Comment by DanielleMolloy

Surprised this hasn‘t been mentioned at all in such a long discussion:

I became pretty suspicious of most supplement brands last year. Many omega-3 capsules are rancid (which can have adverse effects and can easily go unnoticed with a capsule), and the vitamin D brands I tried didn‘t seem to do anything for me at all.

I switched to cod liver oil instead. It‘s a staple in Scandinavian cultures, so there are several well-controlled brands available that taste neutral (or are lightly flavored, e.g. lemon). It’s a combined substance containing omega 3, vitamins D, E, and A, and appears to be much more bioavailable than many capsule-based supplements, especially given the oxidation issues. Don’t want to prime anyone - try it yourself - but many people, myself included, report fairly immediate effects. I am not talking about the capsules, they are a fairly recent invention, I mean the plain oil on a spoon like in the old days.

Alongside magnesium, it’s currently my only „supplement“.