Side bar : L citrulline is thought to be more effective than arginine.

One downside that I don’t see discussed much, as I’ve watched multiple recalls over recent years for supposed contamination of things like tmao and other toxins in either the manufacturing process or packaging process, I wonder how many supplements are contaminated. I have never seen an analysis even from the vendors who do pretty hefty chemical composition analysis.

> I wonder how many supplements are contaminated. I have never seen an analysis even from the vendors who do pretty hefty chemical composition analysis.

Why do you think food supplements would be more contaminated than other processed foods? Or even things like toothpaste or shampoo, those are also made from highly processes ingredients.

There's a large amount of precedence, that's why. Rather than asking the room, one would think the first step would be to obtain information and inform yourself.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5753965/

https://pubmed.ncbi.nlm.nih.gov/34022259/

https://theconversation.com/natural-supplements-can-be-dange...

Why so defensive? I'm asking the room because it's a smart room, usually, and often there's someone who'll be far better informed than I could be with a quick search. That's literally why I spend time here.

Regarding your links, I'm sure I could find similar studies about nearly any kind of food. I have a friend who won't eat peanuts because he's afraid of aflotoxins, which are real, genuinely dangerous, and if you think that peanut products are tested well enough to 100% guarantee the aflotoxins are always below safe levels in all peanut products you'll ever eat... Well, I'll disagree.

https://inspection.canada.ca/food-safety-for-industry/food-c...

So again, why do you think supplements are worse than other food products? I don't agree that your links answer this question.

They do show that there's often contaminants in supplements. They _don't_ show that supplements are unusual in this regard when compared to other food products.

Your third link focuses on heavy metals in supplements. Here's a similar study showing they are also in baby food:

https://www.health.harvard.edu/blog/heavy-metals-in-baby-foo...

So is it just supplements and baby food? Unlikely. More likely it's that supplements and baby food are both things that make people worry about contamination, so they test them more. Meanwhile your ketchup might be loaded with all kinds of contaminants but you'd never think of testing it.

"These things are also contaminated" is shoddy argumentative reasoning at best, it is not the "got ya" that you think it is . I never claimed that there aren't contaminants in food, and I don't see how it defeats my claim that dietary supplements are unsafe -- the FDA is more stringent in regulation and testing with respect to food, as opposed to dietary supplements, because, you know, we need to eat to survive.

Please take a second to read my comment here, before responding: https://news.ycombinator.com/item?id=36930128

One would think the first step would be to look it up.

> Most healthy people do not need to supplement with arginine because it is a component of all protein-containing foods[15] and can be synthesized in the body from glutamine via citrulline.

I do not understand how someone can wish to know something, but refuse to expend effort to obtain the information they wish to seek? I hope it would be ok for you to explain this behaviour, please?

This seems unfairly aggressive. GP asked what the downside is to preventatively taking l-arganine as a supplement, your quote addresses only whether it's required.

In short, you can't test your own blood so you don't know when your levels may be low. If there were no downsides to constantly supplementing then what reasons may there be to not do this?

That is I think the actual question.

My quote answers the question of "why don't we all supplement with L-arginine long term" with "it's in basically all protein containing-foods, so it is not necessary".

While you are right there may be individual variation, the rule of medical advice is that we cannot assume what we do not know, and preventative ingesting of a substance that is not too well understood may have unintended side-effects. Especially in the case of synthetic synthesis.

It is unfairly aggressive and they did this twice just in this thread. The other was here:

> There's a large amount of precedence, that's why. Rather than asking the room, one would think the first step would be to obtain information and inform yourself.

https://news.ycombinator.com/item?id=36930036

I don't know why this person feels the need to roam around the conversation policing how people are engaging in it. It's incredibly obnoxious. Especially frustrating given that they do seem to have some information to share, which they could do and just omit the completely gratuitous and unwarranted hostility.

I clearly made a point of inquiring why the behaviour was performed, it was an honest inquiry, I am genuinely curious.

> taking care to be polite

If what you consider “polite”, several people call out as aggressive, then maybe you should re-evaluate your definition of the word.

Your comment does not read polite. At best, passive aggressive.

Asking questions fosters discussion. For a site centered around discussion, that seems warranted. Telling people to just look it up is pretty much the antithesis of discussion.

> Telling people to just look it up is pretty much the antithesis of discussion.

On the contrary, the quality of discussion would be much higher if people took one entire minute beforehand to research something. It is shameful and disappointing that the techbros here cannot be bothered to do this, and prefer to live in ignorance.

That doesn’t necessarily answer his question though and doesn’t even seem like a well reasoned point. Just because your body can produce something doesn’t mean it can’t benefit from more.

Likewise just because your body requires something doesn't mean that large doses of it are beneficial. See my followups, which address that and were written 30 minutes before your post :/

Arginine has good short-term endothelial effects but bad long term effects. Most studies last <1 month observing the good effects but not monitoring future bad effects:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4069264/

I am skeptical of this because as far as I understand, Arginine is naturally occurring in many foods.