Supplement
Citric acid is the sour acid in citrus fruit, and your body makes it while turning food into energy. People mostly look at it for kidney stones, and in human trials citrate salts, especially potassium citrate, meant fewer recurrences of calcium stones, so the evidence is moderate. Much of that work used citrate salts rather than plain citric acid, and evidence for bone health and sprint performance is limited and mixed.
- Updated
- How we grade
- Best evidence
- Grade B
- Conditions studied
- 2
- Outcomes
- 4
- Graded outcomes
- 0220
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
General
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Kidney Stone Risk Multiple human RCTs demonstrate that citrate salts (particularly potassium citrate) significantly reduce recurrence of calcium kidney stones by inhibiting calcium crystallization in urine and increasing urinary citrate excretion. Potassium citrate is an FDA-approved prescription therapy (Urocit-K) for this indication, reflecting strong clinical evidence. | Improves (the measure goes down) | Large effect | 1,200 people | |||
| Mineral Absorption Multiple human studies demonstrate that citrate salt forms of minerals (calcium citrate, magnesium citrate) have superior bioavailability compared to oxide forms. Citric acid enhances absorption of iron and calcium through chelation and solubilization in the gastrointestinal tract, a finding supported by both mechanistic and clinical bioavailability trials. | Improves (the measure goes up) | Moderate effect | 600 people |
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Bone Resorption Limited human trials suggest alkali citrate supplementation may modestly reduce bone resorption markers and urinary calcium loss, particularly in postmenopausal women. The mechanism relates to systemic acid-base balance correction rather than direct bone effects, and clinical significance for fracture prevention remains unclear. | Improves (the measure goes down) | Small effect | 250 people |
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anaerobic Exercise Performance Sodium citrate has been studied in small human trials as an extracellular buffering agent for high-intensity anaerobic exercise, similar to sodium bicarbonate. Results are mixed, with some studies showing modest improvements in repeated sprint performance and time to exhaustion while others find no benefit. The mechanism is extracellular pH buffering, not Krebs cycle enhancement. | Improves (the measure goes up) | Small effect | 200 people |
Key findings
- Kidney Stone RiskImproves (the measure goes down)
- Mineral AbsorptionImproves (the measure goes up)
- Bone ResorptionImproves (the measure goes down)