As someone who takes Adderall daily and has for many years, I can tell you the Teva brand generics work very well while the malinkrokdt (sp?) in the same dosage do almost nothing, and I crash very fast and need a nap in the afternoon and have to go to sleep early.

Conversely, I got some random Indian-HQ brand from Walmart many years ago (a pink tablet) that kept me up for 3 days. I was begging God for sleep. Placebo or nocebo my ass. Pretty sure someone "accidently" added a methyl group and was overly gracious with the dosage.

The book Bottle Of Lies goes into this much deeper. https://www.npr.org/sections/health-shots/2019/05/12/722216512/bottle-of-lies-exposes-the-dark-side-of-the-generic-drug-boom

But it's also noticable in OTC meds. If you get real, severe inflammatory pain (not 'oh I have le headache'), buy a bottle of ibuprofen from the local dollar store and then buy brand-name Ibuprofen from a big box store, and blind test yourself.

(I may be misremembering the specifics on this part) Generics can only be 80% similar to the brand name in formulation, and often times they use fillers and binders that aren't as good as the formulation created by the R&D department of PharmaCo.

I'm not saying generics do nothing, I'm just saying my boss asks me what's wrong when I can't get my Tevas filled and have to use another manufacturer.