The fact that oil and water don't mix is common knowledge, but water and oil are both in nearly every lotion or cream. In a mixture, the two remain separate unless combined with an ingredient that keeps them bonded—an emulsifier. Skincare products on the market typically use synthetic emulsifiers, but natural emulsifiers are available for whipping up homemade lotions and potions.
These are the two types of emulsions:
- Oil in water: Oil suspended in water; generally thinner (e.g. vinaigrette).
- Water in oil: Water suspended in oil; generally thick (e.g. butter).
Beeswax has been used in skin care for centuries. It has softening and healing properties on its own but also works well as a thickener and emulsifier. It's best used in oil-in-water emulsions, though it can make a base for creams when used along with other emulsifiers. Beeswax is great for formulas designed to absorb quickly.
For a plant-based and allergy-free wax emulsifier, there's candelilla wax. It comes from the wild Mexican candelilla plant, which forms the wax on the outside of its leaves to protect it from water loss. While most waxes are best suited for lighter formulations, candelilla works well in thicker, heavier, water-in-oil formulations. Lotions made with candelilla wax sit on the skin longer without breaking down, making them great for drier or sensitive skin that need more protection.
This fatty phospholipid mixture is a perennial favorite of DIYers thanks to its versatility and ease of use. Lecithin is found in a wide variety of plant and animal products, including soybeans, rapeseed, corn, and egg whites. Lecithin typically combines best with oil but is highly effective in water-based emulsions as well. It's humectant, meaning it draws moisture from the air and deposits it on the skin, and also helps ingredients penetrate better—ideal for anti-aging products for drier, more mature skin.
Derived from African acacia tree sap, acacia gum can be found in many forms, including thick gel, liquid, and powder. It has its own soothing and anti-inflammatory properties. Acacia is added to the water in oil-in-water emulsions, so it's ideal for the lightest formulations. For thicker creams, combine it with another emulsifier.