Most healthy dogs don't need extra of either vitamin. Dogs make their own vitamin C in the liver, and a complete and balanced dog food already supplies the vitamin E they need. Small added amounts, like those in some joint chews, work as everyday antioxidant nutrition rather than a fix for a deficiency.
Each Everhound Hip & Joint chew includes 75 mg of vitamin C and 25 IU of vitamin E. Here is what each vitamin does, what the joint research actually found, and when to be careful.
Do dogs need vitamin C?
Unlike people, dogs can make vitamin C. They synthesize it from glucose in the liver, and AAFCO, the group whose nutrient profiles US pet foods follow, sets no dietary vitamin C requirement for dogs (Merck Veterinary Manual).
Vitamin C still does useful work. It is an antioxidant, and it plays a role in collagen synthesis, the process that builds the structural protein found in cartilage, tendons and skin. Merck notes that supplementation "may provide additional health benefits," but it doesn't list a specific one for healthy dogs.
Vets also use vitamin C as a medication in specific situations, for example as an antioxidant for certain poisonings (VCA Animal Hospitals). That is a medical use at medical doses, chosen by a vet, and very different from the small amount in a daily chew.
Vitamin E for dogs: an essential nutrient
Vitamin E is the opposite case. Dogs can't make it, so it has to come from food (PetMD). It works as an antioxidant that protects cell membranes from oxidative damage (Merck), and PetMD adds that it supports immune function and normal metabolism.
Deficiency is uncommon in dogs eating a complete and balanced dog food. When it does happen, Merck lists muscle weakness, reproductive problems and retinal degeneration among the signs. Dogs on home-cooked or unusual diets are the ones to discuss with your vet, who can check vitamin E levels with a blood test.
What the research says about vitamin E and dog joints
Vitamin E comes up in arthritis conversations because of its antioxidant role, and PetMD notes vets sometimes recommend it for osteoarthritis. The best test so far, though, didn't find a benefit. In a 2023 blinded, placebo-controlled trial, 57 dogs with osteoarthritis, each weighing 20 to 40 kg (about 44 to 88 lb), received 400 IU of vitamin E or a placebo every day for 90 days. Vitamin E did not improve pain, lameness or quality of life compared with placebo, and the authors concluded it could not be recommended for that purpose (Gordon et al., Journal of Veterinary Internal Medicine, 2023).
That's a useful reminder for any vitamin: it is nutrition, not pain medicine. If your dog's mobility is changing, or your dog is suddenly limping or struggling to stand, a vet exam comes first.
Why a joint chew includes vitamins C and E
In Everhound Hip & Joint, vitamin C (as ascorbic acid, 75 mg per chew) sits next to egg shell meal, which the label lists as a source of collagen, and the body uses vitamin C to make collagen. You can read about that ingredient in eggshell membrane for dogs. Vitamin E (25 IU per chew) adds antioxidant nutrition. Neither is there to correct a deficiency; they round out the formula.
You may also spot "mixed tocopherols" farther down the ingredient list. Tocopherols are forms of vitamin E, and there they act as a natural preservative. PetMD notes vitamin E is added to dog foods partly to keep them from spoiling.
Serving goes by weight, from one chew a day under 25 lb up to five over 100 lb, so daily amounts range from 75 to 375 mg of vitamin C and 25 to 125 IU of vitamin E. The full chart is in how to give joint chews with food, and our guide on how to read a dog joint supplement label shows how to tell actives from preservatives on any label.
Can a dog get too much vitamin C or vitamin E?
Vitamin C. Merck notes that excess vitamin C has raised concerns in dogs with a history of calcium oxalate bladder stones, because vitamin C breaks down into oxalate. VCA lists diarrhea as a side effect, advises against vitamin C for dogs with copper storage disease, and urges caution in dogs with kidney or bladder stones (VCA).
Vitamin E. Merck calls it one of the least toxic fat-soluble vitamins, but very high doses can interfere with absorption of the other fat-soluble vitamins. Because it is fat-soluble, it can build up in the body, so PetMD advises against adding a vitamin E supplement without your vet's input.
Human vitamins. These carry a separate risk. The FDA lists chewable vitamins and dietary supplements among products that may contain xylitol, which can cause a fast, dangerous drop in blood sugar in dogs (FDA). Human doses are also sized for people, not for a 20 lb terrier.
Everhound Hip & Joint is a chicken-flavor soft chew for adult and aging dogs. Its vitamin C and E sit beside glucosamine, chondroitin, MSM, turmeric, yucca and egg shell meal, each listed by amount. It supports joints, cartilage, and mobility as daily nutrition. The ingredient research is on our science page.
FAQ
Should I give vitamin C and E with food?
Food is a good idea. VCA says vitamin C can be given with or without food, and its vitamin E page notes that oral supplements are best absorbed with a meal. Giving a joint chew at mealtime covers both.
Can I give my dog vitamin E capsules from my medicine cabinet?
Not without asking your vet. Human capsules are dosed for people and some supplements contain xylitol or other ingredients that aren't safe for dogs. If your vet wants your dog on extra vitamin E, they will recommend a product and an amount.
Do senior dogs need extra vitamin C?
Dogs of all ages make their own vitamin C, and there is no dietary requirement for it in dog food. A small amount in a joint chew is fine for most dogs, but a dog with a history of bladder stones should get your vet's okay first.