beauty
cleaning
food
industrial

Sodium hydroxide

CAS 81133-20-2 · 70/100 · High conf.

Also registered as 6 other CAS numbers

8012-01-9 · 1418731-95-9 · 2319645-49-1 · 2391974-94-8 · 1310-58-3 · 1310-73-2

Concern score

70/100High concern based on regulatory listings.

High confidence

Sodium hydroxide in plain language

What it is: On cosmetic ingredient lists it appears as “Potassium hydroxide”.
Also known as Potassium hydroxide · Sodium hydroxide solutions · Caustic soda · Potassium or sodium hydroxide · Aetznatron · Lye
Show all 38 names
Potassium hydroxide / sodium hydroxide · Stamperprep · Anhydrous · Ascarite · Caustic soda flakes · Collo-Grillrein · Collo-Tapetta · E-524 · Fuers Rohr · Hydroxyde de sodium · INS-524 · Na(OH) · Natrium causticum · Natriumhydroxid · Natriumhydroxyde · Promoter 3308B · Plung · Rohrputz · Rohrreiniger Rofix · Sodium hydrate · Sodium hydroxide flakes · Soda lye · hydrate Soda · kaustische Soda · Sodium hydroxide (Na(OH)) · Sodium hydroxide dimer · Tosoh pearl · White caustic · kalii hydroxidum · natrii hydroxidum · sodium hydroxide (sara iii) · sodium hydroxide (cercla)
What it does: Used in cosmetics as a pH buffer and a denaturant. Potassium Hydroxide is the inorganic base.
Buffering
Denaturant
Acidity regulator
Surfactant
pH adjuster
Fragrance
Is it a concern?: High concern: no hazard classifications on record. It is restricted in EU cosmetics.

Why it's flagged

Potassium or sodium hydroxide is restricted in cosmetic products under Annex III of the EU Cosmetics Regulation (EC) 1223/2009.

RestrictedEU EC — restricted

The score describes this ingredient's chemical identity — its hazard profile from published classifications and regulatory status — not the safety of any product it appears in.

Regulation

Restrictions first, then routine listings from published regulatory sources.

EU Annex III — restricted
EU restricted in cosmetics
Inactive ingredient in US drugs

Recorded in these product areas

Found in consumer products
Beauty
Cleaning
Pharma
Industrial

EUEC
Annex III of EU Cosmetics Regulation (EC) 1223/2009: substances which cosmetic products must not contain except subject to the restrictions laid down. Product types: (a) Nail cuticle solvent (b) Hair straightener (c) pH adjuster for depilatories (d) Other uses as pH adjuster Callosity softener/remover (entry 15d) Maximum concentration: (a) 5% (b) 2% (General use) and 4.5% (Professional use) Entry 15d: 1,5% Other conditions: (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 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
restricted
View source →

