FIGHT VIRUSES, DISEASES, AND CANCERS.

Critical Immune Defense for Dogs & Cats
Critical Immune Defense for Dogs & Cats
Critical Immune Defense for Dogs & Cats
Critical Immune Defense for Dogs & Cats
Critical Immune Defense for Dogs & Cats
Critical Immune Defense for Dogs & Cats
Critical Immune Defense for Dogs & Cats
Critical Immune Defense for Dogs & Cats
Critical Immune Defense for Dogs & Cats

Critical Immune Defense for Dogs & Cats

Sale price$65.00 USD
Size: Small Bottle | 70 Scoops
Free shipping on all US mainland orders

There simply isn't another product of this quality and strength available on the market, with THOUSANDS of testimonials about the results!

Critical Immune Defense is a safe, all-natural immune booster that can add years to the life of your dog or cat.
Made in the USA with certified organic mushrooms.

Just sprinkle a small amount of powder on your dog or cat's food. It tastes great, even for the most finicky of pets!

✔︎ Boosts immune system

✔︎ Reduces inflammation

✔︎ Promotes normal cell growth

✔︎ Protects against toxins in food, water & environment

✔︎ Supports long-term health in dogs and cats
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"I've lost two golden retrievers to cancer, so I've been doing a ton of research since I got my newest puppy. I want to give him the best chance of living a long and healthy life and Critical Immune Defense is a key part to that equation. He likes it and I believe in being proactive! So glad I found this company!"

- Audrey (Verified Customer)

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“My cat is 15 and has feline herpes. In the past, I have given her lysine with very little results. Since taking Critical Immune Defense I have seen a steady improvement. Hardly any eye discharge and her nose isn’t wet anymore. No difficulty breathing at all. My son said, “What took you so long to find this stuff?” I also give it to my 3-year-old dog, she’s healthy but …..just in case. They both eat it and have no problem eating all their food.”

- Lisa (Verified Customer)

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"Wish there was a human version!! Our large male German shepherd was getting growths on his neck and by his eye. They were getting larger. I saw this product and ordered one canister, not expecting much. However, within 2 weeks, the growths were getting smaller. They finally disappeared! We now give this as a preventative to both of our dogs! Highly recommend it!! Worth the money!!"

- Carla (Verified Customer)

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"30 days ago I went to a cancer specialist who told me that my dog’s prognosis was not very good and he would eventually get lumps and tumors all over his body. I left very depressed.
I found your product online by a miracle, and I started giving it to him. I don't know what it’s doing, but all older cancer tumors are gone and it seems to have eliminated the new tumors as well. I've been giving the VetSmart product twice a day for approximately 30 days. I'm just so grateful and so thankful that it works so well. He is looking really, really good. Thank you so much! I need to order more soon.”

- Paul (Verified Customer)

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Your pet's immune system is the key to its health! Here's why:

It’s your job to feed and nourish it, and make sure it operates at optimal levels to fight disease and cancers. In today’s world, viruses and diseases are rampant, and it can be challenging to protect your pet.

Let’s face it: your pet lives in a world filled with contamination.

They spend 90% of their waking hours on the floor, mopping up toxins, chemicals, and pollutants.

The household cleaning products, fertilizer on the lawn, and preservatives in their foods can be harmful. Bacteria, airborne contaminants, and viruses transmitted by humans can challenge their health.

Most pets do not eat an optimal diet, and likely do not get as much exercise as they require.

What do you do?

You need to put your pet’s immune system in overdrive! Research shows that a well-balanced and functional immune system is essential to your pet’s overall health and well-being.

"The immune system acts like a nonstop housekeeper", describes Dr. Donna Raditic, an American College of Veterinary Nutrition (ACVN) diplomate in Athens, Georgia.

It identifies potentially harmful pathogens like bacteria, viruses, fungi, and parasites, then works to eliminate them before they can do harm.

And a pet's immune system monitors cells to ensure they’re working properly.

“When other cells are aging or functioning abnormally—such as a cancer cell reproducing too rapidly—the immune system attempts to step in and maintain proper physiological function and balance,” Dr. Raditic explains.

