What Causes Acne and What Are the Best Treatments?

What Should You Do First if You Have Acne?

Start with a gentle cleanser and an over-the-counter product containing benzoyl peroxide 2.5% or adapalene 0.1% gel. Apply once daily at night, gradually increasing to twice daily as tolerated. If you see no improvement after 8 to 12 weeks, consult a board-certified dermatologist for prescription options.

The American Academy of Dermatology recommends a stepwise approach to acne treatment, beginning with the mildest effective therapy and escalating as needed. For most people with mild acne, this means starting with over-the-counter topical agents before considering prescription-strength products. The goal is to reduce active lesions, prevent new breakouts, and minimize the risk of scarring, which can have lasting psychological and physical effects on patients of all ages.

Before applying any active treatment, establish a basic skin care routine. Wash your face twice daily with a gentle, non-comedogenic cleanser and lukewarm water. Avoid scrubbing or using abrasive products, as mechanical irritation can worsen inflammation. Apply a lightweight, oil-free moisturizer to maintain the skin barrier, and always use a broad-spectrum sunscreen with SPF 30 or higher during the day, especially if using retinoids that increase photosensitivity.

Patience is critical when treating acne. Most topical treatments take a minimum of six to eight weeks to show visible results, and some retinoids may cause an initial purging period where breakouts temporarily worsen. The AAD advises patients to commit to a consistent routine for at least twelve weeks before concluding that a treatment has failed. Switching products too frequently can irritate the skin and delay progress toward clearer skin.

The AAD evidence-based guidelines recommend benzoyl peroxide and topical retinoids as first-line therapies for mild-to-moderate acne vulgaris[1]

What Causes Acne Breakouts?

Acne develops when hair follicles become clogged with excess sebum and dead skin cells, creating an environment for Cutibacterium acnes bacteria to thrive. Hormonal fluctuations, particularly androgens during puberty, stimulate sebaceous glands. Inflammation then drives the progression from comedones to papules, pustules, and cysts.

The pathogenesis of acne vulgaris involves four interconnected factors: excess sebum production, abnormal follicular keratinization, colonization by Cutibacterium acnes (formerly Propionibacterium acnes), and inflammation. Androgens, particularly dihydrotestosterone, stimulate sebaceous glands to produce more sebum. Simultaneously, keratinocytes lining the follicle shed abnormally and clump together, forming a microcomedone — the precursor to all visible acne lesions.

Cutibacterium acnes is a commensal bacterium that normally lives on the skin. However, when it proliferates in the oxygen-poor environment of a clogged pore, it triggers an innate immune response. The bacteria produce lipases that break down sebum triglycerides into free fatty acids, and they activate toll-like receptor 2 on immune cells, leading to the release of pro-inflammatory cytokines including interleukin-1 alpha, interleukin-8, and tumor necrosis factor alpha.

Genetics play a significant role in acne susceptibility. Studies of twins have demonstrated that heredity accounts for approximately 80 percent of the variation in acne prevalence. If both parents had acne, their children are far more likely to develop moderate-to-severe acne. Genetic factors influence sebum production rates, inflammatory response patterns, and even the composition of the skin microbiome, all of which affect acne severity.

Hormonal fluctuations are a major driver of acne at all ages. During puberty, rising androgen levels trigger the first onset of acne. In adult women, hormonal acne often flares along the jawline and chin in relation to the menstrual cycle. Polycystic ovary syndrome (PCOS) is a common cause of persistent adult acne in women due to elevated androgen levels, and should be considered when acne does not respond to standard treatments.

A landmark twin study found that genetics account for approximately 81 percent of acne variance[2]

How Does Benzoyl Peroxide Treat Acne?

Benzoyl peroxide kills Cutibacterium acnes bacteria through oxidative destruction, reduces inflammation, and has mild comedolytic properties. Available in concentrations from 2.5% to 10%, it is one of the most effective and accessible over-the-counter acne treatments. Importantly, bacteria do not develop resistance to benzoyl peroxide.

Benzoyl peroxide works by generating free oxygen radicals that destroy C. acnes bacteria on contact. Unlike topical antibiotics such as clindamycin or erythromycin, benzoyl peroxide kills bacteria through a non-specific oxidative mechanism, which means resistance cannot develop regardless of how long it is used. This makes it an essential component of nearly every acne treatment regimen, either as monotherapy for mild acne or in combination with antibiotics to prevent antibiotic resistance.

Research has shown that lower concentrations of benzoyl peroxide are equally effective as higher concentrations for most patients, while causing significantly less irritation. A well-cited randomized controlled trial published in the Journal of the American Academy of Dermatology found that 2.5% benzoyl peroxide produced the same bacterial reduction as 5% and 10% formulations. The AAD now recommends starting with 2.5% to minimize dryness, peeling, and erythema.

