What’s oily, a bit waxy, and secreted from your skin head-to-toe? Though it may not be the most pleasant-sounding skin-care term, sebum is a crucial component of the skin barrier — and when it’s thrown off balance (which can happen for a number of reasons), a variety of issues can occur. What’s more, though the terms sebum and oil are sometimes used interchangeably in reference to skin, they are not one and the same.
“When people refer to oil on the skin, sebum is generally thought to be one component of it,” explains Marisa Garshick, a board-certified dermatologist in New York City. “But [oil] also often includes sweat and other environmental buildup that can occur on the skin.”
So then what exactly is sebum and where does it come from? To find out more, including why sebum is so important to overall skin-barrier health, we spoke to a slew of dermatologists. Consider this sebum 101: Here is everything you need to know.
What Is Sebum?
To get technical, sebum is “a complex mixture of fatty acids, sugars, waxes, and other natural chemicals that form a protective barrier against water evaporation,” explains Karen Hammerman, a board-certified dermatologist at Schweiger Dermatology Group in Garden City, New York. To get even more technical, the composition of sebum is made up of “triglycerides, wax esters, squalene and free fatty acids, which together help to keep the skin moisturized,” Garshick explains.
So again, “what we call ‘oil’ on our skin is made up of more than just sebum,” Hammerman says. “It also contains a mixture of sweat, dead skin cells, and tiny particles of whatever else is in the dust floating around you.”
In sum: Sebum and oil are not one and the same. Rather, sebum is just one of the many components of oil.
Where Does Sebum Come From?
Sebum is produced by the sebaceous glands, which naturally cover our bodies from tip to toe. There are two types of sebaceous glands: Those that are connected to a hair follicle, and those that are not.
“Sebaceous follicles are most commonly found on the face, behind the ears, and on the upper portions of the chest and back,” explains Ramin Fathi, a board-certified dermatologist in Phoenix, Arizona. On the face itself, you’ll find the highest concentration of sebaceous glands around the T-zone, which is why this area is generally more prone to developing acne.