 20 grams per day, split into four daily doses, then switch to a maintenance load of 3 to 5 grams per day. You can also skip the loading phase and just stick to 3 to 5 grams, in which case it will take about four weeks to max out. This latter approach may be less likely to cause water-related weight gain.
• Once your creatine levels are high, if you stop supplementing they’ll take about a month to drift back down to baseline levels. You can cycle on and off creatine depending on your training or racing goals.
• Aim to take creatine close to your workout (e.g. right after), ideally with some carbohydrates.
• There’s some evidence that women have higher baseline creatine levels, and thus get less benefit from supplementation. More generally, as with everything in life, there’s plenty of individual variation, so the only way to know how you’ll respond is to try it.

There’s one final point that’s not addressed in the review. A separate stream of creatine research these days focuses on its potential benefits (in combination with resistance training) for helping older adults slow down the inevitable muscle loss that accompanies aging. I’ve never tried creatine myself, but that’s the angle that interests me most.

So if it’s good for endurance athletes, maybe it’s especially good for aging endurance athletes. As someone who sits right in the middle of that Venn diagram, it’s enough to make me consider whether—as Jose Antonio would no doubt suggest—I should rethink my usual supplement aversion.

For more Sweat Science, join me on Twitter and Facebook, sign up for the email newsletter, and check out my book Endure: Mind, Body, and the Curiously Elastic Limits of Human Performance.