Everything you need to know about sebaceous filaments.

Sebaceous filaments are microscopic structures located within hair follicles that play a crucial role in the transportation of sebum to the skin's surface. To clarify, sebum is a lipid substance produced by the sebaceous glands. Its primary function is to maintain skin hydration and form a protective barrier against external aggressions, such as pollutants and pathogens. The sebaceous filaments are thus natural structures of the skin pore walls, unlike blackheads, with which they are often confused.

More specifically, sebaceous filaments are composed of sebum, fragments of keratin from dead cells, and microorganisms, primarily bacteria naturally present on the skin such as Cutibacterium acnes. They are often visible in areas rich in sebaceous glands, particularly on the nose, forehead, and chin, corresponding to the infamous T-zone. To the naked eye, sebaceous filaments take the form of small greyish or white lines in enlarged pores. It happens that the tip of the sebaceous filaments darkens slightly due to the oxidation of the sebum's fatty acids that cover it when exposed to air, making them then difficult to distinguish from blackheads.

Apart from their unsightly appearance, sebaceous filaments are not dangerous and do not indicate a pathological condition.

Sebaceous filaments have a natural origin : they are skin structures that facilitate the transport of sebum to the skin's surface. However, while everyone has them, they tend to be more visible on oily skin. Indeed, sebaceous filaments only become visible when the pores are filled with sebum and dilate, a phenomenon more common in oily skin. The appearance of sebaceous filaments can also be influenced by certain hormonal imbalances, particularly during adolescence or at certain times of the menstrual cycle in women, where fluctuations in oestrogen and androgen levels can stimulate the activity of the sebaceous glands. Finally, the use of unsuitable cosmetics, whether they are comedogenic or too aggressive, leading to a reactive hyperseborrhoea, can also accentuate the visibility of sebaceous filaments.

Several factors can influence the emergence of sebaceous filaments. However, the primary cause lies in the normal functioning of the sebaceous glands, which produce sebum to maintain skin hydration and protection.

Even though they may be aesthetically displeasing, it is advised against trying to get rid of sebaceous filaments by manually extracting them. This method, already risky for blackheads, is even more so for sebaceous filaments, which are not imperfections but natural structures of the skin. This process could not only cause skin inflammation, but also promote bacterial proliferation, which could eventually lead to the outbreak of comedones. Furthermore, even if you manage to remove them "cleanly", they will quickly return within 30 days, or even sooner if you have oily skin.

Sebaceous filaments are a natural feature of the skin that can be minimised but not eliminated.

However, it is possible to reduce the visibility of sebaceous filaments by adopting a skincare routine that allows for the regulation of sebum production and the dilation of pores. For this, rely on active ingredients that are astringent, sebum-regulating and purifying, such as zinc, azelaic acid or even bamboo extract. Also, ensure to thoroughly cleanse your face every evening, or morning and evening if you feel the need, in order to remove impurities and sebum accumulated in the pores. A weekly exfoliation also helps to unclog the skin's pores and tighten them.

Finally, even if you have oily skin, do not neglect hydration : it is essential to limit the evaporation of water from the stratum corneum and maintain the water balance of your skin. Indeed, when it is not sufficiently hydrated, oily skin can react by intensifying its sebum production, a phenomenon known as reactive hyperseborrhea and which can promote the appearance of sebaceous filaments.

How to remove a sebaceous filament according to scientific literature?

The only solution to date mentioned in scientific literature for tackling sebaceous filaments is the topical use of tretinoin, an active ingredient typically prescribed for treating acne. Thanks to its keratolytic properties, tretinoin prevents the obstruction of skin pores, thereby reducing the risk of sebaceous filaments becoming visible. However, this is a substance available only on prescription and subject to numerous usage precautions. Therefore, tretinoin cannot be considered a conventional approach for tackling sebaceous filaments.

• GANS E. & al. Tretinoin: A Review of Its Anti-inflammatory Properties in the Treatment of Acne. Journal of Clinical and Aesthetic Dermatology (2011).

• DABBAS D. & al. Sebaceous filaments. Dermatology Practical & Conceptual (2021).

• ADLER J. & al. A Case Report of Sebaceous Filaments. Cureus (2023).