Your gut doesn’t get a memo when the fever breaks. People tend to think of being sick as something that starts and ends cleanly, you feel bad for a few days, then you’re “better,” and everything resets. The gut doesn’t work on that timeline, and if you’ve been through a rough stretch of back-to-back colds, …

Years into writing research-based health content, I came across something that genuinely surprised me. The probiotic strains appearing most frequently in peer-reviewed clinical trials, things like Lactobacillus rhamnosus GG, Bifidobacterium longum BB536, Saccharomyces boulardii, show up on pharmacy shelves far less consistently than you’d expect. The products dominating the market often contain strains chosen for …

Every office has one. The person who sits two desks over from someone hacking through a meeting, shares a coffee pot with half the building during flu season, and somehow comes out the other side untouched. Coworkers usually chalk it up to good genes, or joke that they’re “built different.” There’s a sliver of truth …

Four things are quietly working against your immune defenses right now. None of them feel dramatic. Most of them don’t feel like anything at all, which is exactly what makes them hard to address. The slow erosion of immune function rarely traces back to one cause. What it traces back to is a cluster of …

The misconception I kept running into when writing health content was that gut health and immunity supplements lived in separate categories. Two different aisles at the pharmacy, two different decisions, two different kinds of people. Someone would describe taking zinc lozenges and elderberry syrup from October through March, and in that same conversation mention that …

The number of times I’ve heard someone say their immune system must be “weak” because they got sick, I’ve stopped counting. It comes up constantly. And right behind it is the flip-side assumption: that if you could just “boost” your immunity somehow, you’d stop getting sick. Both ideas get it backwards. A fever isn’t your …

Around 40% of American adults are clinically deficient in vitamin D. Not just “a little low.” Deficient. And during the winter months, that number climbs meaningfully for anyone living above approximately 35 degrees north latitude, which covers the majority of the United States, all of Canada, and most of Europe. The part that keeps surprising …

Researchers checked volunteers into a hotel, measured their stress levels, dripped actual cold viruses directly into their nostrils, and then monitored them closely for five days. What determined who got sick wasn’t hygiene habits. It wasn’t age or baseline health. It was stress. The people who reported higher psychological stress before the experiment were significantly …

The misconception I keep running into is that six hours is basically fine and a longer sleep on the weekend fixes whatever accumulated during the week. I hear this from people who genuinely care about their health, who are not dismissing sleep as a priority. They’re operating on an outdated mental model of what chronic …

In a 2015 study published in the journal Sleep, researchers exposed 164 volunteers to rhinovirus directly via nasal drops, then monitored who actually got sick. Participants who reported sleeping fewer than 6 hours a night were 4.2 times more likely to develop a clinical cold than those sleeping 7 or more hours. Not 20 percent …