INCI Name: Butylene Glycol
Appearance: Clear, colorless, low-viscosity liquid
Solubility: Water-soluble; also miscible with alcohols
Usage Rate: 1% – 10%
Function: Humectant, solvent, viscosity reducer, penetration enhancer
Butylene Glycol is a widely used multifunctional ingredient in cosmetic formulations. It serves as a humectant to draw moisture into the skin, a solvent for active ingredients, and a texture enhancer to improve product spreadability and feel.
Butylene Glycol is a versatile ingredient that supports hydration, dissolves active ingredients, and enhances skin feel. It also helps improve the penetration of ingredients into the skin and keeps products from drying out over time.
Q1. What makes Butylene Glycol such a common ingredient in cosmetics?
It’s a multifunctional ingredient: humectant, solvent, texture enhancer, preservative booster, and penetration aid. Few ingredients deliver so many benefits at such a low usage level.
Q2. How does Butylene Glycol compare to Glycerin as a humectant?
Both attract water, but Glycerin is stickier and can leave a tacky film. Butylene Glycol gives lighter, silkier hydration and enhances product glide. Most modern formulas combine the two for balanced moisturization.
Q3. Does Butylene Glycol help with active delivery?
Yes. It improves solubility and skin penetration of actives like Niacinamide, Tranexamic Acid, and botanical extracts. This makes formulations more effective at lower concentrations of actives.
Q4. Why is Butylene Glycol used as a preservative booster?
It lowers water activity in formulas, making it harder for microbes to grow. When paired with preservatives (like phenoxyethanol or organic acids), it improves overall system robustness, sometimes allowing for lower preservative levels.
Q5. Does Butylene Glycol affect formula stability?
Yes. It helps prevent crystallization of actives (e.g., salicylic acid, ferments) and improves freeze-thaw stability in gels and serums. Without it, many products would separate or form gritty particles.
Q6. How does it perform in sensory feel?
It reduces tack, improves spread, and gives water-based formulas a smoother application. It’s especially useful in toners, essences, and serums where elegance matters.
Q7. Is Butylene Glycol safe for sensitive or acne-prone skin?
Yes. It’s non-comedogenic and generally well-tolerated. Occasional sensitivity has been reported, but it’s rare compared to harsher glycols like Propylene Glycol.
Q8. Can Butylene Glycol replace Propylene Glycol or Pentylene Glycol?
Propylene Glycol: similar solvent/humectant properties but more irritating.
Pentylene Glycol: stronger antimicrobial boosting and richer skin feel, but costlier.
Butylene Glycol is the budget-friendly, skin-friendly middle ground.
Q9. Can Butylene Glycol fix my cloudy or crystallizing serum?
Yes. Butylene Glycol dissolves and stabilizes actives like niacinamide, ferments, or acids that often fall out of solution. Adding it helps serums stay clear, smooth, and particle-free.
Q10. Can Butylene Glycol stop my formula from feeling sticky?
Yes. Glycerin-heavy formulas can leave tack on the skin. Swapping part of the glycerin with Butylene Glycol reduces stickiness while keeping hydration levels high.
Q11. Can Butylene Glycol help my preservative system work better?
Yes. Butylene Glycol lowers water activity, which makes it harder for microbes to grow. At 3–5%, it strengthens preservation and helps formulas pass challenge tests more reliably.
Q12. Can Butylene Glycol make my lightweight serum feel more elegant?
Yes. It improves glide and layering, giving watery formulas (like toners, essences, and serums) that silky K-beauty feel instead of drag or heaviness.
