Is Guanidine Hydrochloride safe in cosmetics?
Guanidine Hydrochloride has a safety rating of "MODERATE" in our database. EU status: prohibited. US status: permitted. 1 toxicological study endpoint(s) are available in our database.
Guanidine Hydrochloride
Also known as: Aminoformamidine hydrochloride, Aminomethanamidine hydrochloride, Carbamidine hydrochloride, EINECS 200-002-3, Iminourea hydrochloride (+3 more)
INCI: GUANIDINE HCL
Guanidine Hydrochloride (CAS 50-01-1) is a cosmetic cosmetic ingredient functioning as Buffering. NOAEL 100 mg/kg bw/day (cross-referenced against ToxValDB ECHA IUCLID); EU Regulation 1223/2009 status: prohibited, max 7%. 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 50-01-1 →
Auto-generated CPSR Part A draft with source citations
Cross-Vertical Regulatory Divergence
Guanidine Hydrochloride is prohibited in EU cosmetics at max 7% but has active industrial GHS classifications (H302, H315, H319).
Source: Cosmetics: ingredients.eu_status/eu_max; Chemicals: ghs_classifications.signal_word/hazard_statement_code
Function
Buffering
Safety Rating
MODERATE
Chemistry & Identifiers
IUPAC Name
guanidine;hydrochloride
InChIKey
PJJJBBJSCAKJQF-UHFFFAOYSA-N
Regulatory Status
EU EU Status
prohibited
EU Max Conc.
7%
US US Status
permitted
US Notes
Permitted; no specific FDA cosmetic restriction, but used primarily in no-lye hair relaxer systems
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for Guanidine Hydrochloride.
Calculate MoS for your specific formulation with the MoS Calculator.
Toxicological Studies
1 study endpoint found for Guanidine Hydrochloride. NOAEL (No Observed Adverse Effect Level) values are used to calculate the Margin of Safety per SCCS methodology.
| Endpoint | Value | Route | Species | Study Type | Source |
|---|---|---|---|---|---|
| NOAEL | =100 mg/kg bw/day | oral | Rat | subchronic | ToxValDB_ECHA_IUCLID |
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 irritating to the eyes and skin.
Routes of Exposure
The substance can be absorbed into the body by ingestion.
Pre-Calculated Safety Assessment
Pre-calculated NOAEL → SED → MoS audit trail for Guanidine Hydrochloride across SCCS product categories, with measured dermal absorption where available.
EU CLP Annex VI Harmonized Classification
Legally binding harmonized classification per Regulation (EC) No 1272/2008 (CLP) Annex VI.
Signal Word
Warning
Pictograms
Harmful / Irritant
Hazard Class and Category
Acute Tox. 4 *; Skin Irrit. 2; Eye Irrit. 2
Hazard Statements
- H302 Harmful if swallowed
- H315 Causes skin irritation
- H319 Causes serious eye irritation
Inserted via ATP: CLP00
ECHA REACH Registration
European Chemicals Agency REACH dossier and Substances of Very High Concern listing.
Registration Type
Full
Tonnage Band
100 - 1,000 tonnes
Substance Type
SUBSTANCE
SVHC Candidate
No
Hazard classification: Restricted (Annex XVII)
PubChem Annotations
Safety and regulatory annotations from PubChem (NCBI) aggregated sources.
Safety (1)
ICSC Safety Card
0894
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Function Categories & List Membership
Cosmetic/Chemical Function Categories
No specific technical function
pH regulating agent
Expert Verdict
Expert safety assessment and concern-level summary for Guanidine Hydrochloride.
NOAEL Studies Summary
View details ->Public NOAEL study rows linked to Guanidine Hydrochloride by CAS number or substance name.
Studies
1
Lowest NOAEL
100 mg/kg bw/day
Highest NOAEL
100 mg/kg bw/day
ToxValDB_ECHA_IUCLID
Known Synonyms
Aminoformamidine hydrochloride
Aminomethanamidine hydrochloride
Carbamidine hydrochloride
EINECS 200-002-3
Iminourea hydrochloride
USAF EK-749
UNII-3YQC9ZY4YB
GuCl
Chemical Function
pH regulating agent
No specific technical function
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
GUANIDINE HYDROCHLORIDE
ChEMBL ID
CHEMBL1200728
Max Phase
4
Frequently Asked Questions
Is Guanidine Hydrochloride allowed in the EU?
Guanidine Hydrochloride EU regulatory status: prohibited. Maximum allowed concentration: 7%. This is based on EU Regulation 1223/2009 and its amendments.
What does Guanidine Hydrochloride do in cosmetics?
Guanidine Hydrochloride functions as: Buffering. It is classified as a cosmetic ingredient in our database. CAS number: 50-01-1.
What is the NOAEL for Guanidine Hydrochloride?
The NOAEL (No Observed Adverse Effect Level) for Guanidine Hydrochloride is =100 mg/kg bw/day based on a subchronic study via oral route in Rat. Source: ToxValDB_ECHA_IUCLID.
Is Guanidine Hydrochloride used outside cosmetics?
Guanidine Hydrochloride 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.
Does Guanidine Hydrochloride have different safety status in cosmetics vs industrial chemicals?
Guanidine Hydrochloride is prohibited in EU cosmetics at max 7% but has active industrial GHS classifications (H302, H315, H319).
Compliance Tools
Check Guanidine Hydrochloride 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
Related Ingredients
Acrylates/Vinyl Neodecanoate Crosspolymer
Excellent
Same category
Emulsion stabilising, film forming
Adipic Acid
Excellent
Same category
Buffering
Aluminum Magnesium Oxide
Excellent
Same category
Absorbent, bulking agent, opacifying ...
Ammonium VA/Acrylates Copolymer
Excellent
Same category
Antistatic, binding, film forming, ha...
Ammonium VA/Crotonic Acid Copolymer
Excellent
Same category
Antistatic, film forming, hair fixing...
Aphanothece Sacrum Polysaccharide
Excellent
Same category
Absorbent, emulsion stabilising, film...
(20S)-Protopanaxadiol
Moderate
Similar safety
(Cnidium Officinale/Coptis Chinensis/Glycyrrhiza Uralensis) Root Extract
Moderate
Similar safety
Skin conditioning
(Cryptomeria Japonica/Chamaecyparis Obtusa) Stem Ferment Extract
Moderate
Similar safety
Antimicrobial, antioxidant, humectant
(Eclipta Prostrata/Houttuynia Cordata) Leaf Extract
Moderate
Similar safety
Skin conditioning
(Lepidium Meyenii/Sarcodon Aspratus) Root Water
Moderate
Similar safety
Skin conditioning
(Licorice/Reynoutria Japonica) Root/Stem Extract
Moderate
Similar safety
Skin conditioning, antioxidant
Ascorbic Acid
Excellent
Chemical family
Antioxidant; ROS scavenger; vitamin E...
Ascorbic Acid (Vitamin C)
Excellent
Chemical family
Antioxidant, skin brightening
Ergocalciferol
Moderate
Chemical family
Skin Conditioning
Is Guanidine Hydrochloride in Your Products?
Scan any product label with Piro — our free ingredient scanner. Point your camera at the ingredients list and get instant safety scores for every ingredient.
Try Piro Free →Analyze Your Full Ingredient List
Paste any INCI list into the Decoder for instant safety analysis, or calculate the Margin of Safety for Guanidine Hydrochloride in your formulation.