Personally i'm convinced they work. If and only if you believe in the working of supplements.

I am also convinced they do not work for me, because of the premises.

What is amazing is you dismissing the entire domain of the science with a single unsubstantiated sentence. Feel free to read some schoolar journals and research papers, rather then popular zines, if that is not too much trouble...

If you could fight deficiency with a mind, we would not have deficiency disesases.

I'm only speaking from experience.

> If you could fight deficiency with a mind, we would not have deficiency disesases.

That is so true. The thing is, a lot of diseases get treated as a deficiency disease.

Experience is highly overrated. Some stuff may work for you some not, depending on your current state (dynamic thing, daily changing). Many stuff you can't experience but you must measure.

Science is important. In accute phase response deficiency is the norm, as one example.

Vitamin B1 won a Nobel Prize in 1929 and solved a major generational illness in Japan. Lack of vitamin B3 has the same symptoms as schizophrenia (look up pellagra) and many people are misdiagnosed with it instead of tested for low brain B3 or genetic defects leading to lower absorption of B3.

> There is literray almost zero downside to it except wasting money.

And/or nasty interactions with prescription drugs when you do it incorrectly.

And nasty depletions due to some drugs when you do it correctly - NSAID against C, beta blockers against CoQ10 etc...