> Vitamin D shouldn't do anything noticeable, unless you have a severe deficit. Health influencers have been trying to exaggerate the effects of Vitamin D and exaggerate how many people might be deficient for a long time. Too many people taking too high of a dose without ever even trying to test their blood levels.

Agreed. However when I was prescribed it my levels were several times lower than the minimum normal values. However physiology and biology affects a lot of things, so it is tough to say why I didn't feel anything.

> NAC is actually routinely used as medicine: It's used to great effect in cases of Tylenol overdose.

(Yep, I'm aware of this! :) What I meant is as a supplement though, not in the ER.

> However, NAC is another compound for which the effects have become greatly exaggerated and the potential downsides ignored. You can find scattered reports on Reddit about NAC having life-changing properties on the first dose, it's hard to untangle that from placebo effect. It's much harder to find people who have continued taking it for a long time with great effect.

> It has actually been studied multiple times over for OCD, but the studies haven't been great quality and haven't revealed the same miraculous effects reported by health influencers: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4423164/

That's certainly possible, I myself haven't felt anything from NAC. However iirc anti depressants like SSRIs have been shown to barely be more effective than placebos in many cases, but that doesn't stop doctors from prescribing them willy-nilly. (Example link I found https://www.nature.com/articles/ncpneuro0803)

Lithium for example too, benefits some people but not all equally. So why not try NAC if the risks are low and potential benefits are high?

> This is just false. L-Tyrosine on an empty stomach can have a minor modulating effect on dopamine, but the effect is nowhere near as potent as stimulant medication, fades quickly, is prone to rapid tolerance, and can't be repeated unless the person has an empty stomach (~2 hours since last meal).

I was a bit scarce on the details for privacy reasons, but I am "some people" :)

It's probably helpful to note that folks with ADHD like me probably have some other wonkiness in the dopamine pathways, but I legitimately cannot differentiate between a l tyrosine tablet (forget the dose) and a normal-low dose of methylphenidate. (Yes, 20mg of methyl. will not be the same, but given the side effects the lower doses are slightly better for me.)

I'm aware of the quantities in food, I agree that the empty stomach part and low tolerance also very likely played a role in my experience.

> Given the examples you provided, I think you're overestimating your own knowledge of supplements. You're also underestimating the effects of prescription medication if you think L-Tyrosine is on the same level as Schedule II prescription stimulants.

I most certainly do not think I have anywhere close to the fraction of the knowledge an expert who truly understand the brain would have. However, I think neither do most people, and I also think doctors are too overworked/pessimistic/old-fashioned/underpaid (take your pick) to actually learn about new substances and prescribe them. I have also witnessed first hand the need to advocate for yourself in front of doctors, and read about the sometimes fatal risks of not doing so. I don't assume malice, but I do assume other issues in the healthcare system at large in today's world.