How Much Sodium Is in Sodium Bicarbonate?

Sodium bicarbonate is roughly 27% sodium by weight. Every gram of sodium bicarbonate (the chemical behind ordinary baking soda) contains about 274 milligrams of sodium. That fraction is baked into the molecule itself and cannot be reduced or removed, so anyone watching their sodium intake needs to account for it whether they are using baking soda in cooking, as an antacid, or as a supplement. The proportion is lower than what you find in table salt, but it is still high enough to matter, especially at the doses used for heartburn relief or athletic performance.

Where the 27% Comes From

Sodium bicarbonate has the chemical formula NaHCO₃. The molecule contains one sodium atom, one hydrogen atom, one carbon atom, and three oxygen atoms. Sodium accounts for 23 out of the total molecular weight of 84, which works out to about 27.4%. That ratio is fixed. It does not change based on brand, grind, or packaging. Every box of baking soda on every grocery shelf delivers the same proportion of sodium per gram.

When sodium bicarbonate dissolves in water or stomach acid, it splits apart into sodium ions and bicarbonate ions almost immediately. The bicarbonate portion reacts with acid to form carbon dioxide and water, which is why baking soda fizzes in vinegar and why it neutralizes stomach acid. But the sodium goes nowhere. It stays in solution and gets absorbed into the bloodstream, where the body handles it the same way it handles sodium from any other source.

How It Compares to Table Salt

Table salt, sodium chloride, is about 39% sodium by weight. Gram for gram, baking soda delivers roughly two-thirds as much sodium as table salt. That comparison can be misleading, though, because the amounts people use differ wildly between the two. You might shake a pinch of salt onto your dinner, but someone using baking soda as an antacid could swallow a full teaspoon or more in one dose.

One level teaspoon of baking soda weighs approximately 4.6 grams and contains around 1,260 milligrams of sodium. For context, most health guidelines recommend keeping total daily sodium below 2,300 milligrams, and many cardiologists suggest 1,500 milligrams for people with high blood pressure or heart disease. A single teaspoon of baking soda, taken as a home remedy for indigestion, chews through more than half the general daily limit in one shot.

Common Doses and Their Sodium Load

The sodium content of sodium bicarbonate only becomes a real concern when you consider how much people actually take for different purposes. Here is a rough breakdown of common use cases and the sodium they carry:

Baking: A typical recipe calls for half a teaspoon to one teaspoon of baking soda, which contributes roughly 630 to 1,260 mg of sodium to the entire batch. Split across a dozen cookies or a loaf of bread, the per-serving sodium from the baking soda alone is modest, though it adds to whatever else is in the recipe.
Antacid use: The traditional home-remedy dose for heartburn is half a teaspoon dissolved in water, delivering about 630 mg of sodium. Some people take more, and repeated doses throughout the day can stack up fast.
Athletic performance: Sports research typically uses doses around 0.3 grams per kilogram of body weight. For a 70-kilogram (roughly 154-pound) person, that works out to 21 grams of sodium bicarbonate, containing about 5,750 mg of sodium, well over double the recommended daily limit from a single pre-exercise dose.
Chronic kidney disease: Clinicians sometimes prescribe oral sodium bicarbonate to manage the acid buildup that comes with declining kidney function. Doses vary, but they are prescribed with the sodium load explicitly in mind. One multicenter trial noted that the study was designed to only partially offset acid production specifically because of concern about how much sodium the patients would be taking in.

The athletic dose stands out. Competitive and recreational athletes who follow sodium bicarbonate loading protocols for high-intensity exercise are consuming a large sodium bolus in a short window. The bicarbonate dissolves quickly in the stomach, and the released sodium ions are absorbed into the bloodstream along with whatever bicarbonate survives the stomach acid.

What Happens to All That Sodium in the Body

Once absorbed, the sodium from sodium bicarbonate enters the same pool as dietary sodium from food. The kidneys are responsible for clearing excess sodium, and they do so by excreting it in urine. A systematic review of trials in chronic kidney disease patients found that oral sodium bicarbonate increased 24-hour urinary sodium excretion by about 24 milliequivalents per day compared to controls, confirming that the kidneys ramp up sodium clearance in response to the extra load.¹ In healthy people with normal kidney function, the kidneys handle this job efficiently. In people with impaired kidneys, the sodium can accumulate, leading to fluid retention and higher blood pressure.

