Sodium bicarbonate is baking soda. Athletes take it before intense exercise ("bicarbonate loading") because it briefly makes the blood less acidic, which may delay fatigue in hard efforts lasting a few minutes or in stop-and-go sports.
Also known as: baking soda, bicarbonate loading, bicarb.
Sodium bicarbonate has no intake value or upper limit. ODS says reviewers generally agree that about 300 mg per kg of body weight, taken 1 to 2 hours before exercise, is the amount studied; that is about 4 to 5 teaspoons of baking soda for most people. These are study protocols, not a recommendation.
It is sold in the US as a dietary supplement. Under the 1994 dietary supplement law (DSHEA), FDA does not approve dietary supplements before they are marketed, and the maker, not FDA, is responsible for safety and labeling.
ODS says many small lab studies in swimmers, cyclists, rowers, boxers and others have tested bicarbonate, with conflicting results. Reviewers generally agree it might give a minor to moderate benefit in strenuous exercise lasting several minutes and in sports with repeated bursts of high intensity, and it is most likely to help trained athletes. People respond differently: it does not help some, and it can make performance worse in others.
Safety, per ODS: the main side effect is stomach upset, including nausea, stomach pain, diarrhea and vomiting. Sodium bicarbonate is 27.4% sodium; a teaspoon (4.6 g) has 1,259 mg of sodium, and a 70 kg person taking 300 mg per kg would get about 5,750 mg of sodium. That can cause temporary fluid retention and weight gain. Long-term use over months has not been studied. If you have high blood pressure, heart or kidney disease, or have been told to limit sodium, ask your clinician first.
We could not find a single published half-life or time to peak for sodium bicarbonate that applies to a supplement dose, so we do not list one. ODS describes its effect as a short-term rise in blood pH after a dose taken 1 to 2 hours before exercise.
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