My cats would not eat
I have 2 sixteen year old cats, one of whom had renal failure. Bought these and vet said specialist renal diet might help turn his kidneys around. Neither of my cats would touch it.
Cats w kidney disease can be very fussy eaters and I decided to try a wide range of products so I could swap around when they got tired on one or didn't like it. This was a definite "didn't like".
Can't comment on efficacy for renal support, as Kaspar died from kidney failure within a few weeks of my purchase.