Citric acid
Citric acid as a food additive is classed as generally recognised as safe by the FDA, and the only well-supported health use is as the salt potassium citrate, which reduces recurrent calcium kidney stones and is recommended in the AUA guideline for people with low urinary citrate. That evidence is for the prescribed citrate salt, not for citric acid powder or lemon juice.
The clear everyday caution is teeth, since acidic drinks contribute to enamel erosion; the claim that manufactured citric acid causes inflammation rests on four case reports.
At a glance
Last reviewed 10 October 2026What it's used for
Evidence is rated per use. The same ingredient can be strong for one thing and traditional for another.
| Use | Evidence | What the research shows |
|---|---|---|
| Preventing recurrent kidney stones (as potassium citrate)Compare remedies for bladder & urinary → | Moderate | A Cochrane review of 7 trials (477 people, mostly calcium oxalate stones) found citrate salts cut new stone formation (risk ratio 0.26, 95% CI 0.10 to 0.68) and stone growth, though the trials were small and reported moderate to poor quality, and dropouts due to side effects were higher (mostly upper gut upset). The AUA guideline says clinicians should offer potassium citrate to patients with recurrent calcium stones and low or relatively low urinary citrate (Standard; Grade B), preferring potassium over sodium citrate. The trials used citrate salts, not citric acid powder, so they say nothing about swallowing citric acid or lemon juice.2,3 |
| Food additive (E330 preservative and acidity regulator) | Limited | The FDA affirms citric acid as generally recognised as safe (GRAS) in food with no limits other than good manufacturing practice, and permits production by fermentation with Aspergillus niger. That is a regulatory status, not a health benefit or a trial result; the 2018 case-report authors note that the GRAS status was not backed by research on large chronic intakes. We could not open a European EFSA opinion on E330 itself, so no EU position is stated here.1,8 |
| Effect on teeth (enamel erosion) | Limited | This is a harm. A systematic review in adolescents found dietary acids contribute to erosion, most consistently from carbonated drinks and acidic drinks at bedtime, though studies were inconsistent. In a laboratory study on extracted teeth, lime and pineapple juice reduced enamel hardness and increased roughness, with lime juice (higher acidity) causing the most enamel loss. The evidence is about acidic drinks in general; it does not isolate citric acid alone.4,5 |
| Cosmetic pH adjuster and skin exfoliation (AHA-type use)Compare remedies for skin → | Traditional | The Cosmetic Ingredient Review panel concluded citric acid is safe in cosmetics as currently used, where it works as a pH adjuster, chelating agent or fragrance ingredient. A 2024 review of alpha-hydroxy acids found glycolic and lactic acid improve texture and photoaging, but citric acid was not singled out, and optimal concentrations were not defined. We found no trial of citric acid as a peel or exfoliant.6,7 |
| Inflammatory reactions to manufactured citric acid (case reports) | Traditional | A 2018 paper reports four patients with repeated inflammatory symptoms (joint pain, respiratory symptoms, bowel symptoms, muscle pain, fatigue) after foods, drinks or vitamins containing manufactured citric acid. These are case reports: they cannot show the additive caused the symptoms, there was no control group, and the authors themselves say no safety studies of large chronic intakes exist. It raises a question worth studying, not a finding.8 |
How much
Ranges below are what studies used and what supplements commonly contain. They are not a recommendation for you. Start at the low end.
How people take it
Safety
Who should avoid
- Kidney stones — ask your doctor before self-treating with citrate or lemon juice
- Frequent sipping of acidic drinks, especially at bedtime — enamel erosion risk
- Treating stones or pain with citric acid powder — unproven; see a doctor for stone symptoms
Known interactions
Questions people ask
Is citric acid safe to eat?
The FDA classes citric acid as generally recognised as safe in food, with no limit other than good manufacturing practice. Four case reports suggest some people react to manufactured citric acid, but those cannot show cause and no controlled study has tested this.
Does citric acid help kidney stones?
The salt potassium citrate does: a Cochrane review found fewer new stones (risk ratio 0.26), and the AUA guideline tells clinicians to offer it to people with recurrent calcium stones and low urinary citrate. Those results do not apply to plain citric acid powder or lemon juice, which were not tested in the sources we read.
Does citric acid damage teeth?
Acidic drinks are a recognised risk for enamel erosion, particularly carbonated drinks and acidic drinks at bedtime. In a laboratory study lime juice softened and roughened enamel. Citric acid is one acid among many, so the research does not isolate its effect.
Is citric acid good for skin?
It is mainly a pH adjuster in cosmetics, judged safe as used by the Cosmetic Ingredient Review panel. Glycolic and lactic acid have evidence as exfoliants, but we found no trial showing citric acid does the same, and acids can irritate.
Does manufactured citric acid cause inflammation?
Only four case reports suggest it might, with symptoms such as joint pain and breathing trouble after eating foods containing it. Case reports are a hypothesis at best: no controlled study has tested it.
Sources (8)
- Regulator/health agency US FDA. 21 CFR 184.1033 Citric acid.
- Clinical guideline Pearle MS, Goldfarb DS, Assimos DG, et al. Medical management of kidney stones: AUA guideline. J Urol. 2014.
- Cochrane review Phillips R, Hanchanale VS, Myatt A, et al. Citrate salts for preventing and treating calcium containing kidney stones in adults. Cochrane Database Syst Rev. 2015.
- Systematic review Chan AS, Tran TTK, Hsu YH, Liu SYS, Kroon J. A systematic review of dietary acids and habits on dental erosion in adolescents. Int J Paediatr Dent. 2020.
- Laboratory study Mohamed Rasheed ZB, Zakaria ASI, Abdul Rahman F, et al. Evaluating the Erosive Effects of Freshly Squeezed Local Fruit Juices on Human Dental Enamel and Consumption Patterns Among Malaysian Adults. Nutrients. 2025.
- Safety assessment Fiume MM, Heldreth BA, Bergfeld WF, et al. Safety Assessment of Citric Acid, Inorganic Citrate Salts, and Alkyl Citrate Esters as Used in Cosmetics. Int J Toxicol. 2014.
- Review Almeman AA. Evaluating the Efficacy and Safety of Alpha-Hydroxy Acids in Dermatological Practice: A Comprehensive Clinical and Legal Review. Clin Cosmet Investig Dermatol. 2024.
- Case reports Sweis IE, Cressey BC. Potential role of the common food additive manufactured citric acid in eliciting significant inflammatory reactions contributing to serious disease states: A series of four case reports. Toxicol Rep. 2018.
Last reviewed 10 October 2026 · Next review April 2027 · How we rate evidence
Reader notes
Experiences and questions from readers, read by an editor before they appear. They are personal accounts, not evidence, and are not medical advice.