Redonyl Ultra Feline by Dechra is an over-the-counter powder and total game changer when it comes to treating cats with itchy skin from allergies. My best plan for treating cats with allergies has been twofold. First, managing the allergies daily with Zyrtec and/or Redonyl. Secondly, use prednisolone (steroid) only for flareups. By using Redonyl, I’ve been able to decrease the use of steroids in treating cats with allergies.
Let’s take a look at how Redonyl works, along with how it helped two of my foster cats. One clearly had allergies and the other likely had skin issues related to stress.
Note: This post is only about managing one aspect of allergies as it pertains to itchiness and skin irritation. If you want more information about cats with allergies overall, take a look at my articles here or here.
Redonyl – How It Helps Cats With Allergies & Skin Itchiness
To explain how Redonly works, it’s important to understand why cats get itchy when exposed to allergens.
What Causes the Itch
For cats with allergies, the immune system can interpret something harmless, like dust, as harmful. To respond, it tells specific white blood cells called mast cells to release a chemical called a histamine. Mast cells are found more densely where our bodies meet the environment: skin, lungs, and intestines. Histamines increase blood flow, which in turn, causes inflammation. This is why allergies can cause symptoms in these areas, like a runny nose, itchy skin, and even diarrhea. It’s also important to note that stress and anxiety can also cause mast cells to release histamines.
But why do we feel itchy and then scratch ourselves? According to the American Academy of Allergy Asthma & Immunology, our brain triggers us to scratch to remove parasites and protect us from anything harmful. Unfortunately, a response to a harmless allergen causes more harm than good. Animals often end up over scratching, damaging their skin, and getting infected wounds.
While you can tell yourself or another person not to scratch, good luck telling your cat. Cats with severe allergies will literally rip their skin open because they are so uncomfortable.
This is why it’s important to reduce scratching and itchiness for cats with food, flea, or environmental allergies.
How Redonyl Stops the Itch in Cats With Allergies
According to Dechra, Redonyl Ultra is “A hypoallergenic nutraceutical to support skin health.” The FDA defines a nutraceutical as a food or part of a food that has a medical benefit. Supplements are nutraceuticals. For example, zinc has been proven to shorten the length of colds. It’s not a medicine, but it does have medical benefits.
Redonyl is made of ultra-micronized palmitoylethanolamide (PEA). First, the very broken down particle size allows for faster absorption and effectiveness. Second, PEA is a naturally occurring lipid that fights pain and inflammation. The PEA in Redonyl targets mast cells, slowing the cells’ ability to release:
- Histamines by 54%
- PGD2 by 25% and TNF-alpha by 29% (other allergy mediators believed to cause inflammation)
Ultimately, this creates a more balanced (and non-itchy) environment for the skin.
Redonyl Ultra Dosage
Redonyl Ultra comes in an odorless, tasteless, and palatable powder for cats that you mix in their wet food. Since it’s hypoallergenic, it also doesn’t contain any wheat, beef, chicken, or other flavoring. (The last thing you want to do is expose a cat with allergies to something they react to.) Redonly comes with a tiny scoop, and the dose is 1-2 scoops per day depending on weight.
Foster Cat 1: Gizmo, Allergies
Gizzy was surrendered to ACCT Philly with red, inflamed skin, and persistent ear infections. His owner didn’t know what to do or how to help him. This is the case for many cats who suffer from environmental allergies.

After trying a ton of different meds, a combo of Zyrtec and prednisolone got his allergies under control. He looked fabulous. But the vet and I really wanted to get Gizzy off the steroid. Every time I tapered it, he would start to turn red and flare.


While cats tolerate steroids better than humans or dogs, it’s still better to get them off steroids if possible. There are side effects to long-term use, so getting them off is really ideal. A vet with holistic experience recommended Redonyl to me. The feline formulation had just come out, and although she hadn’t used it, she saw it work very well on dogs.
I tried it with Gizzy, and slowly decreased his steroid until he wasn’t on it at all. No redness. No itching. All winning!


Gizmo was adopted and his family keeps him on daily Zyrtec and Rednoyl to control his allergies. He’s living his best itch-free life!
Foster Cat 2: Bella, Stress

Bella was an abuse case that came from the PSPCA. Her ribs had all been broken and she was quite scared of people, even aggressive toward me. In two of her three foster homes (including mine), she was scratching open her back and neck.

Even though she didn’t show any other signs of allergies (like red skin), I tried Zyrtec and putting her in a shirt. The shirt helped prevent her from her nails coming in contact with the skin, but she still tried. It seemed like the Zytrec wasn’t enough, which led me to believe it was stress related.


I started giving Bella Redonyl, and within two days, her skin started healing and she was scratching less and less. Soon, she was completely healed inside and out. Her skin closed. Her fur grew back. She also wasn’t scared of people anymore! Now, she’s available for adoption with another one of my foster cats, Morty.



Where to Get Redonyl Ultra Feline
Redonyl Ultra Feline really helped the two cats I mentioned, and that’s enough for me to recommend to anyone with a cat (or dog) with allergies and skin issues. It’s OTC and much more affordable than many of the prescription allergy meds. You can order it from a variety of sites, but be sure to talk to your vet before giving it to your cat: