Sodium bicarbonate (NaHCO₃) is the chemical in household baking soda and in many over-the-counter (OTC) antacids. In sport it is used as a buffering agent: taken an hour or more before hard exercise, it raises the amount of bicarbonate in the blood, which helps the body clear the acid that builds up during intense efforts.
It is one of the few supplements that major sports bodies rate as having good evidence. The International Society of Sports Nutrition (ISSN) 2021 position stand concludes that doses of 0.2–0.5 g/kg improve high-intensity exercise lasting roughly 30 seconds to 12 minutes, with 0.3 g/kg as the best-studied dose (Grgic et al., JISSN 2021). The main drawback is gut distress, which is common and can cancel out the benefit. These doses are scaled to body weight and are much larger than labeled antacid doses.
This page summarizes what the position stands, meta-analyses, trials and US antacid labeling report. It is for education only and is not medical advice.
| Property | Detail |
|---|---|
| Class | Extracellular (blood) buffering agent; OTC antacid active ingredient |
| Chemistry | NaHCO₃, molecular weight 84.007 g/mol (PubChem) |
| Route | Oral: powder dissolved in water, tablets, or gelatin or enteric-coated capsules in trials |
| Studied ergogenic doses | 0.2–0.5 g/kg single dose; 0.3 g/kg most studied; multi-day loading at 0.4–0.5 g/kg/day |
| Studied timing | 60–180 min before exercise (ISSN); 60–150 min (IOC) |
| Time course | No single half-life applies. Blood bicarbonate typically peaks ≈60–70 min after a dose, but the range is 10–240 min |
| Typical effect | Small: ≈1.7% higher mean power in a 1-minute sprint (meta-analysis) |
| US status | OTC antacid under the FDA monograph (21 CFR 331); daily limit 200 mEq sodium and 200 mEq bicarbonate under age 60 |
| WADA status | Not on the 2026 Prohibited List; IV infusions over 100 mL per 12 h are a prohibited method |
What it is
Sodium bicarbonate is a white, water-soluble salt. In water or stomach acid it splits into sodium (Na⁺) and bicarbonate (HCO₃⁻) ions. Bicarbonate is the body’s main buffer in blood and the fluid around cells: it binds hydrogen ions (H⁺, the acid part of an acid) and turns them into carbon dioxide and water.
Research on bicarbonate and exercise goes back to the 1930s. The ISSN position stand traces modern work to a 1977 study in 5 people, who cycled to exhaustion for an average of 438 s after sodium bicarbonate, compared with 270 s in the control trial and 160 s after an acidifying salt (ammonium chloride) (Grgic et al., JISSN 2021).
Mechanism: extracellular buffering
The ISSN stand describes the accepted mechanism in steps (Grgic et al., JISSN 2021):
- More bicarbonate in the blood. Bicarbonate cannot cross the muscle cell membrane, so the dose stays outside muscle cells. Plasma bicarbonate rises with the dose, and blood pH rises with it, a mild metabolic alkalosis.
- A steeper acid gradient. During intense exercise, muscle produces H⁺ and lactate. A more alkaline blood increases the gradient that drives H⁺ and lactate out of muscle through transporters called MCT1 and MCT4.
- Slower muscle acidosis. A study using magnetic resonance spectroscopy showed a delayed fall in muscle pH, although other studies of muscle pH conflict. This allows glycolysis (fast carbohydrate breakdown) to keep supplying energy for longer.
- Possible ion effects. One study found lower potassium concentrations, more potassium efflux from exercising muscle and faster potassium reuptake after exercise with bicarbonate. This may help preserve the muscle’s electrical excitability.
This mechanism explains why the effect depends on the type of exercise. Efforts too short to build up much acid, such as a single 10–30 s sprint or a one-repetition maximum lift, show little or no benefit. The IOC consensus statement describes the same mechanism and lists sodium bicarbonate among the few supplements with good evidence (Maughan et al., BJSM 2018).
How it differs from beta-alanine
Beta-alanine is the other common buffering supplement, but it works inside the muscle cell.
| Feature | Sodium bicarbonate | Beta-alanine |
|---|---|---|
| Where it buffers | Outside the muscle cell (blood and the fluid around cells) | Inside the muscle cell, by raising carnosine |
| Time to work | Hours (single dose before exercise) | Weeks of daily intake |
| Main side effect | Gut distress | Skin tingling (paresthesia) |
How it works in the body
Some of a dose reacts with stomach acid and forms carbon dioxide gas, which the ISSN stand links to belching and bloating. The rest is absorbed in the stomach and small intestine (Grgic et al., JISSN 2021).
