Short answer: most supplements for runners do little that good food and training do not already do. A short list has real evidence behind it. Caffeine and nitrate (beetroot juice) can help endurance performance [1][2]. Iron, vitamin D and calcium matter when a runner is actually low, and that is something a blood test and a clinician should decide [2]. If you are drug tested, every product also has to clear the contamination risk [3].

Supplements for runners at a glance

Supplement	What the evidence says	What a tested runner should know
Caffeine	Good evidence for endurance events, including running [1][2]	On the NCAA banned list above a urine limit, and hides under other names [3]
Nitrate (beetroot juice)	Good evidence overall, smaller gains in highly trained athletes [1][2]	Usually sold as a food, not a supplement [1]
Iron	Helps when you are deficient; not recommended routinely [1][2]	Get tested first. Too much iron causes harm [2]
Vitamin D and calcium	Often needed to correct a deficiency; tied to bone health [2]	A clinician should check your status
Carbohydrate gels, drinks and electrolytes	May be needed in events lasting more than about an hour [1][2]	Some gels contain caffeine [2]
Creatine	Little value for distance running, and adds body weight [1][2]	Not banned, but read our creatine guide
Beta-alanine, sodium bicarbonate	Evidence is for short, hard efforts, such as 30 seconds to 10 minutes for beta-alanine [1]	Bicarbonate often upsets the stomach [1]

Do runners need supplements at all?

Usually not many. The NIH Office of Dietary Supplements says a few supplements "might enhance performance only when they add to, but do not substitute for" a solid diet with enough calories, fluid, carbohydrate, protein, vitamins and minerals [1]. The International Olympic Committee (IOC) consensus statement on supplements says the same thing from the other direction: most products marketed to athletes lack good evidence, and only a few, including caffeine, creatine, buffering agents and nitrate, have it [2].

Runners do have one real extra need. The ODS notes that athletes in endurance events lasting more than an hour, or in heat or altitude, might need to replace fluid and electrolytes and take in extra carbohydrate for energy [1]. Sports drinks, gels and electrolyte tablets are simply a convenient way to do that [2].

Which supplements have good evidence for runners?

Caffeine

Caffeine has strong support for endurance events. The IOC describes "well-established benefits" across endurance events, with improvements in time trials across cycling, running, rowing and other sports [2]. The ODS says caffeine is more likely to help endurance activities, such as running, than short sprints or lifting [1].

The catch for college runners is the rulebook, not the science. Caffeine and its sources, such as guarana, green tea extract and yerba mate, are on the NCAA banned list [3]. A test only counts as positive above a urine limit, which our caffeine guide explains. Watch caffeinated gels and chews too. The IOC notes that some gels contain caffeine [2].

Nitrate (beetroot juice)

Beets are one of the richest food sources of nitrate, which the body turns into nitric oxide, a compound that widens blood vessels [1]. In studies, beetroot juice has "generally improved performance and endurance" among runners, swimmers, rowers and cyclists, "but not in all studies" [1].

Two limits are worth knowing:

Benefits are smaller for well trained athletes. The ODS says benefits are more likely in recreationally active nonathletes than elite athletes [1], and the IOC says gains "appear harder to obtain" in highly trained athletes [2].
Pink urine is harmless. Beetroot can color urine pink or red, which the ODS says is not a safety concern [1].

The ODS also notes that beetroot juice labels usually call the product a food, not a dietary supplement [1].

Beta-alanine and sodium bicarbonate

Both work as buffers against the acid that builds up in very hard efforts. The evidence fits short, intense work. A review summarized by the ODS found beta-alanine helped performance, especially in efforts lasting 30 seconds to 10 minutes [1]. The ODS says bicarbonate might help short, intense exercise such as sprinting and swimming, and that its main side effect is stomach trouble, including nausea and diarrhea [1]. That is a poor trade on race day. For beta-alanine's tingling and its NCAA status, see our beta-alanine guide.

What about creatine?

Creatine is one of the most studied supplements there is, but it suits a different athlete. The ODS says it "seems to be of little value" for distance running and leads to weight gain that might hurt performance [1]. The IOC also notes a small gain in body mass is common [2]. A sprinter or thrower is a different case from a cross country runner.

Why do runners worry about iron?

Iron carries oxygen in your blood and muscles. Too little of it can cause fatigue, lower aerobic capacity and slower times [1]. Runners lose extra iron in several ways, according to the ODS [1]:

Foot strike. Repeated foot strikes on hard surfaces can destroy red blood cells in the feet.
Sweat. Some iron is lost in sweat.
Inflammation after training. Exercise causes short term inflammation that reduces how much iron you absorb, through a peptide called hepcidin.
Menstruation. Teenage girls and women need more iron than boys and men.

