Pores don't open and close

You've heard it on every other skincare ad: "open your pores with steam," "close your pores with cold water." Neither happens. Pores aren't muscles.

What pores actually are

A pore is the opening of a follicle — the tiny tunnel that holds a hair and the gland that makes oil. It has no muscle around it. There's no mechanism that lets it dilate or contract on demand.

What you can change is how full the pore looks. A pore stretched by buildup (oil, dead cells, makeup, sunscreen residue) looks bigger. Empty it out, and it looks smaller. That's the entire game.

Why steam still feels like it works

Steam softens the contents of the pore. The buildup gets a little easier to dislodge during cleansing afterward. The pore itself didn't open — the gunk inside it just got more cooperative.

Why cold water feels tightening

It briefly constricts blood vessels in the surrounding skin, which feels firm and refreshing. The pore is unchanged.

Pores aren't muscles. There's nothing to open or close.

What actually makes pores look smaller

• Salicylic acid (BHA) — the only ingredient that goes into the pore and dissolves what's stuck inside.
• Retinoids — speed up cell turnover so debris doesn't settle.
• Niacinamide — modest effect on pore appearance over time.
• Sunscreen — collagen loss makes pore walls sag and look bigger; sunscreen prevents that.

What doesn't: scrubs, ice, "pore strips" (those rip the surface, not the depth), and almost everything labeled "pore minimizing."