Because bicarbonate is a normal body buffer, there is no drug-style half-life. What matters in studies is how much and for how long blood bicarbonate rises:
| Measure | Finding | Source |
|---|---|---|
| Rise in blood bicarbonate, all buffering supplements pooled | +5.2 mmol/L (95% CrI 4.7–5.7) | de Oliveira et al., Sports Med 2022 |
| Rise after 0.1 g/kg | 1–2 mmol/L (too small to help performance) | ISSN |
| Rise after 0.2 g/kg (one study) | ≈5 mmol/L | ISSN |
| Rise in women, pooled from 11 studies | ≈7 mmol/L | ISSN |
| Typical time to peak | ≈60–70 min; individual range 10–240 min | ISSN |
| Time to peak in one study, by dose | 30–150 min (0.1 g/kg); 40–165 min (0.2 g/kg); 75–180 min (0.3 g/kg) | ISSN |
| Time to peak after 0.3 g/kg, by capsule size | 94 min (small), 141 min (medium), 121 min (large) | ISSN |
| Window after 0.3 g/kg | Rise above 5 mmol/L lasting ≈3 h, starting ≈60 min after ingestion | ISSN |
The ISSN stand notes that one study found time to peak was not reproducible within the same person across repeated doses. A higher dose (0.3 g/kg) gives a longer-lasting rise than 0.2 g/kg (Grgic et al., JISSN 2021).
In the de Oliveira meta-analysis, medium blood bicarbonate rises (4–6 mmol/L) were linked to greater performance effects than small rises of 4 mmol/L or less; the estimate for large rises (over 6 mmol/L) pointed the same way but was less certain (de Oliveira et al., Sports Med 2022).
Regulatory status and antacid labeling
OTC antacid
In the US, sodium bicarbonate is an approved antacid ingredient under the FDA’s OTC antacid monograph. The monograph sets these maximum daily amounts (21 CFR 331.11):
| Age | Maximum sodium per day | Maximum bicarbonate per day |
|---|---|---|
| Up to 60 years | 200 mEq (≈4.6 g sodium) | 200 mEq (≈16.8 g sodium bicarbonate) |
| 60 years or older | 100 mEq (≈2.3 g sodium) | 100 mEq (≈8.4 g sodium bicarbonate) |
The monograph also requires antacid labels to warn against taking more than the maximum daily dose, or using the maximum dose for more than 2 weeks, except under a doctor’s supervision (21 CFR 331.30).
Two current Drug Facts labels show how this is applied:
| Label item | Sodium bicarbonate 650 mg tablets | Arm & Hammer Baking Soda (antacid directions) |
|---|---|---|
| Unit | 1 tablet (650 mg) | ½ teaspoon dissolved in ½ glass (4 fl oz) of water |
| Sodium per unit | 178 mg | 656 mg |
| Maximum in 24 h, under 60 | 24 tablets | Seven ½ teaspoons |
| Maximum in 24 h, 60 and older | 12 tablets | Three ½ teaspoons |
| Duration limit | Do not use the maximum dose for more than 2 weeks | Do not use the maximum dose for more than 2 weeks |
| Other warnings | Ask a doctor if on a sodium-restricted diet; ask a doctor or pharmacist if taking prescription drugs | Same, plus a stomach warning and “do not administer to children under age 5” |
Sources: Major sodium bicarbonate tablets, DailyMed; Arm & Hammer Baking Soda, DailyMed.
The baking soda label carries a capitalized stomach warning: do not take it until the powder is completely dissolved, and do not take it when overly full from food or drink. It advises seeing a doctor if severe stomach pain follows.
Ergogenic doses are not a labeled antacid use. They are scaled to body weight: a 0.3 g/kg dose is about 3.5 mmol/kg of bicarbonate (Carr et al., Sports Med 2011). For most adults, one such dose is in the range of, or above, the monograph’s whole 24-hour antacid limit, and multi-day loading protocols repeat this daily.
