What comes out of a blackhead is a small, solid plug made of sebum (your skin’s natural oil), dead skin cells, and bacteria. The plug looks dark or black at the top, but the material underneath is typically white or yellowish. That dark color isn’t dirt. It’s the result of oxidation, a chemical reaction that happens when the plug sits exposed to air at the surface of your pore.
What the Plug Is Made Of
Your skin constantly produces an oily, waxy substance called sebum to keep itself moisturized. Sebum travels up through your pores to reach the surface. At the same time, dead skin cells lining the inside of the pore are supposed to shed and get carried out with the oil. A blackhead forms when this process breaks down: skin cells multiply too quickly and don’t shed properly, creating a sticky buildup that mixes with sebum and gets trapped inside the pore.
Bacteria are also part of the mix. A single hair follicle can harbor up to 100 million colony-forming units of bacteria, primarily a species called Cutibacterium acnes. These microbes thrive in oily, low-oxygen environments, so a clogged pore is an ideal home. When you extract a blackhead, you’re pushing out this entire cocktail: hardened oil, compacted dead skin cells, and a dense colony of bacteria, all fused into a small, waxy plug.
Why the Top Turns Black
Sebum contains traces of melanin (the same pigment that colors your skin and hair) along with certain fatty molecules. Because a blackhead is an open pore, the top of the plug sits exposed to the air. Oxygen reacts with these components in a process called oxidation, turning the exposed surface yellow, brown, or black. It’s similar to how a cut apple browns when you leave it on the counter. The deeper material in the plug, shielded from air, stays its original light color.
Blackheads vs. Sebaceous Filaments
Many people squeeze what they think is a blackhead only to see a thin, wormlike thread come out. That’s likely a sebaceous filament, not a blackhead, and the distinction matters because filaments are completely normal.
Sebaceous filaments are thin, threadlike structures that line your oil glands and help channel sebum to the surface. They’re smaller and flatter than blackheads, usually gray, light brown, or yellow rather than dark black. If you squeeze one, a waxy, threadlike strand emerges. A true blackhead, by contrast, produces a darker, denser plug. The key structural difference: sebaceous filaments don’t have a plug blocking the pore, so oil still flows freely. Blackheads do have a plug, and that plug prevents oil from traveling through. Sebaceous filaments refill within days of being squeezed, because they’re part of your skin’s normal oil-delivery system. Extracting them accomplishes nothing and can irritate the pore.
What Causes Blackheads to Form
Four factors drive blackhead formation. First, the cells lining the pore start overproducing and fail to shed normally, a process driven largely by hormones. Androgens like testosterone stimulate both this excess cell turnover and increased sebum production, which is why blackheads often spike during puberty, menstrual cycles, or other hormonal shifts. Second, the extra sebum fills the pore faster than it can drain. Third, bacteria colonize the clogged environment. Fourth, inflammation can develop around the site.
Diet plays a role too. Insulin-like growth factor, which rises after eating high-glycemic foods (white bread, sugary drinks, processed snacks), can stimulate your oil glands and worsen breakouts. This doesn’t mean a single cookie causes a blackhead, but a consistently high-sugar diet creates conditions that favor clogged pores.
Why You Shouldn’t Squeeze Them Yourself
It’s tempting to push the plug out, but squeezing a blackhead at home carries real risks. Pressing without proper technique can push the blockage deeper into the skin rather than drawing it out, worsening the clog and potentially triggering inflammation. You can also rupture the wall of the pore beneath the surface, spreading bacteria and debris into surrounding tissue. The results: pain, infection, and scarring that lasts far longer than the blackhead would have.
Professional extraction by a dermatologist follows a different process. The skin is prepped, a tiny incision is made at the pore’s surface with a needle to open the path, and a comedone extractor applies controlled, even pressure to push the contents out cleanly. Even with professional technique, incomplete extraction and recurrence are common risks. If you experience pain during the procedure rather than just mild pressure, that’s a sign the technique needs adjusting.
Treatments That Clear and Prevent Blackheads
Rather than extracting blackheads one by one, treatments that address the underlying clog are more effective long-term.
Salicylic acid is the most widely available over-the-counter option. It’s oil-soluble, meaning it can penetrate into the pore and dissolve the mix of sebum and dead skin cells from the inside. OTC products range from 0.5% to 7% concentration depending on the form. Cleansers, pads, and solutions typically contain 0.5% to 2%, while gels can go up to 7%. Starting with a lower concentration and using it consistently matters more than jumping to the strongest product.
Retinoids are the gold standard for stubborn or widespread blackheads. They work by speeding up skin cell turnover, preventing the buildup that clogs pores in the first place. In clinical trials, prescription retinoids reduced blackheads and other non-inflammatory lesions by roughly 30% to 60% over 12 weeks, depending on the specific formulation. One form, adapalene 0.1% gel, is available without a prescription in many countries and is a good starting point. Results take time: most people need at least 8 to 12 weeks of consistent use before seeing significant clearing, and skin often looks worse before it improves as deeper clogs are pushed to the surface.
Whichever treatment you use, consistency matters more than intensity. A gentle daily routine that keeps pores clear will always outperform aggressive squeezing sessions that damage the skin and leave the underlying problem untouched.