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Sodlium Citrate

Also known as: Trisodium citrate, sodium citrate, Sodium citrate

Overview

Sodium citrate, chemically known as Na3C6H5O7, is a sodium salt of citric acid, naturally occurring in citrus fruits. It is widely utilized as a food additive and a dietary supplement, primarily functioning as an extracellular buffering agent. Its main purpose in supplementation is to increase blood alkalinity, thereby counteracting metabolic acidosis that can occur during high-intensity exercise. This mechanism is believed to enhance exercise performance. Key characteristics include its ability to induce metabolic alkalosis and expand plasma volume, which may positively influence both endurance and anaerobic performance. Research into sodium citrate's ergogenic effects is moderately mature, with various randomized controlled trials and systematic reviews evaluating its efficacy, particularly in sports contexts. While evidence quality varies and some findings are mixed depending on the specific exercise type and duration, it is generally recognized for its potential to improve performance in certain high-intensity activities.

Benefits

Sodium citrate supplementation primarily benefits high-intensity exercise performance by increasing blood bicarbonate concentration, which enhances the body's buffering capacity against exercise-induced acidosis. This effect is most pronounced in activities lasting approximately 1–4 minutes, particularly those involving anaerobic or high-intensity efforts. Meta-analyses indicate that extracellular buffering agents, including sodium citrate, can positively impact exercise capacity, though sodium bicarbonate may offer superior benefits for certain sprint performances. Specific studies have shown that sodium citrate, at doses around 0.5 g/kg body mass, can improve tennis skill performance and increase anaerobic cycling work and peak power. Additionally, it can induce plasma volume expansion and water retention, potentially aiding post-exercise hydration. However, its effectiveness for longer endurance performance, such as 5,000-m running, is inconsistent, especially in non-heat-acclimated athletes. Effect sizes from meta-analyses suggest moderate improvements in exercise outcomes, but these benefits can vary significantly based on the sport and specific exercise protocol.

How it works

Sodium citrate functions as an extracellular buffer by elevating blood pH and bicarbonate levels, which helps to neutralize the accumulation of hydrogen ions during intense physical activity. This buffering action delays muscle acidosis and the onset of fatigue, potentially facilitating ATP resynthesis and enhancing anaerobic energy metabolism. Unlike sodium bicarbonate, sodium citrate may lead to intracellular citrate accumulation, which could potentially blunt ATP resynthesis, explaining some observed performance differences between the two agents. Furthermore, sodium citrate promotes plasma volume expansion through water retention, influencing hydration status and cardiovascular function during exercise. It is rapidly absorbed, with its peak alkalosis effects typically observed approximately 60–90 minutes following ingestion.

Side effects

Sodium citrate is generally considered safe when consumed within recommended dosages, typically around 0.5 g/kg body mass. The most common adverse effects, affecting more than 5% of users, are gastrointestinal in nature. These include nausea, bloating, and diarrhea, which are more likely to occur at higher doses or if the supplement is not properly timed with food or water. In rare instances, excessive consumption could lead to electrolyte imbalances. While no significant drug interactions are extensively documented, individuals on sodium-restricted diets or those with impaired kidney function should exercise caution. Contraindications include hypersensitivity to citrate salts and any medical conditions necessitating strict sodium restriction. There is insufficient safety data for special populations such as children and pregnant women, thus its use in these groups is not recommended without medical supervision.

Dosage

For effective alkalosis and performance enhancement, the minimum effective dose of sodium citrate is approximately 0.3–0.5 g/kg body mass. The optimal dose range commonly used in research studies is 0.5 g/kg body mass. It is generally recommended not to exceed 0.5–0.6 g/kg due to an increased risk of gastrointestinal side effects. For optimal timing, sodium citrate should be ingested 60–90 minutes prior to exercise to allow for peak blood alkalosis. It is typically administered as a powder dissolved in water. To improve absorption and minimize side effects, it should be taken with sufficient water, and high-fat meals should be avoided around the time of ingestion. While no specific cofactors are required, an individual's hydration status can influence its overall efficacy.

FAQs

Is sodium citrate better than sodium bicarbonate?

Sodium bicarbonate often shows slightly better performance benefits in short sprints, possibly due to differences in how it affects intracellular ATP resynthesis compared to sodium citrate.

Can sodium citrate cause stomach upset?

Yes, gastrointestinal discomfort like nausea, bloating, and diarrhea is common, especially with large doses or insufficient water intake.

How soon before exercise should it be taken?

For optimal blood alkalosis and performance benefits, it should be taken approximately 60–90 minutes before exercise.

Does it improve endurance performance?

Evidence is mixed; benefits are more consistently observed in high-intensity, short-duration efforts rather than prolonged endurance events.

Research Sources