Anti-doping
Sodium bicarbonate is not named on the WADA 2026 Prohibited List, and oral use is permitted. However, the list prohibits intravenous infusions or injections of more than 100 mL per 12-hour period outside hospital treatment, surgery or clinical investigations (method M2.2), whatever the substance. The IOC consensus statement warns that supplements in general carry a risk of contamination with prohibited substances (Maughan et al., BJSM 2018).
What the research shows
Overall effect size
Several meta-analyses agree on a small, real benefit for the right kind of exercise:
| Meta-analysis | Scope | Main result |
|---|---|---|
| Carr et al., Sports Med 2011 | 38 studies, 137 estimates for sodium bicarbonate | +1.7% mean power (90% CL ±2.0%) in a single 1-min sprint at ≈0.3 g/kg; benefit smaller in non-athletes and women |
| de Oliveira et al., Sports Med 2022 | 189 articles, 2,019 participants (158 with sodium bicarbonate) | Overall effect size 0.17 (95% CrI 0.12–0.21) for all buffering agents; sodium bicarbonate more effective than sodium citrate |
| Grgic et al., Sports Med 2020 | 13 muscular-endurance and 11 strength studies | Muscular endurance SMD 0.37 (95% CI 0.15–0.59); strength SMD −0.03 (95% CI −0.18 to 0.12), no effect |
| Ge et al., Front Nutr 2026 | 20 studies, 241 team-sport athletes | High-intensity intermittent exercise Hedges’ g 0.23 (95% CI 0.07–0.39); prediction interval crossed zero; low certainty |
| Miller et al., JISSN 2025 | 11 crossover trials, 126 participants, continuous running | SMD 0.18 (95% CI −0.01 to 0.36), not significant after adjusting for GI dropouts; SMD 0.40 in the 8 men-only studies |
An effect size around 0.2 is conventionally called small. Carr et al. found the benefit grew slightly with dose and with the number of sprint bouts.
Exercise duration
The ISSN stand concludes that benefits are best established for high-intensity tasks lasting about 30 s to 12 min (Grgic et al., JISSN 2021). Results it summarizes:
- Single 30-s sprint (Wingate test): a meta-analysis found a trivial effect on mean power (d 0.02; 95% CI −0.07 to 0.11).
- Repeated 30-s sprints: effects grew in later bouts, up to d 0.62 in bout 4, mainly with short rests (3–6 min).
- 800-m run (n = 6): 0.3 g/kg cut time by 2.9 s (1.8%).
- 4-km cycling time trial (≈6 min): times fell by 5–8 s (≈2%).
- Events over ≈20 min: results are mixed. One study found that bicarbonate taken before and during a 3-h simulated race raised mean power in a final 90-s sprint by ≈3%.
The 2022 meta-analysis found effects for efforts of 0.5–10 min (ES 0.18) and also over 10 min (ES 0.22) (de Oliveira et al., Sports Med 2022). In contrast, the 2025 running meta-analysis (tests lasting 1–30 min) found no significant benefit once gut-related dropouts were accounted for (Miller et al., JISSN 2025).
Sport-specific results
As summarized in the ISSN position stand (Grgic et al., JISSN 2021):
| Sport or test | Pooled or reported effect |
|---|---|
| 2,000-m rowing (meta-analysis) | +1.4% (90% CI 0.1–2.6%) |
| 200–400-m swimming (meta-analysis) | d 0.22 (≈1.3%); no effect on 100-m events |
| Yo-Yo intermittent recovery test (meta-analysis) | d 0.36 (≈16% more distance) |
| Judo (Special Judo Fitness Test) | ≈2 more throws (6%) in bouts 2 and 3 |
| Boxing sparring (0.3 g/kg, 60 min before) | More punches over four 3-min rounds |
| Multiple sets of resistance exercise | 157 vs 164 total repetitions over 13 sets (4.5%) in one study |
Dose
The ISSN stand summarizes the single-dose evidence as follows (Grgic et al., JISSN 2021):
| Single dose | Finding |
|---|---|
| 0.1 g/kg | Not ergogenic; blood bicarbonate rises only 1–2 mmol/L |
| 0.15 g/kg | Unclear; effective in 1 of 2 studies |
| 0.2 g/kg | Ergogenic in several studies; considered the minimum effective dose |
| 0.3 g/kg | Most studied; consistently ergogenic; considered optimal |
| 0.4–0.5 g/kg | Ergogenic but no extra benefit over 0.3 g/kg, with more and worse side effects |
In one study, 0.2 g/kg helped 8 of 12 participants and 0.3 g/kg helped 11 of 12; the difference was not significant. A 1992 dose-response study found no difference in effect from 0.3 to 0.5 g/kg but more side effects at 0.4 and 0.5 g/kg.
