Emulsifier Selection Guide
Choosing the Right Emulsifier for Your Formulation
Emulsifiers are the backbone of any lotion, cream, or conditioner. They hold water and oil together in a stable, uniform mixture that would otherwise separate within minutes. Choosing the right emulsifier affects everything — texture, absorption, stability, and skin feel.
This guide covers the emulsifiers available in LotionMath's ingredient database, explains how the calculator handles emulsifier percentages automatically, and helps you pick the right workflow and emulsifier for your next project.
LotionMath Auto-Calculates Emulsifier Percentages
You don't need to manually enter emulsifier percentages. When you add an emulsifier in LotionMath, the calculator automatically determines the correct amount based on your formulation:
- O/W formulations: Emulsifier is set to 25% of your oil phase weight. If your oil phase is 20%, the calculator assigns 5% emulsifier.
- W/O formulations: Emulsifier percentage is determined by a tiered system based on your water phase percentage. Each emulsifier has its own tier table — more water requires more emulsifier. If an emulsifier doesn't have specific tiers, averaged defaults are used.
- HLB mode: For O/W HLB, the total emulsifier (25% of oil phase) is automatically split between your high-HLB and low-HLB emulsifiers to match your oils' required HLB. For W/O HLB, the calculator uses a 70/30 primary/secondary split with tiered percentages.
O/W vs W/O Emulsifiers
Oil-in-Water (O/W)
Oil droplets are dispersed in a continuous water phase. This is the most common type — it produces lotions and creams that feel light, absorb quickly, and rinse off easily with water. Most body lotions, facial moisturizers, and hair conditioners are O/W emulsions.
In LotionMath: Choose "O/W BLEND" for a single pre-blended emulsifier, or "O/W HLB" to combine a high-HLB and low-HLB emulsifier pair matched to your oils' required HLB.
Water-in-Oil (W/O)
Water droplets are dispersed in a continuous oil phase. These feel richer and more occlusive, forming a protective barrier on the skin. Cold creams, barrier creams, and some sunscreens are W/O emulsions.
In LotionMath: Choose "W/O BLEND" for a single pre-blended W/O emulsifier, or "W/O HLB" to combine individual low-HLB emulsifiers with primary/secondary roles. W/O uses a tiered calculation — emulsifier percentage scales with your water phase percentage rather than a flat ratio.
The Four LotionMath Workflows
LotionMath offers four workflow modes that determine which emulsifier dropdowns and calculation methods are used:
O/W BLEND
Uses a single pre-blended O/W emulsifier system (like Emulsifying Wax NF, BTMS-50, or Olivem 1000). The emulsifier percentage is auto-calculated as 25% of your oil phase. No HLB knowledge needed — the emulsifier is already optimized.
O/W HLB
Uses a pair of individual emulsifiers — one high-HLB and one low-HLB — blended to match the weighted-average required HLB of your oil phase. The calculator determines the required HLB from your oils, then splits the total emulsifier (25% of oil phase) between the two based on their HLB values.
W/O BLEND
Uses a single pre-blended W/O emulsifier (like ABIL EM 90, CreamMaker PASTE, or Olivem 2090). The emulsifier percentage is auto-calculated using a tiered system based on your water phase percentage — each emulsifier has its own tier table defining how much is needed at different water levels.
W/O HLB
Uses individual low-HLB emulsifiers with defined roles: primary emulsifiers can work alone, while secondary emulsifiers enhance stability when paired with a primary. The calculator uses a 70/30 primary/secondary split with the same tiered water-phase-based percentages.
O/W Emulsifier Blends (Pre-Blended Systems)
These are complete emulsifying systems available in O/W BLEND mode. LotionMath auto-calculates the percentage at 25% of your oil phase weight.
Emulsifying Wax NF (Polawax)
INCI: Cetearyl Alcohol & Polysorbate 60
Max oil phase: 40%
Best for: Rich body creams, general-purpose lotions, beginner formulations
The workhorse of emulsifiers. Reliable, inexpensive, and forgiving. Produces a classic creamy texture. The most common starting point for new formulators.
