I think centrophenoxine and racetams are fairly well tolerated. I've cycled them on and off for a few years with only positive outcomes. They've been studied for decades. It's probably worse to take something like tylenol pm every night, which is FDA approved, OTC etc. http://www.health.harvard.edu/blog/common-anticholinergic-dr...
When you are chemically toying with your brain, it is good to know if there are any adverse long terms effects. Risk vs. reward. Surely some non chemical ways of modifying the your brain can also have adverse effects: like eroding concentration due to constant multitasking.
Here is an account of long term centrophenoxine use. Not sure there is lots of study demonstrating 35 years of use is safe in large qty of the population so this should be treated as an anecdotal report only. It does cite other study he has done.
nootropics have been around for a long time and the base agents like aniracetam have been studied for decades.
also, you're "messing" with the chemicals in your brain any time you consume something... unless you're aware of studies that have shown negative affects attributed to nootropic use.
I use a stack of nootropics and it's better than coffee, but not like some magic wonder drug, it just helps with alertness and focus.
I also use a tcds machine when I really need to get things done, I have found, for myself, an arrangement that kicks my brain into full gear.
the downsides of my config are:
my teeth feel like they've got batteries stuck to them for a week or so after. it's not that bad, but it's uncomfortable.
I get over powered I suppose is a good enough word combo, I feel too awake and need to sit in a dark room and relax for a bit.
the upsides are:
ultra focus, very able to context switch and maintain previous data whilst working on large infrastructure issues and or writing complex software applications for large infrastructure goals. much much more so than I get when it's just me and a cup of coffee.
depression just goes away, hell I forgot what it was like to be depressed for a while, it was nice, it's like all the negative thoughts aren't able to make themselves known. I am currently on a 6 month break to give me a good idea of lasting effects (depression is back sadly).
I would have to say that the benefits of both tcds and nootropics are not yet fully understood, and neither are the downsides, but I can say for myself, it's been a positive experience.
my only advice on the tcds portion, if you have the skills, build it yourself, you want really good components, or buy a really nicely made Analog one, there's a difference between smoothly generated output and a cheap digital machine you buy off amazon for 100 bucks. you can feel the difference.