Timing and multi-day loading
Most trials gave a single dose 60–180 min before exercise, and the ISSN stand concludes this window is effective (Grgic et al., JISSN 2021). The IOC lists 0.2–0.4 g/kg taken 60–150 min before exercise, with split doses over 30–180 min as an alternative (Maughan et al., BJSM 2018). Some trials timed the dose to each person’s measured peak in blood bicarbonate, which requires a blood gas analyzer.
Multi-day protocols give the supplement for several days and usually stop the evening before testing, so no dose is taken on the day of the event. According to the ISSN stand:
- Protocols of 3–7 days needed 0.4–0.5 g/kg per day; 0.3 g/kg per day was generally not enough.
- The daily amount was split into smaller doses, for example 0.1–0.2 g/kg at breakfast, lunch and dinner.
- In the original study, 0.5 g/kg per day for 5 days raised total work by ≈14% and peak power by ≈10% in a 60-s cycling test.
- A 10-day protocol with much smaller, rising doses (0.025 to 0.100 g/kg per day) improved some outcomes in one research group’s studies, but has not been replicated elsewhere.
The IOC statement also describes serial loading with 3–4 smaller doses per day for 2–4 days.
Women
Only about 20% of sodium bicarbonate studies included women. A meta-analysis of the 11 studies that reported results for women found an effect size of 0.37, similar to men, but the evidence base is much smaller (Grgic et al., JISSN 2021). The running meta-analysis found that male sex and higher body mass predicted larger benefits (Miller et al., JISSN 2025). In 11 female CrossFit athletes, enteric-coated sodium bicarbonate at 0.3 g/kg improved a 2-km rowing time trial by 2.24% (Martin et al., Eur J Appl Physiol 2023).
Training adaptations
A few studies gave bicarbonate before every training session. In one, 16 women took 0.4 g/kg or placebo before each of 24 interval sessions over 8 weeks; tested without the supplement afterward, the bicarbonate group improved lactate threshold more (26% vs 15%) and time to fatigue more (164% vs 123%) (Grgic et al., JISSN 2021). Two other small studies (4–6 people per group) found no added benefit on rowing or strength, so the evidence is limited.
Placebo effect
The ISSN stand estimates that about 30% of the performance benefit of buffering agents may come from expectation (placebo). In one study, a placebo that participants were told was sodium bicarbonate improved 1,000-m running time by 1.5%, close to the 1.7% seen with the real supplement (Grgic et al., JISSN 2021). Gut symptoms can also reveal to participants which trial they are in, which weakens blinding.
Combinations with other supplements
From the ISSN stand (Grgic et al., JISSN 2021):
- Beta-alanine: the best-studied combination. A meta-analysis found larger effects with both than with beta-alanine alone (d 0.43 vs 0.18), though several individual studies found no added benefit.
- Caffeine: only 1 of 8 studies in a review found an additive effect, and some of those studies had high rates of side effects.
- Creatine: a few studies reported additive effects.
- Dietary nitrate: the single study found no effect of either supplement, alone or combined.
Side effects and risks
Gut symptoms
Gut distress is the main problem. Carbon dioxide forms when bicarbonate meets stomach acid, and the ISSN stand lists bloating, nausea, vomiting and abdominal pain as the most common effects. Their frequency and severity rise with the dose (Grgic et al., JISSN 2021).
| Finding | Detail |
|---|---|
| GI symptoms in running trials | 29.5% with bicarbonate vs 2.6% with placebo (OR 5.9) (Miller et al., JISSN 2025) |
| Withdrawal due to GI symptoms | 8.7% vs 1.6% (OR 2.9) (same source) |
| Effect on results | In one study, a benefit appeared only after excluding 4 of 21 participants with gut discomfort (ISSN) |
The IOC statement notes that gut distress can impair rather than improve performance (Maughan et al., BJSM 2018).
