Oily skin is a common nuisance for many acne patients. It not only makes your skin look and feel yucky but excessive oil production clogs the pores and can lead to acne. Scientists now believe oxidative damage to sebum is the trigger that starts the acne formation process. Therefore, the more sebum your skin produces, the more likely you are to get acne.
Contrary to what many people believe, the oil your skin produces has no relationship with dietary fat; eating more fat doesn’t make your skin oilier. Sebum is produced by organisms called sebaceous glands. Sebaceous glands produce cells called sebocytes that are a bit like water balloons filled with sebum. These ‘oil balloons’ make their way into the skin pores and burst, releasing the sebum. How much sebum your skin produces depends on how quickly the sebaceous glands produce these ‘oil balloons’.
Sebum production is primarily controlled by genetics and hormones. Since this article focuses on topical treatments, I’m nog going to talk about the genetics of oily skin. On the hormonal side, male sex hormones (androgens) and insulin/insulin-like growth factor 1 (IGF-1) are the biggest factors.
The skin is a hormonally active organ, and a large portion of the androgens it uses are produced in the skin; more precisely, they are converted from precursor hormones. Out of the androgen family, testosterone (T) and dihydrotestosterone (DHT) stimulate sebum production the most. They are 10 to 60 times more potent than their precursor hormones, dehydroepiandrosterone sulfate (DHEAS) and androstenedione. Unfortunately, the skin has everything it needs to convert these precursor hormones to testosterone and DHT. So the amount of T and DHT in the skin depends on the availability and activity of these enzymes.
An enzyme called 5-alpha reductase (5-AR) converts T to DHT. Scientists have tested whether inhibiting this enzyme could reduce sebum production and acne, and indeed there is limited evidence to support this – though it’s far from proven.
Several studies have looked at the effect of various 5-AR inhibitors, sometimes called DHT blockers, on sebum production. While the results aren’t mind-blowing, studies show the right topical treatments can reduce sebum production by 20 to 40%.
Inflammation, stress, and bacteria
In addition to hormones, exposure to stress can also increase sebum production. Stress exposure triggers the release of corticotropin-releasing hormone (CHR) that’s been shown to stimulate the sebum producing cells in the skin.
Stress in this context includes both psychological stress and oxidative stress (such as exposure to UV rays, air pollution and bacteria). There’s some evidence to show that topical antioxidants can mitigate this stress-related increase in sebum production.