Acne: Causes, Types, Treatments, and Prevention

You've followed every skincare routine, tried every product, and still wake up to new breakouts. Or maybe your skin was clear for years, and suddenly you're dealing with painful cysts that won't respond to anything topical. The disconnect isn't in your routine. It's in the assumption that acne is only a skin problem.

Key Takeaways

• Acne is an inflammatory condition driven by sebum, bacteria, and immune response.
• Four core mechanisms interact: excess sebum production, follicular plugging, bacterial overgrowth, and inflammation.
• Hormones, insulin signaling, and gut health influence acne severity systemically.
• Comedonal, inflammatory, and cystic acne reflect different stages and immune responses.
• Sudden cystic acne often signals hormonal shifts or metabolic changes.
• Individual variation in acne presentation stems from genetics, microbiome, and androgen sensitivity.
• Persistent acne may indicate underlying conditions like PCOS or insulin resistance.

What Acne Actually Is and Where It Starts

Acne vulgaris is an inflammatory disease of the pilosebaceous unit, the structure that houses the hair follicle and its attached sebaceous gland. The visible lesion is the endpoint of a cascade that starts deep in the follicle, involving four interconnected processes:

• Increased sebum production stimulated by androgen hormones
• Abnormal shedding of skin cells inside the follicle (follicular hyperkeratinization)
• Colonization by Cutibacterium acnes bacteria in the oxygen-poor, plugged environment
• Activation of the skin's immune response, releasing inflammatory mediators that cause redness, swelling, and lesion formation

Sebaceous glands produce sebum, an oily substance that normally protects and lubricates the skin. When androgen hormones stimulate these glands, sebum production increases. The cells lining the follicle begin to shed abnormally, and instead of exiting the pore, these sticky cells clump together with sebum, forming a plug. As C. acnes populations expand in this environment, they release inflammatory mediators that trigger the immune system, resulting in papules, pustules, nodules, or cysts.

The clinical understanding of acne has shifted significantly. What was once dismissed as a cosmetic nuisance is now recognized as a chronic inflammatory condition with systemic drivers. Research shows that inflammation may precede the visible lesion, meaning the immune system is already activated before a pimple appears. This reframes acne as a complex interplay between hormones, metabolism, immunity, and the skin's microbial ecosystem.

How Acne Connects to Hormones, Insulin, and the Gut

Androgen signaling and sebaceous gland sensitivity

Androgens, including testosterone and its more potent derivative dihydrotestosterone (DHT), are the primary hormonal drivers. These hormones bind to receptors in sebaceous glands, triggering increased sebum production and altering its composition. Even individuals with normal androgen levels can develop acne if their sebaceous glands are hypersensitive to these hormones.

Insulin and IGF-1 pathways

Elevated insulin levels, often seen in insulin resistance or after consuming high-glycemic foods, stimulate androgen production and increase IGF-1. IGF-1 activates a cellular pathway called mTORC1, which promotes sebum production, follicular hyperkeratinization, and inflammation. This is why acne often worsens in conditions like polycystic ovary syndrome (PCOS), where both hyperandrogenism and insulin resistance are present.

The gut-skin axis

Gut microbiome composition influences systemic inflammation through the production of metabolites, immune signaling molecules, and the integrity of the intestinal barrier. When gut permeability increases, bacterial endotoxins can enter circulation, amplifying inflammatory tone throughout the body, including the skin. Studies have found that individuals with acne often have lower microbial diversity and altered ratios of beneficial bacteria like Bifidobacterium and Faecalibacterium.

What Drives Flares and Severity

Acne severity fluctuates based on inputs that either amplify or dampen the underlying mechanisms. High-glycemic foods, refined carbohydrates, and dairy products have been consistently linked to acne exacerbation through insulin and IGF-1 signaling: rapid spikes in blood sugar drive insulin release, which in turn stimulates androgen production and sebaceous gland activity. Dairy, particularly skim milk, contains hormones and bioactive molecules that may further stimulate IGF-1 and mTORC1 pathways.

Hormonal fluctuations during puberty, menstruation, pregnancy, and perimenopause mark periods of shifting androgen and estrogen levels. In women, acne that flares premenstrually or appears along the jawline and chin, often referred to as acne on cheeks and lower face, typically reflects hormonal influence. Sudden onset of severe cystic acne in adulthood, especially when accompanied by irregular periods or unexplained weight gain, may signal an underlying condition like PCOS or adrenal hyperplasia.

Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, increasing cortisol production. Cortisol impairs skin barrier function, increases sebum production, and modulates immune response in ways that favor inflammation. Stress also triggers the release of neuropeptides that directly stimulate sebaceous glands and mast cells, amplifying the inflammatory cascade.

Skin barrier disruption from harsh cleansers, over-exfoliation, or environmental irritants can worsen acne by triggering compensatory sebum production and allowing bacteria and allergens to penetrate more easily. The skin microbiome also plays a role: not all strains of C. acnes are equally inflammatory. Some strains are associated with clear skin, while others produce more inflammatory byproducts. Antibiotic use, whether topical or systemic, can shift the balance of these strains and reduce microbial diversity, sometimes leading to treatment resistance over time.

