Although the two terms are often used interchangeably, knowing the difference between hydrating and moisturising can quickly revive your skin.
Hydrating is about maintaining an adequate level of water in the skin. Moisturising means to create a skin barrier to prevent water loss from the skin.
Humectants are skin hydrators; they attract water from the atmosphere and hold water molecules to the skin and help increase water content within the cell membrane. If you are wearing a moisturiser with a humectant ingredient, it is actively sucking water from the air around you and sticking it onto your face. This is why humectants are considered an important ingredient for a dry, dehydrated skin.
Some humectants are even capable of holding up to 1000 times their own weight in water.
The following are all humectants that are often referred to as hydrophilic ingredients in skincare.
- Hyaluronic Acid
- Sodium PCA
- Seaweed & Algae
An emollient is an ingredient that smooths the skin’s surface by filling in cracks between skin cells. They make the skin more soft and flexible and contribute to the creamy texture of a moisturiser. However, they are not always effective or long lasting. There are many emollients used in cosmetics, most of which are oils or lipids.
Some emollients are:
- Plant oils
- Mineral oil
- Shea butter
- Cocoa butter
Occlusive agents are the ingredients in skincare that form a film on the skin and prevent water loss through the skin. The classic cosmetic occlusive agent is petrolatum, or petroleum jelly. It is a byproduct of petroleum products and was first used as a cosmetic ingredient in the late 1800s. It is the most effective occlusive agent, capable of blocking 98% of water loss from the skin.
Other occlusive agents include:
- Zinc oxide
- Castor, mineral and jojoba oil
Choosing the right skincare product
By identifying the balance of humectants, emollients and occlusive agents within skincare products, finding the right product for your skin becomes less of a chore.
Dry skin, for example, lacks oil. Skin tends to become drier as we age. Moisturisers that target dry skin have a higher level of emollients to help smooth and fill in any cracks between skin cells. Dehydrated skin, on the other hand, is skin of any type that lacks water. This can be addressed by a higher level of humectants or occlusive agents to attract and seal in water to the skin.