Technically speaking, coconut oil does oxidize, but to a small degree even when heated, because it carries about 10% unsaturated fats despite that most of its contents are saturated fats.
We all know that unsaturated fats are prone to oxidation even at room temperature. And the oxidation gets worse upon heated. However, in the case of coconut oil, this oxidation is not as damaging as you think it is. Allow me to explain.
Imagine that very small amount of unsaturated fats are spatially spaced out by the very much larger number of saturated fats, that will interrupt the interactions among the unsaturated fats, leading to almost zero chain reaction.
If they’re closely packed together, like those common cooking oils (such as peanut oil, soybean oil, sunflower oil or even olive oil) which comprise mainly unsaturated fats, then the chain reactions will be super destructive and toxic substances will emerge as a result.
That explains why researchers place olive oil in a dark, cool and dry place and its beneficial properties dramatically degrade after a year whereas coconut oil remains as good as a year before even when it’s kept at room temperature.
The key here is the chain reaction.
As long as there is little or no chance for unsaturated fats to interact among one another, coconut oil will not oxidize in a manner that will impair your health, unless you heat it up to a temperature so high that it starts to smoke.
I have been taking coconut oil for more than 10 years. Cooking with it on medium heat as well. If coconut oil oxidizes easily, I would have had my arteries clogged and suffered from heart disease long ago already. And I wouldn’t be alive and kicking here telling you about how coconut oil benefits you.
Another solid evidence to show that coconut oil does not oxidize easily but instead helps to fight oxidation is its ability to “block” UV from the sun when you apply it to your skin.
I was riding under the hot sun for 4 hours without getting sunburn one summer during my Taiwan trip. Thanks to coconut oil’s saturated fats which work against free-radical activities even when the temperature is so high that you can literally fry eggs on the steaming ground. Free radicals are infamous for causing oxidation and inflammation.
In conclusion, coconut oil does not oxidize easily even when heated to certain temperatures like 300 °F (149 °C). Therefore, you can safely consume coconut oil for health benefits, or use it topically to protect your skin against UV.