My Protein .com is good for whey protein powder, cheap and effective.
It’s a lack of carbs that tend to make my legs feel dead though, protein powder is just an optional boost for recovery after particularly hard rides (assuming an average diet). And without recovery time there’s no amount of whatever you can eat to get the leg pep back. If your rides are under an hour just take them really, really slow at times, better for you than the same pace all the time. Much over an hour and it’s probably not recovery anymore at any pace, not sure though.
I expect rego has other good things in it too, SIS stuff is good ime but it seems ott w/o proper training plans etc.