Sebum is an oily, waxy substance produced by your body’s sebaceous glands. It coats, moisturizes, and protects your skin.

It’s also the main ingredient in what you might think of as your body’s natural oils.

So, what exactly is sebum made up of? As an article from Harvard Medical School explains, “sebum is a complex mixture of fatty acids, sugars, waxes, and other natural chemicals that form a protective barrier against water evaporation.”

To be more specific, sebum contains triglycerides and fatty acids (57%), wax esters (26%), squalene (12%), and cholesterol (4.5%).

If you have very oily skin, your body may be producing an excess amount of the mixture of lipids (fat-like molecules) that make up sebum.

Of course, what we call “oil” on our skin is made up of more than just sebum. It also contains a mixture of sweat, dead skin cells, and tiny particles of pretty much whatever else is in the dust floating around you.

Sebaceous glands cover the vast majority of your body. Although they’re often grouped around hair follicles, many exist independently.

Your face and scalp contain the highest concentration of glands. Your face, in particular, may have as many as 900 sebaceous glands per square centimeter of skin.

Your shins and other smooth surfaces typically have fewer glands. The palms of your hands and the soles of your feet are the only areas of skin without any glands at all.

Each gland secretes sebum. To help you picture the process more clearly, it might be helpful to think of your tear ducts and the way they secrete your eyes’ natural moisture.

Although sebaceous glands are much smaller than tear ducts, they work in a similar way.

Sebum production is a complex process that scientists don’t fully understand.

That said, researchers do know that its primary function is to protect your skin and hair from moisture loss.

Some scientists speculate that sebum may also have an antimicrobial or antioxidant role. It may even help release pheromones. Research into these potential functions is ongoing.

Your androgens help regulate your overall sebum production.

Very active androgens, like testosterone, are produced by your adrenal glands and your ovaries or testes.

These glands are, in turn, regulated by your brain’s pituitary gland. Your pituitary gland is in charge of your body’s entire endocrine (hormonal) system.

The more active your androgens are, the more sebum your body may produce.

Although progesterone — a female-specific sex hormone — isn’t an androgen, it does appear to have an effect on sebum production.

Progesterone weakens the effect of the enzyme 5 alpha-reductase. 5 alpha-reductase activates sebum production.

So, in theory, high progesterone levels should cause sebum production to go down.

But that typically isn’t the case. Researchers have found that when progesterone levels spike, sebum production actually goes up. More research is needed to understand why.

You might be surprised to learn that you begin to use your sebaceous glands before you’re even born.

While in the womb, your sebaceous glands produce vernix caseosa. This white, paste-like coating protects and moisturizes your skin until birth.

Your sebaceous glands begin to produce sebum after you’re born.

For the first three to six months of life, your glands produce as much sebum as an adult’s. From there, sebum production slows until you hit puberty.

When you hit puberty, sebum production may increase up to 500 percent. Male adolescents tend to produce more sebum than their female counterparts. This often results in oily, acne-prone skin.

Your sebum production will likely peak before you reach adulthood.

Although adult males produce slightly more sebum than adult females, everyone’s sebum production declines with age. This often results in dry, cracked skin.

There are several medications, underlying conditions, and other outside factors that can make your sebaceous glands more or less active.

This, in turn, affects how much sebum your glands produce.

Increased production

Hormonal medications often increase sebum production. This includes testosterone, some progesterones, and phenothiazine.

Parkinson’s disease has also been associated with an uptick in sebum production.

In many cases, pituitary, adrenal, ovarian, and testicular conditions can cause either an increase or decrease in production.

Decreased production

Certain birth control pills, antiandrogens, and isotretinoin typically decrease sebum production.

Starvation and long-term malnutrition are also associated with a decline in sebum production.

As previously stated, pituitary, adrenal, ovarian, and testicular conditions can cause either an increase or decrease in production.

You can typically use creams, soaps, and other topicals to help treat the symptoms associated with too much or too little sebum.

Although more research is needed, there’s some evidence to suggest that your diet can affect how much sebum your body makes. If you aren’t able to easily identify specific triggers, you may find it helpful to try an elimination diet.

In severe cases, your doctor may prescribe hormonal medication or supplements to help balance your sebum production from within.

How to reduce sebum production if you have oily skin or hair

You may consider talking to your doctor about combination birth control pills. The combination of estrogen and progestin may help reduce your sebum production.

If you’re already taking the progestin-only pill or a combination birth control pill, talk to your doctor about switching. They may be able to recommend a different pill that suits your needs.

If you’re experiencing severe acne, your doctor may also prescribe isotretinoin. This oral medication may lower sebum production by up to 90 percent.

Certain foods have also been linked to excess oil production and acne. Avoiding foods that disrupt your blood sugar levels or are high in saturated fat might help to curb your oil production from within.

How to boost sebum production if you have dry skin and hair

If you’re dealing with dryness, take an inventory of the products you’re using on your skin and hair.

This includes shampoos, cleansers, makeup, laundry detergent — anything that comes into contact with your body.

Alcohol, acids, and fragrances are all common ingredients known to cause irritation. If you can, switch to products catered toward sensitive skin or fragrance-free versions.

Switching from hot to lukewarm showers can also help. Spending time in excessively hot water strips the oils from your hair and skin.

And if you aren’t already using moisturizer on your face and lotion on your body, now is the time to start.

Increasing your water intake and eating more healthy fats, like omega 3s, may also help.

If you suspect that your lack of sebum is related to a hormonal imbalance, talk to a doctor or other healthcare provider. They may recommend testosterone therapy to help increase production.

Sebum is a necessary component of healthy skin. It moisturizes and protects the surface of almost your entire body.

But it’s possible to have too much of a good thing, or too little. Everyone’s body is different, so there’s no exact amount to have.

If you’re dealing with chapped and cracking skin, oily patches, or severe acne, talk to a doctor or healthcare provider.

They may be able to recommend different things you can do at home to help restore balance. In some cases, they may also be able to prescribe clinical treatments.