In general, nothing you add to the fuel will be particularly good at cleaning fouled injectors.
Most fuel additives contain stuff like alcohols (to allow water to mix with the fuel, aka gas line antifreeze), dispersant (soluble gums which stop dust, grit and debris from settling to the bottom of the tank), solvents (which can unstick ultra-fine debris from filters, allowing it go through the engine, and freeing up fuel flow on the filter), and detergents (to help prevent carbon or varnish build-up on injectors).
Of course, fuel contains all this stuff anyway. However, it may not contain the best blends, or high quantities - just enough to meet the standard that the manufacturer wants to achieve (either the legal minimum, or an industry standard such as "top tier").
Remember that a fuel manufacturer doesn't necessarily want to put the best additives into their fuel, if the additive might improve gas mileage. I have come across anecdotes from chemists working with additive companies that big oil companies have trialled a new premium additive product, but decided not to order after testing found it to improve gas mileage (only a couple of %, but enough to erode their profit margin and catch the attention of the guys in suits).
Aftermarket additive companies don't have this conflict of interest (but they may have others). Quite how an average Joe is supposed to tell which additives are worth buying is anyone's guess.