BTMS-50
INCI: Behentrimonium Methosulfate & Cetearyl Alcohol
Max oil phase: 25%
Best for: Hair conditioners, lightweight lotions, products needing a silky dry feel
A cationic emulsifier that conditions hair and skin. Produces a light, non-greasy feel. The "50" means it contains ~50% active behentrimonium methosulfate.
BTMS-25
INCI: Behentrimonium Methosulfate & Cetyl Alcohol
Max oil phase: 30%
Best for: Same uses as BTMS-50 but at a higher usage rate
Contains 25% active behentrimonium methosulfate, so you need more of it than BTMS-50 for the same conditioning effect.
Olivem 1000
INCI: Cetearyl Olivate & Sorbitan Olivate
Max oil phase: 25%
Best for: Natural formulations, lightweight facial moisturizers, sensitive skin products
Derived from olive oil chemistry. Creates a liquid-crystal structure that mimics the skin's own lipid barrier. Eco-certified and popular in natural cosmetics.
Emulsifying Wax C20
INCI: Cetearyl Alcohol & Ceteareth-20
Max oil phase: 30%
A complete O/W system that creates stable lotions. Similar reliability to Emulsifying Wax NF with slightly different skin feel.
Other O/W Blends in LotionMath
ECOMulse (olive-derived, eco-cert), Lotionpro 165 (creates silky lotions), Montanov 68 (glucose-based, natural), Montanov 202 (creates liquid crystals), Calcium Stearoyl Lactylate (food-grade compatible), and several PEG-based systems (PEG-100 Stearate, PEG-20 Almond Glycerides, PEG-20 Methyl Glucose Sesquistearate).
W/O Emulsifier Blends (Tiered Systems)
These are complete W/O emulsifying systems available in W/O BLEND mode. LotionMath auto-calculates the percentage using a tiered system — the emulsifier amount scales with your water phase percentage.
ABIL EM 90
Type: Silicone-based W/O emulsifier
Max water phase: 75%
Tier example: 2% at 5–15% water → 3% at 15–30% → 4.25% at 30–50% → 6% at 50–65% → 8.5% at 65–75%
Creates silky W/O products with a unique feel. Silicone-based, so it works well with dimethicone and cyclomethicone in the oil phase.
CreamMaker PASTE
Type: PEG-free, prebiotic-enhanced W/O emulsifier
Max water phase: 75%
Tier example: 4% at 5–30% water → 5.5% at 30–50% → 7% at 50–70% → 9% at 70–75%
Creates rich W/O creams. PEG-free and conditioning. A good choice for natural-leaning W/O formulations.
Olivem 2090
Type: Olive/castor derived W/O emulsifier
Max water phase: 75%
Tier example: Similar tiered structure based on water phase
PEG-free W/O specialist. Creates rich, protective creams and balms. Derived from olive and castor oils.
Glyceryl Stearate SE
Type: Self-emulsifying, anionic W/O emulsifier
Max water phase: 75%
Tier example: 2.5% at 5–15% water → 4% at 15–30% → 6% at 30–50% → 8% at 50–65% → 10.5% at 65–75%
"SE" means self-emulsifying — it contains a small amount of soap (sodium or potassium stearate). Economical and creates soft creams. Note: anionic charge, so avoid pairing with cationic ingredients.
Beeswax + Borax
Type: Traditional natural W/O emulsifier (anionic soap formed in situ)
Max water phase: 40%
A classic cold-cream method. The borax saponifies fatty acids in beeswax to create an emulsifier in situ. Requires alkaline pH (8–10). Limited to low water percentages. Some regions restrict borax in leave-on cosmetics.
Individual Emulsifiers (HLB Mode)
In HLB mode, you combine individual emulsifiers rather than using a pre-blended system. LotionMath calculates the required HLB from your oil blend and auto-splits the emulsifier amounts.
