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Immune Support for Cats: 6 Supplements to Consider

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Have you ever felt an illness coming on and quickly decided to take an immune-boosting supplement with vitamin C or zinc to ward it off? When we think about our fur babies, we can’t help but wonder if they also should be taking similar precautions. Are there cat supplements that boost immunity? The short answer is yes. There are a variety of cat immune support products that you can give your feline friend for overall health and maintenance. 

“Illnesses and diseases result from defects in feline immunity, so anything from a cold to kidney failure and cancer require immune support most often provided by supplements,” explains integrative veterinarian Carol Osborne, DVM, of Chagrin Falls Pet Clinic.

There are plenty of health issues to protect your cats from, and prevention is key, Osborne says. While you do the best you can with annual vet visits, proper nutrition, and all-around good care, there are supplements that can help your cat when she is sick, too.

Let’s take a closer look at how immune support cat supplements work, plus explore our top picks. 

Our List

How Immune Support Cat Supplements Work 

“Immune support supplements work by helping the cats’ bodies and defenses to become stronger so they can ward off diseases and illnesses,” Osborne says.

While your cat should be getting sufficient nutrients from her food, a supplement may be a good idea if she has an immune deficiency (whether it’s temporary or ongoing) or suffers from allergies.

“Feline owners should always consult with their vet any time they have a question about their cat’s health,” advises Osborne. “Be sure the supplements you are considering are safe and effective for your cat.”

If your vet gives you the green light, he or she should also be able to tell you which supplements or immune support products to look for based on your cat’s specific needs. Some of these may include probiotics for digestive health (in addition to immune support), a multivitamin, or essential fatty acids to help prevent inflammation.

Best Immune Support Supplements for Cats: 6 Options to Consider

All featured products are chosen at the discretion of the author. However, Great Pet Care may make a small affiliate commission if you click through and make a purchase.

Best Liquid Immune Booster for Cats

Our pick: Zesty Paws Pure Wild Alaskan Salmon Oil for Dogs & Cats


This tasty treat—that can be added to wet or dry food—packs a powerful punch with omega-3 fatty acids derived from salmon oil. Zesty Paws Wild Alaskan Salmon Oil aims to keep your pet’s skin healthy while also giving their immune system a boost. The omega fatty acids in salmon oil are also known to support hip, joint, and heart function. 


  • Promotes skin health and supports a healthy, shiny coat
  • No artificial flavors, preservatives, or synthetic colors
  • Made in the USA
  • There are over 20,000 Amazon reviews touting this product’s efficacy from happy buyers
  • Available in 16- and 32-ounce bottles
  • Suitable for cats and dogs of all ages
  • Can be added to wet or dry food

Things to Consider

  • Don’t let the vessel fool you. This product looks like it’s in a shampoo or lotion bottle, but it is something to be eaten
  • The product is formulated for cats and dogs, so pay close attention to the directions and dosage for administering
  • Fish oil can cause soft stool in some cats, so you may want to start at a lower dose and build gradually to your cat’s recommended dose

Best Immune Boosting Cat Chews

Our pick: VetriScience Vetri Lysine Plus

cat supplement

During stressful moments in a cat’s life (like a big move or the introduction of a new pet into a household), your cat may need a little help with immunity. Upper respiratory issues can sprout during those transitions, as chronic viral infections reactivate during times of stress. This immune support product from VetriScience comes with a blend of L-lysine (an essential amino acid for cats) and dimethylglycine (DMG). Recent studies suggest that lysine does not play as large of a role in immune support as we once thought; however, many veterinarians feel that its use may still offer benefits.


  • Flavored with chicken liver and shaped like fish
  • Approximately 120 bite-sized chews per bag
  • Suitable for both cats and kittens of all weight ranges
  • Made in the USA
  • 60-day satisfaction guarantee

Things to Consider

  • Comes in bite-sized chews, so you’ll have to get your cat to eat them like a treat or snack
  • Package recommends giving adult cats 1-2 chews, twice daily; for kittens, give 1 chew twice daily

Best Immune Support Cat Supplement for Kidney and Urinary Health

Our pick: Great Pet Great Kidneys Cat Supplement

cat supplement

These soft chews from Great Pet aim to improve overall kidney health in cats and ward off urinary tract infections. Made of astragalus root extract, an herb that has antibacterial and anti-inflammatory properties, this chicken-flavored supplement also contains rehmannia powder, a medicinal herb used to regulate the adrenal glands. Even picky cats may readily accept this chew as a daily treat.


  • Contains 60 mg astragalus root powder to boost the immune system and fight infections
  • Contains 30 mg rehmannia powder to support kidney function 
  • Inactive ingredients include carob, catnip, chicken, chicken liver, and garbanzo flour
  • Made in the USA
  • Manufactured under Current Good Manufacturing Practices (cGMP) conditions

Things to Consider

  • Consult with your veterinarian before using this product
  • Number of chews per day depends on your cat’s weight. If you have a larger cat who weighs 20 pounds, he may require 4 chews per day, whereas a 10-pound cat would only need 2 chews
  • Keep out of reach of children
  • Store in a cool, dry place

Best Immune Support Supplement for Cats With Respiratory Issues

Our pick: Tomlyn Immune Support L-Lysine Powder

cat supplement

This powder cat supplement is formulated to support a healthy immune system and respiratory system in cats, plus maintain normal eye health and function. If your cat is prone to colds, sniffles, and conjunctivitis, this could be a good option for your pet. It contains 500 milligrams of L-lysine per scoop. It has a chicken and fish flavor most cats approve of when mixed into their regular food.


