Blackheads form when a pore fills with a mix of oil and dead skin cells, and the top of that plug stays open to the air. The exposure to oxygen turns the surface dark, giving blackheads their signature appearance. They’re one of the most common skin concerns out there: roughly 85% of people between ages 12 and 25 experience some form of acne, and blackheads are often the earliest and most persistent type.
Understanding what drives this process helps explain why some people get more blackheads than others, and why certain areas of the face seem especially prone.
How a Blackhead Actually Forms
Your skin constantly sheds dead cells from its surface and from inside each pore. At the same time, tiny glands attached to every pore produce an oily substance called sebum, which keeps skin moisturized and flexible. Normally, dead cells and sebum travel up through the pore and wash away. A blackhead starts when that process breaks down.
The first step is excess buildup of a tough structural protein called keratin, which makes up most of your dead skin cells. Instead of shedding cleanly, keratin-rich cells clump together inside the pore and stick to its walls. This narrows the opening and traps sebum underneath. As more oil and dead cells accumulate, a visible plug forms near the surface. If the pore stretches open rather than sealing shut (which would create a whitehead), the plug’s surface reacts with oxygen in the air and oxidizes. That chemical reaction, not dirt, is what turns the plug dark brown or black.
This is why scrubbing your face harder won’t prevent blackheads. The clogging happens inside the pore, not on top of it.
Why Hormones Are the Biggest Driver
The single most important factor controlling how much oil your skin makes is androgen hormones, particularly testosterone and a more potent form called DHT. These hormones bind to receptors on the oil glands and signal them to grow larger and produce more sebum. Early experiments showed that prepubertal boys given testosterone injections developed noticeably larger oil glands and significantly higher sebum output.
This is why blackheads so often appear during puberty, when androgen levels surge in both boys and girls. It also explains several other patterns. Women frequently notice more blackheads around their period, during pregnancy, or after starting or stopping hormonal birth control, all times when hormone levels shift. Up to 20% of adult women continue dealing with acne well past their teenage years, compared to about 8% of men, likely because women experience more frequent hormonal fluctuations throughout life.
Other hormones play supporting roles. Growth hormone also stimulates oil glands, while estrogen and certain vitamin A derivatives (retinoids) have the opposite effect, slowing sebum production. Stress hormones can amplify the problem too, since elevated cortisol indirectly boosts androgen activity and increases oil output.
Genetics Set Your Baseline
If your parents had oily skin and visible pores, you’re more likely to as well. Pore size is largely inherited, much like skin tone or hair texture. Several genetic factors feed into this:
- Oil gland size and activity. Some people are born with larger, more productive sebaceous glands, meaning their skin generates more oil by default.
- Skin thickness. Thicker skin tends to have larger, more visible pores that trap debris more easily.
- Collagen production. Lower collagen levels reduce skin elasticity, allowing pores to stretch and appear more prominent over time.
None of this means blackheads are inevitable if your parents had them. It means you may need to be more intentional about managing oil and dead cell buildup than someone with naturally drier, thinner skin.
External Factors That Make Things Worse
Beyond biology, several everyday habits and environmental factors push pores toward clogging.
Heavy skincare and makeup products. Thick creams, foundations, and sunscreens can physically block pore openings. Products labeled “comedogenic” contain ingredients known to promote clogs. Oils like coconut oil and cocoa butter are common culprits, along with certain silicones and waxes. Switching to non-comedogenic or oil-free formulas reduces this risk significantly.
Humidity and sweat. Hot, humid environments increase both sweating and oil production. Sweat itself doesn’t cause blackheads, but when it mixes with excess sebum and sits on the skin, it creates ideal conditions for pore blockage. This is why blackheads often worsen in summer months or for people who exercise frequently without washing their face afterward.
Touching your face and friction. Resting your chin on your hands, wearing tight headbands, or pressing a phone against your cheek transfers oils and bacteria to the skin while also physically pushing debris into pores. Helmets, hat brims, and mask straps create friction that irritates pore linings and accelerates clogging in those specific areas.
Overwashing or harsh scrubbing. This one surprises people. Stripping your skin of all its natural oil with aggressive cleansers or abrasive scrubs triggers a rebound effect where oil glands compensate by producing even more sebum. Gentle cleansing twice a day is more effective than frequent, harsh washing.
Why Certain Areas Get More Blackheads
The nose, chin, and forehead (the T-zone) have a far higher concentration of oil glands than other parts of the face. Your nose alone can have thousands of active sebaceous glands packed into a small area, each one feeding into pores that are naturally larger to accommodate the higher oil flow. This is why the nose is almost universally the first place blackheads appear and the hardest place to keep them away.
The chin and jawline are particularly sensitive to hormonal fluctuations, which is why hormonally driven breakouts in adult women tend to cluster in the lower face. The forehead, meanwhile, collects oil from both the skin and the hairline, especially if you use hair products containing oils or waxes that migrate onto the skin.
What Keeps Blackheads Coming Back
One frustrating reality about blackheads is that extracting them, whether with strips, tools, or professional treatments, doesn’t address the underlying cause. The pore that produced one blackhead still has the same oil gland, the same tendency toward keratin buildup, and the same hormonal signals driving sebum production. Without ongoing management, the pore typically refills within days to weeks.
Effective long-term control targets the root mechanisms. Ingredients that speed up skin cell turnover, like salicylic acid, work by dissolving the keratin bonds that hold dead cells together inside the pore, keeping the lining clear. Retinoids normalize the way skin cells shed, preventing them from clumping in the first place. Oil-reducing strategies, whether topical or hormonal, lower the volume of sebum available to form plugs.
The key insight is that blackheads aren’t a hygiene problem. They’re the result of biology, primarily how much oil your glands make and how efficiently your pores shed dead cells. Both of those processes are shaped by hormones you can’t fully control and genetics you inherited. Managing blackheads means working with that biology rather than trying to scrub it away.