Steam opens your pores. Cold water closes them. You've probably heard this countless times — from beauty influencers, skincare brands, and well-meaning friends. It's one of the most repeated pieces of skincare advice out there.
It's also completely false.
Pores do not open. Pores do not close. They never have. Here's what's actually going on.
What Pores Actually Are
Before debunking the myth, it helps to understand what a pore actually is.
A pore is an opening on the surface of your skin that connects to a hair follicle beneath it. Each follicle is associated with sebaceous glands — the glands that produce the oil (sebum) that lubricates and nourishes your skin and keeps the follicle healthy. The pore is essentially the exit point for both the hair and the sebum produced below.
Crucially, pores contain no muscles. They have no biological mechanism that would allow them to contract or expand on command. The idea that temperature can trigger them to "open" or "close" isn't just an oversimplification — it's anatomically impossible.
So What Does Steam Actually Do?
Steam does have a legitimate role in a skincare routine — just not the one it's usually given credit for.
When heat and steam are applied to the skin, they cause the skin to expand slightly and soften the sebaceous material that builds up inside follicles. This loosens the debris and oil sitting in and around your pores, making it easier to cleanse them effectively.
That's a real and useful effect. But it has nothing to do with pores opening. Steam is a preparation step for cleansing — not a mechanism for changing pore size.
And Cold Water?
When cold water hits your skin, it triggers something called vasoconstriction — a tightening of the small blood vessels beneath the skin's surface. This causes the skin itself to tighten and appear temporarily firmer and smoother.
It feels like your pores have shrunk. But what you're actually experiencing is a temporary change in the surrounding skin tissue, not any change in the pore itself. The moment your skin returns to its normal temperature, the effect reverses.
Cold water is refreshing. It can help reduce puffiness and give your skin a temporarily brighter appearance. But it is not closing your pores.
What Actually Determines Pore Size?
If pores don't respond to temperature, what does influence how visible they are?
The honest answer is largely genetics and follicle size. The diameter of your pores is determined primarily by the size of the follicle beneath them — and that is something you are largely born with. Some people naturally have larger, more visible pores; others have smaller ones. No product or ritual can fundamentally change this.
What can affect the appearance of pores over time is age and sun damage. As skin loses elasticity — due to collagen degradation, UV exposure, and the natural ageing process — the tissue surrounding follicles becomes looser. This can cause pores to appear larger and less defined over time.
This is why long-term skin health matters. Preserving the elasticity of the skin around your follicles through consistent sun protection and barrier care is the most effective way to keep pores looking their best as you age.
What You Can Actually Do
Since pore size is largely fixed, the focus should shift to what you can control: keeping them clean and supporting the surrounding skin.
Cleanse consistently. Pores can accumulate oil, dead skin cells, and environmental debris over time. This buildup can make pores appear larger and lead to congestion and breakouts. A gentle, effective cleanser used regularly is the single most important step for pore health.
Protect against sun damage. UV exposure degrades the collagen and elastin that keep skin firm. Over time, this loosens the tissue surrounding your follicles and makes pores more visible. Daily SPF is one of the most effective long-term tools for maintaining pore appearance.
Don't chase the myth. Time spent on steam rituals and cold-water rinses with the expectation of changing pore size is time that could be spent on steps that actually work. Use steam to prep skin for cleansing if you find it helpful — but understand what it's doing and what it isn't.
The Bottom Line
Pores have no muscles. They cannot open or close. Steam loosens debris and cold water temporarily tightens surrounding tissue — both useful effects, neither of which changes your pore size.
Your pore size is largely genetic. What you can influence is how clean they are, how healthy the surrounding skin is, and how well you protect that skin from the cumulative damage of UV exposure over time.
That's the actual protocol. And it's a lot simpler than the beauty industry would have you believe.
A Cleanser Built Around This
If consistent cleansing is the single most important step for pore health, the cleanser you choose matters. The Shvéta Labs Face Cleansing Mousse is formulated to remove the oil and debris that accumulate in follicles without stripping the acid mantle or disrupting your skin's natural barrier — the two things a harsh cleanser tends to do first.
It's the kind of product the science actually points to: effective enough to keep pores clear, gentle enough not to cause the inflammation and barrier damage that create bigger skin problems down the line.
Shop the Face Cleansing Mousse →
This is part of an ongoing series on the science of skin. Follow along for more on what your skin actually needs — and why.