Acne is one of the most common skin conditions worldwide. It mainly affects teenagers but can occur at any age. Although acne is often associated with oily skin and puberty, it is in reality a complex condition in which sebum production, keratinization, the skin microbiome, inflammatory processes, genetics, and environmental factors all play a role.
What is acne
Acne develops in the hair follicle, also known as the pilosebaceous unit. This consists of a hair, a sebaceous gland, and the canal that opens at the skin surface. The sebaceous gland produces sebum, an oily substance that protects the skin and keeps it supple. In acne, these processes are disrupted, allowing a combination of sebum, dead skin cells, and bacteria to build up in the pore.
Scientific literature describes acne as a complex condition. There is no single cause, but several biological and environmental factors contribute to the development of acne. Important pillars are increased sebum production, abnormal keratinization in the pore, changes in the composition of sebum, activity of specific bacteria, and inflammatory responses in the skin.
If you want to approach acne from a practical perspective, also read what you can do yourself for acne and which habits you are better off avoiding. These articles translate the theory into everyday care.
How acne develops step by step
In many dermatological publications, four core processes are named that together contribute to the development of acne.
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Increased sebum production
Under the influence of hormones in particular, sebaceous glands can produce more sebum. This leads to extra buildup of oils in the pore. -
Abnormal keratinization in the follicle
The skin renews itself continuously. In acne, keratinocytes (horn cells) in the follicle channel clump together more quickly and shed less evenly. This is called keratinization. -
Formation of comedones
The combination of extra sebum and clumped skin cells creates a partial or complete blockage of the pore. This appears as open comedones (blackheads) and closed comedones (whiteheads). -
Bacterial overgrowth and inflammation
The bacterium Cutibacterium acnes normally forms part of the skin microbiome. In an enclosed follicle with lots of sebum and little oxygen, this bacterium can multiply more quickly. That leads to local inflammatory reactions with red bumps, pimples, and sometimes deeper nodules.
The role of sebum and its composition
Sebum is a complex mixture of triglycerides, waxes, squalene, free fatty acids, and small amounts of cholesterol and antioxidants. The amount of sebum is important, but the composition also plays a role in acne.
Because sebum production plays a major role, it can help to better understand your own skin type. For example, read what oily skin actually means or how combination skin behaves.
Studies show that especially the ratio between different fatty acids and the degree of lipid oxidation can have an effect. A relatively low level of linoleic acid in sebum has been linked to an increased tendency for pores to become clogged. Oxidized squalene can also activate inflammatory signals in the skin, which may worsen existing lesions.
Sebum is at the same time a protective substance and a possible part of the problem in acne. The challenge is therefore not to remove sebum entirely, but to understand the balance between production, composition, and outflow.
Disrupted keratinization in the pore
The top layer of the skin consists of keratinized cells that function like a kind of bricks with lipids in between. The keratinization process is called keratinization and takes place both at the surface and in the follicle.
In acne, keratinocytes in the follicle channel change in number and behavior. They build up faster and shed less evenly. As a result, the chance increases that sebum and cells together form a plug that blocks the pore. This process often begins at an early stage, before visible pimples appear.
Skin microbiome and bacteria
The skin is home to a large number of microorganisms, including bacteria, yeasts, and viruses. This community is called the skin microbiome. In a healthy situation, there is a good balance between different types of microorganisms.
In acne, Cutibacterium acnes plays an important role. It is not only the presence of this bacterium that matters, but also the variation in strains and the interaction with other microorganisms and with the immune system. Certain strains of Cutibacterium acnes seem to cause more inflammation than others.
So acne is not simply the result of an infection, but of a disrupted interaction between sebum, keratinization, the microbiome, and immune responses.
Immune system and inflammatory processes
Inflammation is a core part of acne. The immune system responds to signals from the follicle, such as bacterial components, oxidized lipids, and damaged cells. This leads to the production of inflammatory mediators such as cytokines and chemokines.
Researchers have shown that inflammatory processes are often already present in an early stage of acne, sometimes even before clearly visible comedones (blackheads) appear. That underlines that acne is not a purely mechanical problem of blockage, but that the immune system is actively involved.
The intensity and duration of these inflammatory reactions differ from person to person and may be partly determined by genetic factors. This explains why some people mainly have blackheads, while others more quickly develop inflamed papules and pustules.
Hormones and genetic predisposition
Hormones are a well-known factor in acne. Hormones stimulate the growth and activity of sebaceous glands. During puberty, hormone production increases, causing sebum production to rise. Hormonal fluctuations in adults, for example around the menstrual cycle, can also play a role.
Genetic predisposition partly determines how sensitive the sebaceous glands are to hormonal signals and how keratinization in the follicle occurs. People in whose family acne is common have a greater chance of developing acne themselves to a greater or lesser extent.
Lifestyle and environmental factors
In addition to biological factors, lifestyle and environment can influence the severity of acne. These factors can strengthen or reduce the existing predisposition.
The following aspects are mentioned in the literature, among others:
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Stress
Stress hormones can affect inflammatory processes in the skin and sebum production. -
Heat and high humidity
This can promote sweating and trapping, causing pores to become blocked more quickly. -
Cosmetics or clothing
Products or materials that barely allow the skin to breathe can contribute to clogged pores. -
Nutrition
There is no simple nutritional pattern that applies to everyone. Some studies suggest that patterns with a high glycemic load or certain dairy products may be associated with more acne in some people, but the individual response varies greatly.