Strategies tested in trials to reduce gut symptoms
| Strategy | What trials found |
|---|---|
| Lower dose (0.2–0.3 g/kg) | Fewer and milder symptoms than 0.4–0.5 g/kg (ISSN) |
| Longer gap before exercise | Less discomfort 180 min after the dose than at 60 or 120 min, with a similar bicarbonate rise; symptoms peaked ≈90 min after ingestion in another study (ISSN) |
| Taking it with a carbohydrate meal | 0.3 g/kg with a meal of 1.5 g/kg carbohydrate gave alkalosis with the fewest symptoms (ISSN; IOC) |
| Enteric-coated capsules | Fewer symptoms than gelatin capsules (details below) |
| Multi-day loading | Avoids dosing on the day of competition (ISSN) |
The enteric-capsule data come from a small group of crossover trials:
- Symptom study (n = 14 trained men, 0.3 g/kg): symptom severity was 2.8 arbitrary units with enteric-coated capsules vs 7.0 with gelatin capsules. However, blood bicarbonate rose less with the enteric-coated form (Hilton et al., IJSNEM 2020).
- Cycling study (n = 11 trained men, 4-km time trial): times improved by 8.5 s with enteric-coated and 9.6 s with gelatin capsules vs placebo, with no difference between them. Gut symptoms occurred in 3 participants with enteric-coated vs 7 with gelatin capsules (Hilton et al., Eur J Appl Physiol 2020).
The ISSN stand cautions that enteric coating may prevent stomach symptoms but is unlikely to prevent intestinal effects such as osmotic diarrhea, and that larger studies are needed.
Sodium load
Sodium bicarbonate is a sodium salt. The labels above list 178 mg of sodium per 650 mg tablet and 656 mg per ½ teaspoon of baking soda. For comparison, the US Dietary Guidelines advise adults to limit sodium to under 2,300 mg per day (FDA).
The ISSN stand notes that long-term use at common doses (0.3 g/kg) adds to habitual sodium intake and may push it over the tolerable upper intake level, and that effects on kidney function have not been studied (Grgic et al., JISSN 2021). Antacid labels tell anyone on a sodium-restricted diet to ask a doctor before use.
Excessive intake: alkalosis and stomach rupture
Large or repeated doses outside the labeled limits have caused serious harm:
- Poison-center data: California recorded 192 symptomatic cases of baking soda misuse from 2000 to 2012. Most (55.2%) had symptoms needing medical evaluation, and 12 people were admitted to hospital with electrolyte imbalances, metabolic alkalosis or slowed breathing (Al-Abri and Kearney, J Clin Pharm Ther 2014).
- Pattern of toxicity: a review of 78 published cases found that acute, massive ingestion was often complicated by stomach rupture and was linked to high mortality, while chronic overuse mainly caused severe metabolic alkalosis and electrolyte problems (Inokuchi et al., Am J Emerg Med 2026).
- Stomach rupture: a review of 36 spontaneous gastric rupture cases found 10 associated with sodium bicarbonate; the authors’ own two cases followed a large meal (Han et al., J Eat Disord 2022). This is why the baking soda label warns against taking it when overly full.
Interactions and who should be cautious
- Prescription drugs: antacid labels state that antacids may interact with certain prescription drugs and advise asking a doctor or pharmacist first.
- Sodium-restricted diets: labels advise asking a doctor before use.
- Pregnancy and breastfeeding: the tablet label advises asking a health professional before use.
- Children: the baking soda label says not to give it to children under 5.
- Older adults: labeled daily maximums are halved from age 60.
Key takeaways
- An extracellular buffer. It raises blood bicarbonate and pH, which speeds the removal of acid from working muscle; it does not enter muscle cells.
- A small benefit for the right effort. Meta-analyses show small gains (≈1–2%, effect sizes ≈0.2–0.4) for high-intensity work lasting roughly 30 s to 12 min, and for repeated sprints or sets. It does not improve maximal strength or single short sprints.
- 0.3 g/kg is the best-studied dose. The ISSN stand calls 0.2 g/kg the minimum and 0.3 g/kg optimal, taken 60–180 min before exercise; higher doses add side effects without extra benefit.
- Gut distress is common and can erase the benefit. About 30% of runners had GI symptoms in one meta-analysis. Lower doses, a carbohydrate meal, a longer gap before exercise and enteric-coated capsules reduced symptoms in trials.
