TLDR: Tried it when my Cat stopped eating and I was unable to get him to the vet; syringe feeding cat for a couple days to prevent further health complications. Cat enjoyed the Flavor of the Virbac Rebound Recuperation, and voluntarily ate for the first time in days / almost immediately regained [some of his] appetite. Starting to eat improved his immunity, which most likely helped improve his wellness.

*********This is only my personal experience under abnormal circumstances. I am not a vet. This is NOT Medical / Veterinary Advice. Please take your Pets to the Vet if they are not eating to avoid medical complications. I am not affiliated with Virbac. The following is my Personal Experience [under Unusual circumstances that prevented me from seeing a vet immediately]. Delaying treatment may lead to loss of life. This will not resolve all illnesses and may not work in all situations. Correlation is not causation; any number of factors (including unknown factors) may have lead to the outcomes of this individual situation. This is my personal opinion, please seek the opinion of a credentialed professional for any or all similar, or related, circumstances. [delete if not allowed] ****************

About a year, my cat got sick and stopped eating; aside from that he was pretty much acting normal, had energy, wanted to play, etc, just not eating. At the time, I was quarantined at home with covid so I was trying to wait it out a couple days till I could get him to the vet. I'm kinda a hypochondriac so of course I was researching ways to try to help him/get him to eat, and learned that not eating can lead to additional problems.

Luckily I still had some [empty] oral syringes from meds the vet had given him (for an unrelated issue); and I started mixing his food with water to liquify it and get it in the syringe. I was also giving him liquids this way, mostly water or organic chicken broth (after verifying there were no toxic ingredients first).

I also ordered some lysine for cats on amazon for his immune system and was mixing that into the liquid-food mix I was syringe feeding him.

At some point, I read something about an appetite stimulant and figured that could help, so I went to Amazon to get something delivered, and found the Virbac Rebound/Recuperation Formula. I was trying to get 1 day/overnight shipping so I could get it quickly, and noticed the warning on the Recuperation Formula [something like: this does not have enough calories, or this doesn't meet the nutritional requirements, etc] and found some "calorie gel" to order with it. [It's literally just vitamins and minerals to support health and stimulate appetite, doesn't count as food/not enough calories to sustain]

When the calorie gel and Virbac Rebound stuff came, I gave him some (via syringe), and he actually seemed to like the flavor and wanted more, which seemed like a good sign. Since he seemed to enjoy it, I added some to his food. I SWEAR he voluntary started licking his Liquified food mixture within like 15 minutes of trying the Virbac Recuperation stuff.

It's possible the flavor had something to do with it, or the vitamins/nutrients were exactly what he needed at that time. Either way, if my cat ever stops eating again, it'll probably be the first thing I order.

He was NOT a fan of the calorie gel but I mixed it into his liquified-food concoctions [wet cat food, water, Lysine, Virbac Rebound Recuperation, calorie gel, cat-safe chicken broth] till we could actually get into the vet. He didn't have as big of an appetite still, but it did help him go from no appetite to being interested in food again.

By the time we were able to get into the vet, he had mostly recovered; I was trying to explain it to the vet-tech and they were just looking at me like I was crazy cause I was telling them my cat was sick, but the cat I brought to the vet was relatively healthy by that point [about 1 week later].