Your pet's immune system is the key to its health! Here's why:

It’s your job to feed and nourish it, and make sure it operates at optimal levels to fight disease and cancers. In today’s world, viruses and diseases are rampant, and it can be challenging to protect your pet.

Let’s face it: your pet lives in a world filled with contamination.

They spend 90% of their waking hours on the floor, mopping up toxins, chemicals, and pollutants.

The household cleaning products, fertilizer on the lawn, and preservatives in their foods can be harmful. Bacteria, airborne contaminants, and viruses transmitted by humans can challenge their health.

Most pets do not eat an optimal diet, and likely do not get as much exercise as they require.

What do you do?

You need to put your pet’s immune system in overdrive! Research shows that a well-balanced and functional immune system is essential to your pet’s overall health and well-being.

"The immune system acts like a nonstop housekeeper", describes Dr. Donna Raditic, an American College of Veterinary Nutrition (ACVN) diplomate in Athens, Georgia.

It identifies potentially harmful pathogens like bacteria, viruses, fungi, and parasites, then works to eliminate them before they can do harm.

And a pet's immune system monitors cells to ensure they’re working properly.

“When other cells are aging or functioning abnormally—such as a cancer cell reproducing too rapidly—the immune system attempts to step in and maintain proper physiological function and balance,” Dr. Raditic explains.

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“I have a rescue and keep 8 senior and special needs cats. I give them this for cats, and it has proven to extend the lives of those who were in danger of losing their lives from cancer, renal failure, and, frankly, only God knows what else! I am grateful for this formula being available for seniors we adore and aren’t really ready to cross the 🌈 yet❣️👍😻 This was Foxy Loxy. He had been failing(14 yrs old), but as he received Pet Wellness Support, he recovered his enjoyment of life, and I could love him for 2 more years❣️ I have other kitties' who had experienced similar recoveries through Pet Wellness. Thank you again!”

- Mat (Verified Customer)

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"My female pitbull was diagnosed with lymphoma back in 2020. We did chemo for 2 years. During this time, I found the product and started using it on all my dogs, even healthy ones.

We are now in almost 4 years later, and my girl Haven has been in remission for almost 2 years. I only give the product in the dinner feedings. I believe it saved her."

- Diane (Verified Customer)

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52%

CANCER RATES ARE SKYROCKETING

THE DOCTORS AGREE

Mushrooms = Anticancer Activity

“As a pet lover, I think it makes sense that the compounds in mushrooms be included in your pet’s diet or included by nutritional supplements. Certain mushrooms contain agents with anticancer activity and immunomodulatory properties that may help fight cancer and certain other diseases.”

- Dr. Frank Markland, Professor of biochemistry and molecular medicine at the University of Southern California Keck School of Medicine.

Pet owners CAN make a difference.

“It is the responsibility of the pet owner to do everything possible to minimize the risk of cancer in their pets. This includes a sensible lifestyle with sufficient exercise, weight management, drinking clean water, healthy food intake, and avoiding toxins. Giving your pets a high-quality antioxidant supplement is highly recommended to further reduce the risk of cancer.”

– Dr. Shawn Messonnier, Veterinarian and Founder of Paws & Claws Animal Hospital in Plano, Texas.

More dogs and cats are being diagnosed with cancer than ever before. 

“Certain mushrooms and turmeric may be beneficial in helping your pet to boost its immune system to fight diseases,” explains Edwards.

“Cancer is affecting our pets at alarming rates, and it is devastating for both the families of these pets as well as the pets themselves. I am seeing this in my practice on a regular basis.”

- Dr. Jennifer Edwards, Veterinarian at Ponemah Veterinary Hospital in Amherst, New Hampshire.

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"Sienna is 13 years old and is on two of your products. She been on this for several weeks and noticing a difference in enjoying the stairs again. Thank you for both! ❤️❤️❤️
Critical Immune Defense, has made a huge difference with a lump on her shoulder! Sienna is taking two of your products Critical Immune Defense, for a lump on her shoulder which has shrunk, to half its size after finishing first container, working on
Papilloma virus warts and skin tags...have two containers to go.
Sienna started having issues using the steps. I started her on your Hip+Joint product and within 10 days, no longer any issues. Sienna will be 14 this year. Loving these products 🙏🏻🤞🏻 in time Critical Immune Defense will help with the virus...."

