Why Are Polar Oils Better for Sealing Hair than Non-Polar Oils?

28/2/2013

Cross section of hair

Polar oils are oils that have molecules that can migrate into a hair fibre. They are attracted into the hair shaft by the protein keratin found inside the cortex.

Polar oils are effective for sealing in moisture but only for a limited time. Over time, polar oils migrate into the hair fibre so the seal is removed.

On the other hand non-polar oils form a complete barrier and don't allow moisture into or out of the hair fibre. This may sound like a fabulous feature but it isn't because hair natural dries anyway. Once the hair dries a non-polar oil would make it almost impossible to re-moisturise the hair.

Examples of Relatively Polar Oils That Seal Hair For Longer
Castor oil
Flaxseed oil
Grapeseed oil

Examples of Non-polar Oils
Mineral oils
Petrolatum

Polar oils offer you flexibility because whilst they can seal hair effectively they can also be rinsed off easily.

If you follow a no-poo regime or use weaker, sulfate free shampoos then you'll have no problems washing polar oils off. Petrolatums and mineral oils need the strength of a sulfate-containing shampoo to be washed off and they need to be washed off to re-moisturise hair again.