My PR
en
Download
Itinerary · 8Intermediate12 min read

Supplements for running

Gels, drinks, salts, nitrate, beta-alanine and bicarbonate: what to use by distance, how many grams an hour, and how to train your gut to tolerate them.

In running, the supplement with the biggest effect is not a supplement in the usual sense: it is carbohydrate. Once a session goes past a long hour, what you eat while running moves the needle far more than anything else in the cupboard.

The long version is in the running guide

Full fuelling strategy, hydration and GI trouble in eating and drinking on the run. Here we look at the products: which to buy, what dose, and how they differ.

Carbohydrate: how much per hour

What the evidence saysHigh-quality evidence

Mixing glucose and fructose lets you absorb considerably more per hour

The intestinal glucose transporter saturates at around 60 g/hour. Fructose enters through a different transporter, so a 2:1 blend — or the more modern 1:0.8 — allows 90 g/h and, in athletes trained for it, somewhat more. Jeukendrup established this as the practical framework and the later work of Podlogar and Wallis has kept raising the ceiling for very long efforts.

[1] Jeukendrup AE (2014)[2] Podlogar T (2022)[3] Thomas DT (2016)
Effort durationCarbohydrateFormat
Under 45 minNoneWater
45-75 min0-30 g/h, or a mouth rinseA light drink or nothing
1-2.5 h30-60 g/hGlucose alone is enough
2.5-3.5 h (marathon)60-90 g/hGlucose:fructose blend
Over 4 h (ultra)60-90 g/h plus real foodBlend, plus solids and savoury
A standard commercial gel carries 20-25 g of carbohydrate; 90 g/h is about four gels an hour, which almost nobody tolerates without practising it.

The gut is trainable, and needs training

Intestinal tolerance to high carbohydrate doses is adaptable: it improves by practising it on long runs over weeks. Debuting 90 g/h on marathon day is the standard recipe for dropping out with GI trouble. Rehearse it on your long runs with the same product you plan to race on.

Gel
20-25 g per unit

Convenient and concentrated. Needs water unless it is isotonic.

Sports drink
6-8 g per 100 ml

Delivers fluid and carbohydrate at once; takes up space.

Chews and bars
20-30 g

Better tolerated by some; chewing at pace is hard work.

Powder for your own bottle
Whatever you decide

By far the cheapest option: bulk maltodextrin and fructose.

Salts and electrolytes

This is the aid-station category with the most marketing and the least evidence. What sweat mostly takes is sodium, in amounts that vary a great deal between people.

What the evidence saysModerate evidence

Drinking to thirst prevents the serious problem; salt supplements do not

The international consensus on exercise-associated hyponatremia is clear about the direction of the risk: the real danger in long events is drinking too much, not too little, and salt tablets do not protect against it. The NATA position statement and the consensus both recommend being guided by thirst and adjusting sodium in very long efforts, in heavy heat, or in people who sweat very salty.

[4] Hew-Butler T (2015)[5] McDermott BP (2017)
  • When they make sense: over 2-3 hours, heat, or visible white salt marks on your kit.
  • Indicative dose: 300-700 mg of sodium per hour in those conditions.
  • Cramps are not usually an electrolyte problem: the evidence points more to neuromuscular fatigue and running above the pace you trained for.
  • Magnesium, potassium and calcium are lost in small amounts; sodium is the one that matters.

Nitrate: beetroot juice

What the evidence saysModerate evidence

It improves running economy, mostly in less trained runners

Dietary nitrate is reduced to nitrite and then nitric oxide, and lowers the oxygen cost of running at a given pace. Senefeld’s meta-analysis found a small but consistent ergogenic effect, clearer in untrained people than in high-level athletes, where it often disappears. Dose: 6-13 mmol (roughly 400-800 mg of nitrate), 2-3 hours before, or better still for 3-6 consecutive days beforehand.

[6] Senefeld JW (2020)[7] Jones AM (2021)[12] Australian Institute of Sport (2025)

Two practical warnings

Antiseptic mouthwash kills the tongue bacteria that convert nitrate into nitrite: using it wipes out much of the effect. And beetroot juice turns urine and stools red, which is harmless and extremely alarming if you were not expecting it.

Beta-alanine and bicarbonate: the buffers

Both do the same thing by different routes: buffering the acidity that builds up in maximal efforts of between one and ten minutes. Outside that window they add nothing.

ComparisonBeta-alanineSodium bicarbonate
Where it actsInside the muscle (carnosine)In the blood
Dose3.2-6.4 g/day0.2-0.3 g/kg
WhenDaily, 4-12 weeks60-180 min before
Typical effect~2-3% in efforts of 30 s to 10 minSimilar, in the same range
CatchHarmless paraesthesia (tingling)Frequent and sometimes severe GI upset
What the evidence saysHigh-quality evidence

Both work, and only in a narrow window of effort

Saunders’ meta-analysis on beta-alanine puts the benefit in efforts of 30 seconds to 10 minutes, with a small average effect. The ISSN position stand on bicarbonate describes a similar range and warns about what practice confirms: between a third and a half of those who try it get gastrointestinal upset, which is reduced by splitting the dose and taking it with a carbohydrate-rich meal.