Benzoyl peroxide is available as cleansers, gels, creams, and leave-on treatments. Leave-on formulations provide the most sustained antibacterial activity, while cleansers are gentler and may be preferred for sensitive skin. Contact time of at least one to two minutes is important for wash-off products. A common strategy recommended by dermatologists is short-contact therapy, where a 5 to 10% benzoyl peroxide product is applied for five to ten minutes before rinsing, reducing irritation while maintaining efficacy.

A pivotal RCT demonstrated that 2.5% benzoyl peroxide was as effective as 10% with fewer side effects[3]

What Role Do Retinoids Play in Acne Treatment?

Topical retinoids — including adapalene, tretinoin, and tazarotene — are the cornerstone of acne therapy recommended by the AAD. They normalize follicular keratinization, prevent microcomedone formation, reduce inflammation, and improve the penetration of other topical agents. Adapalene 0.1% is now available over the counter as Differin.

Retinoids work at the fundamental level of acne pathogenesis by modulating the differentiation and proliferation of keratinocytes within the hair follicle. By preventing the abnormal clumping of dead skin cells that forms the microcomedone, retinoids address the root cause of both comedonal and inflammatory acne. They also possess direct anti-inflammatory properties by inhibiting toll-like receptor 2 and reducing the expression of inflammatory mediators such as interleukin-12 and interferon-gamma.

Adapalene 0.1% gel (Differin) became available without a prescription in the United States in 2016, marking a significant advance in accessible acne care. Clinical trials have shown that adapalene is as effective as tretinoin 0.025% for most acne types while being significantly better tolerated. It is photostable and chemically compatible with benzoyl peroxide, making it the preferred retinoid for combination therapy. The FDA approved the over-the-counter switch based on extensive safety data from more than 20 years of prescription use.

Tretinoin (Retin-A) remains the most extensively studied topical retinoid and is available in concentrations from 0.025% to 0.1% in cream, gel, and microsphere formulations. The microsphere formulation (Retin-A Micro) releases tretinoin gradually, reducing irritation while maintaining efficacy. For patients who do not respond adequately to adapalene or tretinoin, tazarotene is the most potent topical retinoid available but is also the most irritating, and is typically reserved for moderate-to-severe acne under dermatologist supervision.

Retinoids require careful counseling regarding side effects and expectations. Dryness, peeling, and erythema are common during the first two to four weeks and usually resolve with continued use. Dermatologists recommend starting with every-other-night application, using a pea-sized amount for the entire face, and applying moisturizer before or after the retinoid to buffer irritation. Sun protection is essential during retinoid therapy because these medications increase photosensitivity and the risk of sunburn.

The AAD recommends topical retinoids as a foundational component of acne therapy for nearly all patients[1]

Clinical trials demonstrated adapalene 0.1% non-inferiority to tretinoin 0.025% with superior tolerability[4]

When Should You See a Dermatologist for Acne?

See a board-certified dermatologist if over-the-counter treatments have not improved your acne after 12 weeks, if you have moderate-to-severe inflammatory acne with nodules or cysts, if acne is leaving scars, or if acne is significantly affecting your mental health. Early dermatologist intervention can prevent permanent scarring.

Moderate-to-severe acne, defined as widespread inflammatory papules, pustules, and nodules or cysts, typically requires prescription-strength therapy that only a dermatologist can provide. Options include higher-concentration topical retinoids, combination prescription products like adapalene-benzoyl peroxide (Epiduo Forte) or clindamycin-benzoyl peroxide (Duac), oral antibiotics such as doxycycline or minocycline for inflammatory flares, and hormonal therapy including spironolactone or combined oral contraceptives for adult women.

Isotretinoin, commonly known by its former brand name Accutane, is the most effective treatment for severe nodulocystic acne and is the only medication that can induce long-term remission. A standard course of 0.5 to 1.0 mg per kilogram per day for 16 to 24 weeks achieves complete clearance in most patients, with approximately 60 to 70 percent maintaining remission long-term. However, isotretinoin requires enrollment in the FDA iPLEDGE program due to its teratogenic risk, and patients need monthly blood monitoring for liver enzymes and lipids.

Scarring is a compelling reason to escalate treatment quickly. Post-inflammatory hyperpigmentation (dark spots) and erythema (red marks) are common and usually fade over months, but true atrophic scars (ice pick, boxcar, rolling) and hypertrophic scars are permanent without procedural intervention. Research published in the British Journal of Dermatology shows that early aggressive treatment reduces the lifetime burden of scarring. Dermatologists can also offer procedures such as chemical peels, microneedling, and laser resurfacing to improve existing scars.

Isotretinoin achieves long-term remission in approximately 60–70% of patients after a single course[5]

How Do Hormonal Treatments Help Adult Acne?

