Here’s something that genuinely surprised me when I first read the research, and it flips a common assumption on its head. When you exercise, your muscles produce reactive oxygen molecules — the very things antioxidant marketing tells you to fear. And it turns out those molecules are a required part of how exercise makes you stronger.
Let me back up and set the foundation, since not everyone reading this follows exercise biology. Your cells produce reactive signaling molecules as part of normal function. In muscle, contracting fibers generate a burst of these molecules, and rather than simply causing damage, that burst acts as a signal. It tells the muscle to adapt — to build more mitochondria, to remodel, to get better at handling the demand you just placed on it.
Researchers have spent 40 years on this, and the modern understanding is what they call biphasic, or hormetic. A transient, controlled amount of redox signaling drives beneficial adaptation. Excessive, uncontrolled amounts cause harm. The health of the system lives in that balance — not in eliminating the molecules, and not in maximizing them.
This connects to aging in a pointed way. There’s evidence that older muscle responds to these exercise signals less effectively — the redox response gets blunted, which is part of why building and maintaining muscle gets harder with age. The signaling machinery that translates a workout into an adaptation isn’t as sharp as it once was.
It also reframes what “support” means. Supporting redox signaling isn’t about dumping antioxidants on your body to shut the signals down — that can work against you here. It’s about keeping the signaling system itself functional, which is a very different goal than the one most supplement marketing is aimed at.