Sodium bicarbonate (baking soda)
Summary
Doses near 0.3 g/kg body weight raise blood bicarbonate and give a small performance gain in high-intensity exercise (grade B), but the benefit for continuous running was negligible once stomach-related dropouts were counted. Stomach upset is common. Each gram carries about 270 mg of sodium, and very large amounts have caused dangerous alkalosis.
Key facts
- Small positive effect across buffering trials (ES 0.17; 189 articles, 2,019 participants); greatest for efforts of 0.5–10 minutes (ES 0.18) and over 10 minutes (ES 0.22)[1]
- ISSN: 0.2 g/kg minimum and about 0.3 g/kg optimal, 60–180 minutes before exercise[2]
- GI symptoms in 29.5% with bicarbonate vs 2.6% with placebo in running trials[3]
- Antacid labels warn people on a sodium-restricted diet to ask a doctor first[8]
- A 2026 review of 78 toxicity cases found severe metabolic alkalosis and hypernatremia after large ingestions[7]
- 4 graded human outcomes on this page
- October 13, 2026
How it works
EstablishedExtra bicarbonate in the blood increases the capacity to buffer hydrogen ions that accumulate during intense exercise; trials show blood bicarbonate rising about 5 mmol/L after supplementation.[1][2]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Exercise | Grade B | Improved | Meta-analysis of 189 trials · n = 2,019 · 2022 | 2 rows |
| Kidney | Grade C | Improved | RCT · n = 134 · 2009 | 2 rows |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| High-intensity exercise capacity and performance | Improved | Grade B | Meta-analysis · n = 2,019 · 2022 Adults in 189 placebo-controlled studies (158 with sodium bicarbonate) Form: Sodium bicarbonate and other extracellular buffers · Dose: Varied; typically 0.2–0.3 g/kg · Duration: Single dose to multi-day Overall effect versus placebo ES 0.17 (95% CrI 0.12–0.21); largest for 0.5–10 minute efforts (ES 0.18) and >10 minutes (ES 0.22). Blood bicarbonate rose 5.2 mmol/L. | 34687438 (opens PubMed)Source [1] |
| Kidney function decline in advanced CKD with low bicarbonate | Improved | Grade C | RCT · n = 134 · 2009 Adults with CKD (creatinine clearance 15–30) and serum bicarbonate 16–20 mmol/L Form: Oral sodium bicarbonate vs standard care · Dose: Oral sodium bicarbonate (dose not stated in the abstract) · Duration: 2 years Creatinine clearance declined 1.88 vs 5.93 mL/min/1.73 m² per year; rapid progression 9% vs 45%; fewer reached end-stage kidney disease. | 19608703 (opens PubMed)Source [4] |
| Continuous running performance | Mixed | Grade C | Meta-analysis · n = 126 · 2025 Mostly male runners in 11 crossover trials Form: Sodium bicarbonate (single dose) · Dose: Typically 0.3 g/kg · Duration: Single dose After adjusting for GI-related withdrawals and publication bias, the effect was negligible and not significant (SMD 0.18, 95% CI −0.01 to 0.36); GI symptoms 29.5% vs 2.6% with placebo. | 41416636 (opens PubMed)Source [3] |
| Physical function and kidney function in older adults with CKD | No effect | No effect | RCT · n = 300 · 2020 UK adults 60+ with eGFR <30 and serum bicarbonate <22 mmol/L Form: Oral sodium bicarbonate vs placebo · Dose: Up to 3 g/day · Duration: Up to 2 years No effect on the Short Physical Performance Battery at 12 months (−0.4 points) or on GFR; adverse events were more frequent with bicarbonate (457 vs 400) and quality of life was lower. | 32268897 (opens PubMed)Source [5] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Baking soda powder | Varies[2] | Same compound as tablets; dosed by body weight in exercise studies.[2] | GI distress is the common limit; ISSN notes higher doses (0.4–0.5 g/kg) add side effects without extra benefit.[2] | Exercise performance |
| Capsules or enteric-coated tablets | Varies[6] | Delivers the same bicarbonate load.[6] | A 2026 review lists spreading intake over hours, enteric-coated capsules and mini-tablets in a carbohydrate gel as ways to reduce GI symptoms.[6] | Exercise performance |
| OTC antacid tablets (650 mg) | Varies[8] | Labelled for heartburn and acid indigestion.[8] | Label limits daily use and duration and warns about sodium-restricted diets and prescription drugs.[8] | Antacid use, not exercise |
