Sodium Bicarbonate

Sodium bicarbonate (baking soda) is a supplement that provides dietary bicarbonate, which can increase serum levels of bicarbonate (normally produced by the kidneys) and subsequently buffer acid production in the body. The main mechanism of action of sodium bicarbonate is in negating the effects of acidosis. It provides benefits both in situations of chronic mild acidosis, commonly seen in metabolic ailments or during aging as kidney function slowly declines, and in exercise-induced acidosis.

In athletes, the standard doses of sodium bicarbonate supplementation (200-300 mg/kg) tend to reliably benefit performance when failure on the exercise is associated with metabolic acidosis, aka “the burn.” Sports where failure occurs due to the cardiorespiratory system or due to force production by the central nervous system (e.g., single sprints or rowing in elite rowers) do not appear to reliably benefit from supplemental bicarbonate.

Benefits of sodium bicarbonate can be observed with a single dose taken 60-90 minutes before exercise, but supplementation should be approached cautiously as it can cause gastrointestinal side effects if too much is taken at once or, if it’s consumed too rapidly.

Additionally, 5 g of sodium bicarbonate taken daily appears to be somewhat effective in reducing acidosis induced by the diet or the aging process (although using potassium bicarbonate appears to be better), and therefore it may reduce the rate of bone loss over time in susceptible populations.

There are mechanisms in place for sodium bicarbonate to be a fat-burning agent (it increases ketone production and lipolysis and causes a minor increase in metabolic rate), but these have not yet been linked to actual weight loss in trials.

Supplemental sodium bicarbonate can be baking soda bought from the grocery store; they are the same molecule, so store-bought baking soda will work.

Supplemental dosages of sodium bicarbonate are in the 200-300 mg/kg range when used before exercise. Although 500 mg/kg is slightly more effective, it tends to be associated with a higher degree of intestinal side effects if taken all at once.

If taking sodium bicarbonate acutely for exercise, a dose should be taken 60-90 minutes before anaerobic activities associated with metabolic acidosis (i.e.. “the burn”) for maximum benefit. For other activities that might be longer in duration, sodium bicarbonate should be taken 45-60 minutes before.

Sodium bicarbonate can be taken with meals rather than acutely before exercise, and should be similarly effective. In this case, up to 500 mg/kg can be well tolerated if divided into three doses throughout the day (just over 150 mg/kg per dose) with no inherent need to take bicarbonate on the day of activity.

Some health effects (increase in metabolic rate or attenuation of metabolic acidosis) can be achieved at more reasonable doses, such as 5-10g, and may be more practical for nonathletes.

Additionally, as 27.3% of sodium bicarbonate's weight is due to sodium, every 100 mg/kg confers about 27 mg/kg sodium to the diet; this needs to be accounted for, and severely limits usage by persons with salt-sensitive hypertension.

As the doses are measured in reference to body weight, obesity may result in a falsely high oral dose. If you are not within a normal or overweight BMI range, estimate your oral dose based on your “ideal weight” instead.

The means of consuming bicarbonate is important, as excessively high doses or rapid ingestion can cause gastric upset due to a reaction between bicarbonate and stomach acid. Bicarbonate should be sipped slowly over a period of a few minutes with a moderate amount of water (500 mL), and the first time bicarbonate is used a half-dose should be ingested to assess tolerance.

Rapidly ingesting the drink, or taking too much, is likely to induce stomach pain and nausea within an hour followed by increased diarrhea and flatulence; sticking to 200 mg/kg may alleviate the risk of these side effects.

Independent of the dose taken, caution should be exercised with the manner by which sodium bicarbonate is ingested, so as to minimize intestinal and gastric side effects; these side effects occur with rapid or excessive consumption of bicarbonate, and include nausea and diarrhea.

The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what effects sodium bicarbonate has on your body, and how strong these effects are.

Grade	Level of Evidence [show legend]
	Robust research conducted with repeated double-blind clinical trials
	Multiple studies where at least two are double-blind and placebo controlled
	Single double-blind study or multiple cohort studies
	Uncontrolled or observational studies only

