Is Calcium Hydroxide safe in cosmetics?
Calcium Hydroxide has a safety rating of "MODERATE" in our database. EU status: restricted. US status: permitted.
Calcium Hydroxide
Also known as: Ca(OH)2, Calcium hydroxide (Ca(OH)2), Bell mine, Caswell No. 144, EINECS 215-137-3 (+6 more)
INCI: CALCIUM HYDROXIDE
Calcium Hydroxide (CAS 1305-62-0) is a cosmetic cosmetic ingredient functioning as pH adjuster, depilatory agent, hair straightener. EU Regulation 1223/2009 status: restricted, max 7%. Industrial safety data is also available in the chemical safety database. Same-CAS public records also appear in industrial chemical safety, pharmaceutical, and food safety data.
Cross-Vertical Regulatory Divergence
Calcium Hydroxide is classified GHS Danger (H314, H315, H318, H335, H370, H373) in the chemicals database but is restricted in EU cosmetics at max 7%.
Source: Cosmetics: ingredients.eu status/eu max; Chemicals: ghs classifications.signal word/hazard statement code
Function
pH adjuster, depilatory agent, hair straightener
Editorial assessment
MODERATE
Preliminary editorial note — not a computed safety verdict.
Chemistry & Identifiers
IUPAC Name
calcium dihydroxide
InChIKey
AXCZMVOFGPJBDE-UHFFFAOYSA-L
Regulatory Status
EU EU Status
restricted
EU Max Conc.
7%
US US Status
permitted
US Notes
Adequate when Annex III limits are respected
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for Calcium Hydroxide.
Calculate MoS for your specific formulation with the MoS Calculator.
GHS Hazard Classification
Globally Harmonized System classification per ECHA C&L inventory and ILO/WHO International Chemical Safety Cards.
Short-term Exposure Effects
The substance is corrosive to the eyes and skin. The substance is irritating to the respiratory tract. Medical observation is indicated.
Long-term Exposure Effects
Repeated or prolonged contact with skin may cause dermatitis. Repeated or prolonged inhalation of dust particles may cause effects on the lungs.
Routes of Exposure
The substance can be absorbed into the body by inhalation of its aerosol and by ingestion.
EPA ToxValDB — Toxicity Values
2 toxicity values from EPA ToxValDB (aggregated from CCTE, HPV, ToxRefDB, IRIS, and other regulatory dossiers).
| Endpoint | Value | Species | Route | Duration | Source |
|---|---|---|---|---|---|
| LD50 | =7300 mg/kg | Mouse | oral | - | ChemIDplus |
| LD50 | =7340 mg/kg | Rat | oral | - | ChemIDplus |
ECHA REACH Registration
European Chemicals Agency REACH dossier and Substances of Very High Concern listing.
Registration Type
Full
Tonnage Band
1,000,000 - 10,000,000 tonnes
Substance Type
SUBSTANCE; GROUP
SVHC Candidate
No
Expanded Jurisdictional Detail
Additional regulatory detail beyond the 7-jurisdiction summary: Saudi SFDA, Korea MFDS, ASEAN ACD, Japan/Korea, Brazil/India, and cross-jurisdictional restriction entries.
SA Saudi SFDA (III - Restricted)
Product type: (a) Hair straighteners containing two components: calcium hydroxide and a guanidine salt (b) pH ajuster for depilatories (c) Other uses (e.g. pH adjuster, processing aid). Max: (a) 7% (as calcium hydroxide).
JPKR Japan/Korea Cosmetics
Korea (Restricted): max 7.0
BRIN Brazil/India Cosmetics
India: Restricted · max (a) 7% (as calcium hydroxide)
Additional Jurisdictional Restrictions (2)
| Jurisdiction | Status | Max % | Product Type |
|---|---|---|---|
| BR | restricted | 7 | Hair relaxers (2-component: Ca(OH)2 + guanidine salt): 7% as Ca(OH)2; Depilatories pH 12.7; Other uses pH 11 |
| ASEAN | restricted | 7% in mixtures | Hair straighteners |
PubChem Annotations
Safety and regulatory annotations from PubChem (NCBI) aggregated sources.
