Is Magnesium Hydroxide safe in cosmetics?
Magnesium Hydroxide has a safety rating of "MODERATE" in our database. EU status: restricted. US status: permitted.
Moderate
Cosmetic Ingredient
Magnesium Hydroxide
Also known as: Magnesium hydroxide (Mg(OH)2), EINECS 215-170-3, Hydro-mag MA, Lycal 96 HSE, Magmesia hydrate (+6 more)
INCI: MAGNESIUM HYDROXIDE
Magnesium Hydroxide (CAS 1309-42-8) is a cosmetic cosmetic ingredient functioning as Absorbent, pH buffering/neutralizing agent, filler, texturizer. NOAEL 1000 mg/kg bw/day (cross-referenced against ToxValDB ECHA IUCLID); EU Regulation 1223/2009 status: restricted. Industrial safety data is also available in the chemical safety database. Same-CAS public records also appear in industrial chemical safety and pharmaceutical data.
View industrial chemical safety profile for CAS 1309-42-8 →
Auto-generated CPSR Part A draft with source citations
Function
Absorbent, pH buffering/neutralizing agent, filler, texturizer
Safety Rating
MODERATE
Chemistry & Identifiers
IUPAC Name
magnesium dihydroxide
InChIKey
VTHJTEIRLNZDEV-UHFFFAOYSA-L
Regulatory Status
EU EU Status
restricted
US US Status
permitted
US Notes
Allowed - not on FDA's prohibited/restricted list for cosmetics; also has GRAS status as a food additive
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for Magnesium Hydroxide.
Calculate MoS for your specific formulation with the MoS Calculator.
Pre-Calculated Safety Assessment
Pre-calculated NOAEL → SED → MoS audit trail for Magnesium Hydroxide across SCCS product categories, with measured dermal absorption where available.
ECHA REACH Registration
European Chemicals Agency REACH dossier and Substances of Very High Concern listing.
Registration Type
Full
Tonnage Band
100,000 - 1,000,000 tonnes
Substance Type
SUBSTANCE
SVHC Candidate
No
Additional Ingredient Properties
3 property records from structured ingredient metadata.
deodorant
{"cas_number": "1309-42-8", "ingredient_class": "odor_neutralizer", "mechanism_of_action": "pH_modification", "antiperspirant_efficacy_sweat_reduction_pct": "0", "deodorant_efficacy_hours": "8-16", "odor_reduction_pct": "55-75", "bacteriostatic": "limited", "bactericidal": "no", "microbiome_impact": "neutral", "axillary_microbiome_effect": "pH modification", "pH_modification_range": "alkalinizes t…
ecotoxicity
{"biodegradable": "no", "biodegradation_days": "non-biodegradable", "bioaccumulative": "no", "aquatic_toxicity_level": "low", "coral_reef_safe": "yes", "marine_toxicity": "low toxicity", "freshwater_toxicity": "minimal impact", "soil_toxicity": "inert mineral", "endocrine_disruptor": "no", "persistent_organic_pollutant": "no", "microplastic": "no", "nano_particle": "no", "hawaii_banned": "no", "eu…
mineral_clay
{"cas_number": "1309-42-8", "ingredient_class": "magnesium_compound", "chemical_formula": "Mg(OH)2", "mineral_origin": "synthetic", "particle_size_range_um": "0.1-10", "surface_area_m2_per_g": "10-40", "crystal_structure": "hexagonal", "color_appearance": "white", "opacity": "opaque", "refractive_index": "1.58", "oil_absorption_g_per_100g": "40-80", "water_absorption_capacity": "80-150%", "surface…
PubChem Annotations
Safety and regulatory annotations from PubChem (NCBI) aggregated sources.
Regulatory (2)
JECFA Evaluation
MAGNESIUM HYDROXIDE | 1965 | NOT LIMITED | NMRS 40/TRS 339-JECFA 9/16 | FAS 67.29/NMRS 40A,B,C-JECFA 9/159
Source: Joint FAO/WHO Expert Committee on Food Additives (JECFA)
EU Food Improvement
Food additives
Source: EU Food Improvement Agents
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Absorbent
Adhesion/cohesion promoter
Binder
Conductive agent
Drier
Dye
Filler
Flame retardant
Flavouring and nutrient
Processing aids not otherwise specified
Regulatory List Membership (2)
EPA Safer Chemical Ingredients List (SCIL)
FDA Substances Added to Food (EAFUS)
Expert Verdict
Expert safety assessment and concern-level summary for Magnesium Hydroxide.
Regulatory Flags
epa_safer_alternative
fda_food_additive
jecfa_safe
NOAEL Studies Summary
View details ->Public NOAEL study rows linked to Magnesium Hydroxide by CAS number or substance name.
Studies
18
Lowest NOAEL
299 mg/kg bw/day
Highest NOAEL
6810 mg/kg bw/day
ECHA_REACH_reach_study_results_dossiers_23-05-2023.zip
Known Synonyms
Magnesium hydroxide (Mg(OH)2)
EINECS 215-170-3
Hydro-mag MA
Lycal 96 HSE
Magmesia hydrate
Magnesium hydroxide gel
Nemalite
UNII-NBZ3QY004S
Magnesia, [Milk of]
Mg(OH)2
magnesium hydrate
Chemical Function
pH regulating agent
Absorbent
Flame retardant
Binder
Regulatory Lists
inert_ingredient; Pesticides
active_ingredient; animal_products; Europe; pharmaceutical; residue
Europe; supplements
Europe; food_additive; supplements
Europe; plastic_additive
food_additive; Substances Added to Food (formerly EAFUS) (2/2019)
SCIL (9/2019)
Canada; pharmaceutical
Canada; pharmaceutical
inert_ingredient; non_food_use; Pesticides
Australian Status
AICIS status: listed
Cross-Vertical Safety Context
Same-CAS public records found in pharmaceutical data.
SOURCE
ChEMBL / DrugCentral / FAERS
DB_PHARMA CAS match
Pharmaceutical Data
Same-CAS rows from the pharmaceutical spoke database.
Compound
MAGNESIUM HYDROXIDE
ChEMBL ID
CHEMBL1200718
Max Phase
4
Adverse Event Associations
4173
Frequently Asked Questions
Is Magnesium Hydroxide allowed in the EU?
Magnesium Hydroxide EU regulatory status: restricted. This is based on EU Regulation 1223/2009 and its amendments.
What does Magnesium Hydroxide do in cosmetics?
Magnesium Hydroxide functions as: Absorbent, pH buffering/neutralizing agent, filler, texturizer. It is classified as a cosmetic ingredient in our database. CAS number: 1309-42-8.
Is Magnesium Hydroxide used outside cosmetics?
Magnesium Hydroxide also appears in industrial chemical safety and pharmaceutical data. The cross-vertical cards on this page render same-CAS public rows from the matched databases.
Compliance Tools
Check Magnesium 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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