  • Veterinarian formulated
  • Has the NASC (National Animal Supplement Council) quality seal
  • Since it’s a powder, you can easily sprinkle it on your cat’s food to get them to eat it.
  • Inactive ingredients include brewer’s dried yeast, hydrolyzed fish, and hydrolyzed poultry liver 
  • Many reviewers said they mixed it in with their cat’s food and they didn’t notice and ate it anyway. 
  • We love that this product is also budget-friendly

Things to Consider

  • Packaging recommends giving half a scoop twice daily to kittens under 6 months and one rounded scoop twice daily to cats 6 months and older—or as directed by your veterinarian
  • Giving the product with meals or after your cat has eaten can help reduce gastrointestinal upset
  • Store in a cool, dry place

Best Immune Supplement for Cats with Cancer

Our pick: Pet Wellbeing Life Gold Trusted Care for Cat Cancer

cat supplement

This bacon-flavored liquid supplement for cats provides immune system support and antioxidant protection, specifically for cats suffering from cancer. Cancer weakens a cat’s immune system, making it hard for them to fight diseases and infections. These cat drops feature a proprietary blend of astragalus root, blessed thistle, sheep sorrel, burdock root, slippery elm bark, and ginger rhizome. Other potential benefits include supporting vital systems of detoxification, reducing oxidative stress, and scavenging free radicals.


  • Life Gold products are organic and its ingredients are all ethically harvested
  • Manufactured in FDA-registered facility that adheres to cGMP
  • Natural bacon flavor
  • Every batch is tested to ensure quality, purity and potency
  • Available in 2- and 4-ounce bottles
  • 90-day money back guarantee

Things to Consider

  • The product is formulated for cats and dogs, so pay close attention to the directions and dosage for administering
  • A little more pricey than other immune support products
  • Use caution if your cat is taking immune-suppressing drugs
  • Give this at least one hour apart from other medications your cat may be taking
  • Shake well

Best Immune Support Powder Supplement for Cats 

Our pick: EcoImmune Immune Support & Booster Supplement for Dogs & Cats

cat supplement

Packed with immune-boosting ingredients like cod liver, echinacea, mushroom extract, antioxidants, and beta glucans, this EcoImmune powder aims to support cats (and dogs) who are recovering from illnesses or combating allergies or chronic issues. You can add this chicken liver-flavored supplement directly to your pet’s food once per day to give them the boost they need.


  • Made with all-natural ingredients
  • Measuring scoop included in bag
  • No artificial preservatives
  • No grains or gluten
  • 100 percent satisfaction guarantee

Things to Consider

  • The product is formulated for cats and dogs, so pay close attention to the directions and dosage for administering
  • Not recommended for cats under 12 weeks old
  • Keep in a cool, dry place

Cat Immune Support Supplement Buyer’s Guide

Though we presented you with some great options for cat immune support, you should also consider the following factors before making a purchase:

Form: Immune boosters for cats are available in a variety of forms, such as powders, chews, oils, and gels. No two are created equal, and some target specific challenges to keep cats healthy. It can be tricky to get a cat to take an oral supplement, so consider your individual cat’s preferences and temperament when choosing a form. If your cat won’t readily accept a chew as a treat, for example, you might want to try a powder or oil that can be mixed with food. On the other hand, if your cat is super finicky and can detect even the slightest change when something is added to his food, you might be better off with a chew.

Active ingredients: Read the packaging to see the product’s active ingredients and potential health benefits. Common active ingredients in cat immunity supplements include omega-3 fatty acids like EPA and DHA, which can help with organ and tissue function; L-lysine, an amino acid that is thought to support immunity; beta-glucans, which are soluble fibers that help with gut health; and medicinal herbs like astragalus root, which has antibacterial and anti-inflammatory properties. 

Flavor: We’ve seen cat immunity supplements in a variety of flavors, including chicken, fish, and bacon. If you know your cat detests a certain flavor, you should probably steer clear of any supplement that contains it!

Quality: Check to see if the product is third-party tested for quality, purity, potency, and safety and that the product is manufactured under Current Good Manufacturing Practices (cGMP). You can also look for the National Animal Supplement Council (NASC) quality seal, which classifies products made by companies who are committed to quality and improvement to promote the well-being of pets. When you see the seal on the product or in the product listing online, that means that the manufacturer or supplier is doing their part to be responsible. 

Vet approval: Ask your veterinarian for recommendations on what type of supplement to consider, and even what brands to trust. 

Cat Immune Support Supplements: Tips and Advice

One of the most important things to understand about immune boosters for cats is that they’re not a cure for an actual illness. While they can certainly help your cat ward off disease and secondary illnesses when they’re already sick, cat parents should understand that immune support is not an alternative to actual medicine (like antibiotics), vaccinations, and general wellness care. 

You should still continue to do the following to boost your cat’s immune system:

  • Feed your cat a well-balanced diet
  • Give your cat the opportunity to exercise
  • Take your cat to the veterinarian for regular checkups
  • Keep up with your cat’s vaccination schedule
  • Avoid exposure to ingredients that are toxic for cats (e.g., some essential oils)
  • Pay attention to any worrisome changes in your cat, such as weight gain, weight loss, or lethargy

Lastly, we can’t stress this enough: consult your veterinarian every step of the way. They know you and your cat best. Knowing your feline’s medical history and your specific concerns can make all the difference when coming up with a preventative maintenance plan or treatments to ensure your fur baby is as healthy as can be.

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