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Sodium Phosphate Supplements

Review of Sodium Phosphate

What is Sodium Phosphate?

Sodium phosphate is a generic term that may refer to any sodium salt of phosphoric acid. Sodium phosphate is often used by endurance athletes as a means of increasing endurance performance during competition.

Who Should Consider Taking Sodium Phosphate supplements?

Anyone looking to improve their rate of recovery, reduce the risk of overtraining, increase muscle size and strength should benefit from ZMA supplements.

Summary of Sodium Phosphate's Phyiological Effects:

  • Appears to increase the aerobic capacity
  • May enhance time to exhaustion
  • Helps to buffer the build up of lactic acid
  • May enhance weigh loss

Sodium Phosphate Research

Phosphate supplementation is believed to increase endurance performance, primarily by increasing the delivery of oxygen to the working muscles.  Many endurance athletes routinely load up on phosphate (normally either sodium phosphate or potassium phosphate) for a period of 3-7days, just prior to an important race, to improve their race performance.

Sodium Phosphate was first used during World War I, by German troops, as German scientist believed that phosphates boosted energy levels and improved stamina (Anderson, 1996). Phosphate supplementation is believed to improve endurance performance through 3 mechanisms: 1) Phosphates buffer the build up of lactic acid in the muscles and lactate in the blood.  This reduces the effects of lactic acid – lactic acid causes the burning sensation in muscles during intense exercise – allowing athletes to race at higher intensities before feeling the negative effects of lactic acid; 2) Phosphates help to improve the delivery of oxygen to working muscles; 3) Phosphates are used to make Adenosine triphosphate (ATP – this is the chemical form of energy within cells) and Creatine Phosphate (CP – an immediate energy store that is used to re-synthesize used ATP molecules) and therefore are believed to increase the chemical store of energy within cells.

The main method in which phosphate supplementation is believed to improve performance is through increased levels of the chemical enzyme 2,3-diphoshoglycerate (2,3-DPG) following supplementation.  Research conducted at the University of Florida (Cade et al., 1984) found that phosphate loading, increased serum phosphate levels, raised 2,3-DPG levels, increased VO2max by up to 12%, lowered lactate levels (an indication of increased oxygen delivery), and increases work output.

Research by Kreider et al., 1990, found that sodium phosphate loading increased blood haemoglobin levels by 5%, increased VO2max by 9% (from an already impressive 74ml/kg.min to 80ml/kg.min), and increased ventilatory anaerobic threshold by 12%.  This led to an average 12 second improvement in 5mile run performance.  Which, might not sound a lot, but these were elite runners, where a 12 second improvement can make a significant difference to their race performance.

Phosphate loading has also been demonstrated to increase the time taken to reach exhaustion. Stewart et al., 1990 demonstrated a 16% increase in time to exhaustion following phosphate supplementation.

Is Sodium Phosphate effective?

Sodium phosphate and appears to be effective at enhancing muscular endurance and stamina. It may also help to enhance weight loss.

How to take Sodium Phosphate?

Endurance athletes looking to improve race performance should aim to take approximately 4-6grams of phosphate (either sodium phosphate or potassium phosphate) per day for 3-4days.  This should be split into 1gram doses taken throughout the day either with water or fruit juice. Athletes should load up with phosphate approximately 4-7 days prior to competition.  A small number of athletes may find they experience stomach upsets following phosphate loading. Anecdotal reports suggest that a potassium phosphate causes less stomach upsets than sodium phosphate.


Andersen, O. (1996) PP CONFERENCE EXTRA: Carbs, creatine & phosphate: combined, they create a performance powerhouse for the endurance athlete. IN: PEAK PERFORMANCE (2000) Special Conference Issue, Sports Science for the Millenium. Robert Troop, Editor. 128. 

Cade, R., Conte, M., Zauner, C., Mars, D., Peterson, J., Lunne, D., Hommen, N., Packer, D. (1984) effects of phosphate loading on 2,3-diphosphoglycerate and maximal oxygen uptake. Medicine and Science in Sports and Exercise. 16, 263-268. 

Kreider, R. B., Miller, G. W., Williams, M. H.,  Somma, C. T. and Nasser, T. A. (1990) Effects of phosphate loading on oxygen uptake, ventillatory anerobic threshold, and run performance. Medicine and Science in Sports and Exercise. 22, 250-256. 

Stewart, I., Mcnaughton, L., Davies, P. and Tristram, S. (1990) Phosphate loading and the effects on VO2max in trained cyclists. Research Quarterly in Exercise and Sport. 61, 80-84.