Propylene Glycol vs. Vegetable Glycerin: Differences, Grades & Uses
Propylene glycol (PG) and vegetable glycerin (VG) are two of the most common liquid ingredients in DIY personal care and formulation work. They're often used together, but they behave differently. Here's how they compare.
Quick comparison
| Propylene Glycol (PG) | Vegetable Glycerin (VG) | |
|---|---|---|
| Source | Synthetic | Plant oils |
| Viscosity | Thin, flows easily | Thick, syrupy |
| Main role | Solvent and carrier | Humectant (holds moisture) |
| Feel | Light, non-greasy | Rich, can feel tacky at high levels |
| Common uses | Soaps, lotions, fragrance and extract bases | Lotions, soaps, hair care, glycerites |
Propylene glycol
PG is a clear, low-viscosity liquid that dissolves many ingredients that don't mix well with water alone. Formulators use it as a solvent and carrier in soaps, lotions, moisturizers, and fragrance or botanical extract bases.
Vegetable glycerin
VG is a thick, plant-derived humectant that helps formulas hold moisture. It's common in lotions, melt-and-pour soap, hair care sprays, and alcohol-free botanical extracts.
Why use them together?
Blending PG and VG lets you adjust a formula's thickness and feel. More PG gives a thinner, lighter liquid, while more VG gives a thicker, richer one.
What does "USP grade" mean?
USP grade means the ingredient meets the identity, purity, and quality standards published by the United States Pharmacopeia. Compass Laboratory PG and VG are sourced as USP-grade material from a certified supplier and repackaged in Mena, Arkansas, with a lot number and expiration date on every bottle for traceability.
Handling tips
- Store tightly capped at room temperature, away from heat and direct sunlight.
- Some people are sensitive to PG on the skin, so patch test new formulas.
- Keep out of reach of children and pets.
Shop the Propylene Glycol & Vegetable Glycerin 2 Pack
This article is for general educational purposes only. Compass Laboratory PG and VG are sold as formulation ingredients for personal care and DIY use.