If you follow health and beauty trends on social media, you may have noticed a certain ingredient popping up in cooking and skin care posts: beef tallow. 

Beef tallow is fat rendered from beef trimmings. While some people make it at home, it’s also readily available to buy online or at grocery stores.

Beef tallow is sometimes promoted as a replacement for other cooking oils, especially seed oils, along with claims that seed oils lead to inflammation and contribute to chronic disease. Skin care fans also tout beef tallow’s benefits as a moisturizer and treatment for wrinkles.

But what exactly is beef tallow, and when does it make sense—or not—to use it?

Alice H. Lichtenstein, senior scientist at the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) and the Stanley N. Gershoff Professor of Nutrition at the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy, and Farah Moustafa, assistant professor of dermatology at Tufts University School of Medicine and a dermatologist at Tufts Medical Center, recently offered their input to help consumers decide if beef tallow is right for their skin or their stomachs.

Cooking Quandaries

First, claims that beef tallow causes less inflammation in humans than seed oils aren’t based on scientific data, Lichtenstein said, adding that there’s “no data” that she’s aware of to indicate that the amounts of seed oils that a typical person consumes lead to adverse health outcomes such as inflammation. Claims that seed oils cause inflammation likely come from animal studies or cell cultures in which the animals or cells are exposed to extreme amounts of the oil, she said.

The most important factor in determining which cooking oil is best for one’s health is whe