Choosing between Polysorbate 20 and PEG-40 Hydrogenated Castor Oil for clear shampoo and serum formulas
Question
Hello,
Are Polysorbate 20 and PEG-40 Hydrogenated Castor Oil both emulsifiers/solubilizers for water and oil that can make a formula clear in the same way?
Is there a way to choose which one to use? I’m going to make shampoo and serum, and I’m not sure which one I should buy.
Thank you.
Answer
Choosing Between Polysorbate 20 and PEG-40 Hydrogenated Castor Oil as Solubilizers
Both Polysorbate 20 and PEG-40 Hydrogenated Castor Oil are commonly used as solubilizers in cosmetic formulations like shampoos and serums to help mix oil-based ingredients (such as fragrances or small amounts of oils) into water-based systems, aiming for a clear final product.
While both serve a similar purpose, the choice between them can depend on several factors:
- Solubility Characteristics: Polysorbate 20 is readily soluble in water and Glycerin. However, it may cause turbidity when mixing with oils, meaning the resulting solution might not be perfectly clear, especially with higher oil loads. PEG-40 Hydrogenated Castor Oil is also effective at solubilizing oils and fragrances in water and is often used when a clear solution is desired.
- Type of Oil/Fragrance: The effectiveness of a solubilizer can vary depending on the specific oil or fragrance you are trying to incorporate. Some solubilizers work better with certain types of lipophilic (oil-loving) ingredients than others.
- Desired Clarity: If achieving a perfectly crystal-clear product is critical, you might find one works better than the other for your specific formula. PEG-40 Hydrogenated Castor Oil is often chosen for its ability to create clear solutions with fragrances.
- Other Formula Ingredients: The presence of other ingredients in your shampoo or serum base can influence how well the solubilizer performs.
- Odor: The PEG-40 Hydrogenated Castor Oil available is noted as having a low odor, which might be preferable in certain formulations.
In practice, the best way to determine which solubilizer is most suitable for your specific shampoo or serum formula is through testing. You would typically start by trying to solubilize your oil/fragrance at different ratios with each solubilizer to see which provides the desired clarity and stability in your base formula.
Updated Review: May 2026
This section was added after reviewing the original answer against current product availability and formulation knowledge at the stated point in time.
Update (2026-05-17): While Polysorbate 20 and PEG-40 Hydrogenated Castor Oil remain standard choices, modern formulations often utilize high-performance blends for superior clarity and stability. HiPure™ PS20 provides a super-refined version of Polysorbate 20 with lower impurities for sensitive applications. For better temperature stability and clarity, Flora Solve™ Clear is a highly effective alternative. If you are working with difficult-to-solubilize ingredients like Vitamin E or natural oils, Ultra Solve™ or the cost-effective Eco Solve™ are recommended. For PEG-free formulations, Free Solve™ is now available. To ensure the best results, always pre-mix the solubilizer with your fragrance or oil thoroughly before slowly adding the water phase.