Solubilizers in Cosmetic Formulation: From Synthetic Polysorbates to Natural Alternatives

Creating clear cosmetic products like toners, facial mists, or micellar waters often requires solubilizers to disperse oils (essential oils, fragrance oils, or botanical extracts) in water.

Choosing the right solubilizer is a balance of clarity, performance, skin feel, and formulation philosophy. In this post, we compare synthetic solubilizers like polysorbates with natural alternatives, providing practical guidance on HLB, use levels, and formulation tips.

What Is a Solubilizer?

A solubilizer is a surfactant that allows oils to disperse in water in extremely small droplets, producing a clear or translucent solution. Unlike emulsifiers, which stabilize higher oil fractions in emulsions, solubilizers are best for low oil concentrations (generally under 10% of the formula).

Solubilizers are essential for:

• Micellar waters

• Facial and body mists

• Gentle cleansers

• Fragrance or essential oil sprays

  
  

Synthetic Solubilizers

Polysorbate 20

• INCI: Polysorbate 20

• HLB: ~16.7

• Nature: Synthetic (PEG-based)

• Typical Use Level: 1–20%

• Use: Light essential oils and fragrance oils

  
  

Pros: Excellent clarity, gentle, compatible with most aqueous systems

Cons: PEG-based (synthetic), can feel slightly tacky at higher usage (in cosmetic formulations such as mists or toners we typically don't use above 5% to avoid tacky/sticky feeling.)

Formulation Note: Common starting ratio is ~5:1 to ~10:1 solubilizer to oil. Best for light essential oils or fragrance blends.

Polysorbate 60

• INCI: Polysorbate 60

• HLB: ~14.9

• Nature: Synthetic (PEG-based)

• Typical Use Level: 1 -3%

• Use: Balanced solubilization for moderate oil/fragrance loads

Pros: Provides a good balance between solubilization and mildness

Cons: Less commonly used alone; may require testing for clarity

Polysorbate 80

• INCI: Polysorbate 80

• HLB: ~15.0

• Nature: Synthetic (PEG-based)

• Typical Use Level: 1 - 10%

• Use: Heavier fragrance oils or essential oil blends

  
  

Pros: Strong solubilization for heavier oils, broad pH compatibility

Cons: PEG-based (synthetic), can feel slightly tacky at higher usage (in cosmetic formulations such as mists or toners we typically don't use above 5% to avoid tacky/sticky feeling.)

Formulation Note: Common starting ratio is ~5:1 to ~10:1 solubilizer to oil. Best for light essential oils or fragrance blends.

PEG-40 Hydrogenated Castor Oil

• INCI: PEG-40 Hydrogenated Castor Oil

• HLB: 13–14

• Nature: Synthetic (PEG-based)

• Typical Use Level: 0.5–5%

• Use: Strong solubilization of fragrance oils

  
  

Pros: Reliable, widely used, broad compatibility

Cons: PEG-derived, may feel sticky if overused

Natural and Naturally Derived Solubilizers

Olive Solubilizer (Sodium Olivate)

• INCI: Sodium Olivate

• HLB: ~12

• Nature: Natural, plant-derived

• Typical Use Level: 0.5–6%

• Use: Mild essential oils, natural formulas

  
  

Pros: Fully natural, mild, clean skin feel

Cons: Lower solubilization power than polysorbates, may require testing

Caprylyl/Capryl Glucoside

• INCI: Caprylyl/Capryl Glucoside

• HLB: ~15

• Nature: Naturally derived (sugar + coconut)

• Typical Use Level: 1–5%

• Use: Very low essential oil loads, gentle formulas

Pros: Mild, COSMOS/ECOCERT approved. Can use at higher percentage in cleansing products (up to 40%)

Cons: Limited oil solubilization, cloudiness possible. Can drive up pH.

