Best Dog Antioxidant Supplements of 2025

"I trust Resources as one of the most reliable companies out there. Both my traditional and holistic vets recommended this supplement. My girls are 11 years old and have taken these antioxidants for years. They've only had routine checkups and adjustments, and thankfully, no health issues. While I can't say this supplement is the sole reason for their great health, I believe it supports their immune systems."

"Since my Scotty-Schnauzer mix started on this supplement, her chronic skin issues improved significantly. She had been on Prednisone and was experiencing unpleasant symptoms. After switching from Select Antioxidant by Vetoquinol to this product, I noticed less smell, flaking, and bump-free skin. My vet approved the switch, and I recommend this for anyone dealing with similar issues!"

"After rescuing my black lab who suffered from constant itching, I tried everything until I found this product on Amazon. Since incorporating it into her meals, the scratching stopped, and she seems much happier and more comfortable. It's a blessing for our family!"

"I purchased Zesty Paws Urinary Tract Chews to support my dog's urinary health. I’m truly impressed with the results! My dog has had occasional urinary issues, and I wanted a natural solution to prevent future problems. Since starting her on these chews, her urinary health has been much more balanced, and there have been no issues. Knowing that the cranberry and marshmallow root ingredients are gentle yet effective gives me peace of mind. Plus, she absolutely loves the taste—she thinks they’re treats and gets excited every time I open the jar. I highly recommend these for anyone wanting to support their dog's urinary health in a tasty way!"

"I’m thrilled with how Zesty Paws Cranberry Bladder Bites have worked for my 7-year-old dog! She loves the chicken flavor, treating them like snacks, which makes giving them to her effortless. After a few weeks, I’ve noticed she seems much more comfortable and has more energy. The blend of D-Mannose, Vitamin B6, and L-Arginine is impressive, and it feels great to know these chews support her urinary tract health, as well as her immune and gut health. I’m so relieved to have found a natural supplement that truly works!"

"Initially skeptical, I tried this product for my 17-year-old dog, Sampson, who has to wear washable diapers. After noticing a constant drip and frequent diaper changes, I decided to give this a shot. After using it for a month, I’m delighted to share that he now only goes through 2-3 diapers a day! I couldn’t be happier with the results!"

"I have a 13-year-old black lab who is very arthritic. Despite being on a vet-prescribed regimen for years, she was still stiff. After starting these supplements, she's noticeably more comfortable and even trots to chase a tennis ball again. It’s not a miracle, but I see a real difference. I recommend hiding the pills in soft cheese to get her to take them."

"My 14-year-old dog seems to benefit from these for her joint issues. She still moves fast and chases squirrels, which is great to see!"

"Two of these every morning and my dog is back to running with others! They’ve significantly alleviated his joint and muscle pain, and he takes them directly from my hand without any fuss."

"This product has truly made a big difference for my older dog. She has regained her energy and is able to go up and down the stairs with ease now. I’ve been giving her the recommended dosage for months, and she loves the improvement in her quality of life!"

"After starting my 11-year-old dog on this cardio support, I noticed she became more energetic right away. Our vet was surprised at her stable heart condition since she began taking these tablets. They may not be tasty, but I find crushing them in moist food helps!"

"I initially bought this for my dog nearing the end stage of heart failure, but I should have started sooner. Now, my new dog Pebbles has shown great improvement after starting this supplement, with her heart murmur downgraded significantly at her last vet visit!"

"I don't usually write reviews, but I had to for CAS Options. This supplement literally saved my dog's life. After being exposed to harmful pesticides, my dog was on the brink of death. Thanks to CAS Options, he regained his health and lived 6 more years! Though it’s a bit pricey, it saved me from thousands in vet bills and heartache. I highly recommend it!"

"For over 6 years, I've used this product for my dogs, and it keeps them very healthy! I'm thrilled with the results."

"I started giving CAS Options to my 10-year-old Schnauzer mix, who had slowed down significantly. Within 2 months, he became more active and some of his fatty tumors shrunk. The same goes for my 8-year-old Shepherd. Although a little pricey, it's totally worth it because my dogs are acting like puppies again!"

"I purchased my second bottle of this product for my dog who developed a harmless bump in her armpit, identified as a papilloma. After trying various remedies, I decided to sprinkle the contents over her food. Within one week, the bump was over half its size, and by the second week, it was completely gone. My dog's rashes fully subsided, and I haven't had to use apoquel in almost three months. This product has been a miracle for her skin allergies!"

"I bought this for my 4-year-old Bernese Mountain Dog who suffers from chronic ear infections. After starting her on this supplement, we have only had to clean her ears once! The previous black nastiness is gone, and her ears look normal now. My other dog showed similar improvements, and I’m committed to giving this to them for life!"

"I was really hopeful about this product based on the reviews, but my cat did not react well. After three days, she vomited five times and had diarrhea, leading her to stop eating altogether. I had to discontinue the supplement, and thankfully, she's slowly recovering now. I advise using this product with caution!"

"My dog comes running when I open the bag. At 12 years old, she's still spunky, and I believe these help with her joints and calm her during storms."

"I give this to all three of my dogs before bedtime. They sleep well and wake up energized, plus it made a huge difference for my older dog, who now acts like a puppy!"

"I really wanted to love this product because I like the ingredients, but my dog wouldn’t eat them no matter what I tried. I’m disappointed that it isn't eligible for return!"

"Since starting this supplement, my dogs have had no urinary tract issues. They love the taste, and I give it to them 2-3 times a week."

"I have two dogs, and the chewable tablets are like treats for them. They both enjoy them daily, and my female now urinates much less. I'm really pleased with the results!"

"After trying many remedies for my dog's UTIs, I saw a huge difference in her urinary frequency within just a few days of using this product. It's been a year now, and she hasn't had a single UTI since!"

"I have a pit bull/dachshund mix named Riley who was struggling with constipation. After reading numerous reviews, I decided to try Naturvet Stool Ease and it worked great! I give him one a day, and if he gets constipated again, I give him two. He even thinks they are treats!"

"My dog has been taking these chewables without any issues, and I’ve noticed a significant decrease in her scratching and chewing on her paws. They have really made a difference!"

"I bought these for my dog who was always itching. After trying them, he hardly scratches anymore and seems to feel much better. These work better than the more expensive vet treatments I tried!"

“I have Labs, and I’ve noticed a significant improvement in their movements.”

“I called a friend at a vet’s office about my young giant schnauzer, and she recommended Comfort. It's much cheaper on Amazon, and I've seen a marked improvement in just two weeks. I will definitely keep him on these.”

“My little hound loves them. I can't explain why they work, but I can tell she’s less spry and uncomfortable when I run out. So, I keep using them because they do work.”