USFDAinactive ingredient database174 entries — 53 administration routes
- Route: DENTAL; Dosage form: PASTE; Potency: 0.6 %w/wSource →
- Route: DENTAL; Dosage form: SOLUTION; Potency: ADJ PHSource →
- Route: ENDOTRACHEAL; Dosage form: INJECTION; Potency: ADJ PHSource →
- Route: ENDOTRACHEAL; Dosage form: POWDER, FOR SUSPENSION; Potency: ADJ PHSource →
- Route: ENDOTRACHEAL; Dosage form: SUSPENSION; Potency: ADJ PHSource →
- Route: EPIDURAL; Dosage form: INJECTION; Potency: ADJ PHSource →
- Route: EPIDURAL; Dosage form: INJECTION, SOLUTION; Potency: ADJ PHSource →
- Route: EPIDURAL; Dosage form: SOLUTION; Potency: ADJ PHSource →
- Route: EXTRACORPOREAL; Dosage form: INJECTION; Potency: ADJ PHSource →
- Route: INFILTRATION; Dosage form: INJECTION; Potency: ADJ PHSource →
- Route: INFILTRATION; Dosage form: INJECTION, SOLUTION; Potency: ADJ PHSource →
- Route: INTERSTITIAL; Dosage form: INJECTION; Potency: ADJ PHSource →
- Route: INTRA-AMNIOTIC; Dosage form: INJECTION; Potency: ADJ PHSource →
- Route: INTRA-ARTERIAL; Dosage form: INJECTION; Potency: 176 mgSource →
- Route: INTRA-ARTERIAL; Dosage form: INJECTION, POWDER, FOR SOLUTION; Potency: ADJ PHSource →
- Route: INTRA-ARTERIAL; Dosage form: INJECTION, POWDER, LYOPHILIZED, FOR SOLUTION; Potency: ADJ PHSource →
- Route: INTRA-ARTERIAL; Dosage form: INJECTION, SOLUTION; Potency: ADJ PHSource →
- Route: INTRA-ARTERIAL; Dosage form: SOLUTION; Potency: ADJ PHSource →
- Route: INTRA-ARTICULAR; Dosage form: INJECTION; Potency: ADJ PHSource →
- Route: INTRA-ARTICULAR; Dosage form: INJECTION, SOLUTION; Potency: ADJ PHSource →
- Route: INTRA-ARTICULAR; Dosage form: INJECTION, SUSPENSION; Potency: ADJ PHSource →
- Route: INTRA-ARTICULAR; Dosage form: SUSPENSION, EXTENDED RELEASE; Potency: ADJ PHSource →
- Route: INTRABURSAL; Dosage form: INJECTION; Potency: ADJ PHSource →
- Route: INTRACARDIAC; Dosage form: INJECTION; Potency: ADJ PHSource →
- Route: INTRACAUDAL; Dosage form: INJECTION; Potency: ADJ PHSource →
- Route: INTRACAUDAL; Dosage form: INJECTION, SOLUTION; Potency: ADJ PHSource →
- Route: INTRACAVERNOUS; Dosage form: INJECTION, POWDER, LYOPHILIZED, FOR SOLUTION; Potency: ADJ PHSource →
- Route: INTRACAVITARY; Dosage form: INJECTION; Potency: ADJ PHSource →
- Route: INTRACAVITARY; Dosage form: INJECTION, POWDER, LYOPHILIZED, FOR SOLUTION; Potency: ADJ PHSource →
- Route: INTRADERMAL; Dosage form: INJECTION; Potency: ADJ PHSource →
- Route: INTRADERMAL; Dosage form: INJECTION, POWDER, FOR SOLUTION; Potency: ADJ PHSource →
- Route: INTRADERMAL; Dosage form: SUSPENSION, EXTENDED RELEASE; Potency: ADJ PHSource →
- Route: INTRADISCAL; Dosage form: INJECTION, POWDER, FOR SOLUTION; Potency: ADJ PHSource →
- Route: INTRALESIONAL; Dosage form: INJECTION; Potency: ADJ PHSource →
- Route: INTRALESIONAL; Dosage form: INJECTION, SUSPENSION; Potency: ADJ PHSource →
- Route: INTRALESIONAL; Dosage form: SUSPENSION, EXTENDED RELEASE; Potency: ADJ PHSource →
- Route: INTRAMUSCULAR; Dosage form: INJECTION; Potency: 176 mgSource →
- Route: INTRAMUSCULAR; Dosage form: INJECTION, POWDER, FOR SOLUTION; Potency: 7.01 mgSource →
- Route: INTRAMUSCULAR; Dosage form: INJECTION, POWDER, LYOPHILIZED, FOR SOLUTION; Potency: 0.35 %w/vSource →
- Route: INTRAMUSCULAR; Dosage form: INJECTION, SOLUTION; Maximum daily exposure: 78 mgSource →
- + 134 more entries not shown
EUCosIngActive3 entries
- Restriction: III/15aSource →
- Potassium Hydroxide is the inorganic base Restriction: III/15a, 15dSource →
- Cosmetics Regulation annex III / ref 15a.Source →
EUEFSAEFSA opinion2 entries
- Scientific Opinion on the evaluation of the substances currently on the list in the annex to Commission Directive 96/3/EC as acceptable previous cargoes for edible fats and oils - Part II of III (EFSA CONTAM)Source →
- Scientific Opinion on the safety and efficacy of sodium hydroxide for dogs, cats and ornamental fish (EFSA FEEDAP)Source →
GLOBALJECFANOT LIMITEDJECFA evaluation lists ADI NOT LIMITED. Functional class: acidity regulator.
- JECFA evaluation lists ADI NOT LIMITED. Functional class: acidity regulator.Source →
GLOBALJECFAEvaluatedJECFA evaluation record.
- JECFA evaluation record.Source →
USEPAcommercial use observedEPA CPDat observed this chemical in 11688 composition records across product categories including Construction and building materials, Raw materials, Home maintenance. EPA CPDat classifies this chemical for functional uses including pH regulating agent, pH balancer, alkalinizing agent.
- EPA CPDat observed this chemical in 11688 composition records across product categories including Construction and building materials, Raw materials, Home maintenance. EPA CPDat classifies this chemical for functional uses including pH regulating agent, pH balancer, alkalinizing agent.Source →
USFDAlisted in openFDA substanceopenFDA substance registry classifies this ingredient as chemical.
- openFDA substance registry classifies this ingredient as chemical.Source →

