Also known as: Trisodium citrate, Citrate buffer, Extracellular buffer
EnduranceGood evidence
A buffering agent that raises blood alkalinity, working the same way as sodium bicarbonate with considerably less digestive trouble. The trade is a larger dose and a longer wait.
Typical dose
0.4–0.5 g/kg per day
120-180 minutes before the effort, split with fluid
What it is
Sodium citrate is the sodium salt of citric acid, used widely as a food additive and in effervescent formulations.
In sports nutrition it serves as an extracellular buffer, raising the pH and buffering capacity of the blood so that hydrogen ions produced in muscle during hard efforts can be cleared more effectively.
It is the main alternative to sodium bicarbonate. Bicarbonate has the larger evidence base and a lower effective dose; citrate is markedly easier on the stomach, which matters a great deal if bicarbonate has ever caught you out mid-race.
How it works
Citrate is metabolised in the citric acid cycle, consuming hydrogen ions in the process and raising blood bicarbonate concentration and pH.
That steeper pH gradient between muscle and blood helps move hydrogen ions out of working muscle, delaying the acidity that contributes to fatigue in efforts lasting roughly one to eight minutes.
The route differs from bicarbonate, which raises blood bicarbonate directly and releases carbon dioxide in the stomach on the way. That gas production is precisely what causes bicarbonate's digestive problems, and citrate avoids it.
What the evidence shows
Trials have reported improved performance in high-intensity efforts of one to eight minutes, including rowing, running and cycling time trials.
The effect size is broadly comparable to sodium bicarbonate, though the evidence base is smaller and findings are somewhat less consistent.
Response varies considerably between individuals, as it does with all buffering agents. The practical implication is to test it in training across several sessions before relying on it for anything that matters.
Dosing
Doses are 0.4 to 0.5 g per kg of body weight, so 32 to 40 g for an 80 kg athlete. That is a considerably larger amount than the 0.2 to 0.3 g per kg used for bicarbonate.
Timing is later too. Blood alkalinity peaks around 120 to 180 minutes after ingestion, against 60 to 90 minutes for bicarbonate, so take it well in advance.
Split the dose across 30 to 60 minutes with plenty of fluid, and take it with a small carbohydrate-containing meal. The sodium load is substantial, which is worth counting if you are managing intake, and it may cause some water retention on the day.
At a glance
Common forms
Sodium citrate powder, Trisodium citrate dihydrate, Capsules, Within buffering formulas
Half-life / duration
Blood alkalinity peaks at 120-180 minutes and remains elevated for several hours
Timing
120-180 minutes before the effort, split with fluid
Competition status
Permitted — not on the WADA Prohibited List
Category
Endurance
Safety and side effects
Sodium citrate is considerably better tolerated than sodium bicarbonate, with far fewer reports of bloating, cramping and urgent digestive problems. Some discomfort is still possible at these doses.
The sodium load is the main consideration. Doses of this size supply a large amount of sodium, which matters if your blood pressure is being managed.
Speak to your doctor before use if you have been told your kidneys are not working normally, or if you take regular medication. Trial it in training rather than on competition day.
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. Always trial in training before competition. Not established 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.