- Gloria (Verified Customer)

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Organic Turkey Tail Mushrooms

This colorful mushroom has been used for centuries in Asia to treat disease and contains high levels of active compounds that have been proven to inhibit the growth of cancerous tumors.

✔︎ Delivers significant amounts of tumor-fighting Polysaccharopeptides (PSPs)

✔︎ Approved by the United States Food & Drug Administration for use in treating prostate and breast cancer in humans

✔︎ Proven to delay the growth of cancerous tumors in pets and improve their survival rate

Organic Reishi Mushrooms

This woody fungi is known as one of the top natural superfoods and has been used for 1000s of years to fight inflammation, cancer, heart disease, hormonal imbalances and more.

✔︎ Contains beta-glucans that increase the immune system’s T-cell levels

✔︎ Lowers inflammatory responses caused by stress, poor diet, and other environmental factors

✔︎ Contains ganoderic acids that have been shown to lower cholesterol levels and blood pressure

Organic Shiitake Mushrooms

According to the Journal of Nutrition, shiitake mushrooms provide antiviral, antibacterial and antifungal protection and help to control blood sugar and reduce inflammation.

✔︎ Contains all 8 essential amino acids as well as linoleic acid, an essential fatty acid

✔︎ Used in Japan to treat heart disease, hepatitis, high blood pressure, and infectious diseases

Organic Maitake Mushrooms

Maitake mushrooms are loaded with vitamins and active ingredients that stimulate the immune system and promote natural hormone balance and healthy cell growth.

✔︎ Contains beta-1, 6 glucan polysaccharide components that stimulate the immune system and reduce abnormal cell growth

✔︎ Used in Asia to help minimize the toxic effects of radiation and chemotherapy treatment

White Turmeric Root Extract

Turmeric has been used for centuries to reduce pain and inflammation. Its active ingredient, curcumin, has proven to be effective at blocking the growth of certain cancers and protecting against neurodegenerative diseases, arthritis, cardiovascular risks and liver damage.

Our proprietary extract is six times more bioavailable than standard turmeric root, which means it’s more effectively absorbed into your pet’s body and they need less of it to get the same effect. It’s also colorless and milder tasting, making it easier to handle -- and tastier for your pet! No more turmeric stains!

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"My dog is now 21 years old and this has helped so much. She is on her 3rd bottle, things were grown on face they are much smaller. She used to go to bathroom on herself, now she gets out of bed to go. She is close to 22, she eats at least 2 big meals a day! I know each day is a blessing with her! She is a Boston terrier and Rat terrier. this has helped tremendously! Thank you for giving her new time! Her eyes have also gotten much brighter too!"

- Gina (Verified Customer)

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Not only is it easy to use (just sprinkle it over your pet’s food), but also your pet will love the taste!

It’s your job to feed and nourish it, and make sure it operates at optimal levels to fight disease and cancers.
Order now

Not only is it easy to use (just sprinkle it over your pet’s food), but also your pet will love the taste!

It’s your job to feed and nourish it, and make sure it operates at optimal levels to fight disease and cancers.
Order now

Not only is it easy to use (just sprinkle it over your pet’s food), but also your pet will love the taste!

70 Scoops in a small bottle
210 scoops in a large bottle
10% Additional Saving

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"This product has been a blessing for our Ellie. Diagnosed with mast cell cancer given 1 year to live that was almost 4 yrs ago. She will be 12 in a few months we started her on this when she was 8 yr old. Still doing fantastic plays and acts like a puppy. Love this product.”

- Edie (Verified Customer)

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The All-Natural Solution. Trusted By Veterinarians.

Originally designed for veterinarians, VetSmart Formulas delivers the clinical-strength, quality and efficacy veterinarians demand of solutions they provide and recommend.

