Pimples = oily skin? There seems to be a clear and real relationship between excess sebum and acne. But in the fight against blemishes, it is important to understand that things are a bit subtler.
The skin works as a ecosystem, which needs to be preserved and protected on a daily basis. Sebum plays an essential and positive role for healthy skin. It would be a mistake to try to completely eliminate it, even for acne-prone skin: instead, it should be regulated and rebalanced. Our experts are here to tell you all about sebum, including its purpose, and explain the causes of hyperseborrhoea and the role of dysseborrhoea.
Note that sebum is produced by the sebaceous glands, which are attached to hair follicles, in response to hormonal stimulation. This is why puberty is a period favourable to acne.
Sebum is a complex mixture of lipids synthesised under hormonal stimulation by sebaceous glands in the dermis. Among other things, it helps hydrate your skin and delivers lipophilic antioxidants (lipophilic = with affinity for fats) onto its surface.
In subjects with acne-prone skin, there is abnormal sebum production and a lack of vitamin E. These disruptions can lead to the development of acne, blackheads or whiteheads. Squalene oxidation is higher in men than in women but starts earlier in women.
Sebum is composed of lipids and contributes to the skin barrier function. It protects the skin from damage, especially UV-induced oxidation. At temperatures below 30°C, it thickens and forms a barrier that repels rain for example, whereas heat makes it more fluid, enabling it to mix with perspiration and retain water.
It is therefore very important to the cutaneous ecosystem, provided that its quality is good and that the right quantity is produced.
Hyperseborrhoea = excess sebum. Excessive sebum production leads to oily skin; certain factors heavily influence this production.
Influence of hormones
Sebaceous gland activity is regulated by hormones: it is reduced by oestrogens and increased by androgens. An abnormally high level of androgens, for example during menstruation, can cause sebum secretion to increase in women.
Location on the body
Pimples usually occur on areas where sebum is abundant: these include the scalp, face, neck, shoulders, chest area, upper back and thoracic region. On the face, sebum production is highest on the T-zone and the cheeks; it is lower on the upper eyelids and neck.
Age
Under the influence of the mother’s hormones, the sebaceous glands become active in the first month of life. Their activity decreases after that until puberty, when there is a sharp increase in secretion that lasts until adulthood. Sebum secretion slowly decreases in men after the age of 50; it drops most dramatically in women after the menopause.
Seasons and climate
A 1°C increase in cutaneous temperature leads to a 10% increase in sebum secretion, which is therefore higher in spring and summer.
Time of day
Sebum secretion is highest between noon and 2 pm.
Dysseborrhoea = poor-quality sebum. Excess sebum was long considered to be the main cause of acne, but it is only partly responsible for our skin blemishes. Oily skin does not necessarily mean pimples and blackheads! In fact, we recently discovered that the real culprit in acne lesions is a change in sebum composition due to a lack of vitamin E.
Vitamin E acts as a shield for our skin.
There are studies suggesting that vitamin E prevents the surface lipids in sebum from oxidising. It therefore allows our skin to remain healthy. The highest levels of vitamin E are found in sebum-rich areas such as facial skin.
Analyses have shown that the lipids of an acne patient’s open and closed comedones contain a higher level of squalene peroxide (a lipid resulting from the oxidation of squalene, which itself is a component of sebum), a highly comedogenic substance that irritates the skin. It is therefore essential to target the transformation of micro-comedones in the prevention of acne.
