We use solubilizers to solubilize small amounts of oil or oil soluble ingredients (like essential or fragrance oils) into mostly watery concoctions (like toners or hand washes), and to add water-soluble properties to anhydrous products (like a cleansing oil or bath bomb). There are lots of options, and they all have different strengths and weaknesses that help determine why you might use one over the other.
I get a lot of questions about solubilizer swaps/alternatives, so I thought I’d make a chart of the ones I use, along with usage notes to help you understand why I might’ve selected one over another so you can make your own substitution decisions.
General notes
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These are just the solubilizers I’ve worked with personally! There are many more. I’ll add more as I get ‘em!
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You’ll need to experiment with your specific solubilizer and your specific oil/essential oil/fragrance oil blend to find the precise ratio of solubilizer:solubilized to keep everything solubilized and clear as this varies with the solubilizer, what you’re solubilizing, and the rest of your formula. Check with your supplier for specific usage rates/ratios. You will typically need much more solubilizer than whatever you’re solubilizing.
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In a skin care project where a solubilizer is required to solubilize essential oils I really don’t recommend eliminating the solubilizer in favour of shaking the end product before each use; this doesn’t allow for thorough distribution of the essential oils and can lead to sensitization due to high essential oil dosing.
| Ingredient INCI | Contains water? | HLB | Usage notes |
|---|---|---|---|
| Polysorbate 80 | No | 15 | Polysorbate 80 is really useful for solubilizing small amounts of oils into otherwise mostly watery things, like toners or body mists. I’ll also use it in 100% oil based products (like cleansing balms or oils) or products that need very low water levels (like bath bombs). In a cleansing balm or oil it functions as a cleansing/rinse-off-boosting ingredient because one end of the molecule loves oil while the other end loves water; the oil loving end grabs oil soluble things from the skin and the water soluble end grabs into the water you’re washing with for easier wash off. Polysorbate 80 tends to be sticky in leave-on products, so be sure to experiment with your formula to see if the amount you’re using works with the skin feel you want. I tend to prefer to use polysorbate 80 in wash-off products for this reason. |
| Polysorbate 20 | No | 16.7 | Polysorbate 20 is used to solubilize small amounts of essential or fragrance oils into otherwise mostly watery things, like toners or body mists. In a pinch you can try swapping polysorbate 80 and 20 around, but I really would recommend having both as they do have different strengths and are quite inexpensive. Polysorbate 20 tends to be sticky in leave-on products, so be sure to experiment with your formula to see if the amount you’re using works with the skin feel you want. I tend to prefer to use polysorbate 20 in non-skin-things (room sprays, hair mists, etc.) for this reason. An alternative for polysorbate 20 is to use the hydrosol version of the essential oil you’re looking to incorporate, if one exists. |
| Caprylyl/Capryl Glucoside | Yes | ~15 | C/C glucoside is primarily a surfactant, but it has great solubilizing properties. For this reason I tend to use it in a lot of liquid foaming products (hand washes, body washes, etc.) as it will both contribute to the lather of the product and solubilize any added essential or fragrance oils. It contains water, so it is not a good solubilizer choice for 100% oil based products (like cleansing balms or oils) or products that need very low water levels (like bath bombs). It is quite unique among the solubilizes I’ve used due to primarily being a surfactant, so if you need to substitute it out you will need to determine if it is functioning primarily as a surfactant or solubilizer. The alternative I typically suggest is coco glucoside for the cleansing/lathering with added polysorbate 20 and/or 80 to solubilize whatever the c/c was solubilizing. You’ll also need to pH adjust if you use coco glucoside as it has a much higher pH than c/c glucoside. |
| Olive Oil PEG-7 Esters (Olivem300) | No | 11 | Olivem 300 can also be called water soluble olive oil, though that’s not entirely accurate. It does have some solubilizing powers, but isn’t a very strong solubilizer. I tend to include it in anhydrous products that I would like to have some self-emulsifying abilities (like a body oil that would self-emulsify with water when applied to damp skin, or a bath oil), or in watery products that I’d like to add some richness to (like a toner). In general the leave-on feel is far superior to that of the polysorbates, which can be quite sticky. I’ve used it in cleansing balms, cleansing oils, and bath bombs as well. |
| PEG-50 Shea Butter (Water soluble shea butter) | No | 14–16 | Water soluble shea butter is similar to Olivem 300; it has some solubilizing properties, but I mostly use it to add richness to watery products and self-emulsifying properties to products that add water at the time of use (cleansing oils, bath oils, body oils to be applied to damp skin). In general the leave-on feel is far superior to that of the polysorbates, which can be quite sticky. I don’t use this too often as I’ve only found it for sale in the USA. |
| Sulfated Castor Oil (Turkey Red Oil) | No | Turkey Red oil is castor oil that has been treated with sulphuric acid, and it’s one of the oldest surfactants around. I’ve found it to be useful for solubilizing essential and carrier oils into watery things, but I don’t use it much anymore. It has the potential to be very irritating (especially in larger amounts), and I’ve found it to go rancid quickly. It is also quite heavy and sticky. If you have it I would recommend using it up in projects like self-emulsifying (“blooming”) bath oils and bath bombs where it will be heavily diluted in bath water. If you don’t have it, I wouldn’t recommend purchasing it. |
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