Discreet yet omnipresent in cosmetic formulations, Pentylene Glycol contributes to the stability and comfort of skincare products. Behind this technical name lies a multi-functional ingredient, often unfamiliar to the general public. What exactly is the role of Pentylene Glycol in a cream or serum? And is it truly a safe ingredient? Find out more below.
What is Pentylene Glycol and what is its function?
Summary
Published on January 26, 2022, updated on February 23, 2026, by Maylis, Chemical Engineer — 6 min of reading
Themes:
Key points to remember about Pentylene Glycol.
Pentylene glycol is a diol used in cosmetics for its humectant, solvent and preservative functions.
Owing to its water-retention capacity, it contributes to maintaining the hydration of the skin and hair whilst improving formulation stability.
Scientific assessments indicate a generally favourable safety profile, with low toxicity, minimal irritation and a limited risk of sensitisation. However, rare cases of contact allergy have been reported.
As with any cosmetic ingredient, caution is recommended in the event of compromised, damaged or allergy-prone skin.
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"Pentylene Glycol": what exactly is it?
Pentylene glycol, also known as pentane-1,2-diol, is an aliphatic diol with the molecular formula C₅H₁₂O₂. Its chemical structure features two hydroxyl groups on the first and second carbon atoms of the chain, conferring intermediate polarity and excellent miscibility with a wide range of both hydrophilic and lipophilic compounds. At room temperature, it appears as a colourless, low-viscosity, virtually odourless liquid—physicochemical properties that underpin its use in cosmetic product formulations.
Chemical structure of pentylene glycol.
Source: PubChem.
Historically, the pentylene glycol used in cosmetics was largely sourced from petrochemical synthesis routes based on mineral oils. Advances in the industry have, however, enabled the development of production pathways using renewable raw materials obtained by conversion of plant sugars notably from maize or sugarcane. This bio-based origin, now favoured in many so-called natural or certified organic formulations, does not alter the compound’s molecular structure but rather addresses environmental concerns and resource sustainability.
At Typology, we use pentylene glycol of vegetable origin, derived from sugar cane.
| Chemical and physical properties | Values |
|---|---|
| Chemical formula | C5H12O2 |
| Names | Pentylene glycol, pentane-1,2-diol, 1,2-dihydroxypentane |
| Aspect | Clear and transparent liquid |
| Molar mass | 104.15 g/mol |
| Dosage | Between 0.5% and 10%, typically around 5% |
| Solubility | Soluble in water |
Physico-chemical characteristics of Pentylene Glycol.
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What are the cosmetic properties of pentylene glycol?
Pentylene glycol is a versatile compound, valued in cosmetic formulation for its technological functions, notably as a solvent and preservative, but also for the effects it can bring to the skin and hair.
Pentylene glycol is first and foremost a humectant, meaning it helps to retain water in the superficial layers of the epidermis. The presence of two alcohol (-OH) groups in its structure gives it a particular affinity for water molecules, explaining its hydrophilic nature. By limiting water loss, pentylene glycol helps to maintain skin hydration and preserve skin suppleness. This hygroscopic capacity can also benefit hair fibres and explains why it is frequently found in treatments for dry or damaged hair.
Pentylene glycol also acts as a solvent within formulations. Its compatibility with numerous ingredients, whether hydrophilic or partially lipophilic, facilitates the dissolution and homogeneous dispersion of active ingredients. This characteristic contributes to the overall stability of the product and to a more uniform distribution of compounds upon application, without interacting undesirably with other constituents of the formulation.
Finally, pentylene glycol contributes to the control of microbial contamination. While not always employed as the sole preservative, it possesses antimicrobial activity that can bolster the overall efficacy of a cosmetic product’s preservative system. By restricting the proliferation of bacteria or yeasts, it thereby enhances the microbiological safety of the formulation, its stability over time and the maintenance of its performance.
Is pentylene glycol a safe ingredient?
Data from toxicological evaluations indicate that pentylene glycol exhibits low toxicity, limited irritant potential and no significant risk of skin sensitisation.
These factors explain its widespread use in cosmetics, including in products intended for daily use. However, despite this favourable safety profile, rare cases of contact dermatitis allergic have been reported, primarily in individuals with sensitive skin or following application to thin skin areas such as the eyelids. For example, one clinical case described a 44-year-old woman who developed two episodes of severe facial eczema after using a moisturiser containing pentylene glycol. Patch tests confirmed a positive reaction to pentylene glycol at concentrations of 5% and 10%. Conversely, tests carried out in fifteen other volunteers showed no skin reaction, emphasising the individual nature of this type of allergy.
Sources
FRUIJTIER-PÖLLOTH C. Safety assessment on polyethylene glycols (PEGs) and their derivatives as used in cosmetic products. Toxicology (2005).
ANDERSEN F. A. & al. Safety assessment of 1,2-glycols as used in cosmetics. International Journal of Toxicology (2012).
BORGHI A. & al. Pentylene glycol: An emerging cosmetic allergen? Contact Dermatitis (2021).
GILLIET M. & al. Allergic contact dermatitis from pentylene glycol in "hypoallergenic" eye cosmetics. Contact Dermatitis (2022).