Sucrose Esters (Sucrose Laurate)

• INCI: Sucrose Laurate

• HLB: 15–16

• Nature: Naturally derived

• Typical Use Level: 0.5–3%

• Use: Sensitive skin products, low EO load

  
  

Pros: Biodegradable, gentle, natural

Cons: May require heat or co-solubilizers, limited clarity at higher oil loads

Polyglyceryl-4 Caprate / Polyglyceryl-10 Laurate

• INCI: Polyglyceryl-4 Caprate or Polyglyceryl-10 Laurate

• HLB: 14–16

• Nature: Naturally derived (vegetable glycerin + fatty acids)

• Typical Use Level: 1–5%

• Use: Essential oils, fragrance oils, botanical extract

  
  

Pros: PEG-free, smooth skin feel

Cons: Lower solubilization than synthetic polysorbates, slight opalescence

Lecithin (Soy or Sunflower)

• INCI: Lecithin

• HLB: 7–9

• Nature: Natural (phospholipid)

• Typical Use Level: 0.5–3%

• Use: Low oil, cloudier formulas, shake-before-use products

  
  

Pros: Skin-beneficial, fully natural

Cons: Weak solubilizer, cannot produce clear solutions

SymbioSolv Clear Plus MB

• INCI: Caprylyl/Capryl Glucoside, Aqua, Sodium Cocoyl Glutamate, Glyceryl Caprylate, Citric Acid, Polyglyceryl-6 Oleate, Sodium Surfactin

• HLB: ~14–15

• Nature: 100% naturally derived, PEG-free

• Typical Use Level: 1–6%

• Use: Clear tonics, micellar waters, wet wipes, body washes, foams, sprays

  
  

Pros: Naturally derived, COSMOS-compliant, low odor/color, pleasant skin feel

Cons: Slightly more expensive than single-component solubilizers, may require testing for high fragrance loads

Quick Reference Table

Solubilizer	Natural/Synthetic	HLB	Typical Use Level	Best For
Polysorbate 20	Synthetic	16.7	1–20%	Light EO & fragrances
Polysorbate 60	Synthetic	14.9	Moderate	Balanced oil loads
Polysorbate 80	Synthetic	15.0	Moderate–High	Heavy fragrance oils
PEG-40 HCO	Synthetic	13–14	0.5–5%	Strong fragrance solubilization
Olive Solubilizer	Natural	12	0.5–6%	Mild EO, natural formulas
Caprylyl/Capryl Glucoside	Natural-derived	15	1–5%	Low EO, gentle formulas
Sucrose Esters	Natural	15–16	0.5–3%	Sensitive skin formulas
Polyglyceryl Esters	Natural-derived	14–16	1–5%	Premium natural skincare
Lecithin	Natural	7–9	0.5–3%	Cloudy or shake-before-use products
SymbioSolv Clear Plus MB	Natural	14–15	1–6%	Clear natural tonics, micellar waters

Formulator Tips

1. Pre-mix oils with the solubilizer before adding water.

2. Follow manufacturer's instructions.

3. Allow 24–48 hours for complete clarity.

4. Adjust solubilizer-to-oil ratios based on fragrance chemistry.

5. Ensure preservative compatibility and check pH.

6. Consider skin feel: natural solubilizers (sodium olivate, polyglyceryl esters, SymbioSolv) feel lighter; polysorbates may feel tacky at high levels.

7. Nothing beats spending time in the lab learning how the solubilizer performs first hand. Always write EVERYTHING down.

8. Learn from successes as well as mistakes. It's how you grow as a formulator.

Bottom Line

Polysorbates offer strength, reliability, and versatility for any essential oil or fragrance load, while natural solubilizers like sodium olivate, polyglyceryl esters, and sugar esters excel in mild, eco-conscious, or sensitive formulations. Choosing the right solubilizer is a blend of performance, sensory experience, and brand philosophy.

If you want further guidance on choosing a solubulizer or optimizing a formulation book a discovery call.

Aromatic blessings,

Tricia