Hormesis

Hormesis is when a large dose is bad but a small dose is good. “Antifragility” is similar. Exercise is the classic example: if you lift weights it tears your muscles a little, but they build back stronger. Getting a little bit of “muscle tearing” every day is way better than never getting any. Other examples:

• getting too hot or cold (sauna/cold plunge)
• ingesting trace minerals like selenium, zinc, copper (you need a little bit certainly not a lot)
• sunlight (vitamin D and nitric oxide from some sun is good, but sunburn is bad)
• forest fires keeping forests healthy
• “creative destruction” in economics

Toxicity

Toxicity is when a large dose is bad and a small dose is also bad. “Allostatic Load” is similar. Examples:

• ingesting lead, mercury, cadmium, or PFAS (doesn’t help the body at all)
• poison ivy (repeated exposure usually makes it worse)
• hypersensitivity (e.g. when your toddler is doing something minorly annoying for the 1000th time and it drives you nuts)
• rust, corrosion, erosion (if the wind wears away 0.1" of the cliff every year, it’s not like it makes the cliff stronger)

What about them?

It’s important to distinguish between them accurately! Imagine if you thought muscle soreness was a “toxicity” problem and you never exercised. Or if you thought you should eat a little mercury every day to prevent mercury poisoning.

But it’s extra hard to distinguish between them in psychology. Probably a lot of things are hormetic:

• “Exposure therapy” for a lot of fears/anxieties: explicitly hormesis
• Building any skill or learning anything is hormesis
• Most emotions are hormetic (I think? The entire therapyverse is devoted to “all feelings are ok”, and indeed, being shut off from them seems to point to a bad life.)
• Even things we lump under “trauma” may be hormetic (intense experiences when safe and controlled are fine, we just use the word “trauma” for when you get a large dose and it’s bad)

What’s toxic? Maybe depression, ennui, or existential dread/angst? Look at the most flourishing people you know; they do have the full range of emotions including sadness, but they don’t seem to have any dose of the muddy stuck blahs that depressed folks have. And depression seems to be self-reinforcing: you don’t do all the outgoing active social things that might pull you out of depression.

One reason it’s hard to distinguish is that “bad” includes both toxic things, and hormetic things where you’ve just been getting too high a dose. E.g. sunburn is toxic, but sun exposure is hormetic, so maybe it’s more fair to say “sun is hormetic but sunburn indicates you’re getting out of the hormetic range.”

I don’t have much of a conclusion here. Make sure you know what’s hormetic and what’s toxic.¹