Hormonal therapies target androgen-driven sebum production, making them effective for adult women with acne along the jawline and chin. Combined oral contraceptives containing estrogen and progestin are FDA-approved for acne, and spironolactone at 50 to 200 mg daily is widely used off-label by dermatologists.

Adult female acne affects approximately 12 to 22 percent of women and often resists conventional topical treatments because it is driven by hormonal factors rather than purely bacterial ones. The hallmark presentation is deep, tender nodules along the lower face, jawline, and neck that flare in relation to the menstrual cycle. Combined oral contraceptives reduce acne by suppressing ovarian androgen production and increasing sex hormone-binding globulin, which binds free testosterone and reduces its availability to stimulate sebaceous glands.

The FDA has approved four combined oral contraceptives specifically for acne treatment: Ortho Tri-Cyclen (norgestimate-ethinyl estradiol), Estrostep (norethindrone acetate-ethinyl estradiol), Beyaz and Yaz (drospirenone-ethinyl estradiol). A Cochrane systematic review of 31 trials confirmed that combined oral contraceptives significantly reduce both inflammatory and non-inflammatory acne lesions. The effects typically become apparent after three to six menstrual cycles, so patience and consistent use are essential.

Spironolactone is an aldosterone receptor antagonist with potent anti-androgen properties that has become a mainstay of adult female acne treatment, despite never receiving an FDA indication for this use. It blocks androgen receptors in the skin and reduces sebum production. Typical dosing starts at 25 to 50 mg daily and can be titrated up to 200 mg. Common side effects include increased urination, lightheadedness, and menstrual irregularities. Potassium monitoring is generally not required in healthy young women according to recent studies published in JAMA Dermatology.

A Cochrane review of 31 trials confirmed combined oral contraceptives significantly reduce acne lesions[6]

What Over-the-Counter Ingredients Work Best for Acne?

Beyond benzoyl peroxide and adapalene, effective OTC acne ingredients include salicylic acid (0.5–2%), which exfoliates inside pores; azelaic acid (up to 10% OTC), which reduces inflammation and hyperpigmentation; and niacinamide (2–5%), which regulates sebum and calms redness. Choose products based on your acne type and skin sensitivity.

Salicylic acid is a beta-hydroxy acid that is oil-soluble, allowing it to penetrate into the pore lining and dissolve the sebum and dead cell buildup that causes comedones. Available in concentrations of 0.5 to 2% in cleansers, toners, and leave-on treatments, salicylic acid is most effective for blackheads and whiteheads rather than deep inflammatory acne. It also has mild anti-inflammatory properties. The AAD recommends salicylic acid as an alternative first-line treatment for patients who cannot tolerate benzoyl peroxide or retinoids.

Azelaic acid is a naturally occurring dicarboxylic acid with antibacterial, anti-inflammatory, and anti-tyrosinase properties. At 15 to 20% prescription strength, it is FDA-approved for acne and rosacea. Over-the-counter formulations at up to 10% concentration are available and can be particularly beneficial for patients with acne and concurrent post-inflammatory hyperpigmentation, as azelaic acid inhibits abnormal melanin production. It is pregnancy category B, making it one of the few acne treatments considered safe during pregnancy.

Niacinamide (vitamin B3) has gained significant popularity as an acne-fighting ingredient with strong tolerability. At concentrations of 2 to 5%, niacinamide reduces sebum production, decreases the size of pores, and has anti-inflammatory effects. A randomized controlled trial published in the International Journal of Dermatology found that 4% niacinamide gel was comparable to 1% clindamycin gel for moderate inflammatory acne. Unlike antibiotics, niacinamide carries no risk of bacterial resistance and is well-suited for long-term maintenance therapy.

A randomized trial found 4% niacinamide gel comparable to 1% clindamycin for moderate acne[7]

Can Lifestyle Changes Improve Acne?

While lifestyle changes alone cannot cure acne, certain habits can reduce flare-ups. Avoid touching your face, change pillowcases frequently, manage stress, choose non-comedogenic skin care and cosmetics, and consider reducing high-glycemic foods. These modifications work best alongside evidence-based medical treatments.

Non-comedogenic skin care is essential for acne-prone individuals. Products labeled non-comedogenic have been formulated to avoid ingredients known to clog pores, such as coconut oil, cocoa butter, and certain silicones. When choosing moisturizers, look for lightweight, oil-free formulations containing hyaluronic acid or glycerin. For makeup, mineral-based formulations with zinc oxide or titanium dioxide can provide coverage without aggravating breakouts and may even offer mild anti-inflammatory benefits.

The relationship between diet and acne remains an active area of research. A 2020 meta-analysis in JAMA Dermatology found statistically significant associations between acne and intake of high-glycemic-index foods, dairy products, and fatty and sugary foods. The mechanism may involve insulin-like growth factor 1 (IGF-1), which stimulates sebocyte proliferation and androgen production. However, the overall quality of evidence remains moderate, and the AAD does not recommend specific dietary restrictions as a standard acne treatment but encourages patients to identify personal dietary triggers.

