If you can be bothered with careful application, Rex lube is one of the best out there
Over the years I’ve tested loads of chain lubes and two have stood out — Muc-Off’s excellent C3 ceramic and ProGold’s Prolink. Put a drop of either of these on your chain and your cranks will literally whizz backwards.
Rex is a similar low-friction lubricant; the difference I’ve found is that it’s more tenacious. In fact the first time I used I went over a month before I had to top it up, and that was riding around 4-5 times a week!
It doesn’t feel quite as slippery as the ProGold, but this tiny 30g bottle (there are 30 applications) last ages and works out better value.
As with most of these high-tech lubes, you do have to be methodical, cleaning and lubricating every link, but if you can be bothered with all that, I reckon Rex lube is one of the best out there.