A water-compatible diol used to retain moisture and dissolve ingredients in cosmetic formulas.
Sources: 11,3-Propanediol, Propane-1,3-diol, Trimethylene glycol
Not assessed
No pregnancy- or breastfeeding-specific assessment has been completed for this record. A cosmetic safety review is not a pregnancy rating.
Not assessed
Propanediol
What it does
Supports hydration and acts as a solvent or carrier. It may also contribute to a deliberately designed preservation system.
Sources: 1Good for
- Moisturizing formulas
- Water-based ingredient delivery
How to use it
Use the finished serum, cleanser or moisturizer as directed. This ingredient does not require a separate routine step.
Sources: 1Who should be careful
A finished product can still sting or trigger a contact reaction. Do not assume that plant-derived and petroleum-derived grades have different biological effects solely because of their origin.
Sources: 1Pairs well with
No supported pairings have been documented for this record.
Usage, safety and formulation details
Mechanism of action
The hydroxyl groups of propane-1,3-diol interact with water. Its structure differs from propane-1,2-diol, usually labeled propylene glycol.
Sources: 1Potential adverse effects
Stinging or contact reactions are possible in an individual product; many other formula components can also be responsible.
Sources: 1Formulation considerations
Concentration and the surrounding formula influence feel, solubility and tolerance. A solvent or preservative booster does not replace microbial challenge testing.
Sources: 1Pregnancy and breastfeeding
Not assessed
No pregnancy- or breastfeeding-specific assessment has been completed for this record. A cosmetic safety review is not a pregnancy rating.
Safety tags
- Fragrance allergen
- Not assessed
Not separately assessed in this draft.
- Essential oil
- Not assessed
Not separately assessed in this draft.
- Drying alcohol
- Not assessed
Not separately assessed in this draft.
- May irritate sensitive skin
- Not assessed
Not separately assessed in this draft.
What remains uncertain
- Exact concentration, final pH and the full composition of any unprovided finished product
Clinical evidence and research
Clinical evidence
Evidence for its main benefitNot assessed
The cited references support identity, formulation role or safety context. No standalone clinical efficacy rating has been completed for the main benefit in this draft.
Sources: 1Regulation and ingredient label names
Regulatory information
No jurisdiction-specific assessment is recorded. An inventory listing is not blanket approval.
Names on ingredient lists
propanediol
Chemical identity and molecular structure
Chemical information
Chemical structure
| Detail | Value | Source |
|---|---|---|
| PubChem CID | 10442 | PubChem compound 10442: chemical identity |
| molecular formula | C3H8O2 | PubChem compound 10442: chemical identity |
| molecular weight | 76.09 g/mol | PubChem compound 10442: chemical identity |
| iupac name | propane-1,3-diol | PubChem compound 10442: chemical identity |
Content updated 9 November 2026.
Sources (2)
Scientific sources
- CIR: Safety assessment of alkane diolssafety assessment · 2024
- PubChem compound 10442: chemical identitychemical identity
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