Also known as: Bicarb, Baking soda, NaHCO3, Buffering agent, Sodium hydrogen carbonate
EnduranceStrong evidence
Baking soda, and one of the best-evidenced performance supplements in existence. Costs almost nothing, works reliably for the right efforts, and will wreck your session if you get the protocol wrong.
Typical dose
200.0–300.0 mg per day
60-180 minutes before the effort, split across several doses with food
What it is
Sodium bicarbonate is the same compound sold as baking soda in every supermarket. There is no meaningful difference between the sports supplement version and the baking aisle version beyond packaging and price.
It works as an extracellular buffer, raising the blood's capacity to absorb the hydrogen ions produced during hard exercise. This makes it the counterpart to beta-alanine, which raises buffering capacity inside the muscle instead.
Because the two act in different compartments, they combine sensibly rather than duplicating each other, and several trials have looked at using them together.
How it works
During high-intensity exercise, anaerobic glycolysis produces hydrogen ions faster than they can be cleared, lowering muscle pH and interfering with the machinery of contraction.
Ingesting bicarbonate raises blood bicarbonate concentration, increasing the gradient that drives hydrogen ions out of the working muscle and into the bloodstream, where they are buffered.
This is the key distinction from beta-alanine. Beta-alanine raises carnosine inside the muscle cell, buffering acid where it is produced. Bicarbonate improves the removal of acid from the cell. Same problem, two different points of attack, which is why using both is coherent.
What the evidence shows
Sodium bicarbonate has one of the most robust evidence bases of any ergogenic aid. Meta-analyses covering many controlled trials consistently report performance improvements in high-intensity efforts.
The effect is concentrated in efforts lasting roughly one to ten minutes, where acid accumulation is the limiting factor. Rowing, middle-distance running, swimming, track cycling and repeated high-intensity intervals all sit in this window.
Efforts too short to accumulate acid, such as a single maximal lift, and efforts too long to be limited by it, such as a marathon, fall outside the useful range. Improvements are typically around 2 per cent, which is small in absolute terms and substantial in a competitive context.
Dosing
Dose is per kilogram of bodyweight: 0.2 to 0.3 g per kg, which for an 80 kg athlete is 16 to 24 g. That is a substantial amount of powder.
Timing is 60 to 180 minutes before the effort, and it varies between individuals more than most supplements. Blood bicarbonate peaks at different times for different people, which is why the window is so wide.
The gastrointestinal distress is the real problem and the reason people abandon it. Three things reduce it substantially: take it with a carbohydrate-rich meal, split it into several doses over 30-60 minutes rather than one hit, and use enteric-coated capsules if you can. Never trial this for the first time on competition day. Test it in training, repeatedly, until you know your own timing and tolerance.
At a glance
Common forms
Baking soda (powder), Enteric-coated capsules, Bicarbonate gels, Sodium citrate (alternative)
Half-life / duration
Blood bicarbonate peaks 60-180 minutes post-dose and remains elevated for a few hours
Timing
60-180 minutes before the effort, split across several doses with food
Competition status
Permitted — not on the WADA Prohibited List
Category
Endurance
Safety and side effects
The dominant issue is gastrointestinal distress: bloating, nausea, cramping and diarrhoea. This is common rather than rare at effective doses, and it can be severe enough to make performance worse rather than better, which is the great irony of an otherwise excellent supplement.
Splitting doses, taking it with food and using enteric-coated capsules all help considerably. Some people simply do not tolerate it, and sodium citrate is a gentler alternative.
The sodium load is substantial and worth accounting for if your blood pressure is being managed. Speak to your doctor before use if you take regular medication or have been told your kidneys are not working normally.
Who should avoid it
Take care if your blood pressure is being managed, given the substantial sodium load. Speak to your doctor before use if you have been told your kidneys are not working normally, or if you take regular medication. Never use it for the first time on competition day. Not established at these doses in pregnancy or breastfeeding.
This entry is provided for information only. Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. Consult a qualified healthcare professional before use if you are pregnant, breastfeeding, taking medication or under medical supervision.