Safety (2)
ICSC Safety Card
0408
Source: WHO/JECFA
Skin Eye Respiratory Irritation
Skin irritant, avoid inhalation | Dust irritates eyes, nose and throat. | Skin: Moderately irritating. Calcium hydroxide is a relatively strong base and hence a moderately caustic irritant to all exposed surfaces of the body. /Human/
Source: Hazardous Substances Data Bank (HSDB)
Regulatory (2)
JECFA Evaluation
CALCIUM HYDROXIDE | 1965 | NOT LIMITED | NMRS 40/TRS 339-JECFA 9/16 | FAS 67.29/NMRS 40A,B,C-JECFA 9/156
Source: WHO/JECFA
EU Food Improvement
Food additives
Source: EU Food Improvement Agents
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Binder
Catalyst
Chemical reaction regulator
Degradant/impurity
Filler
Flame retardant
Flavouring and nutrient
Flocculating agent
Hardener
Processing aids not otherwise specified
Regulatory List Membership (3)
EPA Safer Chemical Ingredients List (SCIL)
FDA Substances Added to Food (EAFUS)
EU CosIng Cosmetics Ingredient Database
Editorial summary
Preliminary editorial summary for Calcium Hydroxide — not a computed safety verdict. See the sourced toxicological data above.
Regulatory Flags
epa_safer_alternative
fda_food_additive
eu_cosing_listed
jecfa_safe
Known Synonyms
Ca(OH)2
Calcium hydroxide (Ca(OH)2)
Bell mine
Caswell No. 144
EINECS 215-137-3
EPA Pesticide Chemical Code 075601
Kemikal
UNII-PF5DZW74VN
Kalziumhydroxid
Loeschkalk
geloeschter Kalk
Chemical Function
pH regulating agent
Regulatory Lists
Europe; plastic_additive
active_ingredient; Europe; Pesticides
drinking_water; Europe; manufacturing; plastic_additive
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Pesticides
active_ingredient; Europe; Pesticides
inert_ingredient; Pesticides
Australian Status
AICIS status: listed
Cross-Vertical Safety Context
Same-CAS public records found in pharmaceutical and food safety data.
SOURCE
ChEMBL / DrugCentral / FAERS
DB_PHARMA CAS match
Pharmaceutical Data
Same-CAS rows from the pharmaceutical spoke database.
Compound
CALCIUM HYDROXIDE
ChEMBL ID
CHEMBL2106388
Max Phase
3
SOURCE
EFSA / FDA GRAS
food_additives
Food Safety Data
Same-CAS food additive or FDA GRAS records from the core public database.
Food Name
Calcium hydroxide
E Number
E526
ADI
NOT LIMITED mg/kg bw
Food Category
preservative
Frequently Asked Questions
Is Calcium Hydroxide allowed in the EU?
Calcium Hydroxide EU regulatory status: restricted. Maximum allowed concentration: 7%. This is based on EU Regulation 1223/2009 and its amendments.
What does Calcium Hydroxide do in cosmetics?
Calcium Hydroxide functions as: pH adjuster, depilatory agent, hair straightener. It is classified as a cosmetic ingredient in our database. CAS number: 1305-62-0.
Is Calcium Hydroxide used outside cosmetics?
Calcium Hydroxide also appears in industrial chemical safety, pharmaceutical, and food safety data. The cross-vertical cards on this page render same-CAS public rows from the matched databases.
Does Calcium Hydroxide have different safety status in cosmetics vs industrial chemicals?
Calcium Hydroxide is classified GHS Danger (H314, H315, H318, H335, H370, H373) in the chemicals database but is restricted in EU cosmetics at max 7%.
Compliance Tools
Check Calcium Hydroxide compliance across multiple jurisdictions:
Ingredient Decoder
Paste a full ingredient list for instant analysis
82 Allergen Checker
Check for EU declarable fragrance allergens
Substance Compliance
Check compliance across multiple jurisdictions
MoS Calculator
Calculate Margin of Safety using SCCS methodology
Heavy Metal Limits
Compare limits across jurisdictions
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