Sodium bicarbonate (baking soda) is taken by dissolving powder in water or swallowing tablets, but the amount, timing, and method depend entirely on why you’re using it. The three most common reasons are relieving heartburn, boosting athletic performance, and managing a medical condition like chronic kidney disease. Each has different dosing rules, and getting them wrong can cause real discomfort or harm.
For Heartburn and Sour Stomach
This is the simplest and most common use. Dissolve 1 to 2½ teaspoons (about 3.9 to 10 grams) of sodium bicarbonate powder in a full glass of cold water and drink it after meals. Cold water dissolves it more slowly than warm, but it reduces the chance of excessive fizzing in your stomach. Stir until the powder is fully dissolved before drinking.
Don’t exceed 5 teaspoons (19.5 grams) in a single day. This is meant for occasional, short-term relief. If you find yourself reaching for baking soda regularly, that’s a sign the underlying cause of your heartburn needs attention rather than repeated neutralization.
For Athletic Performance
Sodium bicarbonate acts as a buffer against the acid your muscles produce during intense effort. It’s effective for high-intensity activities lasting roughly 1 to 10 minutes, including cycling, rowing, swimming, running, and combat sports like boxing and judo.
The minimum effective single dose is 0.2 grams per kilogram of body weight, and the optimal dose is 0.3 g/kg. For a 70 kg (154 lb) person, that works out to about 21 grams, or roughly 5 teaspoons. Going higher (0.4 or 0.5 g/kg in a single dose) doesn’t improve performance and significantly increases the chances of nausea, bloating, and diarrhea.
Timing and Delivery
Take it 2 to 2.5 hours before exercise, alongside a small carbohydrate-rich meal (about 1.5 grams of carbs per kilogram of body weight). The food slows absorption and reduces stomach distress. Blood buffering capacity peaks within that window and stays elevated for 3 to 4 hours, so you have a comfortable margin before competition.
If you’ve never used it before, test your tolerance during training well before any event. Gastrointestinal side effects are the biggest practical barrier, and individual responses vary widely. Some athletes find that splitting the dose across multiple smaller servings over 30 to 60 minutes helps.
An alternative to single-dose loading is a multi-day protocol: take 0.4 to 0.5 g/kg per day, split across the day, for 3 to 7 days before competition. This approach builds up buffering capacity more gradually and tends to cause fewer gut problems on race day.
For Chronic Kidney Disease
When your kidneys can’t remove enough acid from your blood, a condition called metabolic acidosis develops. Sodium bicarbonate tablets are commonly prescribed to correct this. The typical starting dose is a 650 mg tablet twice daily, which provides about 15.5 milliequivalents of bicarbonate per day. From there, the dose is adjusted based on blood test results.
The 2024 KDIGO guidelines recommend treating when serum bicarbonate drops below 18 mmol/L, while also monitoring to make sure levels don’t overshoot above normal. Treatment also needs to avoid worsening blood pressure, potassium levels, or fluid retention. This is not a self-managed situation: your nephrologist will set and adjust the dose based on regular lab work.
Side Effects and Risks
The most common side effects are gas, bloating, stomach cramps, and nausea. These are dose-dependent: higher amounts cause more problems. Sodium bicarbonate reacts with stomach acid to produce carbon dioxide, which is why belching and bloating are nearly universal at larger doses.
The bigger concern with regular use is the sodium load. Each teaspoon of baking soda contains roughly 1,260 mg of sodium, which is more than half the daily recommended limit. People with high blood pressure, heart failure, or kidney disease are particularly vulnerable to sodium-related fluid retention and blood pressure spikes.
Taking too much can also push your blood pH too high, a condition called metabolic alkalosis. Symptoms include muscle twitching, hand tremors, nausea, and confusion. This is rare with occasional antacid use but becomes a real risk if you’re taking large amounts daily.
Medications That Interact With Sodium Bicarbonate
Sodium bicarbonate changes the acidity of both your stomach and your urine, which can interfere with how your body absorbs or eliminates certain drugs. It reduces the absorption of certain antibiotics, including fluoroquinolones like levofloxacin and tetracyclines like doxycycline. It also affects some anti-inflammatory drugs and extended-release medications like certain ADHD stimulants.
On the other side, by making urine less acidic, sodium bicarbonate slows the elimination of amphetamine-based medications, effectively raising their levels in your blood. If you take any prescription medications regularly, separate your sodium bicarbonate dose by at least 2 hours and confirm with your pharmacist that there’s no interaction.
Practical Tips for Any Use
Always dissolve the powder completely in a full glass of water before drinking. Taking it dry or in too little liquid concentrates the reaction in your stomach and worsens side effects. Don’t take it on a very full stomach, as the gas production combined with a large meal can cause significant discomfort. For the same reason, avoid carbonated beverages around the time you take it.
If you’re using tablets, swallow them whole with a full glass of water. Don’t crush them unless the label says it’s safe to do so. Store baking soda in a cool, dry place, and if you’re using a box from your kitchen, make sure it hasn’t absorbed odors from the fridge, as that won’t affect safety but will make it unpleasant to drink.
For occasional heartburn, sodium bicarbonate works within minutes but wears off faster than commercial antacids. It’s a short-acting fix, not a long-term strategy. If you’re using it for athletic performance, keep a log of how your gut responds at different doses and timing windows so you can dial in what works before it matters on competition day.