Hope someone writes a similar letter about nootropics. There's little evidence about their long term effects.
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.