This service provides general educational information, not medical advice.
Build mileage gradually, prevent injury with rest days and proper shoes, and keep carbohydrate energy and fluids topped up. Supplements matter mainly for electrolytes in long or hot runs, and iron when a test confirms you are low.
In endurance, results hinge on injury-free mileage management plus carbohydrate and fluid fuelling. Iron runs low in menstruating or plant-based runners, but high-dose iron without a test is dangerous. Most 'recovery' supplements have weak evidence.
Last reviewed 2026-08-06. Educational only; not diagnosis or treatment.
Where supplements fit: Supplements do not build running ability; fuelling (carbohydrate, electrolytes) and test-backed iron are the exceptions that matter.
Ranked by importance. Supplements are one component of the larger system below.
Injury prevention comes first; sudden mileage spikes, too little rest and poor shoes cause most breakdowns.
Supplement role: No supplement role.
Endurance relies heavily on carbohydrate; on long efforts, fuelling during the run preserves pace and focus. Chronic under-fuelling risks poor health and RED-S.
Supplement role: Gels and drinks are practical fuel for long efforts.
Daily hydration is the base; heavy sweating in heat calls for sodium, while over-drinking water risks hyponatraemia.
Supplement role: Electrolyte drinks or tablets as the situation needs.
Endurance runners — especially menstruating or plant-based — are prone to iron deficiency, a real cause of fatigue and poor performance.
Supplement role: Supplement iron only when a test confirms you are low.
Ordered by usefulness; only consider iron after a test confirms low status. You do not need to take all of these — most matter only when there is a genuine shortfall.
For long or hot runs, they replace lost sodium and carbohydrate, protecting pace and safety.
Sources: NIH Office of Dietary Supplements · National Institute of Health and Nutrition (Japan)
In runners with confirmed deficiency, iron corrects fatigue and performance — especially menstruating or plant-based runners.
Sources: NIH Office of Dietary Supplements · NIH Office of Dietary Supplements · Ministry of Health, Labour and Welfare (Japan)
Supports recovery and repair when your daily protein target is otherwise hard to reach.
Sources: International Society of Sports Nutrition · Ministry of Health, Labour and Welfare (Japan)
Popular for 'reducing inflammation to speed recovery', but evidence for recovery or performance in endurance is weak.
Rehearse in training a plan for carbohydrate (gels, drinks) plus fluids and sodium during the run.
Possible iron deficiency — do not self-dose; get a blood test including ferritin before considering iron.
Replace sodium and fluids to match sweat, using thirst and body-weight change as guides.
Risk of chronic under-fuelling (RED-S); raise total energy and carbohydrate first, and consult a professional if needed.
Commonly over-marketed for this goal. Prioritise food, lifestyle and medical care first.
Routine iron without testing
No benefit without deficiency and a real risk of harmful overload — an unsafe habit.
High-dose antioxidants (mega vitamin C/E)
May blunt the training adaptations you are working for.
Fish oil for 'recovery'
Weak evidence for speeding endurance recovery.
Increase gradually and keep rest days and good shoes.
Trial carbohydrate, fluids and sodium on long runs to find your amounts.
Check iron and related markers for unexplained fatigue or decline.
Supplement only confirmed shortfalls, under guidance.
Review fuelling and how you feel each training block.
Short, concrete plans to try. Reassess early if they do not fit.
| Plan | Best for | Steps | Review |
|---|---|---|---|
| Fuelling rehearsal | People building to long runs or a race |
| Trial a few times to set race-day amounts. |
| Fatigue check | People with persistent fatigue |
| Decide with a clinician based on results. |
Carbohydrate, fluid and sodium fuelling during exercise is well supported. Iron is established only in people who are deficient and can harm others. Recovery products like fish oil and magnesium are weakly supported, and high-dose antioxidants may be counterproductive.
Sources: Ministry of Health, Labour and Welfare (Japan) · NIH Office of Dietary Supplements · NIH Office of Dietary Supplements · National Institute of Health and Nutrition (Japan) · World Health Organization · International Society of Sports Nutrition
Mind self-dosed iron, over-hydration, under-fuelling, and existing conditions.
Take iron only when a test confirms deficiency and under guidance; taken otherwise it can harm. Over-drinking water on long efforts risks hyponatraemia. Menstrual disturbance, stress fractures or extreme fatigue can signal under-fuelling (RED-S) and warrant care. Athletes should check anti-doping contamination risk and their sport's rules.
Sources: NIH Office of Dietary Supplements · NIH Office of Dietary Supplements · National Institute of Health and Nutrition (Japan) · World Health Organization
These are not a purchase ranking. Review the evidence and safety before deciding.
Electrolytes replace sodium, potassium and more lost in sweat. Used by very active people and in hot weather.
Role in the body: Support fluid balance and muscle and nerve function.
View detailsIron is essential for oxygen-carrying red blood cells. Needs vary widely and excess intake requires caution.
Role in the body: Involved in transporting oxygen.
View detailsProtein powders and drinks are a convenient way to add protein when meals fall short. They're used by active people and by anyone who may not get enough protein.
Role in the body: Protein provides building blocks for muscle, skin and enzymes, and supports daily maintenance and post-exercise recovery.
View detailsFish oil supplies omega-3 fatty acids (EPA and DHA) found in oily fish. Considered by people who eat little fish.
Role in the body: Fatty acids that form part of cell membranes and participate in the body's regulation.
View detailsMagnesium is an essential mineral involved in many bodily processes. Considered by those who may fall short in diet or want a calmer evening routine.
Role in the body: Involved in energy metabolism, muscle and nerve function, and bone maintenance.
View detailsRun and go the distance
Runners and endurance athletes who often watch iron and electrolytes.
View detailsSupport an active week
For people who move a lot and want to keep daily condition steady.
View detailsFor runners
| Electrolytes | 1 serving during/after runs | During your run |
| Iron | 5–18 mg / day only if needed | With vitamin C |
| Protein | 20–30 g / serving | After your run |
Electrolytes lost through sweat, and iron, which some endurance athletes watch. Iron is also one to avoid overdoing, so if you're unsure, checking levels with a healthcare provider is safest.
View detailsHydration and electrolytes around the run, plus energy and protein from food, are the basics. Treat supplements as a top-up and adjust to your training load and how you feel.
View detailsBuild mileage gradually, prevent injury with rest days and proper shoes, and keep carbohydrate energy and fluids topped up. Supplements matter mainly for electrolytes in long or hot runs, and iron when a test confirms you are low.
View detailsChoose one relevant outcome before starting, record a baseline, and review it at the interval in the guide. Do not use a supplement feeling as a diagnosis.
View detailsTake iron only when a test confirms deficiency and under guidance; taken otherwise it can harm. Over-drinking water on long efforts risks hyponatraemia. Menstrual disturbance, stress fractures or extreme fatigue can signal under-fuelling (RED-S) and warrant care. Athletes should check anti-doping contamination risk and their sport's rules.
View details