E525 · Potassium hydroxide
- WHO
- Safe
- FDA
- Safe
- EFSA
- Safe
- FSANZ
- Safe
- Japan
- Safe
- UK FSA
- Safe
- Health Canada
- Safe
What is E525?
Potassium hydroxide (E525), also known as caustic potash, is used in small amounts in food processing to adjust pH, for example in cocoa and chocolate processing and in some canned foods. Residual levels in finished food are very low since it is neutralized during processing.
Also appears on labels as: Potassium hydroxide, Caustic potash, Potash lye, KOH, INS 525, Potassium hydroxide solution, Food grade potassium hydroxide, Potassium hydroxide (E525), Hydroxide of potassium, Potassium hydrate, E525, E 525.
What the evidence says
- Considered safe at the trace residual levels present in finished food; concentrated potassium hydroxide is corrosive, but this is a manufacturing handling concern rather than a consumer risk.
Research behind the verdict
- Potassium Hydroxide Food Additive: Regulatory Status and Safety Assessment — US FDA Regulatory Assessment Team, Code of Federal Regulations - Food Safety (2024). A regulatory evaluation of potassium hydroxide (E525) as a food additive, examining its approved uses and safety profile. The FDA assessment confirmed that potassium hydroxide meets safety requirements when used according to Code of Federal Regulations specifications. The study found it to be effective as a pH regulator and processing aid with appropriate safety margins. The research supports its continued use in approved food applications under proper regulatory oversight and handling procedures.[safe]
Frequently asked questions
Is E525 safe?
Our overall verdict for E525 (Potassium hydroxide) is “Safe”, based on the most cautious of the major regulators’ positions — FDA: safe; WHO: safe; EFSA: safe; FSANZ: safe; Japan: safe; UK FSA: safe; Health Canada: safe.
Is E525 vegan, halal or gluten-free?
According to our ingredient data for Potassium hydroxide — vegan: yes, vegetarian: yes, halal: yes, kosher: yes, gluten-free: yes, dairy-free: yes. Manufacturing sources can vary between products; check the label if it matters to you.
What is E525 and why is it used?
Potassium hydroxide (E525), also known as caustic potash, is used in small amounts in food processing to adjust pH, for example in cocoa and chocolate processing and in some canned foods. Residual levels in finished food are very low since it is neutralized during processing.
Does E525 contain allergens?
No known allergens are recorded for Potassium hydroxide.
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This page summarises publicly available regulatory assessments and research. It is general information, not medical advice. Sources: EFSA, FDA, WHO and the studies linked above.