Level of Evidence ? The amount of high quality evidence. The more evidence, the more we can trust the results.	Outcome	Magnitude of effect ? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.	Consistency of research results ? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.	Notes
	Serum Bicarbonate	Strong	Very High See all 47 studies	For the purpose of increasing serum bicarbonate concentrations, orally ingested bicarbonate is the reference compound for it. The increases tend to be around a 30% increase form baseline values (as there is always a circulating bicarbonate concentration)
	Blood Acidity	Notable	Very High See all 46 studies	Although the magnitude of decrease is somewhat minor, this is due to blood pH being highly regulated in the body. acidity appears to be reliably reduced following supplementation of 300mg/kg sodium bicarbonate
	Lactate Production	Notable	- See all 37 studies	Increases of lactate production are noted in short intense exercises (due to allowing more work to be conducted, and the work produces more lactate) while prolonged exercise is associated with a decrease in lactate concentrations relative to placebo
	Anaerobic Running Capacity	Minor	Moderate See all 34 studies	Cardiovascular exercise where failure is associated with metabolic acidosis (ie. 'the burn') appear to get benefit with bicarbonate supplementation to a small degree but reliably. For other exercises (rowing, sprinting, swimming) not characterized by the burn, the benefits are much less reliable
	Power Output	-	Moderate See all 28 studies	Although technically an increase in average power output may occur during exercise associated with the 'burn' (metabolic acidosis) to the degree of 1-2%, saying this is an inherent or reliable increase in power would be misleading; it is an attenuation of the decrease in power that acidosis is able to induce
	Teeth Whitening	Notable	Very High See all 3 studies	There appears to be a time dependent benefit on stain reduction when gum containing sodium bicarbonate is used, with efficacy at 4 weeks (around 30-50% stain reduction) but more at 12 weeks (around 70%)
	Aerobic Exercise	Minor	High See all 3 studies	For cardiovascular exercise that is prolonged in nature (45m or greater) and not exceeding the lactate threshold, there appears to be a small beneficial effect of sodium bicarbonate supplementation on improving time to fatigue or time to complete a test
	Neuromuscular Function	Minor	Very High See all 3 studies	Sports requiring hand-eye coordination (boxing and tennis) appear to be enhanced with supplemental sodium bicarbonate, with improved punch and tennis swing accuracy
	Training Volume	Minor	Moderate See all 10 studies	There might be an increase in work output conducted in tests that are anaerobic (high intensity) and associated with metabolic acidosis ('the burn') but may not extend to other contexts
	Heart Rate	-	Very High See all 5 studies	There is no significant effect of sodium bicarbonate on heart rate at rest or during exercise
	Rate of Perceived Exertion	-	Very High See all 10 studies	Although there is some limited evidence that sodium bicarbonate can increase 'percieved readiness' for a task and ample evidence that it can reduce the rate of neuromuscular decline (seen with fatigue), the actual rate of percieved exertion (how hard an exercise feels) is wholly unaffected.
	VO₂ Max	-	High See all 7 studies	For the most part, peak VO2 consumption is not significantly influenced by supplemental sodium bicarbonate (although VO2 kinetics that are not referring to VO2 max may be influenced somewhat)
	Plasma Endorphins	Notable	- See study	The exercise-induced spike in endorphins appears to be related to the spike in acidity, and supplementation of bicarbonate is able to potently suppress the spike (although not abolish it)
	Fat Oxidation	Minor	- See 2 studies	An increase in fat oxidation has been noted at rest with supplemental sodium bicarbonate which contributed solely to the increase in metabolic rate
	Insulin Sensitivity	Minor	Moderate See 2 studies	Mixed effects on insulin sensitivity in persons who may be suffering form metabolic acidosis, with one positive and one null result
	Judo Performance	Minor	- See study	During a simulated throwing test (throwing one of two partners for time), sodium bicarbonate ingestion is able to improve the amount of throw conducted in a set time
	Lipid Absorption	Minor	- See study	One study in menopausal women with a modest dose of sodium bicarbonate (less than 100mg) noted a reduction in lipid absorption from a meal.
	Muscle Oxygenation	Minor	- See study	The rate of muscle deoxygenation is reduced with attenuation of acidosis (which can be achieved with sodium bicarbonate), and in later stretches of exercise this can be manifest as a relative increase in oxygenation
	Noradrenaline	Minor	- See study	A decrease in exercise-induced noradrenaline has been noted before, but it is unsure if this is correct information (as this was the lone study to measure noradrenaline, three studies have measured adrenaline and are split with the only one noting a decrease in adrenaline also being this study)
	Adrenaline	-	Moderate See 2 studies	Mixed effects, but one intravenous study (not in the human effect matrix) that also noted no significant differences suggest that the increase in catecholamines during exercise is not associated with acidity and thus not suppressed by sodium bicarbonate
	Ammonia	-	Very High See 2 studies	No significant effects on plasma ammonia detected with supplemental bicarbonate
	Blood Glucose	-	Very High See 2 studies	No significant effect on blood glucose concentrations at rest or during exercise is seen with sodium bicarbonate supplementation
	Blood Pressure	-	- See study	No significant influence on blood pressure
	Hydration (Total Body Water)	-	- See study	The addition of sodium bicarbonate to a pre-testing rehydration protocol does not enhance hydration more than the protocol itself (mostly water and carbohydrates)
	Insulin	-	- See study	Fasting insulin concentrations are not affected with sodium bicarbonate supplementation
	Oxygen Uptake	-	- See study
	Ketone Bodies	Minor	Very High See 2 studies	During fasting or ketogenic diets, sodium bicarbonate supplementation may be able to increase ketone body production. This appears to be of somewhat small magnitude and was not associated with additional fat loss
	Metabolic Rate	Minor	- See study	An increase in metabolic rate has been noted and calculated (extrapolated) to be approximately 0.5% extra over the course of 24 hours, associated with a low dose of sodium bicarbonate (17mg/kg)
	Insulin Secretion	-	- See study	No significant influence of supplementaion sodium bicarbonate on insulin secretion
	Weight	-	- See study	Despite the potential increase in metabolic rate and increase in ketone body production, there is currently no evidence to support more fat loss with sodium bicarbonate over placebo

Studies Excluded from Consideration

• Used bicarbonate as either bicarbonate-citrate, bicarbonate-lactate, or bicarbonate-chloride rather than sodium bicarbonate^[1]

• Confounded with creatine^[2]

• Investigating sodium bicarbonate for better endurance performance

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