Lindsay Girl asks: I have used extra virgin coconut oil in my hair as a deep conditioning treatment once a week for several years now. I melt the oil in the microwave. This morning I was reading in an article on the website that the author of the article “heard” that you shouldn’t warm coconut oil in the microwave because that will “alter the bonds” in the oil. What say the Brains? Can I safely put the coconut oil in the microwave to melt it? Or is there a better way?

The Beauty Brains responds:
When LG raised this question in our Forum we said “no problem.” But after further consideration we realized that there is some risk involved with heating coconut oil in a microwave oven.

The danger of microwaving coconut oil

Coconut oil penetrates hair because of its size and the configuration of its carbon chain. Unless you’re heating it above the point where it will decompose, microwaving it should cause no problems. In other words, “melting” it is just fine. BUT you need to be very careful when using this approach. Here’s why:
Microwave ovens work by exciting the bonds between atoms, causing them to vibrate. The motion of the molecules vibrating and bouncing around generates heat. Different substances will absorb microwave radiation differently depending on a property called the “dielectrical constant”. Water molecules have a high dielectical constant; they are very mobile and will bounce around a lot. Oil molecules are larger and more fixed. Their dielectrical constant is smaller so and they will take longer to heat up. HOWEVER, the specific heat capacity of oil is less than water which means that oil will hold about twice as much heat as water will. And that means that it’s easy to over heat oil to the point where it could burn you. (f you really want to geek out on dielectrical constants and specific heat capacity check out this thread about microwave absorption by oil in the Physics Forum.)

The Beauty Brains bottom line
Melting coconut oil in the microwave is unlikely to hurt the oil but you could accidentally over heat it and give yourself a nasty burn. To be safe you might want to melt the oil in a bowl of hot water instead.

How do you heat up your deep conditioner or pre-poo oils? 

CN Says:
For those still ‘noid that microwaving the oil will harm its beautifying powers (I’m not a fan of the microwave in general… ironic, seeing as how I don’t cook), heating it up in a bowl of warm water truly is the answer.  It’s how I warm my oils… hell, it’s how I heated Gia’s refrigerated breast milk.  You’ll get good, even heat!