https://astralcodexten.substack.com/p/highlights-from-the-comments-on-supplement

[Original post here: How Trustworthy Are Supplements?]

1: AvalancheGenesis writes:

I think the bigger issue is that the industry as a whole sort of exists as solutions-in-search-of-problems...deficiencies really aren't that common, or even meaningfully health-affecting unless dire. (Fairly-arbitrary worldwide differences in target levels of IUs also remains puzzling.) Discerning customers can benefit from targeted supplementation. But that's not the median supplement purchaser, far from it. The median supplement user is more like...my former coworker who claimed he never got colds because he took 1000% vitC pills every single day, or whatever. At some point, the explanatory process for That's Not How It Works At All is just too long, so...let people believe things. Supplements are surely an easier way to sell hope and agency than most options. At least he picked something water-soluble and cared about proper hydration.

Vitamin C probably doesn't prevent colds in the general population, though some studies suggest it does prevent colds in athletes, and there's some medium-quality evidence that it might shorten colds a little once you have them.

The supplements I find more interesting are things like melatonin for sleep, ashwagandha or silexan for anxiety, SAMe for depression, or caffeine + theanine for focus. All of these are useful, supported by studies, and good alternatives to medications that some people don't tolerate well. I'm using mental health examples because that's the subject I know about, but there are probably examples in other fields too (probiotics for digestive problems).

Some commenters chimed in to discuss supplements that have anecdotally worked for them (1, 2, 3). And Elizabeth's story here is also a good example of how I think about this.