Sodium bicarbonate is one of the most studied performance supplements in sports science. Over 40 years of research, hundreds of randomized controlled trials, and an official endorsement from the International Society of Sports Nutrition (ISSN) — and yet most athletes have never tried it.
The reason is simple: baking soda dissolved in water causes brutal GI distress. Nausea, cramping, bloating mid-race — consequences bad enough that most athletes who try it once never try again.
This guide covers everything: the mechanism, the evidence, the dosing protocol, the GI problem, and the hydrogel system that solves it.
What is sodium bicarbonate?
Sodium bicarbonate (NaHCO₃) is the chemical name for baking soda — the same compound in your kitchen. As a supplement, it's taken at a precise dose (0.3g per kg of body weight) 90 minutes before high-intensity exercise to increase your blood's buffering capacity.
It's legal under WADA rules. It's FDA-compliant as a food ingredient. It's been used by Olympic athletes since the 1980s. And a 2021 ISSN position stand — based on hundreds of studies — officially classifies it as ergogenic for high-intensity sports.
The mechanism: why your muscles burn
During maximal effort, your muscles produce energy through anaerobic glycolysis — a fast process that doesn't require oxygen but produces hydrogen ions (H⁺) as a byproduct. As H⁺ accumulates, blood pH drops from its resting value of ~7.4 toward ~6.9 during peak effort.
This acidosis is the burn you feel. It impairs muscle contraction, slows enzyme activity, and forces you to back off. The limiting factor in an 800m race or a 5-minute cycling interval isn't usually your aerobic engine — it's the acid environment shutting it down.
Sodium bicarbonate raises your blood's bicarbonate concentration before exercise — expanding your buffer capacity so pH drops more slowly when H⁺ builds up.
The result: your blood pH stays closer to 7.1–7.2 instead of falling to 6.9 during hard efforts. That difference extends how long you can sustain maximal intensity before acid forces you to slow down.
What the research actually shows
The evidence base is substantial. Here are the key findings:
| Study type | Finding | PMID |
|---|---|---|
| Umbrella review (2021) | Improves peak power, anaerobic capacity, endurance 45s–8min, muscular endurance, rowing, and intermittent running | 34794476 |
| ISSN Position Stand (2021) | Ergogenic for muscular endurance, Cohen's d = 0.37 across 20+ sports | 34503527 |
| Meta-analysis (2021) | Significant improvement in time to exhaustion, effect size 1.48 | 33887823 |
| Cycling TT meta-analysis (2023) | Significant benefit for cycling time trials | 35633035 |
| Swimming RCT (2023) | Improved interval swimming in competitive swimmers | 37027014 |
| Honest caveat (2025) | Negligible benefit for continuous steady-state running over 10K pace | 41416636 |
Bottom line: bicarb works best for efforts lasting 45 seconds to 8 minutes at near-maximal intensity. Think 800m–5K running, cycling intervals, rowing, CrossFit WODs, and combat sports. It's not a marathon supplement.
The dose: 0.3g per kg of body weight
The evidence-based dose is 0.3g of sodium bicarbonate per kilogram of body weight. Here's what that looks like in practice:
| Body weight | Dose |
|---|---|
| 60 kg (132 lb) | 18g NaHCO₃ |
| 65 kg (143 lb) | 19.5g NaHCO₃ |
| 70 kg (154 lb) | 21g NaHCO₃ |
| 75 kg (165 lb) | 22.5g NaHCO₃ |
| 80 kg (176 lb) | 24g NaHCO₃ |
If you're new to bicarb, start at 0.2g/kg and build up over 2–3 sessions. Your gut needs to adapt before you hit the full therapeutic dose.
Timing: the 90-minute window
Timing matters more than most athletes realize. Peak blood bicarbonate elevation occurs 60–90 minutes after ingestion. Too early and the buffer is past its peak. Too late and you haven't fully loaded yet.
Take bicarb 90 minutes before your race or hard session, at least 1 hour after your last meal. Don't eat a large meal alongside it — food in the stomach slows absorption and increases GI risk.
The GI problem — and the hydrogel solution
Here's the catch that stops most athletes: when you dissolve 19g of sodium bicarbonate in water and drink it, it reacts with your stomach acid (HCl) immediately — producing CO₂ gas, causing bloating, nausea, and worse.
The solution is hydrogel encapsulation. By mixing bicarb with maltodextrin, fructose, and xanthan gum — and letting it gel for 3–5 minutes in water — you create a thick matrix that protects the bicarb from stomach acid. The gel passes through the stomach largely intact and releases the bicarb in the small intestine, where it absorbs cleanly into the bloodstream.
This is the mechanism behind Maurten's BICARB 100 (retail: $17.50/serving). BICARB.NET uses the same principle with the same ingredients — at $5/serving.
Frequency and gut training
Sodium bicarbonate is high in sodium. Don't exceed 3 doses per week, reduce dietary sodium from other sources on days you take it, and stay well hydrated. Never use bicarb in a race for the first time — practice the protocol in 2–3 training sessions first so you know how your body responds.
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