Studied doses
Doses studied in human trials ranged from 0.2 g/kg to 0.5 g/kg body weight as a single dose 60–180 minutes before exercise, with multi-day schedules of 0.4–0.5 g/kg per day split across meals for 3–7 days.[2]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
Medicines
- Prescription medicines (antacid effect)Drug labelThe OTC label states that antacids may interact with certain prescription drugs and advises asking a doctor or pharmacist before use.[8]
Who should be careful
- Sodium-restricted diets, high blood pressure or heart failure
- The OTC label tells people on a sodium-restricted diet to ask a doctor; exercise doses supply several grams of sodium.[8]
- Kidney disease (unsupervised use)
- In older adults with advanced CKD, bicarbonate did not improve function and caused more adverse events; use only under a nephrologist.[5]
- Large single amounts
- Case reports and reviews describe metabolic alkalosis, hypernatremia, hypokalaemia, urinary alkalinisation and even gastric rupture after excessive ingestion.[7][9]
- Pregnancy and breastfeeding
- The antacid label advises asking a health professional before use.[8]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
Toxicity from large amounts
- Reported harms
- A man who escalated to 480 g for "cleansing" developed pH 7.54, bicarbonate 54.5 mmol/L and sodium 162 mEq/L; a review of 78 cases found uses shifting to pica, drug-test avoidance and natural remedies.[7]
- Label limits
- The OTC antacid label limits use to 24 tablets (adults under 60) or 12 tablets (60 and older) per 24 hours and no more than 2 weeks at the maximum dose.[8]
Frequently asked questions
Does baking soda improve exercise performance?
It gives a small boost in high-intensity efforts, mostly studied between about 30 seconds and 12 minutes; in continuous running trials the benefit was negligible after counting stomach-related dropouts.[1][3]
How much sodium bicarbonate was used in studies?
Usually 0.2–0.3 g per kg of body weight, 60–180 minutes before exercise; higher amounts mainly added side effects.[2]
What are the side effects?
Nausea, bloating and diarrhoea are common; in running trials GI symptoms affected 29.5% versus 2.6% on placebo.[3]
Sources
- [1]Extracellular Buffering Supplements to Improve Exercise Capacity and Performance: A Comprehensive Systematic Review and Meta-analysis.. Sports Med, 2022. meta-analysis
- [2]International Society of Sports Nutrition position stand: sodium bicarbonate and exercise performance.. J Int Soc Sports Nutr, 2021. review
- [3]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. meta-analysis
- [4]Bicarbonate supplementation slows progression of CKD and improves nutritional status.. J Am Soc Nephrol, 2009. RCT
- [5]Clinical and cost-effectiveness of oral sodium bicarbonate therapy for older patients with chronic kidney disease and low-grade acidosis (BiCARB): a pragmatic randomised, double-blind, placebo-controlled trial.. BMC Med, 2020. RCT
- [6]Gastrointestinal Symptoms Associated With Sodium Bicarbonate Supplementation Protocols: A Systematic Review.. Eur J Sport Sci, 2026. systematic-review
- [7]Severe metabolic alkalosis and hypernatremia induced by excessive sodium bicarbonate intake: A case report and literature review.. Am J Emerg Med, 2026. observational
- [8]Sodium Bicarbonate Antacid 650 mg tablets: Drug Facts (Rugby Laboratories). DailyMed, US National Library of Medicine, 2026. label
- [9]Acute toxicity from baking soda ingestion.. Am J Emerg Med, 1994. observational
What changed
- Editorial evidence re-review: key fact no longer says the effect was largest for 0.5–10 minute efforts (the meta-analysis found ES 0.18 there and 0.22 for efforts over 10 minutes); summary and FAQ wording on running matched to the 2025 meta-analysis.
- Second-pass self-review: every PMID re-checked against NCBI esummary (title, year, no retraction or expression-of-concern flag), every dose, n and duration re-read against the PubMed abstract or PMC full text, grades held conservative, and interactions limited to what a cited source supports.
- First draft. Source titles and years taken from NCBI E-utilities esummary; abstracts read for every evidence row.