Can you actually shrink your pores?

Pore size is largely something you are born with, and no evidence turned up that skincare shrinks it for good. Yet instruments sometimes read smaller. They did in one study where a cleanser sat on the skin for twenty minutes. What got smaller was not the pore but what was sitting inside it. Let's start with why that gap exists.

What decides pore size?

When 2,585 women across five countries were measured the same way, mean pore area ran from 0.05 mm² in Chinese participants to 0.37 mm² in Brazilian participants, more than a sevenfold spread (Flament et al., 2015). The largest single variable was what people were born with. The study's Indian participants had the lowest sebum of any group and large, numerous pores.

Sebum output plays a part too. In 60 Korean participants, sebum and pore size showed a weak-to-moderate relationship (r = 0.47 in men, 0.38 in women; Roh et al., 2006). Sebum is one factor in pore size, but not the only one.

Do pores keep growing with age?

Pores don't keep growing. Analysing facial images from a million people in China, pore scores rose from age 22 and plateaued through the forties (Zhou et al., 2024). In women, scores dipped for a stretch from 27.

How clogged pores and the barrier connect is in large pores and blackheads; what sets how much oil you make is in why oily skin is often dry underneath; how the water leaving your skin is measured is in what TEWL is.

What does a smaller pore measurement mean?

Measuring nasal pores in three dimensions, one study left a cleanser on the face for twenty minutes and found the pore measurement down 71.43% (Lee et al., 2015). The twenty minutes is how long the product sat on the skin, not a wait after rinsing. Two authors work for the company that makes the cleanser tested.

Twenty minutes of cleanser cannot have made a pore smaller. So what the instrument read was not the pore itself but the state of the surface at that moment. The pore walls stayed where they were; what changed was what sat inside them.

In Korea's substantiation guideline the only pore-related item is "temporary reduction of pore size and the like" — the word temporary sits inside the name of the claim itself (MFDS substantiation testing guideline, 2024 revision). Nothing in the method looks at the wall of the pore.

Has anything been measured on pores at all?

The evidence for the ingredients most associated with pores is thinner than their reputation. No controlled trial that measured pore size for niacinamide or salicylic acid turned up. Nor did any primary study of pore strips or extraction, and the most-cited retinol comparison did not measure pores (Zasada et al., 2020).

One study has, and it had no control group. Twenty-seven people mixed a 0.1% retinal concentrate into their moisturiser for six weeks, and instrument-measured pore visibility came out 24% lower (Åkerström et al., 2025). It is a before-and-after with no comparison group, and three of the authors work for the company that makes the product, two of them holding stock in it.

Whether what shrank at six weeks was the pore or what happened to be sitting in it that day is not something a before-and-after design can separate. No study re-measured pores after people stopped using a product either.

What should you aim at instead of pore size?

A result labelled "pore reduction" is usually a change in the contents, not the wall. Niacinamide, salicylic acid and pore strips have no measured pore result behind them — not shown not to work, but never checked. Either way, set your expectations below the packaging copy.

One step today

• In a shop, look for retinal on the ingredient list (Korean labels standardise this as 레틴알). Retinal is currently the one ingredient whose effect on pore size has been measured, in a six-week study with no control group. The 24% that study reported was read by an instrument, not a difference you would see in a mirror at that size. If six weeks at the same light and the same distance bring no change, it is fair to look elsewhere.
• Compare at the same point in your cycle. Pore size measured significantly larger around ovulation (Roh et al., 2006), so last week against today will not separate the product from the calendar. Look again one cycle later at the same point, and if only the timing differed, do not read it as the product working.
• Clear the day's oil and dead cells within the day, and leave the skin around the pore alone. Scrubbing or stripping leaves redness, redness casts more shadow, and shadow is what you were looking at. We found no primary study on pore strips or squeezing — no evidence, though nothing about leaving the area alone is harmful. If the area reddens or tightens by that evening, that is irritation.