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pazimzadeh ◴[] No.43306628[source]
> I’ve long found that tea makes me much less nervous than coffee, even with equal caffeine. Many people have suggested theanine as the explanation, but I’m skeptical. Most tea only has ~5 mg of theanine per cup, while when people supplement, they take 100-400 mg. Apparently grassy shade-grown Japanese teas are particularly high in theanine. And I do find those teas particularly calming. But they still only manage ~25 mg per cup

It's not uncommon for a substance to have different, even opposite effects at different doses. For example high dose melatonin can keep you up, and stress you out, whereas in most people you only need up to 1 mg to promote sleep.

https://en.wikipedia.org/wiki/Hormesis

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1. ajb ◴[] No.43309419[source]
That's true, but melatonin is probably not a very representative example, (unless you're only talking about sleep) as its mechanism is really idiosyncratic.

It seems (from [1]) that the body has a day-clock which is synchronised to the actual day by the release of melatonin. Taking melatonin (at the right time) reinforces the signal; taking too much swamps it completely. It seems unlikely that many other body chemicals are part of the signal chain of a biological PLL (phase-locked loop).

[1] https://slatestarcodex.com/2018/07/10/melatonin-much-more-th...