Good Humectant NOAEL Data GHS Classified Sensitization Data Dermal Penetration

Propylene Glycol

INCI: PROPYLENE GLYCOL

CAS Number
57-55-6
Function
Diol humectant, solvent, and penetration enhancer. Attracts water from dermis and environment into epidermis. Also functions as preservative booster and freeze-point depressant.
Safety Rating
GOOD

Regulatory Status

🇪🇺 EU Status permitted
🇺🇸 US Status permitted
US Notes CIR reviewed; considered safe. FDA GRAS for food use. Higher irritation profile at concentrations above 10-15%, particularly on compromised skin. Neither comedogenic nor occlusive at standard use levels.

For full compliance data across 55 jurisdictions, use the Substance Compliance tool.

Safety Data

Margin of Safety (MoS)
adequate
Dermal Absorption
high
Sensitization
low

Calculate MoS for your specific formulation with the MoS Calculator.

Toxicological Studies

10 study endpoints found for Propylene Glycol. 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 2000 mg/kg bw/day oral dog Chronic COSMOS_DB
NOAEL 5000 mg/kg bw/day oral dog Chronic COSMOS_DB
NOAEL 10000 mg/kg bw/day oral rat Subchronic COSMOS_DB
NOAEL 15000 mg/kg bw/day oral rat Multigeneration Reproductive COSMOS_DB
NOAEL 1600 mg/kg bw/day oral mouse Developmental COSMOS_DB
NOAEL 1600 mg/kg bw/day oral rat Developmental COSMOS_DB
NOAEL 1550 mg/kg bw/day oral hamster Developmental COSMOS_DB
NOAEL 1230 mg/kg bw/day oral rabbit Developmental COSMOS_DB
NOAEL 2450 mg/kg bw/day oral rat Chronic COSMOS_DB
NOAEL 13300 mg/kg bw/day oral rat Subchronic COSMOS_DB

GHS Hazard Classification

Globally Harmonized System classification per ECHA C&L inventory and ILO/WHO International Chemical Safety Cards.

Hazard Statements
No hazard classification according to GHS criteria
Short-term Exposure Effects
The substance is mildly irritating to the eyes and respiratory tract. Ingestion of large amounts could cause metabolic acidosis.

Sensitization Profile

Contact sensitization data for Propylene Glycol based on clinical patch test studies and IFRA standards.

Sensitization Rate
moderate
Allergen Class
botanical
EU Allergen Listed
no
Patch Test Positive Rate
2.0%
Cross-reactivity Group
glycol-group
Reaction Type
contact-dermatitis

Source: IVDK; ESSCA; NACDG

Dermal Penetration Profile

Skin absorption and penetration characteristics of Propylene Glycol, relevant to systemic exposure and MoS calculations.

Absorption %
15-30%
Penetration Level
epidermis
Penetration Depth
epidermis
Molecular Weight
76.1 Da
Log P
-0.92
Systemic Absorption
yes
Topical Bioavailability
10-25%
Safety Margin Factor
high

Source: SCCS/1627/21, CIR

Expert Verdict

Well-established humectant with a strong safety record at standard cosmetic use levels (<10%). Irritation risk rises at higher concentrations on compromised skin. Formulate below 10% for sensitive skin applications or substitute with butylene glycol for a lighter, lower-irritation profile. Hygroscopic mechanism pulls water into stratum corneum rather than forming an occlusive barrier. Penetration-enhancing properties require co-ingredient safety consideration.

⚠️
Concern Level: Low

Regulatory Flags

penetration-enhancer irritant-at-high-concentration endocrine_disruptor eu_children_restricted epa_safer_alternative ifra_fragrance fda_food_additive

Frequently Asked Questions

Is Propylene Glycol safe in cosmetics?

Well-established humectant with a strong safety record at standard cosmetic use levels (<10%). Irritation risk rises at higher concentrations on compromised skin. Formulate below 10% for sensitive skin applications or substitute with butylene glycol for a lighter, lower-irritation profile. Hygroscopic mechanism pulls water into stratum corneum rather than forming an occlusive barrier. Penetration-enhancing properties require co-ingredient safety consideration. The EU classifies Propylene Glycol as "permitted". Safety rating: GOOD. 10 toxicological study endpoint(s) are available in our database.

Is Propylene Glycol allowed in the EU?

Propylene Glycol EU regulatory status: permitted. This is based on EU Regulation 1223/2009 and its amendments.

What does Propylene Glycol do in cosmetics?

Propylene Glycol functions as: Diol humectant, solvent, and penetration enhancer. Attracts water from dermis and environment into epidermis. Also functions as preservative booster and freeze-point depressant.. It is classified as a Humectant in our database. CAS number: 57-55-6.

What is the Margin of Safety for Propylene Glycol?

adequate The Margin of Safety (MoS) is calculated using SCCS methodology. A MoS above 100 is generally considered safe. Use the MoS Calculator tool to calculate MoS for your specific formulation and product category.

What is the NOAEL for Propylene Glycol?

The NOAEL (No Observed Adverse Effect Level) for Propylene Glycol is 2000 mg/kg bw/day based on a Chronic study via oral route in dog. A total of 10 study endpoints are available. Source: COSMOS_DB.

Compliance Tools

Check Propylene Glycol 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 55 jurisdictions
 🧮
MoS Calculator
Calculate Margin of Safety using SCCS methodology
 ⚗️
Heavy Metal Limits
Compare limits across jurisdictions

Related Ingredients

Pentylene Glycol
Good
Sodium Hyaluronate Crosspolymer
Excellent
Sodium PCA
Excellent
Sodium Hyaluronate
Excellent
L-Glutamic Acid
Excellent
Browse all 30,000+ ingredients →
📱

Is Propylene Glycol 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 Propylene Glycol in your formulation.

Ingredient Decoder MoS Calculator