In flaxseed oil, a natural compound called γ-tocopherol stops oil from going bad by mopping up harmful molecules, and other natural compounds in the oil help keep γ-tocopherol working longer.

Heating flaxseeds before pressing them and pressing them twice makes more oil that lasts longer — because the heat helps release natural antioxidants that work together to protect the oil.

Adding too much of one type of vitamin E (α-tocopherol) to flaxseed oil can make it go bad faster when it's cool, but helps protect it when it's warm — because another type of vitamin E (γ-tocopherol) lasts longer and keeps working.

When you add both vitamin E and plant sterols to flaxseed oil together, they work better than either one alone to keep the oil from going rancid — this combo could help make healthier oils that last longer.