E525; Potassium Hydroxide
(in 8,822 products)

Potential Risk Index®:

ISCE InhaleISCE SwallowISCE ContactISCE Environment
PRI Legend


1. Acidity Regulator / Buffering Agent - Changes or maintains the acidity or basicity of food/cosmetics.
Potassium hydroxide, commonly called caustic potash, has many industrial and niche applications.
Potassium hydroxide works well in the manufacture of biodiesel by transesterification of the triglycerides in vegetable oil. Glycerin from potassium hydroxide-processed biodiesel is useful as an inexpensive food supplement for livestock, once the toxic methanol is removed. Besides, the saponification of fats with potassium hydroxide is used to prepare the corresponding "potassium soaps", which are softer than the more common sodium hydroxide-derived soaps. Because of their softness and greater solubility, potassium soaps require less water to liquefy, and can thus contain more cleaning agent than liquefied sodium soaps.
In cosmetics, potassium hydroxide is often the main active ingredient in chemical "cuticle removers" used in manicure treatments. In food products, potassium hydroxide acts as a pH control agent, stabilizer, and food thickener with E number 525. It is approved to use as food additive in EU and generally recognised as safe food substance in US. [1]
EU CosIng Annex III Restriction Information:
(EU) No. 622/2016
Regulated By:
Product Type, body parts:
(a) Nail cuticle solvent
(b) Hair straightener
(c) pH adjuster for depilatories
(d) Other uses as pH adjuster
15d- Callosity softener/remover
Maximum concentration in ready for use preparation:
(a) 5% (5) (b) 1. 2% (5) 2. 4.5% (5) 15d- 1,5% (5)
(b) 1. General use
2. Professional use
(c) up to pH 12.7
(d) up to pH 11
15 d Contains alcakali, Avoid contact with eyes
Keep out of reach of chindren ans Read directions for use carefully
Wording of conditions of use and warnings:
(a) Contains alkali
Avoid contact with eyes
Can cause blindness
Keep out of reach of children
(b) 1. Contains alkali
Avoid contact with eyes
Can cause blindness
Keep out of reach of children
2. For professional use only
Avoid contact with eyes
Can cause blindness
(c) Keep out of reach of children
Avoid contact with eyes
SCCS opinions:
1527/14 - Opinion on Potassium hydroxide (KOH) as callosity softener/remover
Scientific References:
Regulatory References:
1. South Korea - Ministry of Food and Drug Safety - Prohibited/Restricted Chemicals
- Ref: 1175
- Ref: III/15a
3. Argentina Ministerio de Salud - Restricciones
- Hidróxido de sodio o potasio
4. EU Approved Food Additive [2018]
- E525
5. Japan’s List of Designated Food Additives under Article 10 of the Food Sanitation Act
- Potassium Hydroxide (Caustic Potash)
6. US FDA Generally Recognized As Safe (GRAS) Food Substances (21 CFR 184) [2017]
- § 184.1631 - Potassium hydroxide

Safety and Hazards (UN GHS):

1. Toxic if swallowed (H301)
2. Harmful if swallowed (H302)
3. May be fatal if swallowed and enters airways (H304)
4. Harmful in contact with skin (H312)
5. Causes severe skin burns and eye damage (H314)
6. Causes serious eye damage (H318)
7. Causes damage to organs (H370)

Potential Health Concerns For:

1. Dermatitis, Irritant (PubMed ID:22906572)

User Comments:

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