Nutritional Supplements for Runners: The Complete Guide

Sports nutrition covers a wide range of products – from whey proteins, energy gels and isotonic drinks to recovery blends. These products form the basis of nutrition before, during and after performance and are a natural part of a runner's training and racing routine.

In this article, however, we will focus not on the basic sports nutrition products, but on specific food supplements that may support performance, delay fatigue or improve recovery. All the substances listed have scientifically supported effects and are part of current recommendations for sports supplementation.

Creatine

Mechanism of action

Creatine is a naturally occurring substance that ensures the resynthesis of adenosine triphosphate (ATP) via phosphocreatine (PCr). Supplementation increases creatine stores in the muscles, which supports ATP production during short-term intense load. In endurance athletes it may help during closing sprints, hills or high-intensity intervals.

Effectiveness

Most studies confirm improved performance in repeated short sections (1–4 minutes), increased strength and improved anaerobic capacity. Long-term supplementation may also lead to an increase in muscle mass and better recovery.

Dosage

• Loading phase: 20 g a day for 5–7 days, split into 4 servings.

• Maintenance phase: 3–5 g a day.
  Combining it with carbohydrates increases absorption.

Side effects

A slight increase in body weight (1–2 kg) due to water retention, occasionally digestive problems. This effect can be eliminated by stopping creatine sufficiently in advance, about 6 weeks before a race.

L-citrulline

Mechanism of action

L-citrulline is an amino acid that is converted in the body into L-arginine – a direct precursor of nitric oxide (NO). It therefore increases vasodilation, blood flow and the transport of oxygen and nutrients to the muscles. Unlike L-arginine, it has better bioavailability and a longer-lasting effect.

Effectiveness

It improves muscular endurance, may delay fatigue and support recovery after load.
In runners, improved performance has been shown in activities lasting 10–30 min and a reduction in perceived exertion. Combined with beetroot it may increase overall NO production.

Dosage

• L-citrulline: 3–6 g about 60 min before performance

• Citrulline malate (2:1): 6–8 g approximately 30–60 min before performance

Side effects

Usually very well tolerated; at higher doses it may cause mild nausea.

Beetroot (nitrate)

Mechanism of action

Nitrates from beetroot are reduced in the body to nitric oxide (NO), which improves blood flow, lowers the energy demands of muscle contraction and increases the efficiency of oxygen use (P/O ratio).

Effectiveness

Studies confirm improved endurance performance (for example by 2–4 %) during load lasting 5–30 minutes. In highly trained athletes the effect is less pronounced, but still observable at doses of 6–8 mmol NO₃⁻ (≈ 370–500 mg of nitrate).

Dosage

• Acutely: 500 ml of beetroot juice (≈ 6–8 mmol NO₃⁻) 2–3 h before performance.

• Chronically: 6–8 mmol a day for 3–7 days.
  Avoid using antiseptic mouthwashes – they disrupt the reduction of nitrates.

Side effects

It may cause pink discolouration of urine or stools (beeturia).

Bicarbonate of soda

Mechanism of action

Sodium bicarbonate acts as a buffer that binds the excess protons (H⁺) produced during intense load, and thereby slows the drop in pH in the muscles.

Effectiveness

Research shows improved performance in activities lasting 1–7 minutes, that is, in sections where anaerobic glycolysis is heavily involved (for example repeated running intervals or finishes).

Dosage

• 0.3 g NaHCO₃ / kg of body weight (for example 20 g for a 70 kg athlete) 60–90 min before performance.
  It is recommended that you test your individual tolerance because of possible GI problems.

Side effects

Bloating, cramps, diarrhoea; it is advisable to split the dose or take it with food.

Beta-alanine

Mechanism of action

Beta-alanine is a precursor of carnosine – an intramuscular buffer that neutralises hydrogen ions (H⁺). A higher carnosine level delays fatigue during repeated or moderately long intense load.

Effectiveness

The greatest benefit has been shown for efforts lasting 1–4 minutes (for example 800–1500 m running, intervals, hills). Combined with training it increases anaerobic capacity and lactate tolerance.

