Poloxamer 338
INCI: POLOXAMER 338
Reviewed by Emma · Last updated 14 Aug 2026
A synthetic emulsifier that stabilises formulations and enables ingredient delivery
Best For Skin Types
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What Is Poloxamer 338?
Poloxamer 338 is a synthetic polymer belonging to the poloxamer family — large molecules composed of repeating units of propylene glycol and ethylene glycol. In skincare, it functions primarily as an emulsifier and surfactant, helping to blend water and oil-based ingredients that would normally separate.
Its role is largely functional rather than active. It allows formulators to create stable, homogeneous textures and can help keep actives suspended or dissolved evenly throughout a product, ensuring consistent delivery to the skin.
How It Works
Poloxamer 338 has both water-loving (hydrophilic) and oil-loving (lipophilic) regions in its molecular structure. This dual nature allows it to sit at the boundary between water and oil phases, preventing them from separating and creating a stable emulsion.
By doing so, it enables formulators to combine ingredients that wouldn't naturally mix, whilst helping ensure that actives are distributed evenly rather than settling or floating to the surface.
Clinical Evidence & References
Published research on poloxamer 338 specifically in skincare is limited. However, related poloxamers — particularly Pluronic F127 (a structurally similar poloxamer) — have been studied in wound healing contexts. Studies suggest that poloxamer-based hydrogels can serve as effective delivery vehicles for therapeutic compounds, with properties including biocompatibility and thermal responsiveness in laboratory settings.
For skincare applications, the ingredient's safety profile is well-established through cosmetic use and regulatory history, though direct clinical evidence on skin outcomes in cosmetic formulations is sparse. It is generally recognised as a functional excipient rather than an active treatment ingredient.
Published Research
How to Use
Poloxamer 338 is present in small amounts within formulations (typically under 1%), so there is no separate usage guidance required. It works behind the scenes to optimise the stability and texture of your product. Simply use the skincare item as directed by the brand.
Safety & Precautions
Frequently Asked Questions
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Take the skin quizOther forms of Poloxamer 338
These appear on ingredients lists under different names but are the same substance. Poloxamer 338 is the common form.
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