The Vitamin

There's a famous Tumblr post that goes:

My deepest darkest fantasy is that I collapse on the street and I am rushed to the hospital. They perform a bunch of tests and find out I am severely deficient in some kind of vitamin. Then I start taking the vitamin and I become the happiest cleverest person alive because all my problems were caused by this one deficiency

I often had a sense that there were a few Candidate Vitamins that many people should know about – iron and vitamin B12 come up a lot for vegetarians, especially vegetarians feeling lethargic – but those are easily testable-for if you think you might be lacking. Recently, though, I've seen a couple of posts from people claiming they have found their Vitamin and it's, like, a specific amino acid (glycine, betaine, etc) that I don't think gets covered in any normal blood test.

So I figured I'd crowd-source: f you've found your Vitamin – a single, simple intervention that weirdly solved many of your problems – I'd love to hear about it. (Bonus points if you're vegetarian, I do suspect there are limits to vegetarian diets that some of us might not notice in real time).

[contrary take: see Spencer arguing most people don't need supplements]