Polyglyceryl-3 Polyricinoleate

Overview

Polyglyceryl-3 polyricinoleate (often abbreviated PGPR) is a W/O emulsifier built from polyglycerol and polyricinoleic acid — the latter derived from castor oil. The HLB is around 3.5, which places it deep in the W/O emulsifier range. It is palm-free and vegan, which matters for formulators avoiding palm-derived emulsifiers.

What makes PGPR genuinely unusual is the kind of W/O emulsion it produces. Traditional W/O systems tend to be heavy, greasy, and thick — think cold cream or heavy barrier ointments. PGPR breaks that pattern. It creates light, low-viscosity W/O emulsions with a silky, almost serum-like skin feel. At the right ratios, the emulsions are thin enough to be sprayable. This is extremely rare in the W/O world and opens up product formats (body sprays, mists, fluid sunscreens) that are normally reserved for O/W chemistry.

PGPR works both cold-process and hot-process. The raw material is a viscous amber liquid, stable for 12-24 months stored cool and sealed.

What it does in a formula

PGPR wraps water droplets in a thin, flexible film of emulsifier within a continuous oil phase. The polyricinoleate tail is long and branched, which gives the interfacial film flexibility and prevents the rigid, heavy feel that plagues many W/O emulsifiers.

The critical formulation detail: PGPR-stabilized emulsions need an electrolyte in the water phase. Adding 0.5-1% sodium chloride (NaCl) or magnesium sulfate (MgSO4) to the water phase before emulsification dramatically improves stability. The electrolyte strengthens the interfacial film by compressing the electrical double layer around the water droplets. Without it, the emulsion may separate within days.

The emulsification technique also matters. The water phase (with electrolyte dissolved) must be added slowly to the oil phase (containing PGPR) under moderate to high shear. Adding oil to water — the typical O/W technique — will not work here.

How to use

Dissolve PGPR in the oil phase. Dissolve your electrolyte (0.5-1% NaCl or MgSO4) in the water phase. Slowly add the water phase to the oil phase in a thin stream while blending with a high-shear mixer or immersion blender. Works cold or hot.

Usage rates by product type:

• Light W/O body lotions: 3-5%
• W/O facial fluids: 3-5%
• Sprayable W/O body emulsions: 3-4%
• W/O sunscreen bases: 4-5%
• Protective hand creams (W/O): 3-5%
• W/O makeup primers: 3-5%

Best for / Worst for

Best for: light W/O emulsions that do not feel greasy, sprayable W/O formats, W/O sunscreens (the continuous oil phase boosts SPF distribution), formulators who want water-resistant products without the heavy traditional W/O texture, palm-free and vegan formulations.

Worst for: O/W emulsions (wrong HLB range entirely), formulators who forget the electrolyte step (emulsion will fail), anhydrous formulas (no water to emulsify), anyone who needs a thick, occlusive barrier cream (PGPR naturally produces thin textures — you would need co-thickeners).

Common pitfalls

Forgetting the electrolyte. This is the number one failure mode. Without 0.5-1% NaCl or MgSO4 in the water phase, the emulsion will separate. It is not optional.

Adding oil to water instead of water to oil. W/O emulsification requires adding the inner phase (water) to the outer phase (oil). Reversing the order gives you a broken, unstable mess.

Adding water too fast. Pour the water phase in a slow, thin stream. Dumping it all at once overwhelms the emulsifier and causes phase inversion or instability.

Expecting it to thicken. PGPR produces thin emulsions by nature. If you want more body, add a wax or oil-phase thickener (beeswax, cetyl alcohol, or a rheology modifier). Do not increase PGPR concentration to thicken — it does not work that way.

Substitutes

• Sorbitan oleate (Span 80) — classic W/O emulsifier, but produces heavier, greasier textures.
• Polyglyceryl-2 dipolyhydroxystearate — another polyglycerol-based W/O emulsifier, slightly different skin feel.
• Cetyl dimethicone copolyol — silicone-based W/O emulsifier, very light feel, but not natural.
• Lanolin (wool wax) — traditional W/O emulsifier, much heavier and not vegan.