That does not mean every runner should take iron. The Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine do not recommend routine iron supplements unless a health care provider directs it, and say iron only helps performance if you are actually low [1]. The IOC is direct: high dose iron "should not be taken unless iron deficiency is present", and too much iron in someone with normal stores can cause vomiting, stomach pain and, in the worst cases, liver failure [2].

The right order is a blood test, a clinician's advice, then a product if you need one.

Do runners need vitamin D and calcium?

Sometimes. The IOC names iron, calcium and vitamin D as the nutrients that often need supplementing when an athlete has, or is at risk of, a deficiency, after a baseline assessment [2]. It links vitamin D deficiency to bone health, and says bone density can reflect low calcium intake, low vitamin D status and disordered eating [2]. For runners, whose bones take a pounding, that is worth a conversation with a doctor or sports dietitian. Whether you need a supplement, and how much, depends on your own status, so we give no dose here.

What about protein?

Runners need protein to repair muscle and recover from training, and many everyday foods contain it, including meat, fish, eggs, dairy, beans and nuts [1]. A protein powder is a convenience, not a requirement. The IOC notes that protein supplements "may contain other ingredients", some of which may raise the risk of contamination [2]. See our protein powder guide for how the NCAA treats it.

What changes for a drug tested runner?

The science above tells you what might work. The rules decide what it could cost you. The NCAA's own warning is clear [3]:

There are no NCAA approved supplements.
Supplements, including vitamins and minerals, can cause a positive test.
Supplements can contain banned substances that are not on the label.
Third party tested products may be options, but "complete elimination of risk is impossible".

USADA says the same: no supplement can be guaranteed to be 100 percent risk free, so it recommends that athletes who use supplements choose ones certified by a third party program that tests for substances prohibited in sport [5]. Our guides to NSF Certified for Sport, Informed Sport and BSCG Certified Drug Free explain what each program checks. Our summary of how often supplements contain banned substances shows why it matters.

What your school can hand out. NCAA Bylaw 16.5.2.7 lets Division I schools provide only six kinds of supplements: carbohydrate and electrolyte drinks, energy bars, carbohydrate boosters, protein supplements, omega 3 fatty acids, and vitamins and minerals, and only if they contain no NCAA banned substances [4]. So a team can stock a sports drink or an iron containing multivitamin, as long as it is free of banned substances. The rule is marked as an area of autonomy, so each Division I subdivision may amend it, and the 2026 to 27 manual prints one version [4]. Ask your compliance office about anything with caffeine in it.

What about high school runners?

The NCAA does not govern high school sport, and your state association and school set the rules. This article gives no doses for anyone, and a high school runner should not start any supplement, including iron, without talking to a doctor, athletic trainer or registered dietitian first. For iron in particular, that conversation should include a blood test.

Checklist before a runner takes a supplement

Scan it in Varsity Stack first. Check the barcode or label against our certification database before you buy.
Ask what problem it solves. If you cannot name the event or the deficiency it addresses, you probably do not need it.
Test before iron or vitamin D. Let a clinician decide from a blood test, not a hunch.
Read every stimulant on the label. Caffeine, guarana, green tea extract and yerba mate all count [3]. Gels and chews included.
Choose certified, then check the lot. Look up the exact lot or batch number on the certifier's own site.
Keep a record. Write down what you take and bring it to your dietitian. Our printable supplement log is one way to do it.

For every banned class and what it means for supplements, see our NCAA banned substances guide.

Check your running supplements with Varsity Stack

The fastest way to check a product is the free Varsity Stack app. Scan the barcode or snap a photo of the label, and Varsity Stack checks it against our certification database before you buy. Recommendations are built around your sport, position, training block and goals, and each one links to a specific certified product. Log what you take so you and your staff always know what is in your stack.

Download Varsity Stack free

For coaches, sports dietitians and athletic trainers: the team dashboard shows every athlete's stack and the certification status of each product. Athletes scan what they buy, and staff approve or reject it for the roster, for example an iron product a runner picked up after a blood test. Request access for your program.

Varsity Stack does not laboratory test supplements, and certification lowers risk without removing it.

Varsity Stack does not provide medical, legal or NCAA compliance advice. This article is for educational purposes only. Consult a qualified healthcare provider or registered dietitian before starting any supplement regimen. Check current NCAA legislation with your compliance staff when reviewing individual products.

Supplements for Runners: What the Evidence Supports