Critical Immune Defense is 100% safe to use, has NO side effects, and can be used in conjunction with chemotherapy, steroid treatments and other medications.

✔︎ Certified organic mushrooms

✔︎ No artificial colors or flavors

✔︎ Wheat-free

NEW Enhanced Formula

Discover Our Enhanced Formula!

We've improved our formula! The new product may appear lighter in color and have a slightly different texture (but the same great taste), thanks to our innovative use of the fruiting body and mycelium of the four mushrooms, instead of mushroom extracts.

 Why the Change?

Traditional mushroom extracts are processed using heated water, which is then sprayed to create a powder. Our research suggests that this heat processing can diminish the valuable nutrients in the mushrooms.

Understanding Fruiting Body and Mycelium

Fruiting Body: This is the part of the mushroom you're familiar with—the cap and stem.

Mycelium: These are the nutrient-packed roots and base of the mushroom.

We use the entire mushroom, grinding it into a nutrient-dense powder that boasts higher levels of beta-glucans and polysaccharides than extract powders. Independent testing has shown that our new mushrooms contain up to 250% more beta-glucans and polysaccharides.

Research-Backed Benefits

According to research published by the National Library of Medicine, beta-glucans and polysaccharides are renowned for their metabolic and immunomodulatory properties, including anticancer, antibacterial, and antiviral effects. In some countries, the mushrooms we use in Critical Immune Defense are prescribed not only to prevent cancers and diseases but also to effectively treat them.

Organic and Sustainable

Our mushroom blend is organically grown in Canada on sustainable farms using patented and breakthrough growing processes to enhance the full spectrum of bioactive compounds. It doesn't get any better for your pet!

Experience the powerful benefits of our enhanced formula and give your pets the best in health and wellness!

Made in the USA to the highest quality standards.

VetSmart Formulas is made in the USA in FDA audited facilities which adhere to cGMP and are audited by Underwriter Labs. Every ingredient is carefully inspected and tested before processing, ensuring a consistently safe, high-quality product for your beloved pet’s health.

Frequently Asked Questions

Still have questions?

Talk to us on Facebook Messenger

Or give us a call at 888-212-8400 Mon-Fri 9:00 to 5:00 PST

Returns | 30-Day Money Back | Ingredients

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average rating 4.8 out of 5
Based on 1600 reviews
  • 5 Stars
    1360 Reviews
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    170 Reviews
  • 3 Stars
    61 Reviews
  • 2 Stars
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  • 1 Star
    7 Reviews
96% of reviewers would recommend this product to a friend
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1600 Reviews
Reviewed by Deborah B.
Verified Buyer
Review posted
I recommend this product
Rated 5 out of 5
Pet Age
10+ Years
Cat Breed
Bengal
Pet Problem(s)
  • Cancer
  • Tumor
  • Bad Breath
Will Consume Product
Nibbled
Pet Happiness
Just Right

High Quality Immune Support

I've been giving this to my cat for 18 months now to help boost her immune system since being diagnosed with a bleeding liver tumor. I had a second ultrasound done last month to see what the status of the tumor was as the vets all said it's an aggressive tumor and she might have days or weeks. The latest ultrasound showed very little growth on 2 margins and a reduction in size by a small amount from the other margin. I didn't expect the tumor to be stopped in its tracks. Now she does have some episodes where it bleeds and causes her pain but that's not often. I ran out of the product a couple months ago and she went without it for 5 days until it arrived and she did end up having a pain episode. So yes, this mushroom blend and nutritional supplement, IS VERY CRITICAL to have for my girl. It has been her best defense against a tumor that has responded very well to these potent immune modulators. Very pleased with this product! I put it in capsules since she won't eat it on her own. This supplement is 100% worth every penny!

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Pet Wellness Direct

Thank you for sharing your sweet girl’s remarkable journey. 💛 We’re so glad to hear she has enjoyed more precious time with you and that her recent ultrasound brought encouraging news. 😺✨ We truly appreciate your 18 months of trust in Critical Immune Defense as part of her care routine and wish her continued comfort and many more cherished moments together.

