Best Supplements for Endurance Runners: A Practical, Evidence-Based Guide

Ask ten runners what the best supplements for endurance runners are and you will get ten different answers. This guide focuses on five ingredients that are widely used and well known in endurance circles: carbohydrates, electrolytes, caffeine, beetroot (dietary nitrate) and creatine. For each, we describe what it is, the formats it comes in and the amounts people typically use, with a list of sources at the end for your own further reading.

A quick note before we start: this is general information, not medical or nutritional advice, and individual results vary. Always do your own research and, if you have a health condition, take medication or are pregnant, check with a GP or a registered sports dietitian before adding anything new.

Carbohydrates: your primary running fuel

Carbohydrate is a macronutrient and one of the body's main energy sources. The body stores a limited amount as glycogen in the muscles and liver, which is why many runners choose to take on additional carbohydrate during longer sessions. A formulated carbohydrate-electrolyte drink (a sports drink meeting the recognised composition) can help maintain endurance performance during prolonged endurance exercise, and can enhance the absorption of water during physical exercise.

How much and when

• During exercise: for efforts longer than 60–70 minutes, a common amount is roughly 30–60 g of carbohydrate per hour, often in a 6–8% carbohydrate solution taken in small, regular sips.
• Longer events (2.5 hours or more): well-trained athletes sometimes go towards 90 g per hour using a blend of glucose and fructose (around a 2:1 ratio). Because these sugars use different gut transporters, larger total amounts can be absorbed, which many athletes find easier on the stomach.
• Daily intake: to keep glycogen stores topped up across heavy training, endurance athletes often aim for 8–12 g of carbohydrate per kilogram of body weight per day.

Gels, drink mixes and chews from brands such as Applied Nutrition and Optimum Nutrition make hitting these numbers straightforward on the move. Practise your fuelling in training — race day is not the time to test a new gel. Browse our carbohydrates range to build a fuelling plan that suits your event.

Electrolytes and hydration

Sweat contains water along with sodium and, to a lesser extent, potassium, magnesium and chloride. Electrolyte products are formulated to replace some of what is lost in sweat. On long or hot runs, individual sweat losses can be considerable, and in rare cases — usually from drinking far more than is lost through sweat — low blood sodium (hyponatraemia) can occur. As noted above, a formulated carbohydrate-electrolyte drink can enhance the absorption of water during physical exercise.

• Fluid: during intense endurance activity, roughly 0.4–0.8 litres per hour suits most runners, adjusted to your own sweat rate and the weather.
• Sodium: for sessions over an hour, many runners add around 0.5–0.7 g of sodium per litre of fluid, which also improves the taste of a drink. Heavy, salty sweaters going long in the heat may use more.

Sweat rates vary enormously between individuals, so a practical step is to weigh yourself before and after a long run to gauge your losses. Electrolyte tablets and powders from USN, Bulk and MyProtein make dialling in your sodium easy. Explore our hydration and electrolytes collection to match a product to your sweat profile.

Caffeine: a popular pre-run ingredient

Caffeine is a stimulant and one of the most widely used ingredients in sports nutrition. It is a common choice among runners before a session, and comes in a range of convenient formats.

• Amount: commonly used amounts are around 3–6 mg per kilogram of body weight, roughly 45–60 minutes before running. For a 70 kg runner that is about 210–420 mg.
• Higher amounts: larger doses (around 9 mg/kg) are generally avoided, as they are more likely to cause jitters, a racing heart and stomach discomfort.

Caffeine is one of the most heavily researched ingredients in sport. It comes in tablets, gels, energy drinks and pre-workouts from the likes of Grenade, Warrior and Per4m; sensitive individuals may prefer to start at the lower end and avoid caffeine late in the day. See our energy drinks range for convenient pre-run options.

Beetroot and dietary nitrate

Beetroot is a natural source of dietary nitrate, which is why it is popular with endurance athletes. It is available as concentrated shots, powders and juices, and is easy to work into a pre-run routine.

• Serving: concentrated beetroot "shots" are typically standardised to around 6–12 mmol of nitrate (roughly 400–750 mg) per serving.
• Timing: people commonly take a shot 2–3 hours before exercise, or use it daily over several days.

A harmless quirk worth knowing about is that beetroot can give urine a pink tinge. Concentrated beetroot shots and powders are widely available from endurance-focused brands.

Creatine: not just for lifters

Creatine is one of the most researched sports supplements, and it has a place in a runner's kit bag as well as a lifter's. For adults doing high-intensity exercise, creatine increases physical performance in successive bursts of short-term high-intensity exercise — such as hill reps, surges and a finishing kick — when taken at 3 g per day.

• Loading (optional): around 20 g per day split into four doses for 5–7 days is sometimes used to raise stores more quickly.
• Maintenance: 3–5 g per day of creatine monohydrate is the most common and most researched approach; the authorised performance benefit applies at 3 g per day.

Creatine monohydrate has a good safety record in healthy adults when used as directed. Trusted monohydrate options come from PhD, NXT Nutrition, Mutant and most major brands.

Sources and further reading

The amounts and background above are summarised in our own words. The following sources are provided for general further reading:

• ISSN position stand on nutrient timing — carbohydrate intake during and around exercise, daily glycogen targets, and the glucose–fructose approach for higher hourly intakes.
• NATA position statement on fluid replacement — fluid and sodium guidance for endurance exercise.
• ISSN position stand on caffeine and exercise performance — commonly used amounts and safety considerations.
• Systematic review of dietary nitrate — typical nitrate dose and timing.
• ISSN position stand on creatine supplementation — efficacy, dosing and safety.
• NHS Eat Well — general healthy-eating context for any supplementation plan.

Putting it together

No supplement replaces consistent training, sleep and a solid everyday diet. Used sensibly, these five ingredients are staples in many endurance runners' kit bags: carbohydrate and formulated carbohydrate-electrolyte drinks for fuelling and hydration, caffeine and beetroot as popular pre-run choices, and creatine for high-intensity efforts. Start with one, practise it in training, and build from there.

Disclaimer: This article is general information only and is not medical or nutritional advice. Individual results vary, and no supplement is guaranteed to work for everyone. Always do your own research and consult a GP or a registered sports dietitian before starting any new supplement, particularly if you have a health condition, take medication or are pregnant.

Ready to sort your race-day fuelling? Browse our carbohydrates collection to stock up on gels, drink mixes and chews from the brands you trust.