Libido always goes down a bit on Deca - however I’m willing to trade that for decreased joint pain. Off Deca, my rotator cuff injury and other joint issues rage on and I have to change my entire weightlifting routine. On Deca - I’m doing one arm overhead kettlebell presses with 65lbs with no issues or pain at all.
Cognitively I noticed no change. In fact I seem calmer and more focused running low dose Deca - perhaps it has something to do with diminished joint pain.