Sebum is the oily, waxy substance your skin naturally produces to keep itself moisturized and protected. It’s made by tiny glands called sebaceous glands, which sit just below the skin’s surface and are attached to hair follicles. Everyone produces sebum, and in the right amounts it’s essential for healthy skin. Too much or too little is where problems start.
What Sebum Is Made Of
Sebum is a complex mixture of fats. Its main components are triglycerides (the same type of fat found in food), wax esters, and squalene. It also contains smaller amounts of free fatty acids, cholesterol esters, and other lipid compounds. Researchers have identified dozens of distinct molecular species within each of these categories, making sebum one of the more chemically diverse substances your body produces.
This particular blend of fats is what gives sebum its characteristic texture. It’s fluid enough to travel up through pores and spread across the skin’s surface, forming a thin, water-repelling film. That film is the reason your skin feels slightly slick a few hours after washing, and it’s doing more than you might expect.
Why Your Body Produces It
Sebum’s most obvious job is hydration. The oily film it creates on your skin reduces water loss through the surface, keeping the outermost layer of skin supple and preventing it from drying out and cracking. Without this barrier, your skin would lose moisture far more quickly, especially in dry or cold environments.
Beyond moisture, sebum plays a role in immune defense. Certain fatty acids in sebum have antimicrobial properties that help prevent harmful bacteria and fungi from colonizing the skin. Sebum also helps coordinate low-level immune activity around hair follicles, contributing to the skin’s overall ability to respond to threats. Think of it as a first line of defense that works quietly in the background.
Where Sebum Comes From
Sebaceous glands are found almost everywhere on your body, with the highest concentration on your face and scalp. The only places completely free of them are the palms of your hands and the soles of your feet, which is why those areas tend to feel drier than the rest of your skin.
The way these glands produce sebum is unusual. Rather than squeezing oil out like a tube of toothpaste, the cells inside the gland gradually fill up with lipids until they rupture and release their entire contents. The cell itself is destroyed in the process, and the mixture of cellular debris and fats is what becomes sebum. New cells continuously form to replace the ones that burst, keeping production going around the clock.
How Hormones Control Sebum Production
Hormones are the primary switch that controls how much sebum your skin makes. Androgens, a group of hormones that includes testosterone, are the main drivers. They bind to receptors on sebaceous gland cells and signal them to grow larger and produce more oil. This is why sebum production ramps up so dramatically during puberty, when androgen levels surge.
A hormone called DHEAS is often the earliest trigger. Rising DHEAS levels in children around age 7 kick off a gradual increase in sebum output that continues climbing through adolescence. The link between androgens and sebum is strong enough that people with nonfunctional androgen receptors never produce adult levels of sebum, and they don’t develop acne. Estrogens and certain vitamin A derivatives, by contrast, have a suppressive effect on sebaceous glands, slowing their activity.
How Sebum Changes Over Your Lifetime
Sebum production follows a surprisingly active pattern from the very start of life. Newborns have high sebaceous gland activity, likely due to hormones transferred from the mother. This is why some babies develop oily skin or small acne-like bumps in their first weeks. That initial burst tapers off during early childhood, creating a relatively dry-skin phase for most kids.
Around age 7, production begins climbing again and accelerates through puberty. For most people, sebum output peaks somewhere in the teenage years and early adulthood, then gradually declines with age. This decline is one reason skin tends to feel drier as you get older, and it’s also why acne is far more common in younger people.
When Sebum Causes Problems
Acne is the most well-known consequence of excess sebum. But sebum alone doesn’t cause breakouts. Acne develops when four things happen together: the skin inside a pore produces too many cells and clogs the opening, sebum builds up behind that plug, a bacterium called C. acnes thrives in that oxygen-poor environment, and the surrounding tissue becomes inflamed.
Excess sebum feeds this cycle by providing the raw material that fills clogged pores and the nutrients that C. acnes feeds on. This is why oily skin and acne so often go hand in hand, and why conditions involving elevated androgens tend to worsen both problems simultaneously. On the other end of the spectrum, too little sebum leaves skin dry, cracked, and more vulnerable to irritation and infection.
What Affects How Much You Produce
Genetics and hormones are the biggest factors, but diet also plays a measurable role. Extreme calorie restriction dramatically lowers sebum output, and those changes reverse once normal eating resumes. Higher intake of carbohydrates or fat can increase production, and the type of carbohydrate matters too. A diet heavy in refined carbohydrates (around 500 grams per day in one study) shifted the fatty acid composition of sebum, increasing the proportion of certain monounsaturated fats that correlated with higher acne lesion counts.
A low glycemic load diet, one that avoids blood sugar spikes, was shown in a 12-week trial to shift sebum composition in the opposite direction, increasing the ratio of saturated to monounsaturated fatty acids. That shift correlated with fewer acne lesions. While diet alone won’t transform oily skin, it can meaningfully influence both the quantity and quality of sebum your skin produces.
Managing Oily Skin
If excess sebum is a concern, a few well-studied skincare ingredients can help. Niacinamide (vitamin B3) is one of the most widely supported options for reducing oil production. Zinc PCA, a compound that combines zinc with a natural skin molecule, also helps regulate sebaceous gland activity. Salicylic acid works differently. Rather than reducing production, it dissolves inside pores to clear out the mix of oil and dead skin cells that leads to clogged follicles.
The goal with any of these approaches is balance, not elimination. Stripping your skin of all its oil with harsh cleansers often backfires, triggering your glands to compensate by producing even more sebum. Gentle, targeted ingredients that bring production into a normal range tend to produce better results over time.