Quick answer: most older dogs eating a complete senior food don't need a cupboard full of supplements. The ones with a real case are a joint supplement and omega-3 for stiffness, daily tooth brushing (or a tested dental product) for teeth, and, for dogs showing signs of doggy dementia, a vet-guided brain-support diet or supplement. Probiotics have little evidence outside short bouts of diarrhoea, and a multivitamin is rarely needed. For the most common problem in older dogs, stiff joints, we'd recommend MedPaw Hip & Joint Chews, a soft chew that's easy on older mouths.
Transparency note: this page is written by MedPaw, which makes a joint supplement. We've included supplements we don't make and linked our sources. Checked 9 October 2026.
Start with a senior check-up
Many changes owners put down to age are treatable conditions. Before you buy anything, a senior health check (and blood tests if your vet suggests them) tells you what your dog actually needs. See a vet rather than reaching for a supplement if your older dog is:
- drinking or peeing more than usual
- losing weight or going off their food
- limping, crying out or struggling to get up
- confused, pacing at night or getting lost in the house
- coughing, breathing fast at rest or tiring very quickly
- growing new lumps, or has smelly breath, bleeding gums or trouble chewing
Supplements for older dogs, need by need
What's worth considering for an older dog, and how good the evidence is
| Need | What to consider | Evidence |
|---|---|---|
| Stiff joints | Omega-3 and a joint supplement | Omega-3 strongest for arthritis pain; glucosamine and chondroitin not shown to relieve pain |
| Brain ageing | A brain-support diet or supplement, through your vet | Promising: positive placebo-controlled trials, but few of them |
| Teeth | Daily brushing first; products with the VOHC seal | Brushing is the gold standard; VOHC products are tested for plaque or tartar |
| Gut | Probiotics | Weak: a very limited effect on acute diarrhoea in a systematic review |
| General health | A multivitamin | Rarely needed on a complete food; too much vitamin A or D can harm |
Joints: the most common need
Osteoarthritis is mainly a disease of older dogs: in a Royal Veterinary College study of UK dogs, the median age at diagnosis was 10.5 years (Anderson et al., 2018). A 2022 review of 72 trials found omega-3 had the clearest effect on arthritis pain (Barbeau-Grégoire et al., 2022). For the full comparison of joint products for older dogs, read our deep-dive on the best joint supplements for senior dogs.
Brain: cognitive dysfunction
Canine cognitive dysfunction, often called doggy dementia, shows as night-time waking, getting stuck in corners, forgetting house-training or not recognising people. The best evidence is for diets rather than single pills. In a placebo-controlled trial of 87 older dogs with signs of cognitive dysfunction, a diet with medium-chain triglycerides (MCT) plus a blend of B vitamins, antioxidants, omega-3 and arginine improved all six categories of signs within 90 days (Pan et al., 2018). A smaller placebo-controlled trial of a cognitive supplement across 20 UK practices also reported improvements in activity and house-training (Heath et al., 2004). Your vet can also discuss medication, so ask them before choosing.
Teeth
Dental disease was the most common problem diagnosed in a VetCompass study of over 22,000 UK dogs, affecting 12.5% (VN Online, 2021). Daily brushing is the gold standard, and if you use chews, diets or water additives, choose ones with the Veterinary Oral Health Council seal, which have been tested for plaque or tartar (VCA). Sore teeth need a vet. See dental care for senior dogs.
Gut
Probiotics are popular, but a systematic review of 17 studies found only "a very limited and possibly clinically unimportant effect" on acute diarrhoea, and no clear extra benefit in chronic gut disease on top of diet (Jensen and Bjørnvad, 2019). An older dog with ongoing diarrhoea, vomiting or weight loss needs a vet.
Multivitamins
A complete food is made to supply all the vitamins and minerals your dog needs, so adding a multivitamin usually adds nothing, and vitamins A and D build up if overdone. Our guide does my dog need a multivitamin and a joint supplement? explains when one does make sense.
Lifestyle first
The basics do more than any supplement: keep your dog lean (see senior nutrition), swap long walks for shorter, more frequent ones, add rugs and a ramp, give them a supportive bed and keep their brain busy with sniffing and food puzzles. Our guide to keeping a senior dog mobile has more, and if your dog is mainly slowing down on walks, see the best supplement for an old dog slowing down.
Don't over-supplement
- Add one product at a time, and give it six to eight weeks before judging.
- Check for overlaps: a fish oil, a joint chew and a multivitamin can each contain vitamins.
- Never give human supplements: some contain xylitol, which is toxic to dogs (see human joint supplements and dogs).
- Tell your vet everything your dog takes, especially before blood tests, surgery or new medication.
How MedPaw fits
MedPaw Hip & Joint Chews at a glance
| What older-dog owners ask | MedPaw |
|---|---|
| What does it cover? | Joints only. All six key joint actives: glucosamine, chondroitin, MSM, green-lipped mussel, hyaluronic acid and Boswellia |
| Main amounts per chew | MSM 185mg, glucosamine 170mg, chondroitin 70mg, green-lipped mussel 70mg, Boswellia 30mg, plus vitamin C 33mg, vitamin E 24 IU and zinc 3mg |
| Easy for an older dog? | Soft chicken and bacon chew, given like a treat |
| Brain, gut or teeth? | No. Use the options above for those |
| Guarantee | 60 days from delivery, for any reason |
Our recommendation: if your older dog is stiff getting up, slower on walks or hesitating at the stairs, and your vet is happy, start them on MedPaw. Give it two to three months, as the label recommends, and keep a note of how they move. If you're not happy, email us within 60 days and we'll refund you, 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 older dogs often take medication, so please check with your vet first. Try MedPaw Hip & Joint Chews.
What supplements should I give my older dog?
Only the ones that match a real need. For most older dogs that means joint support and omega-3 for stiffness, plus tooth brushing or a tested dental product. Get a senior check-up first, because many age-related changes need treatment rather than a supplement.
What is the best supplement for an elderly dog's brain?
The best evidence is for a brain-support diet containing medium-chain triglycerides with antioxidants, B vitamins, omega-3 and arginine, which improved signs of cognitive dysfunction in a placebo-controlled trial. Ask your vet, who can also discuss medication.
Do senior dogs need probiotics?
Not routinely. A systematic review found only a very limited effect on acute diarrhoea. If your older dog has ongoing tummy trouble, see your vet rather than relying on a probiotic.
Should my old dog have a multivitamin?
Usually not, if they eat a complete food in normal amounts. A multivitamin can make sense for dogs on home-made diets or eating very little, but ask your vet, because too much vitamin A or D can cause harm.
Is fish oil good for older dogs?
For stiff or arthritic dogs, omega-3 from fish oil has the strongest evidence of any joint supplement. Ask your vet about the right dose, and tell them before surgery or if your dog has a health condition.
When should I start supplements for my senior dog?
When there's a reason to, such as early stiffness. When that is depends on size and breed, as larger dogs age sooner. See our guide to when a dog is considered senior.
