Luke, what's a vitamin tablet thing?

Just curious because I've rarely tried anything that makes a difference that I can actually feel in well being or whatever, maybe I've rarely been deficient in anything though.
I'm currently not taking anything atm myself, I'm on a keto diet and have lost a little weight over a couple months, I'm very low in money so I try to avoid anything expensive but I'm also taking a break from my favourite drug caffeine.
These are stuff I've tried in the past and had good effect from:
Monster Rehab: Has to be the rehab one, rest of them makes me feel ill maybe simply because they are not good tasting. But yea this gives me better focus than coffee, it actually does what it says on the can for me, keeps me relaxed yet focused at the same time.
Astaxanthin: derived from some sea lifeform which is supposedly very resilient, I felt increase in strength from taking this maybe a month, supposedly it boosts immunity also among other things but at the time I took it only thing I seemed to notice for sure was some maybe 5-10% increase in strength amazingly.
B3 Niacin: you get hot and red from taking this, some don't like it, I think it feels good and has temporarily seemed to help me with mental problems at times, I always ODd on this to get the dilated blood vessels effect which is why it makes your skin go red.
MCT oil: I took this in my coffee along with some ghee before my 100% run at ESA 2014, the run was a great success so I guess this is good stuff, honestly it did seem to give me that calming feeling more easily that I've felt at times on the keto diet so I guess it's a shortcut to use fat as energy or something alike which I've read it should do.
Stuff I had bad effect from:
Sertralin (antidepressant): This might be shite, I actually got a little high from it, it's like I was walking around being slightly drunk all the time, it doesn't seem to help solve much though so I'd like to try something brain enhancing instead, this just seems like a bit of a distraction. Side effects of dry mouth increases risk of cavities, I got a couple while taking these, sexually numbing, makes you tired, sleepy, yea it's kinda shite I won't try it again.