Stress management can play a supporting role in acne control. Psychological stress activates the hypothalamic-pituitary-adrenal axis, increasing cortisol and adrenal androgen production, which stimulates sebum output. Multiple observational studies have documented acne flares during high-stress periods such as academic examinations. While stress reduction techniques including exercise, mindfulness meditation, and adequate sleep cannot replace topical or systemic therapy, they may help reduce the frequency and severity of stress-related flares.

A 2020 meta-analysis found significant associations between acne and high-glycemic-index foods and dairy intake[8]

How Can You Prevent Acne Scars?

The most effective way to prevent acne scars is to treat acne early and aggressively with evidence-based therapies, avoid picking or squeezing lesions, and see a dermatologist promptly for moderate-to-severe breakouts. Topical retinoids help prevent scarring by reducing inflammation and promoting normal collagen remodeling in healing lesions.

Acne scarring occurs when the skin's normal wound healing process is disrupted by severe or prolonged inflammation. Deep inflammatory lesions such as nodules and cysts are most likely to produce scars because they destroy collagen in the dermis. Atrophic scars (ice pick, boxcar, and rolling) result from collagen loss, while hypertrophic and keloid scars result from excess collagen deposition. Research in the British Journal of Dermatology has shown that the duration of inflammatory acne, not just its severity, predicts scarring risk, underscoring the importance of early intervention.

Once scars have formed, several dermatological procedures can improve their appearance. Fractional laser resurfacing, particularly fractional CO2 and erbium lasers, stimulates new collagen production and can improve atrophic scars by 40 to 70 percent over multiple sessions. Microneedling with or without platelet-rich plasma is a less invasive alternative with growing evidence. Subcision involves inserting a needle beneath tethered scars to release fibrotic bands. Chemical peels using trichloroacetic acid at 15 to 35% concentration can improve shallow boxcar scars.

Post-inflammatory hyperpigmentation is not true scarring but is extremely common, particularly in patients with darker skin tones. These flat, dark marks result from excess melanin production triggered by inflammation. They typically fade on their own over three to twelve months but can be accelerated with topical treatments including azelaic acid 15 to 20%, vitamin C serums at 10 to 20% concentration, alpha arbutin, and gentle chemical exfoliation with glycolic acid. Strict sun protection with SPF 30 or higher is essential during treatment, as ultraviolet exposure darkens hyperpigmented areas.

Studies demonstrate that the duration of inflammatory acne is a strong predictor of permanent scarring[9]

What New Acne Treatments Are on the Horizon?

Several novel acne therapies are in development. Clascoterone (Winlevi), the first topical anti-androgen FDA-approved for acne, blocks androgen receptors directly in the skin. Sarecycline is a narrow-spectrum antibiotic designed specifically for acne. New fixed-dose triple combinations and microbiome-targeted therapies are also in clinical trials.

Clascoterone 1% cream (Winlevi), approved by the FDA in August 2020, represents a genuine breakthrough as the first topical anti-androgen for acne. Unlike systemic hormonal therapies, clascoterone works locally by competitively inhibiting dihydrotestosterone binding at androgen receptors within the sebaceous gland and hair follicle. Phase 3 trials published in JAMA Dermatology demonstrated significant superiority over vehicle in reducing both inflammatory and non-inflammatory lesions in males and females aged 12 and older, with minimal systemic absorption and a favorable safety profile.

Sarecycline (Seysara) is a narrow-spectrum tetracycline antibiotic specifically developed for acne treatment. Unlike broad-spectrum tetracyclines such as doxycycline and minocycline, sarecycline targets the bacteria implicated in acne with reduced activity against normal gut flora, potentially lowering the risk of gastrointestinal side effects and antibiotic resistance. Phase 3 data showed significant reduction in inflammatory lesions with a weight-based dosing regimen that simplifies prescribing. The Infectious Diseases Society of America has noted the importance of narrow-spectrum antibiotic development.

The skin microbiome is an exciting frontier in acne research. Rather than simply killing C. acnes, researchers are exploring ways to restore a healthy balance of skin bacteria. Bacteriophage therapy targeting virulent C. acnes strains, probiotic topical formulations, and transplantation of non-pathogenic C. acnes phylotypes are all in early clinical development. Nitric oxide-releasing nanoparticles that selectively target bacteria in follicles represent another emerging approach. While most of these therapies are years from commercial availability, they point toward a future of more targeted, microbiome-friendly acne treatment.

Phase 3 trials of clascoterone 1% cream demonstrated significant efficacy for inflammatory and non-inflammatory acne[10]