Performance aids..

Hail Hail

Of course they are safe and allowed - they wouldnt get past health and safety and trading standards (not to mention having passed the govt's rigourous vetting procedures) if they werent.  As to wether they work, well an elite level athlete may notice improvement from using nothing at all, but most folk are better off using what works for them.  Quite often "performance enhancing supplements" contain more calories than a plodder will use eg 500ml Lucozade contains approx 200cals, so to get the benefit of the contents (without taking on board the extra cals) you need to run at least 2M extra.

I've tried a tub of the normal viper drink (not the extreme version which I think has caffeine in it) and it was way too sweet for me with a v high sugar content. Running Bhoy is right that using a 'good' energy drink/bar/gel won't make much difference but if you're really looking for an extra one per cent there are definitely better drinks out there than lucozade.

The energy you get from lucozade is released very quickly in your body (because it for the most part comes in the form of 'simple' sugars) which means it can boost your performance for up to an hour after you start drinking, but then have an adverse effect by causing your blood sugar levels to crash. This sounds dramatic but, again, it's only really the difference of one or two per cent on your performance.

If you're running over an hour, look for higher amounts of maltodextrin (a more 'complex' and therefore slower releasing type of sugar) which helps boost your performance levels over a longer period of time. But still make sure there is some simple sugar in there, just not in the same amount.

Having some protein in your energy drink while doing a long run can also aid post run recovery.

My favourite energy drink that ticks all the boxes above is called High5 4:1 (i.e. four parts carb to one part protein).

I think there's probably a place for the isotonic stuff when doing really long runs and when it's hot weather.  (Besides gels/LS are easier to swallow on the run than jelly babies!)

I can't be doing with bars, etc, and think it is mainly marketing, and a rip off.
High carb diet generally, carbs and protein soon after a Long Run, and some carbs, water and isotonic drink/gel on the run, if a long session

You'd be better off with lucozade or regular gels. If you want something extra potent, then make your own sports drinks using dextrose powder, your favourite flavour of squash and half a tsp of salt. Then you can control the dextrose (carb) content to the nth degree.

With maximuscle, you can almost be sure that it's a marketing ripoff.