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Supplements for Long-Distance Runners — What Actually Has Evidence Behind It

Store shelves and running influencers' profiles are groaning under supplements promising better long-distance performance, but the International Olympic Committee's official position points to only a handful of substances with solid evidence of effectiveness. Here's a guide to which ones actually matter for a long-distance runner, and which are marketing with no evidence behind them.

MNMichał NowakSeptember 3, 202612 min read

Table of contents

TL;DR — key takeaways

→Why it's worth starting with the IOC statement, not an ad
→Caffeine — the best-studied supplement for endurance
→Nitrate (beetroot juice) — improving running economy
→Creatine — a less obvious choice for long-distance runners
→Sodium bicarbonate and other buffering agents
→Myth vs. fact
→What about magnesium, B vitamins, and multivitamins
→Rule number one: diet first, supplements second
→When it's worth consulting a specialist
→Limitations of this evidence
→Our editorial recommendation

Why it's worth starting with the IOC statement, not an ad

The sports supplement market is enormous, and marketing messaging rarely corresponds 1:1 with the actual strength of the scientific evidence. Rather than evaluating each supplement individually based on single, often sponsored studies, a more practical starting point is to consult a pooled expert statement summarizing the entire body of available literature — one such document is the International Olympic Committee's consensus statement on dietary supplements for high-performance athletes.

IOC consensus statement: dietary supplements and the high-performance athlete

Strong evidence

Maughan RJ, Burke LM, Dvorak J, Larson-Meyer DE, Peeling P, Phillips SM, Rawson ES, Walsh NP, Garthe I, Geyer H, Meeusen R, van Loon LJC, Shirreffs SM, Spriet LL, Stuart M, Vernec A, Currell K, Ali VM, Budgett RG, Ljungqvist A, Mountjoy M, Pitsiladis YP, Soligard T, Erdener U, Engebretsen L · British Journal of Sports Medicine · 2018

A team of international experts under the International Olympic Committee reviewed the entire body of available scientific literature on dietary supplements used by high-performance athletes. The statement's conclusion is unambiguous: only a few substances — caffeine, creatine, nitrate (including from beetroot), and sodium bicarbonate and other buffering agents — have well-documented evidence of benefit for athletic performance, with improvements ranging from 1% to 25% depending on the substance and type of exercise. The authors stress that a complete, properly balanced diet should be assessed and optimized as a first step before considering any supplementation, and that performance-enhancing supplements should only be used after being thoroughly trialed in training — never for the first time on race day.

View study

Caffeine — the best-studied supplement for endurance

Caffeine has one of the most solid confirmations of effectiveness among all ergogenic substances used in endurance sport — numerous studies point to improved perceived exertion (RPE) and actual performance during prolonged aerobic exercise.

Practical tips on caffeine for runners

Typical doses studied for athletic performance are around 3-6 mg per kilogram of body weight, taken 30-60 minutes before exercise
Response to caffeine is highly individual — in some people even low doses cause anxiety or stomach issues, so the strategy needs to be tested beforehand in training, never for the first time on race day
Regular, daily consumption of large amounts of caffeine (e.g., from coffee) may partly reduce its ergogenic effect through developed tolerance
Caffeine in chewing gum or an energy gel acts faster than in tablet or coffee form, which can matter for dosing during a long run

Nitrate (beetroot juice) — improving running economy

Inorganic nitrate, present in high concentration in beetroot juice, is converted in the body to nitric oxide, which improves the efficiency of oxygen use by muscles during exercise — a phenomenon described as improved running economy (lower oxygen consumption at the same pace).

Practical tips on nitrate/beetroot juice

The effect tends to be most noticeable in recreational and moderately trained athletes — in highly trained elite athletes, the benefit is often smaller
A typical protocol is drinking nitrate-rich beetroot juice 2-3 hours before exercise, sometimes combined with a few days of "loading" before an important race
Antibacterial mouthwash can weaken the nitrate effect, since oral bacteria are involved in converting it to nitric oxide
It's worth testing stomach tolerance in training — in some people, larger amounts of beetroot juice can cause digestive discomfort

Creatine — a less obvious choice for long-distance runners

Creatine has one of the best-documented evidence bases among all sports supplements, but its main mechanism of action — increasing phosphocreatine availability for short, intense anaerobic efforts — makes its relevance to typical, long aerobic exercise less direct than in strength or sprint sports.

When creatine can make sense for a long-distance runner

Creatine is sometimes considered by long-distance runners mainly in the context of supporting strength training that complements running (leg muscle strength, injury resistance) or a finish requiring a short, intense acceleration, rather than as a direct "endurance supplement" in the way caffeine or nitrate are.

Sodium bicarbonate and other buffering agents

Sodium bicarbonate (baking soda) acts as a buffer reducing muscle acidification during intense exercise, which can be beneficial for efforts lasting from a few to several minutes at high intensity — so it more often applies to middle-distance races and the final, intense phases of long races than to a full marathon run at a steady, moderate pace.

Side effects limit the practical usefulness of sodium bicarbonate

Sodium bicarbonate is known for frequent, bothersome gastrointestinal issues (diarrhea, abdominal pain, nausea) at the doses used in sports performance research. Because of this risk, any strategy using it requires prior, repeated testing in training — never using it for the first time on the day of an important race.

Myth vs. fact

Myth

The more different "endurance" supplements you take before a run, the better your result will be.

Fact

The IOC statement clearly shows that only a handful of substances have solid evidence of effectiveness, and most products sold as "endurance" supplements have no confirmed effect on athletic performance. Stacking more supplements mainly increases the risk of interactions, stomach issues, and accidental contamination with a substance banned in sport, rather than improving performance itself.

