Do energy drinks like 5-Hour Energy have long lasting medical problems or wear off?

I know that caffeine tolerance is built up really quickly and that caffeine isn’t harmful. What about all those B-vitamins that speed up your metabolism? Do we build up a tolerance to those quickly? Any problems with extended use? My brother’s been taking one of those a day and I’m worried about him…it just seems to me that if it didn’t have any ill effects than everyone would be using it? I know that you guys aren’t medical professionals, but I was hoping I could get a quick answer.