Reviewed by Cynthia W.
Verified Buyer
Review posted
I recommend this product
Rated 5 out of 5
Pet Age
10+ Years
Dog Breed
Golden Retriever
Pet Problem(s)
  • Low Energy
  • Joint Pain
Will Consume Product
Enjoyed
Pet Happiness
Tail Wagging

10 months on Critical Immune Defense!

Molly started on CID December 12,2025 She was 10.5 years old Had a couple of noticeable masses in her lower abdomen She was sluggish & was having difficulty moving her bowels Her energy level had dropped significantly Within a month she had made great strides towards improvement! Energy increased, appetite returned stool movement improved She was swimming in the pool again & playing with her son Very happy with the results & will continue using it as long as we have Golden Retrievers

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Pet Wellness Direct

Thank you for sharing Molly’s wonderful progress! 💛 We’re so happy to hear your sweet Golden Retriever has regained her energy, appetite, and enthusiasm for swimming and playing with her son. 🐶✨ It’s especially encouraging to hear about her improved digestion and quality of life. We truly appreciate your continued trust in Critical Immune Defense and wish Molly many more happy, active days ahead!

Reviewed by Elizabeth A.
Verified Buyer
Review posted
I recommend this product
Rated 5 out of 5
Pet Age
7 - 10 Years
Dog Breed
Shih Tzu
Pet Problem(s)
  • Tumor
Will Consume Product
Nibbled
Pet Happiness
Just Right

This works

I tried critical immune defense before in the past and it’s not cheap so I didn’t want to do the recommended dosage for my two Shih Tzu’s, and they are both very healthy and they were fine and there was really nothing I was addressing. Years later, my male had a lump in his armpit so I ended up getting the bigger size giving them the recommended dosage each day and it has now been one month and I can’t even feel the lump anymore. Definitely definitely worth the money and definitely worth buying. It would’ve been thousands of dollars to have him undergo another surgery, this is a much better alternative. Also, they usually fight some sort of allergy this time of year, the scratching in the looking as not been an issue this year at all. This is definitely a great product, and definitely worth the money.

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Pet Wellness Direct

Thank you for sharing your Shih Tzus’ experience! 💛 We’re so glad to hear you’ve noticed encouraging changes in your boy’s lump and that both dogs are doing well during allergy season. 🐶✨ We truly appreciate your trust in Critical Immune Defense and are happy it has become a valued part of their wellness routine!

Reviewed by John R.
Verified Buyer
Review posted
I recommend this product
Rated 5 out of 5
Pet Age
10+ Years
Dog Breed
Mixed Breed
Pet Problem(s)
  • Hip Pain
Will Consume Product
Devoured
Pet Happiness
Tail Wagging

Great Results

Lucy Belle is 12 years old and I swear she acts like a young dog. I've never seen anything like it and I've raised and trained quite a few dogs. Critical Immune Defense is an amazing product and I highly recommend it.

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Pet Wellness Direct

Thank you for sharing Lucy Belle’s wonderful experience! 💛 We’re so happy to hear she’s thriving at 12 years old and still acting like a young pup. 🐶✨ We truly appreciate your trust in Critical Immune Defense and your recommendation!

Reviewed by Mary D.
Verified Buyer
Review posted
I recommend this product
Rated 5 out of 5
Pet Age
10+ Years
Dog Breed
Chihuahua
Pet Problem(s)
  • Joint Pain
  • Inflammation
  • Low Energy
  • Stress
Will Consume Product
Devoured
Pet Happiness
Tail Wagging

My dogs love it

My dogs get this every day and I have been giving it to them for several years now. My little Chihuahua used to have a heart murmur and it’s gone now and I’m not sure if this has anything to do with it, but I’ll take it as a win and I’ll keep giving them the product.

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Pet Wellness Direct

Thank you for sharing your experience! 💛 We’re so glad to hear your dogs enjoy Critical Immune Defense and that your little Chihuahua received encouraging news about her heart. 🐶✨ We truly appreciate your years of trust and continued support of your pups’ wellness!