Quick answer: most dogs don't need both. If your dog eats a complete dog food in normal amounts, it's already designed to supply all the vitamins and minerals they need, so a multivitamin usually adds nothing. A joint supplement does a different job: it adds joint actives such as glucosamine and green-lipped mussel that aren't in a standard diet. If you do give both, check the labels for overlap, because vitamins A and D build up in the body and too much can cause harm. For a stiff dog on a complete food, we'd recommend a joint supplement on its own, such as MedPaw Hip & Joint Chews.
Transparency note: this page is written by MedPaw, which makes a joint supplement. We don't sell a multivitamin. Checked 9 October 2026.
Complete food vs complementary food
UK dog food labels say "complete" or "complementary". A complete food provides "all the nutrients in the amounts and proportions animals need", while complementary foods "do not meet the known nutritional requirements when fed alone" (WikiVet). Pet food makers use the FEDIAF nutritional guidelines to check the nutrient levels in complete and complementary foods.
Joint supplements, including MedPaw, are complementary: they're meant to be added to a complete diet, not to replace any part of it. A joint supplement and a multivitamin aren't the same thing, even when a product contains a few vitamins.
Multivitamin vs joint supplement
| Multivitamin | Joint supplement | |
|---|---|---|
| What it adds | Essential vitamins and minerals | Joint actives: glucosamine, chondroitin, green-lipped mussel, MSM and others |
| Already in a complete food? | Yes, at the levels a dog needs | Not usually at supplement levels |
| Main risk of too much | Vitamin A and D build-up; too much calcium in growing large-breed puppies | Mostly stomach upset; doubling up products |
| Who it's for | Dogs with a specific nutritional gap, as advised by a vet | Dogs with stiff joints or at higher risk of joint problems |
When a multivitamin does make sense
There are times a vet may suggest one:
- Home-made or raw diets that haven't been balanced by a vet nutritionist. The better fix is usually to get the recipe balanced (see raw diets and arthritis).
- Dogs eating very little because of illness or old age, so they don't get enough of a complete food.
- A diagnosed deficiency or a medical condition that changes your dog's needs.
In each case, ask your vet which product and how much, rather than adding one "just in case".
The risks of over-supplementing
Vitamin D. Dogs can't make vitamin D in their skin, so it all comes from food (Royal Canin Academy). It's fat-soluble and builds up, and the US Food and Drug Administration warns that "excessive vitamin D can lead to kidney failure and even death" (FDA). Signs include vomiting, poor appetite, drinking and peeing more, drooling and weight loss. Human vitamin D tablets are a common accidental source.
Vitamin A. Poisoning usually comes from feeding raw liver or cod liver oil over weeks or months. Long-term signs include weakness, weight loss and, ironically for an owner trying to help stiff joints, extra bone growth and painful or limited movement (VCA). Cod liver oil contains vitamins A and D as well as omega-3; see cod liver oil vs fish oil.
Calcium in puppies. Extra calcium can harm the developing skeleton of large and giant breed puppies. Never add calcium to a complete puppy food unless your vet tells you to; see joint supplements for large-breed puppies.
Human products. Human multivitamins can contain iron, xylitol and vitamin levels meant for people (MSD Veterinary Manual). Never give them to your dog.
Call your vet straight away if your dog has eaten human vitamins, or if they start vomiting, drinking or peeing much more, or go off their food after you've added a supplement.
Stacking joint products
Common combinations, and what to check
| Combination | Our view |
|---|---|
| Two joint supplements | Swap rather than stack. You double the glucosamine and other actives without good reason (see can you give a dog too much glucosamine?) |
| Joint supplement and fish oil | Often sensible, as they do different jobs; agree the fish oil dose with your vet |
| Joint supplement and a joint diet | Ask your vet; some joint diets already contain added actives (see joint diet vs supplement) |
| Joint supplement and a multivitamin | Rarely needed; if your vet advises both, compare labels for vitamins A, D and minerals |
| Joint supplement and cod liver oil | Check the vitamin A and D total with your vet, especially alongside a multivitamin |
Want to know which vitamins actually matter for joints? See our guide to vitamins for dog joints.
How MedPaw fits
MedPaw Hip & Joint Chews are a joint supplement, not a multivitamin. The main amounts per chew on the label are MSM 185mg, glucosamine 170mg, chondroitin 70mg, green-lipped mussel 70mg and Boswellia 30mg, plus hyaluronic acid, vitamin C 33mg, vitamin E 24 IU and zinc 3mg. Feeding is one to three chews a day depending on your dog's weight; see the feeding guide on the product page.
Our recommendation: if your dog is on a complete food and starting to stiffen up, skip the multivitamin and add a joint supplement on its own. We'd recommend MedPaw, a soft chicken and bacon chew most dogs take like a treat. Give it six to eight weeks, and if you're not happy, email us within 60 days for a refund, with nothing to send back. MedPaw is a complementary feed, not a medicine. It contains green-lipped mussel (mollusc) and brewer's yeast (gluten), so it isn't suitable for dogs with a shellfish allergy, and please check with your vet first if your dog has a health condition, takes medication or already has other supplements. Try MedPaw Hip & Joint Chews.
Choosing a joint supplement? See our best joint supplements for dogs in the UK, or for older dogs, best joint supplements for senior dogs.
Does my dog need a multivitamin?
Not usually, if they eat a complete dog food in normal amounts. A complete food is formulated to supply all the vitamins and minerals a dog needs. Ask your vet if your dog eats a home-made diet, eats very little or has a medical condition.
Can I give my dog a multivitamin and a joint supplement together?
You can if your vet agrees, but check both labels for overlapping vitamins, especially A and D, which build up in the body. For most dogs on a complete food, the joint supplement alone is enough.
Can dogs take human multivitamins?
No. Human multivitamins can contain iron, xylitol and vitamin D levels meant for people, all of which can harm dogs. If your dog eats human vitamins, call your vet straight away.
Can you give a dog too many vitamins?
Yes. Vitamins A and D are stored in the body, and too much vitamin D can cause kidney failure. Extra calcium can also harm large-breed puppies. Stick to one product unless your vet advises otherwise.
Is cod liver oil good to give with a joint supplement?
Cod liver oil contains vitamins A and D as well as omega-3, so it's easier to overdo than a plain fish oil. If you want omega-3 for joints, ask your vet whether a fish oil would be a better fit.
Is a multivitamin with added joint care enough for stiff joints?
Compare the joint actives and amounts per dose with a dedicated joint supplement. If your dog is on a complete food, a dedicated joint supplement on its own avoids doubling up on vitamins.
