Most people think of their skin as a wall. Like, stuff stays on the outside and you’re protected. But it’s more like a very selective filter — and some chemicals don’t get filtered out at all. They pass right through.
The outer layer of your skin, called the stratum corneum, is what controls how fast absorption happens. It’s your first line of defense. But it’s not perfect. Certain chemicals — pesticides, ingredients in cleaning products, even some medications — can be small enough and fat-soluble enough to get past it.
Here’s something that actually surprised researchers: not all parts of your body absorb at the same rate. Compared to the forearms, some pesticides are absorbed roughly 12 times faster at the genitals, 4 times faster at the head, and 3 times faster at the trunk. Higher skin temperature also tends to speed things up, which means hot or sweaty conditions during chemical exposure may affect how much gets absorbed.
This isn’t just a job hazard thing, either — though it is that too. More than 13 million workers in the U.S. are potentially exposed to chemicals through their skin. Farmworkers, cleaners, painters, hair stylists — people who handle chemicals regularly and often don’t have access to the right protective gear.
For everyday life, this mostly means paying attention to what you’re handling without gloves. Pesticide residue on unwashed produce. Cleaning sprays that get on your hands. Even some topical medications are literally designed to absorb through skin on purpose — that’s how nicotine patches and certain pain relief creams work. The same mechanism that delivers medicine can also deliver things you didn’t mean to take in.
You don’t need to be paranoid. Just aware. Wash your hands after handling chemicals, wear gloves when you’re using strong cleaning products, and don’t assume that because something touched your skin instead of your mouth it can’t affect you.