Dosage

• 3.2–6.4 g a day for 4–10 weeks (ideally split into several servings).
  Longer supplementation leads to greater carnosine accumulation.

Side effects

Paraesthesia (burning, tingling of the skin) – a harmless phenomenon at higher doses.

Caffeine

Mechanism of action

Caffeine blocks adenosine receptors in the brain, which delays the perception of fatigue, increases alertness and stimulates the central nervous system. Secondarily it supports lipolysis and the sparing of muscle glycogen.

Effectiveness

Meta-analyses confirm an improvement in endurance performance of 2–4 %. The effect shows up especially in races lasting from 45 s to 60 min. Caffeine also increases muscle strength and performance during sprints.

Dosage

• 3–6 mg/kg 30–60 min before performance.
  Lower doses (~3 mg/kg) provide the same ergogenic effect with a lower risk of side effects.

Side effects

Insomnia, nervousness, increased heart rate; in sensitive people gastrointestinal problems. Avoid taking it late before bedtime.

Cherry juice (sour cherry juice)

Mechanism of action

Cherry juice is rich in anthocyanins and polyphenols with antioxidant and anti-inflammatory effects. It helps reduce muscle damage after demanding load and speeds up recovery.

Effectiveness

Studies have shown lower muscle soreness and faster recovery after marathons and interval training. The effect is more pronounced with repeated use for several days before and after a race.

Dosage

• 240–350 ml of concentrated cherry juice twice a day for 4–7 days before performance and 2–3 days after it.

Side effects

No significant risks; only the higher carbohydrate content may be a problem on weight-loss diets.

Cordyceps

Mechanism of action

Cordyceps sinensis is a fungus traditionally used in Asian medicine. It contains bioactive substances (adenosine, cordycepin) that may influence energy transfer and improve oxygen use.

Effectiveness

Research so far is contradictory. In untrained people an increase in VO₂max was recorded, in trained runners and cyclists the effect was not demonstrated. The possible benefit lies more in long-term adaptation than in an acute improvement in performance.

Dosage

• 1–3 g of dried extract a day (usually in capsules).
  The effect appears when it is taken for longer than 3 weeks.

Side effects

Generally well tolerated; occasional insomnia or mild digestive problems.

Omega-3 fatty acids

Mechanism of action

EPA and DHA from fish oil reduce inflammatory processes, improve the membrane flexibility of erythrocytes and support the supply of oxygen to the muscles. They may therefore contribute to more effective recovery after load.

Effectiveness

Some studies have shown a reduction in muscle soreness after intense training and a lower concentration of inflammatory markers. The effect is more pronounced with long-term supplementation.

Dosage

• 1–2 g of combined EPA + DHA a day.
  Best with a meal containing fats.

Side effects

Mild blood thinning at high doses; in sensitive people digestive problems.

Vitamin D3

Mechanism of action

Vitamin D plays a role in calcium metabolism and immune regulation. In athletes with a low level of 25(OH)D (< 50 nmol/l), recovery, immunity and muscle strength may deteriorate.

Effectiveness

In athletes training in winter or mainly indoors, deficiency tends to be common. In people with a low level, supplementation demonstrably reduces the risk of upper respiratory tract infections and improves muscle function.

Dosage

• 1000–2000 IU (25–50 µg) a day, ideally combined with fats.
  Target serum level: 75–120 nmol/l.

Side effects

With excessive dosing there is a risk of hypercalcaemia, but normal doses are safe.

Conclusion

From the point of view of scientific evidence, the substances with the greatest ergogenic potential for runners are these:

• Creatine, nitrate from beetroot, L-citrulline, beta-alanine, sodium bicarbonate and caffeine.
  These supplements directly improve performance or delay fatigue.

• Cherry juice, omega-3 and vitamin D₃ support recovery, immunity and the long-term health of athletes.

• Cordyceps remains a supplement with potential, but with unclear evidence.

Supplements can be an effective tool if they are used purposefully – with an understanding of the mechanism, the dosage and the links to training and nutrition.