Okay, this thread and some painful cramps* last week motivated me to try NUUN (or nuun?) and, yup, it seems to work as claimed.

I used it this week, three consecutive rides on hot afternoons (which I rarely do), and still felt spry after a 45 mile gravel ride Wednesday. That's unusual for me. Normally I need a rest day between rides longer than a few leisurely miles, let alone three rides pushing myself on consecutive days.

I tried both the single serving powders in packets and tablets. Nothing magical or mystical in NUUN, just the familiar medically supported electrolytes. But as others noted, no icky sweet fake fruity flavors or strong flavor at all -- there's just a vague pleasant flavor and slight carbonation tingling when it's fresh.

I drank about 8 oz of the mix before riding, then drank the rest at the rate of one to two ounces per mile (I usually aim to finish a 24 oz bottle of water in a 20 mile ride, unless it's very hot out). Then another 8 oz or so on the cool down leg home where I just loaf around 8-10 mph the last mile. And plenty of plain water too from a second bottle. I felt more energized than usual, rather than exhausted.

Only problem? I didn't have my reading glasses so I forgot which had caffeine and which was caffeine-free. I mixed a bottle of the caffeinated version for the ride home late last night and couldn't sleep until nearly dawn.

*(Primarily due to hypoglycemia. Had it all my life. Usually it's under control with diet but flares up occasionally. In this case it may have been because I'd slept poorly for a couple of days, which zaps my metabolism. It'll often show as abdominal cramps, leg and foot cramps, even before the usual bonk symptoms -- dizziness, weakness, headache, nausea. This was my first bonk in many years, and first since I resumed cycling in 2015. Fortunately I did have Glukos brand glucose tablets with me. I chewed a couple and drank plenty of water, which relieved the symptoms within 15 minutes. I took it easy on the remaining 15 miles home and took a rest day or two before riding again.)