Yesterday we talked about preservatives, now let's talk about anti-oxidants.
So what's the purpose of anti-oxidants, other than the skin care benefits? They retard rancidity in your oils!
Why do oils go rancid and what the heck does "rancid" mean?
Oils are really triglycerides, which is to say they are long chains of carbons and hydrogens connected to a glycerol backbone (check out the link on wikipedia for some great pictures!) In saturated fats, the carbons are SINGLE bonded, which are pretty hard to break, so they stay stable for long periods of time (coconut, palm, and animal fats). In unsaturated fats, the ones we use in our creations, there are double bonds along the chain, and it's easier for these bonds to break and allow oxidation. The more double bonds, the more oxidation can occur, and the faster the oils can go rancid. (Rancidity means the triglyceride is oxidized and goes off!) This is why some of the oils have shorter shelf lives than others (consider grapeseed oil vs. squalane - the "ane" in squalane indicates it has only single bonds, so its bonds are less easily broken and the oil isn't oxidized as quickly - or fractionated coconut oil).
So what can we do? This is where the anti-oxidants come into use in our creations.
The anti-oxidant is what its name implies - it keeps the oils from going rancid by preventing oxidation. Oils will eventually go rancid; our goal is to put that date off into the distant future.
Vitamin E is a very powerful anti-oxidant. It is readily available, and easy to use. You add it at 0.5% to 1% of your total weight. You can get various kinds of Vitamin E - Covi-ox T-50 (meaning it is 50% Vitamin E, 50% other things) or MTS-50 Anti-oxidant blend (again, 50% Vitamin E) are the most common. The higher the percentage of Vitamin E, the less you have to use (and the more it costs!) Try to get at least the 50% Vitamin E.
BHT is a food grade anti-oxidant that is becoming easier to find. I have not used this product, but I understand it is very effective. (Link to the Herbarie...)
Rosemary extract can be a very effective anti-oxidant, but again, I've never used it so I can't comment on its efficacy. (Link to the Herbarie...)
In my humble opinion, Vitamin E really is your best choice for anti-oxidizing properties. It's not that expensive, it's easy to find, and it adds some nice skin-loving qualities to your lotions and creations. Why would you choose another anti-oxidant? Cost: BHT is about 1/4 the price of Vitamin E (although rosemary extract is almost double the price of Vitamin E), so if you are making giant batches, BHT is probably more cost effective. But considering how wonderful Vitamin E is as both an anti-oxidant and a skin loving ingredient, it seems the best choice.