An oily scalp results from hyperactivity of the sebaceous glands, often influenced by hormonal factors. This scalp hyperseborrhea can sometimes be accompanied by more or less significant hair loss. Simple coincidence or a genuine biological link? Find the answer below.
Keywords: itchy oily scalp and hair loss, hair that becomes oily quickly and falls out, oily hair causing itching then hair shedding, oily hair that falls out
Oily hair results from hyperseborrhea related primarily to androgen activity and to the enzyme 5α-reductase.
Hair loss depends on the hair follicle cycle and can be influenced by hormonal, inflammatory, genetic, or environmental factors.
Sebum itself does not directly cause hair loss, but an excess can alter the scalp’s environment.
Studies have demonstrated differences in lipid composition and scalp microbiota among individuals with an oily scalp associated with hair loss.
Low-grade chronic inflammation, driven by an imbalance in sebum and the microbiota, can disrupt the hair growth cycle.
Oily hair results from hyperseborrhea, that is, an excessive production of sebum by the sebaceous glands of the scalp. This hyperactivity is primarily driven by androgen hormones. Testosterone is locally converted into dihydrotestosterone (DHT) by the 5α-reductase enzyme in sebaceous cells, which stimulates lipid synthesis and increases sebum secretion. High activity of this enzyme therefore predisposes to a greasier scalp. In addition to these hormonal factors, environmental elements such as stress, pollution, certain unsuitable hair products, and a high-glycemic diet can indirectly enhance androgen production and seborrhea.
of sebaceous glands on the body.
The hair shedding, on the other hand, relies on distinct mechanisms tied to the hair cycle. Each follicle alternates between a growth phase (anagen), a transition phase (catagen), and a resting phase (telogen), at the end of which the hair falls out. A hair loss that is increased may result from a shortened anagen phase, a premature shift into the telogen phase—a phenomenon called “telogen effluvium”—progressive follicle miniaturization as seen in androgenetic alopecia, or inflammation of the scalp.
Hair naturally sheds every day and this is not considered abnormal hair loss.
Thus, when individuals describe hair that becomes oily quickly and experiences shedding, it is important to remember that sebum production and follicular dynamics are governed by distinct biological processes, even though they can mutually influence one another.
In theory, the sebum is not an enemy of hair. It contributes to fiber lubrication and protects the scalp. However, an excess can alter the follicular environment by affecting local lipid composition and microbiome balance. In this context, some individuals describe an oily, itchy scalp that leads to hair loss. Therefore, the issue is not so much the presence of sebum as its excess associated with potential inflammatory or microbial alterations.
A recent study conducted in young women aged 18 to 35 with oily scalps and hair loss revealed significant differences compared to a control group, both in terms of scalp physiological parameters and in lipid composition and microbiome. Eight differential lipids were identified, mainly ceramides, triglycerides, and diglycerides. Ceramides, key components of the skin barrier, also participate in cell signaling and apoptosis. Abnormal accumulation could thus disrupt the follicular environment. Moreover, two lipid metabolic pathways, including the sphingolipid pathway, were associated with the observed profiles. This pathway is involved in producing bioactive molecules, such as sphingosine-1-phosphate, which regulate cell growth and inflammatory responses. Dysregulation could therefore influence both sebum production and the hair growth cycle.
The study also highlighted differences in the composition of the scalp microbiota. Variations in the abundance of bacteria, such as Cutibacterium or Pseudomonas, as well as yeasts such as Malassezia, were observed. However, these microorganisms interact closely with sebum lipids: some yeasts hydrolyze triglycerides and release fatty acids capable of irritating the scalp, promoting itching and local inflammation. Even moderate chronic inflammation can impair the quality of the follicular environment and disrupt the hair growth cycle.
Differences in the scalp microbiome of young women with oily scalps and hair loss compared to a control group.
Source: ZHAO F. & al. Multidimensional research on hair loss in young Chinese females with oily scalps. Journal of Cosmetic Dermatology (2025).
Nevertheless, the authors emphasize that this is an observational study: the associations identified do not allow us to assert that an oily scalp directly causes hair loss.
In conclusion, an oily scalp does not mechanically cause hair loss, since sebum production and the hair growth cycle are governed by distinct biological mechanisms. However, excess sebum can alter the scalp’s ecosystem, promote microbial imbalances, and sustain low-grade chronic inflammation. Such an inflammatory follicular environment can disrupt the hair growth cycle and exacerbate certain forms of hair loss, particularly in individuals already predisposed. Thus, while hair that becomes oily quickly does not necessarily fall out faster than other hair, an imbalanced scalp can constitute an exacerbating factor in hair loss.
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ZHAO F. & al. Multidimensional research on hair loss in young Chinese females with oily scalps. Journal of Cosmetic Dermatology (2025).
ZHENG Y. & al. Potential causal relationship between extensive lipid profiles and various hair loss diseases: Evidence from univariable and multivariable Mendelian randomization analyses. rnal of Cosmetic Dermatology (2025).
