For quite a few years I've been using antinol, but of late it seems like it's really hard to find. Also, my cat has never really been too good on wanting to eat those gel capsules with her food, so I wind up squeezing them open. I'm thinking she might be getting tired of the taste of whatever's in them also - going along with the recent history of being more picky. So maybe a good time to switch to something else? Let me know what you might suggest. Cosequin or dasuquin perhaps? Antinol has "PCSO-524", which is apparently a proprietary thing they use that has oil from the New Zealand Green-Lipped muscle.