A related question people raise is whether sodium from bicarbonate affects blood pressure the same way sodium from salt does. One controlled study compared the two directly in both normotensive and hypertensive subjects. Sodium chloride did not significantly influence blood pressure in either group during the study period, while sodium bicarbonate actually lowered systolic blood pressure by about 5 mmHg in the hypertensive participants.² That result is counterintuitive and should not be taken as a green light to load up on baking soda if you have high blood pressure. The study was small, and the broader clinical evidence still treats any large sodium load as a concern for people managing hypertension. But it does suggest that the anion paired with sodium, whether chloride or bicarbonate, may play a role in how the body responds to it.

Risks of Taking Too Much

The sodium in sodium bicarbonate is not the only danger of overdoing it, but it is a prominent one. Case reports from emergency departments describe patients who ingested large amounts of baking soda and developed hypernatremia, which is dangerously high sodium levels in the blood. Other complications from excessive ingestion include metabolic alkalosis (the blood becomes too alkaline), dangerously low potassium, and in severe cases, seizures, heart rhythm abnormalities, and cardiac arrest.³

These are not just theoretical risks. A review of acute baking soda toxicity identified a pattern of complications including hypertension, intravascular volume depletion, and urinary alkalinization alongside the hypernatremia and metabolic alkalosis.⁴ Many of these cases involved people using baking soda as a folk remedy for stomach discomfort, sometimes repeatedly and in large quantities, without appreciating that they were consuming what amounts to a massive sodium dose with each glass.

The lesson is straightforward: occasional use of half a teaspoon for heartburn is unlikely to cause problems in a healthy person with normal kidneys. But habitual use, large single doses, or use by anyone with kidney disease, heart failure, or uncontrolled high blood pressure can push the sodium load into dangerous territory.

Why Athletes Accept the Trade-Off

Given the sodium load, you might wonder why anyone would voluntarily swallow 20-plus grams of baking soda before a workout. The answer is that bicarbonate acts as a buffer against the acid that builds up in muscles during intense exercise. When you sprint, swim hard, or push through a rowing interval, your muscles produce hydrogen ions that lower pH and contribute to the burning fatigue you feel. Extra bicarbonate in the bloodstream can soak up some of that acid, potentially allowing you to sustain high-intensity effort a bit longer.

The International Society of Sports Nutrition has recognized sodium bicarbonate as an ergogenic aid, with the most commonly studied dose being 0.3 grams per kilogram of body weight taken 60 to 180 minutes before exercise.⁵ The performance benefit is real but modest, and it comes at the cost of that enormous sodium hit plus common gastrointestinal side effects like bloating, nausea, and diarrhea. The gastrointestinal distress is partly caused by carbon dioxide gas forming in the stomach as bicarbonate reacts with stomach acid. Some athletes spread the dose across multiple smaller servings or take it with a meal to reduce the gut problems, but the total sodium load is the same regardless of timing.

For a competitive athlete in a sport where fractions of a second matter and who trains under medical supervision, the sodium trade-off may be worth it. For a recreational exerciser, the math is harder to justify, particularly if they already have blood pressure concerns or are on a sodium-restricted diet.

Sodium Bicarbonate in Kidney Disease Management

Chronic kidney disease reduces the kidneys’ ability to excrete acid, leading to a condition called metabolic acidosis. This acid buildup accelerates further kidney damage and causes muscle wasting. Oral sodium bicarbonate is one of the standard treatments, prescribed to partially neutralize the excess acid. But every milligram of bicarbonate comes with its molecular companion: sodium.

Clinicians designing trials of sodium bicarbonate in kidney patients have to balance the benefit of acid correction against the risk of sodium overload in a population whose kidneys already struggle to clear excess sodium. One large multicenter trial explicitly noted that doses were chosen to only partially offset the body’s daily acid production, specifically because of concern about the sodium burden.⁶ A meta-analysis of these trials confirmed that sodium bicarbonate supplementation increased urinary sodium excretion and showed a trend toward small increases in body weight, though the weight gain was not statistically significant.¹ The modest weight trend likely reflects some fluid retention from the sodium load.