Expert safety opinions

Independent scientific assessments cited by the records we hold, with the year and link where the record gives one.

SCCS
EU Scientific Committee on Consumer Safety
No SCCS opinion on file.
CIR
Cosmetic Ingredient Review (US expert panel)
No CIR safety assessment on file.
EFSA
European Food Safety Authority
- Scientific Opinion on the evaluation of the substances currently on the list in the annex to Commission Directive 96/3/EC as acceptable previous cargoes for edible fats and oils - Part II of III (EFSA CONTAM)
  2012 · EU EFSA listing · Read the source →
- Scientific Opinion on the safety and efficacy of sodium hydroxide for dogs, cats and ornamental fish (EFSA FEEDAP)
  2012 · EU EFSA listing · Read the source →
JECFA
Joint FAO/WHO Expert Committee on Food Additives
- JECFA evaluation lists ADI NOT LIMITED. Functional class: acidity regulator.
  Year not recorded · GLOBAL JECFA listing · Read the source →
- JECFA evaluation record.
  Year not recorded · GLOBAL JECFA listing · Read the source →

Evidence & sources

No graded research studies for Sodium hydroxide yet. This record is compiled from the published data sources below — registries and regulatory listings, not study findings.

10 data sources

Where this comes from

CosIng
regulatory · updated 2026-09-23
Open →
EU CosIng Cosmetics Regulation Annexes
regulatory · updated 2024-01-11
Open →
EFSA OpenFoodTox
regulatory · updated 2026-10-04
Open →
EPA Chemical and Products Database
exposure · updated september 5, 2012
Open →
EPA DSSTox Identifiers
chemistry · updated 2025-12-29
Open →
FDA Inactive Ingredient Database
regulatory · updated 2026-01-09
Open →
FDA GSRS UNII
registry · updated 2026-02-26
Open →
WHO JECFA Database
regulatory · updated 2026-10-04
Open →
openFDA Substance
registry · updated 2026-05-24
Open →
PubChem Live Enrichment
chemistry · updated 2026-05-17
Open →

Reference links (2)

Openfda substance

codexalimentarius.net

Read →

Openfda substance

en.wikipedia.org

Read →

Suitability

Context-specific fit derived from published classifications and the current ingredient evidence profile.

Food use

Food-use source coverage is present in the current record.

Good fit

The ingredient appears in food-oriented source coverage or allowed-use references, which makes food use easier to support than a context with no domain signal at all.

Fragrance avoidance

Not a strong fit for fragrance avoidance because it carries Fragrance.

Avoid

The ingredient itself is a fragrance-linked signal, so it is better treated as an avoid case when fragrance exposure is the main concern.

Where it has been recorded

How often EPA CPDat has listed Sodium hydroxide in a product composition. These are source records, not Greenveil catalog products.

Source records

11,688

Named organisations

Construction and building materialsRaw materialsHome maintenanceFurniture and furnishingsPersonal careLaboratory supplies

Typical roles

BufferingDenaturantAcidity regulatorSurfactantpH adjusterFragrance

See products using Sodium hydroxide →

Catalog

Found in these products

Their ingredient lists include Sodium hydroxide; each product's own rating depends on its whole formula, so it is shown on the product page, not here.

See all 1000+ →Find products without it →

Co-occurrence

Often appears with

Ingredients that frequently appear alongside Sodium hydroxide in the catalog.