Formulation Issue with Cholesterol Crystals, Shea Butter Heating, and High-Temperature Oils

Question

I made a formula with the following ingredients:

5% Cholesterol
2% Tribehenin
86% shea butter ultrasoft
7% Squalane

The procedure was to mix Cholesterol, Tribehenin, and shea butter, heat until melted, then add Squalane.

After mixing, I observed salt-like crystals that did not dissolve, even when reheating only the sediment from the beaker. I suspect this might be ingredient #1 (Cholesterol) and it doesn't seem to be due to insufficient heating.

My questions are:

Are the crystals from Cholesterol? If so, what are they?
If shea butter is heated to a high temperature to dissolve Cholesterol, will its properties change significantly?
Could you please suggest a list of high-temperature resistant oils, besides Fractionated Coconut Oil, from the Natural Oil category?

Thank you in advance.

MySkinRecipes Expert · Accepted Answer

Formulation Issue and High-Temperature Oils

Regarding the crystals in your formulation, it is highly likely that these are undissolved Cholesterol. Cholesterol has a very high melting point of around 150°C, and the product description notes that it must be heated to this temperature to fully dissolve in the oil phase. If the temperature drops below approximately 80°C during the cooling process before the mixture is fully emulsified or solidified, Cholesterol can recrystallize, forming solid particles.

Heating Shea Butter to 150°C to dissolve Cholesterol is significantly higher than its usual melting point (60-70°C). While Shea Butter will melt and incorporate into the mixture at this temperature, prolonged exposure to such high heat could potentially degrade some of its heat-sensitive beneficial fatty acids and antioxidants. This might reduce some of its unique skin-nourishing properties compared to formulations where Shea Butter is heated only to its melting point.

For high-temperature resistant oils that can be used in formulations requiring heating above 100°C, besides Fractionated Coconut Oil, consider options like:

Mineral Oil: Available in various viscosities, Mineral Oil is a highly stable ingredient that can withstand high temperatures without degrading.
Hydrogenated Castor Oil: While technically a wax, it is often used in oil phases and has a high melting point, making it suitable for high-temperature processing.
Hydrogenated Polyisobutene: A synthetic polymer that functions as an emollient and can tolerate high heat.

These ingredients can help ensure that the oil phase remains stable and fully liquid at the temperatures required to dissolve high-melting point ingredients like Cholesterol.