Why is One of Silly Putty’s Main Components Added to Fast Food Fryer Oil?

Say 'Dimethylpolysiloxane' five times fast

You want tertiary butylhydroquinone with that?

If you think your fast food fries are fried in nothing but pure oil, think again. Check out the McDonald’s ingredients list and you’ll notice that the deep-fried items are “prepared in vegetable oil (canola oil, corn oil, soybean oil, hydrogenated soybean oil) with TBHQ and citric acid to preserve freshness of the oil and Dimethylpolysiloxane to reduce oil splatter when cooking.”

Wait, what?

It’s not just McDonald’s, sadly. Many fast food chains, as well as chain restaurants, use additives in their fryer oil. What are they, exactly? TBHQ, which is a shortened name for tertiary butylhydroquinone, is an antioxidant that’s used as a preservative for many different types of fat. It’s also employed as a corrosion inhibitor in biodiesel and is added to varnishes, lacquers, resins, and perfume. According to the FDA, the amount used in food is safe, but in very large doses it may cause stomach cancer.


Dimethylpolysiloxane is a silicon-based organic polymer, meaning that it’s basically a form of plastic. It’s clear, inert, nontoxic, and can be found in everything from contact lenses to shampoos and lubricants; it ranges in viscosity from a thin pourable liquid to a thick and rubbery solid. Its unique properties can best be seen in Silly Putty, in which it’s one of the primary ingredients, as well as Kinetic Sand, the toy that looks like wet sand but is completely moldable. It’s added to oil as a defoaming agent to prevent splatter during the frying process, so you’ll find trace quantities of it in many fried fast foods. Because silicone is completely inert and nontoxic, it doesn’t pose any harm to humans, but it’s still a little odd to think that it’s hitching a ride on our Chicken McNuggets