Sodium Bicarbonate for Endurance Athletes: Does Bicarb Work?
What bicarb is, what the research says it does, the drawbacks, how to take it, and the bicarb product we'd pick, based on independent Pello Scores.
Bicarb has gone from a niche track trick to something you'll see in pro cycling team buses and distance runners' race kits. It's also one of the few supplements with strong research behind it. But it comes with a real catch, and it's not useful for every event. Here's what it is, what it does, and which product we'd pick.
What is bicarb?
Bicarb is sodium bicarbonate, the same compound as baking soda. Taken in large enough doses before exercise, it raises the amount of bicarbonate in your blood.
That matters because hard efforts produce acid. As acid builds up in working muscles, they fatigue faster. Bicarbonate is one of your body's natural buffers. Raising blood bicarbonate gives your body more capacity to clear that acid, so you can hold a hard effort a little longer.
Sports supplements simply package the right dose in a more convenient, and ideally more stomach-friendly, form than a spoonful of baking soda.
What's the benefit?
The research is strong. The International Society of Sports Nutrition (ISSN) reviewed the evidence in its 2021 position stand and concluded that bicarb improves performance in high-intensity efforts lasting roughly 30 seconds to 12 minutes. That holds for cycling, running, swimming, rowing and combat sports, for both single and repeated efforts, and for both men and women.
Meta-analyses put the improvement at around 2% in time trials and repeated sprints. That's small on paper, but at the sharp end of a race it's a big margin.
Where it helps most:
Where the evidence is weaker: long, steady events like the marathon or a long road race, where acid build-up is rarely what limits you. Research on newer products has started to look at longer efforts. A small 2024 study found well-trained male cyclists completed a 40km time trial 1.5% faster with Maurten's bicarb system than with a placebo. But that study was small, and the evidence for long endurance events is still thin.
The drawbacks
Stomach upset is the big one. The effective dose is large, and the most common side effects are bloating, nausea, abdominal pain, diarrhea and, sometimes, vomiting. For some athletes, these cancel out the benefit entirely, or worse. A bad reaction on race morning can ruin your day.
Newer products try to fix this with enteric-coated capsules, which pass through the stomach before releasing, or by delivering the bicarb inside a carbohydrate gel. Head-to-head research suggests these can reduce stomach problems compared with plain bicarb, though the studies so far are small and mostly in male cyclists.
It's a lot of sodium. Sodium bicarbonate is about 27% sodium by weight. A typical dose for a 70kg athlete, around 21g, contains roughly 5.7g of sodium. If you have high blood pressure, kidney problems or are on a sodium-restricted diet, talk to your doctor before trying bicarb.
It's not useful for every event. If your race is a steady marathon or a long road race, bicarb is unlikely to be what makes the difference. Carbs and hydration matter far more.
It's expensive. Branded bicarb products can cost $9.00–$17.50 per dose. That adds up if you use it for training as well as racing.
How to take it
Bicarb is not on the World Anti-Doping Agency's banned list. But if you're drug tested, choose a product that's batch-tested for banned substances, because the risk with any supplement is contamination.
Our pick
We track five bicarb products. Here's how they compare.
As an Amazon Associate we earn from qualifying purchases. Pello may earn a commission on purchases made through some of these links at no extra cost to you. This never influences our scores or recommendations.Learn more
Our favorite: Flycarb Bicarb
Pello Score: 62 (Good) · $10.00 per serving · 4.1/5 from 92 reviews at The Feed
Flycarb is the only bicarb product we track that's Informed Sport certified, meaning every batch is tested for banned substances. It earns a perfect science score, comes in sizes matched to body weight, and has by far the most athlete reviews of any bicarb product we track. The trade-off is price: at about $0.83 per gram of bicarbonate, it's one of the most expensive options. For anyone who's drug tested, it's the clear choice.
Best value: Carbs Fuel Bicarb
Pello Score: 55 (Average) · $2.50 per pouch
At $0.17 per gram of bicarbonate, Carbs Fuel costs a fraction of the branded systems. It comes in 15g, 20g and 25g sizes matched to body weight and uses enteric-coated capsules to reduce stomach upset. It has no third-party banned-substance testing and no retailer reviews yet, so it's best for athletes who aren't drug tested and want to use bicarb regularly.
Also worth knowing
The bottom line
Bicarb works, and the research behind it is strong. But it works for a specific job: hard efforts of roughly 30 seconds to 12 minutes, or races decided by repeated surges. If that's your event, it's worth testing. Start with about 0.3g per kg, take it 60–180 minutes before with a carb-rich meal, and try it in hard training sessions first. If you're drug tested, choose Flycarb. If you're not, Carbs Fuel gives you the same buffer for far less.
References
1. Grgic J, et al. International Society of Sports Nutrition position stand: sodium bicarbonate and exercise performance. Journal of the International Society of Sports Nutrition. 2021;18:61.
2. Christensen PM, et al. Caffeine and bicarbonate for speed: a meta-analysis of legal supplements potential for improving intense endurance exercise performance. Frontiers in Physiology. 2017.
3. Shannon OM, et al. European Journal of Applied Physiology. 2024. (Maurten Bicarb System, 40km cycling time trial; confirm full title before publishing.)
4. Gough LA, Sparks SA. The effects of a carbohydrate hydrogel system for the delivery of bicarbonate mini-tablets on acid–base buffering and gastrointestinal symptoms in resting well-trained male cyclists. Sports Medicine – Open. 2024.
Get your personalized nutrition plan
Tell us about your event and we'll build a complete pre, during and post protocol
Build my plan →