Why the Same Condition Looks Different in Different People

Two people with acne can have entirely different presentations, severities, and treatment responses. Genetics account for much of this variation:

• Filaggrin gene mutations impair skin barrier function and are associated with both eczema and acne
• Variations in androgen receptor genes determine how sensitive sebaceous glands are to circulating hormones
• Some individuals produce more inflammatory cytokines in response to C. acnes, leading to more severe inflammatory acne
• Others develop primarily comedonal lesions with minimal redness

Skin microbiome composition varies widely between individuals and influences both acne development and treatment response. The ratio of different C. acnes strains, the presence of Staphylococcus epidermidis, and overall microbial diversity all affect how the skin responds to bacterial colonization. Prior antibiotic use, skincare habits, and even geographic location shape the skin microbiome in ways that can either protect against or predispose to acne.

Hormonal baseline and fluctuations differ significantly. Women with higher baseline androgen levels or greater androgen receptor sensitivity are more prone to hormonal acne. Estrogen levels, which can suppress sebum production and modulate immune response, vary across the menstrual cycle and decline during perimenopause, often leading to adult-onset acne. Men typically have higher androgen levels, which is why severe acne is more common in adolescent males, but individual variation in androgen metabolism and receptor sensitivity still determines severity.

Gut health and metabolic factors also contribute. Individuals with insulin resistance, even in the absence of diabetes, are more likely to develop acne due to elevated IGF-1 and androgen levels. Gut microbiome diversity, intestinal permeability, and the presence of inflammatory gut conditions like irritable bowel syndrome or small intestinal bacterial overgrowth (SIBO) have all been linked to acne severity.

When Skin Symptoms Point to Something Systemic

Persistent or treatment-resistant acne, especially when it appears suddenly in adulthood, can be a signal of underlying systemic conditions. Polycystic ovary syndrome (PCOS) is one of the most common. Women with PCOS often present with acne along the jawline and lower face, irregular menstrual cycles, and elevated androgen levels. The condition is also associated with insulin resistance, which amplifies sebum production and inflammation through IGF-1 signaling. Testing for PCOS typically includes free testosterone, DHEA-S, LH/FSH ratio, and fasting insulin or HOMA-IR.

Insulin resistance, even in the absence of PCOS, is increasingly recognized as a driver of acne. Elevated insulin and IGF-1 levels stimulate androgen production and activate mTORC1, a pathway that promotes sebum production and follicular plugging. Individuals with metabolic syndrome, prediabetes, or a family history of type 2 diabetes may develop acne as an early sign of metabolic dysregulation. Measuring fasting glucose, HbA1c, and fasting insulin can help identify this connection.

Gut dysbiosis and intestinal permeability have been linked to inflammatory skin conditions. Conditions like SIBO, inflammatory bowel disease, and chronic gut inflammation can increase systemic inflammatory tone, which then manifests in the skin. Testing for gut health markers, including zonulin (a marker of intestinal permeability) and high-sensitivity C-reactive protein (hs-CRP), can provide insight into whether gut-driven inflammation is contributing to acne.

Thyroid dysfunction, particularly hypothyroidism, can also affect skin health. Low thyroid hormone levels slow skin cell turnover and sebum production, but paradoxically, some individuals with thyroid imbalances develop acne due to altered hormone metabolism and immune function. Checking TSH, free T3, free T4, and thyroid antibodies can rule out thyroid-related contributions.

What Biomarkers Can Tell You When Topicals Aren't Enough

When acne persists despite appropriate topical treatment, or when it appears suddenly in adulthood, looking at internal biomarkers can reveal the underlying drivers:

• Free and total testosterone, DHEA-S, sex hormone-binding globulin (SHBG), and LH/FSH ratio help identify whether androgen excess or androgen sensitivity is driving sebum production
• Fasting insulin, HOMA-IR, and IGF-1 levels provide insight into whether insulin signaling is amplifying acne
• Elevated fasting glucose or HbA1c may indicate prediabetes or metabolic syndrome
• hs-CRP and erythrocyte sedimentation rate (ESR) reflect systemic inflammation
• Vitamin D, zinc, and omega-3 fatty acid levels identify modifiable nutrient deficiencies
• Comprehensive stool analysis or markers of intestinal permeability reveal whether gut dysbiosis is contributing to systemic inflammation

Tracking these markers over time, rather than reacting to individual flares, helps identify patterns and guide interventions. In men, elevated testosterone or DHT levels, or low SHBG, can indicate hormonal contributions. While the gut-skin connection is still being researched, clinical experience suggests that addressing gut health can improve acne outcomes in some individuals, particularly those with concurrent digestive symptoms.

Getting to the Root of What's Driving Your Skin

If your acne keeps coming back despite doing everything right topically, Superpower's 100+ biomarker panel can show you what's happening at the hormonal and metabolic level. Tracking androgens, insulin, IGF-1, inflammatory markers, and nutrient status gives you a clearer picture of the internal drivers that topical treatments don't address. Acne isn't just about what's on your skin. It's about what's happening inside your body, and measuring that over time helps you make decisions based on data, not guesswork.