Most of the women I know — including me — assume that summer is good for our skin. The sun, the melatonin, the general softening of all human edges. Nobody mentions the other version of summer. The one where, sometime in late July, you start breaking out along the jawline, and your skin gets that strange almost-greasy-but-also-tight feeling, and you can't figure out what changed. You're not eating differently. You're not particularly stressed. If anything, you're doing less.
I had this conversation with one of my customers in Vienna last August. She was furious. She had spent two clean, balanced years on the Radiance Powder, and her skin was the best it had been since her twenties. Then, in three weeks of a heatwave, the breakouts came back. Not the deep ones — small, persistent, jawline-only. She wanted to know if I'd changed the formula. I hadn't.
What had changed was the weather.
We talk about summer skin the way we talk about summer in general — as something that happens to the outside of the body. SPF goes on. Sweat comes off. The hydrating mist gets passed around the table at lunch. None of this is wrong, but it misses the actual root of the late-summer breakout, which doesn't start at the skin at all. It starts in the gut.
Heat does something specific to the digestive system that almost no skincare brand will tell you, partly because it's complicated and partly because there's nothing to sell you for it. When the ambient temperature rises above roughly 30°C for several days, the body diverts blood from the digestive tract to the skin to cool itself. Gut motility — the rhythm at which food moves through you — slows down. The microbiome, which is wildly sensitive to small changes, shifts. Sleep gets shallower. Cortisol creeps up, especially in the second half of the night, because the body is fighting to thermoregulate even while you sleep.
None of this would be visible if you weren't also drinking more rosé than usual, eating later, and skipping vegetables for the third night in a row. But you are. We all are. And so the inflammatory load on the gut quietly increases, and the gut signals the skin, and the skin signals back, and somewhere around week three of a heatwave you notice that you have a small, deep one on your chin that won't go.
This is not a moral problem. You are not bad at summer. You are a body, and bodies do this.
I learned it the slow way. My own first really bad adult-acne summer was 2019, in Croatia, and I came home convinced I was reacting to a new sunscreen. I tried five. I tried switching to mineral. I tried not using anything at all. I drank water like a person who had never been told about water. Nothing worked, because the breakouts weren't a topical problem. They were a microbiome problem dressed up as a topical one.
The thing I wish someone had told me — and that I'm telling you — is that the body's internal terrain changes in summer, the same way it changes when you travel, or when you stop eating gluten for a month, or when you go through a stressful quarter. You can't out-cleanse a microbiome shift. You can only support the system underneath it.
What that looks like in practice is unglamorous. It means front-loading water in the morning rather than chasing it all day. It means a small handful of fermented food — kefir, sauerkraut, kimchi, whatever you will actually eat — most days, especially during heatwaves. It means a magnesium supplement at night, because you're losing more than you think through sweat and the heat is taking your sleep apart in ways you can't quite notice from inside it. It means not skipping the Radiance Powder when you're traveling, which is exactly when most people skip it. I'll say it more directly: the women whose skin holds through summer are the ones who do not let their routine break the second the suitcase opens.
It also means accepting that you might need to be ten percent more boring in July and August. Less alcohol. Earlier dinners. An actual vegetable in your evening, even when the apartment is too hot to cook. This isn't because pleasure is bad. It's because the system is already working harder than it does the rest of the year, and you are asking it to do that work while underfed and over-warmed.
It wasn't always.
The breakouts on your jawline in late July aren't a punishment. They're a signal — a small one, written in the most visible language your body has — that something inside is rebalancing. The work is to support the inside.
The skin will follow.
Always does.
