What Is Sebum and How Does Your Skin Produce It?

Sebum is an oily substance that's made by the sebaceous glands in the skin. The function of sebum is to moisten and prevent the skin from becoming too dry. Sebum also has antibacterial properties and is the body's first defense against infection.

The sebaceous glands that make sebum are on just about every surface of the body. While sebum is important for skin health, having too much or too little of the oil can lead to acne, oily skin, and chronic itchiness and skin irritation.

This article will go over what sebum is and what it does in the body. You'll also learn about the skin problems that can result from the overproduction or underproduction of sebum.

Sebum Production

The sebaceous glands, each attached to a hair follicle, produce sebum through a process called holocrine secretion. The glands produce lipids, which remain inside the sac-like glands for about a week until the sac erupts, allowing the sebum to flow freely into the hair follicle. The hair then wicks the oil onto the skin to lubricate and protect it.

All babies are born with sebaceous glands over most of their bodies, with the exception of the palms of the hands, tops and soles of the feet, and lower lips.

These glands produce significant amounts of sebum right after birth. This is because the glands are regulated by hormones, particularly androgens (male sex hormones such as testosterone), which newborns have in abundance.

As a baby reaches toddlerhood, their hormone levels even out and the sebaceous glands become less active: Children produce very little sebum between ages 2 to 6. With the approach of puberty, androgens again flood the body and the glands pump out steady amounts of sebum.

The face, scalp, upper neck, and chest host the most sebaceous glands, so when there's a surge in sebum production, these areas are prone to acne breakouts or oily skin.

The size of these glands and the way hormones influence them are determined by genetics, so if you have close relatives with acne, dry skin, or other sebum-related conditions, you're more likely to suffer from the same problem.

Composition

Sebum is a complex fusion of lipids, mostly glycerides and free fatty acids with a substantial percentage of wax esters and squalene, plus a mix of cholesterol esters and cholesterol. 

These lipids work together to moisturize the skin and defend the body. Squalene and wax esters, for instance, create a protective barrier on the surface of the skin that helps seal in moisture and electrolytes.

Hydrolyzed triglycerides and free fatty acids (particularly sapienic acid) act as antimicrobial agents to keep out potentially harmful microbes and defend against infection.

Role of Sebum in Health

The disbursement of sebum all over the body supports the health of the skin in a number of important ways:

• Hydration: Sebum is essential for pliable skin, but the levels of lipids secreted have to be properly balanced to prevent skin irritation. 
• Antibacterial protection: Lipids secreted by sebaceous glands create a slightly acidic film on the skin—a pH of 4.5 to 6.0—which defends against bacteria, viruses, and other microbes.
• Antifungal protection: Sebum has been shown to prevent fungal infections such as ringworm, which may explain why young children, who release little or no sebum, are especially susceptible to the skin disorder. 
• Sun protection: Squalene has been shown to protect against sunburn and the damage caused by ultraviolet (UV) rays. 

Besides helping the skin, sebum also seems to support heart health. Researchers believe that a major benefit of sebum secretion is that the process eliminates excess lipids and cholesterol, which can block arteries and cause heart disease.

Overproduction 

Sebum production is controlled by hormones, so if you have a hormone imbalance you might have too much sebum, which can cause a number of conditions.

Acne

Especially during adolescence, a spike in hormones can cause a spike in sebum production. An excess of sebum combined with dead skin cells can block pores and cause acne blemishes such as blackheads and pimples.

Acne often is effectively treated with topical creams or oral medications that contain retinoids, antibiotics, and/or hormones. 

Oily Skin

Excessive sebum also can cause oily skin. Oily skin may accompany acne, but it doesn’t always. While testosterone and progesterone are associated with acne, too much growth hormone is connected with sebum production that leads to oily skin. 

When skin is oily, facial pores look larger and skin may seem greasy and unclean. An appropriate facial cleansing routine may be sufficient for dealing with mildly oily skin.

For skin that's extremely oily, however, oral or topical retinoids (vitamin A derived compounds) and/or oral contraceptives may be necessary; these medications can have dangerous side effects for some people and should be used with caution and only with the guidance of a healthcare provider.

Seborrheic Dermatitis

An inflammatory skin disorder, seborrheic dermatitis can cause dandruff of the scalp as well as itchy, flaky, or scaly skin wherever there are overactive sebaceous glands.

Up to 3% of the general population has seborrheic dermatitis. Those with neurological disorders such as Parkinson’s disease and immunosuppressed persons, such as those with HIV/AIDS, are especially at risk.

Usual treatments include topical antifungal or anti-inflammatory creams or washes. Some alternative and homemade remedies may provide relief, but you should discuss these with your healthcare provider to ensure they are safe.

Underproduction

Some medications for treating acne and oily skin work by suppressing sebum production; these include oral contraceptives, anti-androgens, and prescription retinoids (both orally and topical). If you have normal sebum levels to start with, you should be cautious using these medications.

Research also shows that products containing cannabidiol (CBD) may reduce sebum production. Studies have shown that CBD infused into the bloodstream has been effective for suppressing sebum, but more studies are needed to see if topical applications are also effective.

Sebum production can be severely impacted by eating disorders, severe fasting, and malnutrition. Within five days of significantly restricting calories, there’s a drop in sebum that can lead to a type of eczema called asteatosis. 

The most common problem associated with insufficient sebum is dry, red, flaky, and itchy skin that can be exacerbated by harsh soaps or frequent long hot baths or showers.

Mildly dry skin can be eased with a moisturizer containing ceramides, emollients, sorbitol, glycerin, or humectants. Thicker, greasier moisturizers containing ingredients like petroleum jelly and mineral oil can be even more effective but may clog pores.

If your skin is mildly chapped, cracked, or oily, you might talk to your healthcare provider about the best moisturizer for your skin type. A trip to the drugstore may be all you need to maintain smooth, soft, healthy skin.