[8] Saunders B (2017)[9] Trexler ET (2015)[10] Grgic J (2021)

Who they are NOT for

For a marathoner, an ultrarunner or anyone doing easy runs: the effort is not in that window. These are products for 800 m, 1,500, 3,000 and 5,000 on the track, for rowing or track cycling, and for heavily repeated hard intervals.

A plan by distance

5-10 km
Caffeine. Beta-alanine if you race seriously

No fuelling: the effort is too short to eat.

Half marathon
Caffeine + 30-60 g/h of carbohydrate

A gel every 35-45 minutes covers almost everyone.

Marathon
60-90 g/h + caffeine spread out + sodium if it is hot

Rehearsed on long runs, with the same products.

Ultra and long trail
Carbohydrate, sodium, real food and caffeine in the second half

Here variety of flavour and texture matters as much as the grams (trail and mountain).

Track and middle distance
Caffeine + beta-alanine + bicarbonate

The only discipline where all three make sense at once.

What to check when buying sports nutrition

Cost per hour of running is what decides, and it varies enormously between branded gels and mixing your own bottle.

  • Grams of carbohydrate per unitIt is the only figure that matters; the rest of the label is flavour.
  • Glucose:fructose ratio2:1 or 1:0.8 to go past 60 g/h. If it is maltodextrin only, the ceiling is 60.
  • Sodium per servingCompare it with what you actually need; many gels carry token amounts.
  • Price per hour of runningFour gels an hour at €2 is €8/h. Bulk powder is under €1.
  • That you have tried it in trainingThe most important buying criterion on the list.

Takeaways

  • Carbohydrate during the run is the biggest-effect supplement in endurance: 30 to 90 g/h by duration.
  • Going past 60 g/h needs a glucose–fructose blend and a trained gut.
  • Drink to thirst; salts only for long efforts, heat, or very salty sweat.
  • Nitrate works mostly in less trained runners, and mouthwash cancels it.
  • Beta-alanine and bicarbonate only help between 30 seconds and 10 minutes of maximal effort.

Sources for this chapter

  1. [1]Jeukendrup AE (2014). A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine. review
  2. [2]Podlogar T, Wallis GA (2022). New Horizons in Carbohydrate Research and Application for Endurance Athletes. Sports Medicine. review
  3. [3]Thomas DT, Erdman KA, Burke LM (2016). Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise. position stand
  4. [4]Hew-Butler T, Rosner MH, Fowkes-Godek S, et al. (2015). Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference. Clinical Journal of Sport Medicine. position stand
  5. [5]McDermott BP, Anderson SA, Armstrong LE, et al. (2017). National Athletic Trainers' Association Position Statement: Fluid Replacement for the Physically Active. Journal of Athletic Training. position stand
  6. [6]Senefeld JW, Wiggins CC, Regimbal RJ, Dominelli PB, Baker SE, Joyner MJ (2020). Ergogenic Effect of Nitrate Supplementation: A Systematic Review and Meta-analysis. Medicine & Science in Sports & Exercise. meta-analysis
  7. [7]Jones AM, Vanhatalo A, Seals DR, Rossman MJ, Piknova B, Jonvik KL (2021). Dietary Nitrate and Nitric Oxide Metabolism: Mouth, Circulation, Skeletal Muscle, and Exercise Performance. Medicine & Science in Sports & Exercise. review
  8. [8]Saunders B, Elliott-Sale K, Artioli GG, et al. (2017). β-alanine supplementation to improve exercise capacity and performance: a systematic review and meta-analysis. British Journal of Sports Medicine. meta-analysis
  9. [9]Trexler ET, Smith-Ryan AE, Stout JR, et al. (2015). International society of sports nutrition position stand: Beta-Alanine. Journal of the International Society of Sports Nutrition. position stand
  10. [10]Grgic J, Pedisic Z, Saunders B, et al. (2021). International Society of Sports Nutrition position stand: sodium bicarbonate and exercise performance. Journal of the International Society of Sports Nutrition. position stand
  11. [11]Guest NS, VanDusseldorp TA, Nelson MT, et al. (2021). International society of sports nutrition position stand: caffeine and exercise performance. Journal of the International Society of Sports Nutrition. position stand
  12. [12]Australian Institute of Sport (2025). AIS Sports Supplement Framework: clasificación ABCD de suplementos. Australian Institute of Sport. official guideline
Previous

Caffeine

Next

Vitamins and minerals