I've been using Supercharged Collagen in conjunction with EndureX for a few of weeks. I mix a scoop of both into about 10 to 12 ounces of water. The packaging calls for 16 ounces of liquid but I find that to be too much liquid for me to chug right before a session.
The collagen on its own mixed in water does not taste very good to me. I have to choke it down. However, with EndureX mixed in, the flavor is actually pretty decent. Very tolerable. So I just mix both into the same water and drink it about an hour before a climbing session.
I know there is a lot of skepticism out there on products like these, but what I can tell you is that my last 4 or 5 climbing sessions have been the strongest I have ever had resulting in a couple of sends on routes that I was just on the brink of sending previously. In addition, I'm feeling very strong on routes slightly above my max grade doing very well on them.
I feel like I have actually made progress both in strength and endurance in the last 3 weeks with a noticeable result. I'm not claiming that I've shot up 3 grades, or even 1 grade, but I'm getting higher on routes and feeling fresher than I did before.
This has been in combination with some fingerboard and moonboard training for the past month.
Call it a placebo. Call it science. Call it actually working. Whatever the case may be, I'm very happy with the short term progress I've seen in the last few weeks. So I'll continue using these products.