What about magnesium, B vitamins, and multivitamins

Supplement	Status in the IOC statement	When it might make sense
Magnesium	No solid evidence of performance improvement in people without a deficiency	With a deficiency confirmed by a blood test, after medical consultation
B vitamins	No evidence of performance improvement in people without a deficiency	With a diagnosed deficiency, e.g., B12 in people on a plant-based diet
Multivitamin	Not listed as a performance-enhancing supplement	As a supplement for dietary gaps, not as an ergogenic aid
BCAA	No convincing evidence of an advantage over complete dietary protein	Rarely necessary with adequate total dietary protein intake

Supplements popular among runners, but without solid confirmation of performance benefit

This doesn't mean these substances are worthless overall — they can make sense with a real, confirmed deficiency in the body. The difference is that, in that case, their role is correcting a deficiency, not directly boosting athletic performance beyond a normal, healthy level, as with caffeine or nitrate.

Rule number one: diet first, supplements second

Priority order according to the IOC statement

Assess and optimize your basic diet: adequate energy, carbohydrate, protein, and fat intake matched to training volume
Check for specific deficiencies (e.g., iron, vitamin D) with a blood test, instead of guessing and supplementing "just in case"
Only after these two steps, consider supplements with documented performance effects (caffeine, nitrate, possibly sodium bicarbonate for the appropriate type of exercise)
Test any new supplementation strategy repeatedly in training, never for the first time on the day of an important race
Check for independent product testing certifications (e.g., "sport safe"), especially if you're subject to anti-doping testing — supplement contamination with banned substances is a documented risk

When it's worth consulting a specialist

A sports dietitian instead of guessing

The IOC statement explicitly recommends a full assessment of dietary practices and, if needed, consultation with a sports dietitian before deciding on performance-enhancing supplementation — individual needs depend on training volume, race goals, history of gastrointestinal issues, and many other factors that can't be evaluated with generic advice from the internet.

Limitations of this evidence

A consensus statement based on a broad literature review, but general to sport, not running-specific

Strong evidence

The IOC statement is an expert document summarizing hundreds of studies on supplements in sport in general, which makes it a strong, credible reference point. However, it wasn't written exclusively with long-distance running in mind — the size of the effect for each substance (caffeine, nitrate, sodium bicarbonate) varies depending on the type and duration of exercise, so applying these conclusions individually to a specific distance and pace requires judgment, ideally with input from a specialist familiar with the athlete's individual context.

Our editorial recommendation

For most long-distance runners, a reasonable starting point is: first take care of the basic diet and any deficiencies confirmed by a blood test, and among supplements, try caffeine first and possibly nitrate — both substances have the strongest evidence and are relatively easy to access. The rest of the "endurance" supplement market deserves healthy skepticism until a well-documented substance shows up in it.

The most common mistake I see in amateur runners is the reversed order of priorities — they buy a set of trendy supplements first, and only afterward, if at all, think about their basic diet and actual deficiencies. The IOC statement says it plainly: it should be the other way around.

Michał Nowak, VitMode editorial team

Frequently asked questions

The ergogenic effect depends mainly on the dose of pure caffeine itself, so both forms can work similarly if the dose is comparable. The practical difference lies in absorption speed and additional substances (e.g., acids in coffee can worsen stomach issues during a run for some people) — so it's worth testing your chosen form beforehand in training.

Most studies tested a single dose 2-3 hours before exercise, or a short, few-day loading period before an important race, rather than daily, long-term use. Daily drinking isn't necessary to get the effect on race day.

Creatine has a well-documented safety profile at standard doses used in sports research. Its limited direct role in aerobic performance isn't due to safety concerns, but to a different mechanism of action than in strength and sprint sports.

At standard doses in line with recommended daily intakes, the risk of harm is low in healthy people, but there's also no evidence of improved athletic performance beyond a normal level. A multivitamin can make sense as a way to fill dietary gaps, but not as an ergogenic aid.

Its mechanism of action (buffering muscle acidification) brings the greatest benefit for high-intensity efforts lasting from a few to several minutes, rather than the long, moderate pace typical of most of a marathon distance. Additionally, frequent stomach issues make it a risky choice for a multi-hour run.

Not always — a lack of confirmation in the consensus statement means a lack of solid, reproducible evidence of a performance benefit at the time of its publication, not proof of complete ineffectiveness. Still, it's worth treating such products cautiously and not expecting an effect comparable to caffeine or nitrate.

The risk of contamination applies to anyone using a given product, regardless of whether they're subject to anti-doping testing — for an amateur, it mainly means a potential health risk from an uncontrolled composition rather than sporting consequences. Independent product certification (e.g., batch testing) reduces this risk regardless of competitive level.

Sources

Maughan RJ et al. 2018 — British Journal of Sports Medicine

Michał Nowak

MSc in Clinical Dietetics, certified sports-nutrition coach

Michał started out as a long-distance runner, before an injury forced him to rethink his career. Looking for a faster way back into shape, he discovered sports nutrition and never left — fascinated by the gap between the research and what "everyone knows" at the gym. He completed a degree in clinical dietetics, earned a sports-nutrition coaching certification, and ran his own practice for several years before joining VitMode. His writing keeps returning to one theme: a supplement won't replace the basics, but the right one, at the right time, makes a real difference — and that's the difference he tries to describe precisely, with citations instead of slogans. He still runs, though these days, as he puts it, purely for the fun of it.

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Comments (2)

KW
Kasia W. 2 weeks ago
Very clearly explained, especially the interactions section — I hadn't seen it laid out this well anywhere else.
MT
Marek T. a month ago
Are you planning to update this with the newest study from this year? I saw an interesting meta-analysis.