Coconut oil, a potential solution for seborrhoeic dermatitis?

Seborrhoeic dermatitis is a common inflammatory skin condition that mainly affects areas rich in sebaceous glands, such as the scalp, the face—particularly the sides of the nose and the eyebrows—the upper chest, and the area behind the ears. It usually presents with redness, whitish or yellowish scales, and itching of varying intensity. On the scalp, it is often associated with dandruff. Seborrhoeic dermatitis is multifactorial: it results in particular from an interaction between sebum production, a cutaneous inflammatory response, and the proliferation of yeasts of the genus Malassezia, micro-organisms that are naturally present on the surface of the skin but can become problematic when they grow excessively.

To date, the scientific evidence supporting the use of coconut oil in seborrhoeic dermatitis remains limited.

Some studies nevertheless suggest interesting avenues, particularly with regard to the balance of the scalp microbiome. One metagenomic study specifically examined the effect of applying coconut oil on the scalp microbiome. The study followed 140 women, 70 of whom had dandruff, over a period of 16 weeks, including 12 weeks of treatment with coconut oil and 4 weeks of follow-up. The researchers analysed nearly 900 samples in order to observe changes in the bacterial and fungal composition of the scalp. The results showed that regular use of coconut oil altered the microbial ecosystem: it was notably associated with an increase in certain commensal scalp bacteria, such as Cutibacterium acnes, and with a modulation of the presence of yeasts of the genus Malassezia.

These results are interesting because seborrhoeic dermatitis is closely linked to an imbalance of the skin microbiome, particularly to an overgrowth of Malasseziayeasts.

The capacity of coconut oil to modulate this ecosystem could therefore, in theory, help to improve the scalp environment. However, these findings must be interpreted with caution. The study primarily shows changes in the microbiome, without clearly demonstrating an improvement in inflammatory symptoms. It is therefore difficult to assert that coconut oil constitutes an effective treatment for seborrhoeic dermatitis. Moreover, due to its rich, occlusive texture, coconut oil applied neat can sometimes accentuate the greasy appearance of the scalp or of areas already rich in sebum, which may be counterproductive in cases of seborrhoeic dermatitis.

If you suffer from seborrhoeic dermatitis, you may turn to antifungal shampoos containing ketoconazole, ciclopirox olamine or pyrithione olamine. If symptoms persist, do not hesitate to seek advice from a healthcare professional.

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