High-HLB Emulsifiers (O/W HLB Mode)
These have HLB values of 10 or higher and favor O/W emulsions. Examples in LotionMath include Ceteareth-20 (HLB 15.7), Oleth-20 (HLB 15), Isoceteth-20 (HLB 15.7), Isosteareth-20 (HLB 15), Laureth-23 (HLB 16.9), PEG-25 Hydrogenated Castor Oil (HLB 10.8), Polysorbate 20 (HLB 16.7), Polysorbate 60 (HLB 14.9), Polysorbate 80 (HLB 15), Steareth-20 (HLB 15.3), and Steareth-21 (HLB 15.5).
Low-HLB Emulsifiers (O/W HLB and W/O HLB Mode)
These have HLB values below 10 and can favor W/O emulsions. In W/O HLB mode, they are classified by role:
- Primary (can work alone): Glyceryl Stearate, Sorbitan Olivate, Span 60, Span 80, Sorbitan Stearate
- Secondary (enhance stability with a primary): Ceteth-2, Glycol Distearate, Glycol Stearate, Sorbitan Palmitate
Note: In W/O HLB mode, the calculator uses a 70/30 primary/secondary split. Primary emulsifiers get 70% of the total, secondary emulsifiers get 30%. The total is determined by the same tiered water-phase system used in W/O BLEND mode.
The HLB System
HLB stands for Hydrophilic-Lipophilic Balance. It is a scale from 0 to 20 that describes how water-loving or oil-loving a surfactant is. Higher HLB values (10+) favor O/W emulsions; lower values (below 10) favor W/O emulsions.
W/O Tiered Calculation: How It Works
Unlike O/W formulations (which use a flat 25% of oil phase), W/O emulsifier amounts are determined by a tiered lookup based on your water phase percentage. This is because W/O emulsions must stabilize water droplets inside oil — the more water you add, the harder the emulsifier has to work.
| Water Phase | ABIL EM 90 | CreamMaker | GMS SE | Default* |
|---|---|---|---|---|
| 5–15% | 2% | 4% | 2.5% | 2.75% |
| 15–30% | 3% | 4% | 4% | 3.63% |
| 30–50% | 4.25% | 5.5% | 6% | 5.19% |
| 50–65% | 6% | 7% | 8% | 7.0% |
| 65–75% | 8.5% | 9% | 10.5% | 9.5% |
*Default tiers are averaged values used for W/O emulsifiers that don't have specific tier data in the database.
Phase Limits and Warnings
Each emulsifier in the database has maximum phase limits. LotionMath automatically checks these and warns you when you exceed them:
- Max oil phase (O/W): BTMS-50 and Olivem 1000 support up to 25% oil phase. Emulsifying Wax C20 supports 30%. Emulsifying Wax NF supports 40%. Exceeding these limits risks emulsion instability.
- Max water phase (W/O): Most W/O emulsifiers support up to 75% water phase. Beeswax + Borax is limited to 40%. Going beyond these limits means the emulsifier can't hold all that water in the oil phase.
- Usage rate warnings: If the auto-calculated emulsifier percentage falls outside the emulsifier's recommended usage range, you'll see a warning suggesting you adjust your phase ratios.
How to Choose
Use this decision tree to pick the right workflow and emulsifier:
Tips for Working with Emulsifiers
- Always melt your emulsifier into the oil phase, not the water phase. Heat both phases to the same temperature (around 70°C / 158°F) before combining.
- For W/O emulsions, add the water phase slowly to the oil phase while mixing. For O/W, you can add oil to water or water to oil depending on your emulsifier's instructions.
- Use a high-shear mixer or stick blender when combining phases. Stirring by hand rarely produces a fine enough emulsion.
- Trust the auto-calculated amounts in LotionMath. The percentages are based on the specific emulsifier's data and your formulation's phase ratios.
- Watch for compatibility warnings — cationic emulsifiers (BTMS) are incompatible with anionic ingredients, and some emulsifiers are sensitive to electrolytes or extreme pH.
- Always run stability tests (freeze-thaw, centrifuge, heat cycling) before selling any emulsified product.