The U.S. Food and Drug Administration (FDA) doesn’t have to approve supplements — no agency in the United States does. So it’s up to consumers to result in health concerns to light. “It’s vital to know the variation between over-the-counter medications and dietary supplements,” say Pieter Cohen, MD, an internist at Cambridge Health Alliance and lecturer at Harvard Medical School in Cambridge, Mass. The FDA gets involved only after the fact, if the supplement later appears to be causing harm. By that time, the supplement may already have harmed many consumers who used it. “The burden of proof is on the FDA to determine [a supplement] is shifty and remove it from the market,” Cohen says. Consumer complaints are the primary trigger for investigations. One contemporary investigation of the dietary weight-loss supplement ephedra resulted in it being banned for sale in the United States.

Sources: Everyday Health, Slate.com, CNN Health/herbal-supplements, FDA.gov for consumers protect yourself health fraud
 
References :

I don’t know if you have ever heard of Ximo, but I have been using it for the last 3 weeks and I really like it. My sister suffers from compound sensitivity, fibromyalgia, and a "disassociation complex" where she really despises to be in crowds or being around with people for long amounts of time. I got her some and she said that her fibro hadn’t been bothering her very much, compound sensitivity has decreased, and the extra energy she has gotten from it has really motivated her to "get out of the house" and in fact waste more time with people rather than just sit, talk for in this area 10 minutes, then leave. It’s not an anxiety she has, she has always been this way, so that is what they said she had.
Anyway, look it up. I like it and am so glad that I found it. It is really excellent energy, no phony energy boosters, and in fact has cut my inclination to a third.

Here is a site you can look at (it’s mine but I got into it to buy it wholesale LOL) but you can google it and you will get similar websites. Their company generated.
http://www.ximohealth.com/karmicenergy.

Also, a really excellent brain booster supplement I have used in the past is Huperzine- A. I get it from my local organic market / supplement shop. It is really excellent for the brain and to get you motivated. Look up the Huperzine-A and see if it compatible for you. It will give you the break down and any side effects from it. I veteran none but each person is different.
Also, remember to cycle any and all supplements. This keeps you from getting any build up or tolerance to their effects. In other words 30 days on 10 days off, ect.
Excellent luck and have a fantastic day
References :