- Trial doses exceed antacid label limits. The OTC monograph caps sodium bicarbonate at 200 mEq of sodium per day under age 60 and for no more than 2 weeks at that level. Each dose also carries a substantial sodium load.
- Allowed in sport, but not risk-free. It is not on the WADA list. Misuse has caused severe alkalosis and, rarely, fatal stomach rupture.
Sources
- Grgic J, Pedisic Z, Saunders B, et al. International Society of Sports Nutrition position stand: sodium bicarbonate and exercise performance. J Int Soc Sports Nutr. 2021;18(1):61. PubMed; PMC.
- Maughan RJ, Burke LM, Dvorak J, et al. IOC consensus statement: dietary supplements and the high-performance athlete. Br J Sports Med. 2018;52(7):439–455. PubMed.
- Carr AJ, Hopkins WG, Gore CJ. Effects of acute alkalosis and acidosis on performance: a meta-analysis. Sports Med. 2011;41(10):801–814. PubMed.
- de Oliveira LF, Dolan E, Swinton PA, et al. Extracellular buffering supplements to improve exercise capacity and performance: a comprehensive systematic review and meta-analysis. Sports Med. 2022;52(3):505–526. PubMed.
- Grgic J, Rodriguez RF, Garofolini A, et al. Effects of sodium bicarbonate supplementation on muscular strength and endurance: a systematic review and meta-analysis. Sports Med. 2020;50(7):1361–1375. PubMed.
- Miller LE, Bhattacharyya R, Katz SJ, et al. Negligible benefit of oral single-dose sodium bicarbonate on continuous running performance: systematic review with meta-analysis of randomized, double-blind, placebo-controlled trials. J Int Soc Sports Nutr. 2025;22(1):2538606. PubMed.
- Ge X, Sun H, Wu C, Liu S. Effects of acute or short-term oral sodium bicarbonate supplementation on high-intensity intermittent exercise performance and physiological responses in team-sport athletes: a systematic review and meta-analysis. Front Nutr. 2026;13:1936178. PubMed.
- Hilton NP, Leach NK, Craig MM, et al. Enteric-coated sodium bicarbonate attenuates gastrointestinal side-effects. Int J Sport Nutr Exerc Metab. 2020;30(1):62–68. PubMed.
- Hilton NP, Leach NK, Hilton MM, et al. Enteric-coated sodium bicarbonate supplementation improves high-intensity cycling performance in trained cyclists. Eur J Appl Physiol. 2020;120(7):1563–1573. PubMed.
- Martin RAXJ, Hilton NP, Sparks SA, et al. The effects of enteric-coated sodium bicarbonate supplementation on 2 km rowing performance in female CrossFit® athletes. Eur J Appl Physiol. 2023;123(6):1191–1198. PubMed.
- Al-Abri SA, Kearney T. Baking soda misuse as a home remedy: case experience of the California Poison Control System. J Clin Pharm Ther. 2014;39(1):73–77. PubMed.
- Han YJ, Roy S, Siau AMPL, Majid A. Binge-eating and sodium bicarbonate: a potent combination for gastric rupture in adults-two case reports and a review of literature. J Eat Disord. 2022;10(1):157. PubMed.
- Inokuchi R, Maeda A, Komaru Y, et al. Severe metabolic alkalosis and hypernatremia induced by excessive sodium bicarbonate intake: a case report and literature review. Am J Emerg Med. 2026;103:45–49. PubMed.
- Code of Federal Regulations. 21 CFR Part 331: Antacid products for over-the-counter (OTC) human use (§ 331.11 Listing of specific active ingredients; § 331.30 Labeling of antacid products). eCFR.
- Major Pharmaceuticals. Sodium bicarbonate 10 gr (650 mg) antacid tablets, Drug Facts label. DailyMed.
- Church & Dwight Co. Arm and Hammer Baking Soda (sodium bicarbonate) powder, Drug Facts label. DailyMed.
- U.S. Food and Drug Administration. Sodium in your diet. FDA.
- National Center for Biotechnology Information. PubChem compound summary: sodium bicarbonate (CID 516892). PubChem.
- World Anti-Doping Agency. The 2026 Prohibited List. WADA 2026 Prohibited List.