In addition to lifestyle, the way you care for your skin also plays a role. A simple, gentle routine can help support the skin barrier. In this step-by-step routine you can read how to approach this in practice.
Different forms of acne
In dermatology, several clinical forms are distinguished. These can occur at the same time or alternately.
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Acne comedonica
Here, blackheads are the main feature, with relatively few inflamed lesions. -
Acne papulopustulosa
Here, mainly red bumps and pimples are visible. -
Acne nodulocystica or conglobata
More severe forms with deeper inflammation, nodules, and cysts, often with a greater risk of scarring.
The severity of acne is partly determined by the number and type of lesions, the duration, the degree of inflammation, and any scars.
Common misconceptions about acne
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Acne is not the result of poor hygiene
Excessive cleansing or harsh cleansers can actually damage the skin barrier and make the skin more sensitive. -
Acne is not simply an infection
Cutibacterium acnes is a normal resident of the skin. The interaction between bacteria, sebum, keratinization, and immunity determines whether acne develops. -
Acne is not a purely cosmetic problem
Although the inflammation is on the outside, acne is a biologically complex condition that can also have psychological effects. -
Nutrition alone does not explain acne
Nutrition may play a role for some people, but acne is never determined only by eating habits.
What this means for daily skin care
Although acne is biologically complex, skin care does not have to be complicated. In practice, a calm, consistent approach often works better than intensive or changing routines.
- gentle cleansing without stripping the skin
- limited number of products
- supporting the skin barrier
- avoiding excessive stimulation
By disturbing the skin as little as possible, sebum production, keratinization, and inflammatory processes get more of a chance to stabilize. More practical tips can be found in what to do for acne and which gentle ingredients are often pleasant to use.
When to seek medical help
Because acne can be a chronic and sometimes stubborn condition, it may be wise to consult a doctor or dermatologist in the following situations, among others:
- For painful nodules or deep inflammation
- For clear scarring
- When acne has a strong impact on self-image or daily functioning
- When self-care and general skin care do not provide enough improvement
A healthcare professional can then assess which treatment options are appropriate in the specific situation.
At More Natural, we therefore do not approach acne as something that must be 'fought', but as a skin condition that benefits from understanding, calm, and support of the skin's natural function. Less stimulation and more consistency often turn out to be more effective in practice than aggressive or complex routines.
Further reading scientific sources
For those who want to delve further into the scientific background of acne, the following public sources and review articles are a good starting point:
- Overview of acne on PubMed PubMed search results acne vulgaris
- Patient information and background by the American Academy of Dermatology American Academy of Dermatology information about acne
- Dutch general practitioner guideline on acne NHG acne standard
- Patient information at an academic hospital Radboudumc information about acne
These sources are intended as further insight into the current knowledge about the development and course of acne. They are not a substitute for personal medical advice.
Frequently asked questions
How does acne develop exactly?
Acne develops through a combination of four core processes: increased sebum production (often due to hormones), abnormal keratinization in the follicle where skin cells build up more quickly, formation of comedones (blackheads) when the pore becomes blocked, and bacterial overgrowth of Cutibacterium acnes in the blocked follicle, leading to inflammation. It is not a single cause but an interplay of biological factors.
Is acne contagious or the result of poor hygiene?
No. Acne is not contagious and has nothing to do with poor hygiene. Cutibacterium acnes is a normal resident of the skin in everyone. It is the disruption of the balance between sebum, keratinization, and immune responses that causes acne, not the presence of the bacterium itself. Excessive cleansing or harsh cleansers actually damage the skin barrier and can worsen acne.
What role does the microbiome play in acne?
The skin microbiome in acne is not simply "too many bacteria". Research points to the role of specific strains of Cutibacterium acnes — certain strains are more associated with inflammation than others. In addition, the interaction between Cutibacterium acnes, other microorganisms, and the immune system influences the severity of acne. A disturbed microbiome caused by harsh products can therefore actually worsen acne.
Why does acne get worse with stress?
Stress hormones can increase sebum production and intensify inflammatory processes in the skin. As a result, existing acne lesions can worsen and new ones can appear more quickly. This is a biological mechanism, not imagination. Chronic stress is therefore a relevant factor in acne that lies outside the skin itself — stress management and sufficient sleep are part of a holistic approach.
Which oil is good for acne-prone skin?
For acne-prone skin, non-comedogenic, lightweight oils are the safest choice. Jojoba oil is at the top of the list: its wax ester composition mimics sebum and hardly clogs pores. Hemp seed oil has a high linoleic acid content, a light texture, and is non-comedogenic. Both are traditionally used for oily or acne-prone skin. Avoid heavier oils such as coconut oil on the face if you have acne-prone skin. Read more in our blog about ingredients for acne.
When is medical help needed for acne?
See a GP or dermatologist for painful nodules or deep inflammation, for clear or increasing scarring, when acne has a strong impact on your self-image or daily functioning, or when mild self-care and routine adjustments do not provide enough improvement. A healthcare professional can assess which treatment options are appropriate in your situation — including medical options that fall outside the scope of cosmetic care.
