Blackheads form when a hair follicle gets clogged with a mix of oil and dead skin cells, and the surface of that clog is exposed to air. The dark color isn’t dirt. It’s the result of oxidation, the same chemical reaction that turns a sliced apple brown. Understanding what drives this process helps explain why some people get more blackheads than others and what actually works to prevent them.
What Happens Inside the Pore
Every pore on your face contains a tiny hair follicle and an oil-producing gland. The gland secretes sebum, a waxy substance that keeps skin moisturized. Under normal conditions, sebum flows up through the pore and spreads across the skin’s surface. Dead skin cells lining the inside of the pore shed regularly and get carried out along with the oil.
Problems start when the cells lining the pore begin multiplying faster than they can shed. Dermatologists call this hyperproliferation, and it’s the earliest step in blackhead formation. These excess cells stick together inside the follicle rather than being pushed out, forming a microscopic plug called a microcomedone. As the gland keeps producing sebum behind this plug, the blockage grows. If the pore opening stays wide enough for the surface of the plug to remain exposed to air, you get a blackhead (an open comedone). If the opening is too narrow and the plug stays sealed beneath the skin, you get a whitehead instead.
The dark color comes entirely from oxidation. When the mixture of oil and dead cells sits at the pore’s surface, oxygen in the air reacts with it and turns it progressively darker. Because the pore isn’t clearing itself out, the clog just sits there, continuing to oxidize until it looks dark brown or black.
Why Some People Are More Prone
Oil production is the single biggest factor. Research published in the British Journal of Dermatology found that sebum output level correlated more strongly with pore size than any other variable studied. Larger pores collect more material and are more visible when clogged. Several factors determine how much oil your skin produces and how large your pores are:
- Genetics: Your inherited tendency toward oily or dry skin sets a baseline. Some people simply produce thicker, stickier sebum that’s more likely to get trapped.
- Sex: Males generally produce more sebum and have larger pores. The correlation between oil output and pore size is stronger in men (r = 0.47) than in women (r = 0.38).
- Age: Sebum production peaks during the teenage years and early twenties, which is why blackheads are so common in adolescence. Pore size also increases with age due to cumulative sun exposure and loss of skin elasticity.
- Hormones: Androgens (hormones like testosterone) directly stimulate oil glands. Hormonal fluctuations during puberty, menstrual cycles, and pregnancy can all trigger increased sebum production.
Chronic sun exposure also enlarges pores over time by breaking down the collagen that keeps them tight. This creates more room for oil and dead cells to accumulate.
The Role of Diet
What you eat can influence how much oil your skin produces, though the connection is indirect. Foods that spike blood sugar quickly, like white bread, sugary drinks, and processed snacks, trigger a hormonal chain reaction. Your body releases more insulin, which in turn raises levels of a growth hormone called IGF-1. That hormone stimulates oil glands and promotes the kind of rapid cell turnover inside pores that leads to clogging.
A randomized controlled trial found that switching to a low-glycemic diet for just two weeks significantly reduced IGF-1 levels in adults with moderate to severe acne. Dairy products appear to have a similar effect, likely because milk naturally contains hormones and compounds that influence insulin and androgen activity. This doesn’t mean sugar causes blackheads directly, but a consistently high-glycemic diet creates hormonal conditions that make breakouts more likely.
Common Triggers That Make Blackheads Worse
Beyond genetics and diet, everyday habits contribute to clogged pores. Heavy, oil-based moisturizers and makeup can physically block pore openings (products labeled “comedogenic” are the ones most likely to do this). Skipping cleansing at night leaves a full day’s worth of oil, sweat, and environmental grime sitting on the skin. Touching your face transfers oils and bacteria from your hands.
Humidity and heat increase sebum production, which is why many people notice more blackheads in summer. Certain hair products, especially those containing oils or silicones, can migrate onto the forehead and jawline and clog pores along the hairline. Even phone screens pressed against your cheek can trap heat and oil against the skin.
How Topical Treatments Work
The most effective treatments for blackheads target the two components of the clog: excess dead cells and trapped oil.
Salicylic acid is particularly well-suited for blackheads because it’s oil-soluble, meaning it can penetrate into the pore itself rather than just working on the skin’s surface. Once inside, it dissolves the “cement” holding dead cells together, causing the compacted plug to soften, swell, and break apart. You’ll find it in cleansers, toners, and leave-on treatments, typically at concentrations between 0.5% and 2%. It works best with consistent daily use rather than occasional spot treatment.
Retinoids take a different approach. Rather than dissolving existing clogs, they change how skin cells behave inside the follicle. They normalize the shedding process so cells don’t pile up and form plugs in the first place. This means retinoids are better at prevention than quick removal. Over-the-counter retinol is milder, while prescription-strength options are more potent. Results typically take 6 to 12 weeks because retinoids work on the microcomedones forming deep in the skin before they become visible blackheads.
Benzoyl peroxide is another option recommended by the American Academy of Dermatology. It kills bacteria and has mild pore-clearing effects, though it’s better known for treating inflamed acne than blackheads specifically. For stubborn blackheads, combining treatments with different mechanisms, like a salicylic acid cleanser with a retinoid at night, tends to be more effective than relying on a single product.
Why Squeezing Often Backfires
Manually extracting blackheads is tempting because it provides instant visible results. The problem is that squeezing pushes some of the clogged material deeper into the follicle, which can trigger inflammation and even cause the follicle wall to rupture beneath the skin. This turns a simple blackhead into a red, swollen pimple or a cyst. Repeated squeezing also stretches the pore opening, making it more likely to refill.
Professional extractions performed by a dermatologist or licensed esthetician use specialized tools and proper technique to minimize damage. Pore strips can remove the surface portion of a blackhead, but they don’t address the deeper plug or the underlying overproduction of cells, so the blackhead typically returns within days.
Keeping Pores Clear Long-Term
Because the underlying causes of blackheads (oil production, cell turnover rates, pore size) are largely determined by your biology, prevention is an ongoing process rather than a one-time fix. A consistent routine matters more than any single product. Cleansing twice daily with a gentle, non-comedogenic cleanser removes surface oil without stripping the skin so aggressively that oil glands overcompensate by producing even more sebum. Following up with a leave-on product containing salicylic acid or a retinoid keeps pores from re-clogging.
Sunscreen helps too, and not just for UV protection. Since chronic sun exposure enlarges pores and thickens the outer layer of skin (making it harder for dead cells to shed properly), daily SPF use slows the gradual worsening that many people notice in their 30s and 40s. Look for lightweight, oil-free formulas that won’t add to the problem. Shifting your diet toward lower-glycemic foods, more whole grains, vegetables, and fewer sugary processed items, can modestly reduce the hormonal signals that drive excess oil production.