Summer is supposed to be the easy season. More light, more movement, more time outside. So it can be confusing when your body doesn't feel lighter — when the afternoon flattens you for no clear reason, or a stuffy, itchy reactiveness lingers long after spring should have ended.

Underneath the sunshine, your body is quietly working harder than it looks. Two nutrients tend to carry a lot of that load, and they do it better as a pair than either does alone.

Summer asks more of your body than it looks like

Warm weather raises the amount of work your body does even when you're sitting still. Heat, bright sun, more hours outdoors, travel that breaks your routine, and a fresh wave of pollen and mould all add up. Each one creates what scientists call oxidative stress — a kind of internal wear-and-tear your body is constantly cleaning up after.

Most of the time you don't notice this housekeeping. It runs in the background, using up raw materials as it goes. But when the demands stack up across a long, active, warm stretch — a week of travel, a heat wave, a garden you finally got to — the materials run down faster than you replace them. That is often when the tiredness, or the inflammation that won't settle, starts to show.

Vitamin C tends to go first

Vitamin C is one of your body's busiest helpers. It supports your immune system, it is required to build collagen for skin, tendons and the connective tissue that holds joints together, and it is one of the main antioxidants mopping up that everyday wear-and-tear. Your body cannot make it and cannot store much of it, so the supply needs topping back up every day.

When the body is under more physical strain, it draws on vitamin C faster — and low levels seem to show up as fatigue. In one controlled trial, people given vitamin C reported less tiredness, and the effect was strongest in those who started with the lowest levels to begin with (Suh et al., 2012). Food is the first place to look: peppers, citrus, kiwi, strawberries and broccoli are all rich sources, and they deliver it alongside the other plant compounds that come naturally bundled with it.

Quercetin and the inflammation that won't settle

The other half of the summer story is reactiveness — the itchy eyes, the stuffiness, the sense that your body is overreacting to things that shouldn't bother it this much. A lot of that traces back to mast cells, the immune cells that release histamine when they sense a threat. When they fire too readily, you feel it.

Quercetin is a natural plant compound found in onions, apples, capers, berries and leafy greens. In laboratory studies on human immune cells, it calms those mast cells and steadies the release of histamine and other inflammatory signals. Notably, it works best when it is already on board before the trigger arrives, rather than taken once you are already reacting (Weng et al., 2012). It is part of why people who eat a lot of colourful produce tend to be a little less reactive through allergen season.

Why they work better together

Here is the part that is easy to miss: vitamin C and quercetin help each other do their jobs. When quercetin neutralises a free radical, it gets used up and switches off. Vitamin C can hand it back the electron it lost, switching it back on, so the quercetin keeps working for longer (Colunga Biancatelli et al., 2020).

This is why the two so often turn up side by side, both in food and in well-built formulas. On their own, each is useful. Together, they cover for each other — one steadying the body's reactions, the other keeping the whole antioxidant system topped up and running. The pairing is the point.

What this looks like day to day

None of this calls for a dramatic overhaul. The simplest move is to eat the colours: a plate with peppers, berries, onions, apples and greens gives you both nutrients in their natural, food-bound form. Drink more than you think you need when it is hot, since you lose water and minerals faster the moment you start sweating. And pace your active days — recovery is part of the work, not a break from it.

If your diet runs light on fresh produce during a busy or travelling stretch, a supplement can sit in as a backstop. A chewable vitamin C like Certified Naturals PureWay-C Chewable is easy to keep in a bag for the road, and a Bioavailable Quercetin that already pairs the flavonoid with vitamin C leans on exactly the partnership described above. Think of either one as an extension of the plate, not a replacement for it.

This article is for general education and is not medical advice. Supplements are not intended to diagnose, treat, cure or prevent any disease. If you are pregnant, nursing, managing a health condition or taking medication, check with your healthcare provider before adding anything new.