What are antioxidants?

Antioxidants are dietary supplements that protect against cellular damage caused by reactive compounds, such as free radicals or hydrogen peroxide. These reactive compounds are produced as a by-product of inflammation; when inflammation is chronic, the body’s natural antioxidants may become depleted and supplementation may be needed. When reactive compounds accumulate in the cells, DNA damage, and eventually cancer can develop, so antioxidants are very important. Antioxidants are most often used in cats, dogs, and horses.

"Antioxidants are most often used in cats, dogs, and horses."

Antioxidants may include vitamins, minerals, amino acids, herbs, botanicals, enzymes, or other nutraceuticals. Some examples include vitamin C, vitamin E, selenium, and glutathione peroxidase. While many supplements are sold over the counter, they still contain ingredients that have biological effects that should be managed by your veterinarian. Follow your veterinarian’s directions and cautions very carefully as their directions may be significantly different from those on the label.

There are differences in how countries regulate supplements. In the United States, these substances are not as vigorously regulated by the FDA as other medications, which means they can be sold without the manufacturer proving their effectiveness, safety, and without a guarantee of consistent or accurately reported ingredients. In Canada, products that have been evaluated for quality, safety, and effectiveness by Health Canada and authorized for sale will have a license number on the label.


How effective are antioxidants?

Limited studies in animals have been performed, but there is anecdotal evidence that antioxidants work to treat cell damage caused by inflammatory conditions like allergies and arthritis.


How are antioxidants given?

Antioxidants are typically administered by mouth in various forms depending on the type, and may include tablets, capsules, chewable tablets, or liquids. Follow your veterinarian’s instructions or the instructions on the label for how to administer (with or without food, what form, etc.). Measure liquid forms carefully.


What if I miss giving my pet the supplement?

If you miss a dose, give it when you remember, but if it is close to the time for the next dose, skip the dose you missed and give it at the next scheduled time, and return to the regular dosing schedule. Never give your pet two doses at once or give extra doses.


Are there any potential side effects?

Studies in animals are limited for many supplements and therefore specific information regarding side effects is also limited. Antioxidants are generally considered safe when used at the recommended dose. Side effects will depend on the type of supplement and may include mild stomach upset.


Are there any risk factors for this supplement?

Studies in animals are limited for many supplements and therefore specific information regarding risk factors is also limited. Use antioxidant supplementation cautiously in pregnant pets. Dose vitamin A and other fatty vitamins carefully, as high doses can cause serious side effects.


Are there any drug interactions I should be aware of?

There are no known general antioxidant drug interactions. However, always follow your veterinarian’s instructions and read the supplement label for any known drug interactions.

"Vitamins, herbal therapies, and supplements have the potential to interact with each other, as well as with prescription and over the counter medications."

Vitamins, herbal therapies, and supplements have the potential to interact with each other, as well as with prescription and over the counter medications. It is important to tell your veterinarian about any medications (including all vitamins, supplements, or herbal therapies) that your pet is taking.


Is there any monitoring that needs to be done with this supplement?

There is no specific monitoring that needs to be done while your pet is taking this medication. Your veterinarian may monitor your pet to be sure that the medication is working.


How do I store antioxidants?

Most antioxidants should be stored in a cool, dark place, but always follow the specific instructions on the label, as different antioxidants may have different storage recommendations.


What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.

This client information sheet is based on material written by: Rania Gollakner, BS, DVM, MPH

© Copyright 2020 LifeLearn Inc. Used and/or modified with permission under license.