For kidney patients, the sodium content of their bicarbonate prescription is not a side note; it is a central clinical consideration. These patients are often already on sodium-restricted diets to manage blood pressure and fluid balance. Adding a supplement that delivers hundreds of milligrams of sodium daily requires adjustments elsewhere in the diet, and it is one reason some researchers have explored potassium bicarbonate as an alternative.

Potassium Bicarbonate as a Lower-Sodium Alternative

Potassium bicarbonate (KHCO₃) delivers the same bicarbonate ion without any sodium at all. The potassium replaces the sodium in the molecule, so you get the acid-buffering effect without the sodium load. A metabolic balance study in healthy men compared the two compounds head to head, giving participants 60 millimoles per day of either sodium bicarbonate or potassium bicarbonate. Both produced equivalent improvements in acid balance, but their effects diverged elsewhere: sodium bicarbonate led to more positive sodium balance (as expected), while potassium bicarbonate led to more positive potassium balance.⁷

Potassium bicarbonate also reduced urinary calcium excretion and improved calcium balance in that study, while sodium bicarbonate did not. That additional bone-health benefit has made potassium bicarbonate attractive for certain clinical applications. However, potassium bicarbonate is not simply a drop-in replacement for everyone. People with kidney disease or those taking potassium-sparing medications can develop dangerously high potassium levels (hyperkalemia), which carries its own set of serious cardiac risks. Swapping sodium for potassium solves one problem and potentially creates another, depending on the person.

For healthy individuals looking to use a bicarbonate supplement while minimizing sodium intake, potassium bicarbonate is the obvious choice, but it should be discussed with a doctor first, especially for anyone on blood pressure medications or with any degree of kidney impairment.

Hidden Sodium in Products You Might Not Suspect

Baking soda is the most obvious vehicle for sodium bicarbonate, but it shows up in plenty of other products where people may not think to check for sodium. Effervescent antacid tablets like Alka-Seltzer contain sodium bicarbonate as an active ingredient. Some toothpastes are formulated with sodium bicarbonate for its mild abrasive and pH-buffering properties. Certain oral rehydration solutions and electrolyte powders include it. Even in agriculture, sodium bicarbonate is added to dairy cattle feed to buffer rumen acidity; one study added it at 0.8% of the total ration and found that buffered cows ate more and produced more milk.⁸

For human health purposes, the products that matter most are the oral ones: antacids, supplements, and baking soda dissolved in water. If you are on a low-sodium diet, reading labels for sodium bicarbonate is just as important as watching for sodium chloride. Many people are trained to look for “salt” on an ingredient list and may not register that baking soda or sodium bicarbonate is also a significant sodium source. The same goes for sodium citrate, sodium phosphate, and other sodium-containing food additives, but sodium bicarbonate is the one people most often consume in large, deliberate doses outside of food.

Quick Math for Checking Your Own Intake

If you want to figure out how much sodium you are getting from a given amount of baking soda, the calculation is simple. Multiply the weight of sodium bicarbonate in grams by 274 to get milligrams of sodium. So half a teaspoon (about 2.3 grams) gives you roughly 630 mg of sodium. A full tablespoon (about 13.8 grams) delivers around 3,780 mg, which exceeds the entire daily recommended limit in one scoop.

For supplements or prescriptions that list the dose in milliequivalents (mEq) rather than grams, the conversion is that 1 mEq of sodium bicarbonate equals 84 mg of the compound, which contains 23 mg of sodium. If your doctor prescribes 30 mEq of sodium bicarbonate daily, you are taking 2,520 mg of sodium bicarbonate, which delivers about 690 mg of sodium. That is not trivial, and it needs to be factored into your total daily sodium budget alongside everything you eat and drink.

People who use baking soda casually, a pinch in a recipe, a small amount in a cleaning paste, have nothing to worry about. The sodium concern becomes real at medicinal and performance doses, where the quantities are large enough to shift your electrolyte balance. If you rely on sodium bicarbonate for any regular health purpose, knowing the 27% rule and doing the arithmetic keeps you from accidentally overwhelming your daily sodium allowance without realizing it.