Runners are a marketer's dream. We are disciplined, goal-driven, and willing to try almost anything that might shave a few seconds off a personal best, which is why the endurance aisle overflows with powders, gels, and "performance" blends. The truth is that most of what helps a runner is not exotic at all, and most of the exotic stuff barely helps.
Training, sleep, and simply eating enough do the heavy lifting. But a short list of supplements genuinely earns its place, either by fixing a deficiency that is quietly holding you back or by giving a real, measured performance edge. Here is that list, sorted into what is foundational, what actually boosts performance, and what you can skip.
The foundations (fix these first)
Before any "ergogenic aid," cover the basics. These are where most runners actually leave performance on the table.
Carbohydrate (the real performance supplement)
For anything long or hard, carbohydrate is the supplement that wins races. Gels, chews, and sports drinks exist to deliver carbs your muscles can burn when glycogen runs low, roughly 30 to 60 grams per hour for efforts beyond about 90 minutes, more for serious endurance. Practice your fueling in training, never try a new gel on race day, and do not let "clean eating" talk you out of the carbs your running depends on.
Electrolytes and hydration
For long or hot runs, you lose sodium (and some potassium and magnesium) in sweat, and replacing sodium helps you hold onto fluid and avoid cramping and dangerous over-dilution. Everyday short runs need only water, but past 60 to 90 minutes, or in heat, electrolytes matter. See our guides on whether you need electrolytes and the best electrolyte drink mixes.
Iron (especially for women)
This is the deficiency that silently destroys endurance. Runners lose iron through sweat, gut losses, and the breakdown of red blood cells from repeated foot strike, and female runners are at particularly high risk. Low iron leaves you flat and breathless no matter how well you train. Do not blindly supplement, though, get a ferritin blood test, since excess iron is harmful, and treat it under guidance if you are low, paired with vitamin C.
Vitamin D
Common to run low on, especially in winter or for indoor-heavy schedules, and it matters for bone strength (think stress fractures) and muscle function. Vitamin D is worth checking and correcting, taken with a meal that has some fat.
Proven performance boosters
These have genuine evidence for making you faster or able to go harder. They are the legitimate "ergogenic aids."
- Caffeine: the most reliable performance aid in endurance sport. It lowers perceived effort and improves performance, around 3 to 6 mg per kg of body weight, 45 to 60 minutes before running. Rehearse it in training.
- Beetroot or nitrate: the nitrate in beets boosts nitric oxide, improving blood flow and oxygen efficiency. The effect is modest and best for shorter endurance efforts, taken a few hours before, ideally for several days leading in.
- Beta-alanine: buffers acid in the muscle, helping high-intensity efforts lasting roughly 1 to 4 minutes (think track intervals and finishing kicks), less relevant for the marathon. Expect harmless tingling.
- Creatine: best known for power and sprints, and it helps with recovery and glycogen storage too. Distance runners sometimes skip it over a small water-weight gain, but it is safe and useful, especially for those doing speed work and strength training.
Recovery and joints
Useful supporting players, even if they do not make you faster on the day.
- Protein: the real recovery supplement. Hitting your daily protein target (roughly 1.6 to 2.0 g per kg) drives repair; a protein shake is just a convenient way to get there.
- Tart cherry: some evidence for reducing muscle soreness and aiding recovery after hard efforts.
- Collagen with vitamin C: a promising option for tendon and ligament resilience, taken about an hour before training, useful if you are injury-prone.
- Omega-3 and magnesium: omega-3 supports recovery from inflammation, and magnesium is worth correcting if you are low (its effect on cramps specifically is overstated).
What to skip
Plenty of runner-marketed products do little. BCAAs are largely redundant if your total protein is adequate. Most "endurance" proprietary blends hide under-dosed ingredients behind a label (see our take on proprietary blends). Exogenous ketones have mixed-to-unimpressive performance data for the price. And no antioxidant megadose fixes under-training. Spend on the foundations and the proven boosters instead.
A runner's stack by goal
Match it to your running
- Everyone: adequate carbs and protein, plus checking iron (ferritin) and vitamin D
- Long or hot runs: add electrolytes, especially sodium, and in-run carbohydrate
- Race day or hard sessions: caffeine, and beetroot or nitrate beforehand
- Speed work and intervals: beta-alanine, and creatine if you also lift
- Injury-prone or recovering: collagen with vitamin C, tart cherry, omega-3
Notice how much of that is food and testing, not pills. That is the honest shape of running nutrition: nail the foundations, add a couple of proven boosters for the hard days, and ignore the rest.
Frequently asked questions
What supplements do runners actually need?
Most runners do not need much beyond the foundations: enough carbohydrate to fuel hard and long sessions, electrolytes for long or hot runs, and addressing common deficiencies like iron (especially for women) and vitamin D. Beyond that, a few performance boosters have real evidence, mainly caffeine, beetroot or nitrate, and beta-alanine for shorter intense efforts. Almost everything else is optional or hype.
Should runners take iron?
Only if testing shows you need it, but runners are at higher risk of low iron, especially female and high-mileage runners, partly due to foot-strike red-blood-cell breakdown and sweat losses. Low iron quietly wrecks endurance. Ask for a ferritin test rather than guessing, since taking iron you do not need is harmful, and if you are low, supplement with guidance and pair it with vitamin C.
Does caffeine improve running performance?
Yes, caffeine is one of the most reliably effective endurance aids there is. It reduces perceived effort and improves performance across distances, with common doses around 3 to 6 mg per kilogram of body weight taken about 45 to 60 minutes before running. Start at the lower end, practice it in training before race day, and avoid taking it too late to protect your sleep.
Does beetroot juice help endurance?
It can. Beetroot is rich in dietary nitrate, which the body converts to nitric oxide, improving blood flow and muscle efficiency so you use slightly less oxygen at a given pace. The effect is modest and most useful for shorter endurance efforts, taken a few hours before exercise and ideally for several days beforehand.
Do runners need electrolytes?
For everyday short runs, water and a normal diet are usually enough. Electrolytes, especially sodium, matter for long runs (roughly over 60 to 90 minutes), hot conditions, and heavy or salty sweaters. They help maintain hydration and reduce the risk of cramping and over-dilution on long efforts. Match your intake to how long and how hot your runs are.