The supplement aisle for dogs has grown enormous. It is easy to end up with a cupboard full of powders, oils and chews without a clear sense of what any of them are actually doing.
My general approach is the opposite of “more is better.” Some supplements can be genuinely useful. Others only make sense once a specific problem has been identified. Knowing which is which matters more than the brand you choose.
The aim is not to give your dog everything available. It is to match the right support to what your individual dog actually needs.
The direct answer
If I had to choose one supplement with broad potential benefit for many adult and senior dogs, it would be an omega-3 supplement providing EPA and DHA.
Almost everything else—vitamins, CoQ10, probiotics, joint products, kidney and liver formulas, mushroom extracts and cognitive supplements—should be chosen for a specific purpose rather than added automatically.
Most healthy dogs eating a nutritionally complete and balanced diet do not need a general multivitamin or a long list of daily supplements. Supplements can support good nutrition and veterinary care, but they cannot compensate for an unsuitable diet, untreated pain, loss of muscle, dental disease or an undiagnosed medical problem.
Does every dog need supplements?
No.
A complete diet should already provide the essential vitamins, minerals, amino acids and fatty acids your dog needs for that life stage. Adding more does not necessarily improve health. In some cases, it simply adds calories and expense. In others, excessive supplementation can disturb the nutritional balance of the diet or cause harm.
The situation is different for dogs eating a home-prepared diet. These diets usually require a carefully calculated vitamin and mineral supplement to make them complete. The recipe and supplement should be formulated together by a veterinarian with advanced training in nutrition.
Supplements may also be appropriate for dogs with a diagnosed disease, a confirmed deficiency or a particular clinical need. The important thing is to choose the supplement for the dog—not to build the dog’s healthcare around whichever product happens to be popular.
Which supplements have the best evidence?
The table below summarises the most common supplement categories I am asked about. The evidence varies, and the right choice depends on the dog.
| Supplement type | When it may be useful | What the evidence tells us |
|---|---|---|
| Omega-3 fatty acids containing EPA and DHA | General anti-inflammatory support; osteoarthritis, some skin conditions and selected medical conditions | Among the better-supported options, but the dose and formulation matter |
| Joint products such as glucosamine, chondroitin, collagen, UC-II and green-lipped mussel | Osteoarthritis or mobility problems | Mixed. Glucosamine–chondroitin has performed poorly in higher-level reviews; evidence for collagen is weak |
| Probiotics, prebiotics and synbiotics | Selected gastrointestinal problems or periods of digestive disruption | Product- and strain-specific. Evidence for routine use in every healthy dog is limited |
| Medium-chain triglycerides and targeted brain-support diets | Some dogs with cognitive dysfunction or epilepsy | Evidence exists for specific therapeutic diets and formulations, not for casually adding coconut oil |
| Vitamins and minerals | A documented deficiency, properly formulated home-prepared diet or particular medical indication | Essential when genuinely needed; unnecessary or potentially harmful when added blindly |
| Heart, kidney and liver support products | Dogs with a diagnosed condition and a defined treatment goal | Potentially useful adjuncts, but choices must follow the diagnosis, medication and test results |
| Mushroom extracts and other immune-support products | Sometimes considered as adjunctive support, particularly in cancer care | Interesting but limited and product-specific canine evidence; not a proven general longevity treatment |
1. Omega-3 fatty acids: the supplement I use most often
When I recommend omega-3s, I am interested in the amount of EPA and DHA the product provides. These are the long-chain omega-3 fatty acids most often studied in dogs.
Fish and marine oils provide EPA and DHA directly. Plant sources such as flaxseed contain alpha-linolenic acid, which dogs convert inefficiently to EPA and DHA. Flaxseed oil therefore should not be treated as an equivalent substitute when the goal is a therapeutic anti-inflammatory effect.
Omega-3s influence inflammatory pathways throughout the body. The strongest practical evidence is for osteoarthritis. A 2022 systematic review and meta-analysis found clinically meaningful pain-relieving effects from omega-3-enriched diets and supplements. A 2025 review also found supportive evidence for several chronic conditions, including osteoarthritis and atopic skin disease.
In my clinical approach, omega-3s are the one supplement I am comfortable considering for many adult and senior dogs even before a specific disease is diagnosed. That is a clinical judgement based on their broad biological role and safety when used appropriately. It is not evidence that fish oil has been proven to extend lifespan in healthy pet dogs.
How much omega-3 should a dog receive?
A commonly used clinical range is approximately 50–100 mg/kg per day of combined EPA and DHA, but this is not a universal dose. The right amount depends on the purpose, the dog’s diet, body size, medical history and other medication.
Dose the product according to the EPA and DHA listed on the label—not the total amount of fish oil and not simply the number of capsules. A capsule labelled “1,000 mg fish oil” may contain far less than 1,000 mg of combined EPA and DHA.
Introduce fish oil gradually because some dogs develop loose stools when it is started too quickly. Excessive amounts can add substantial calories, cause gastrointestinal upset and alter platelet function. Extra caution may be needed in dogs with pancreatitis, clotting problems or medication that affects bleeding.
Fish oil can also oxidise. Choose a reputable product, follow its storage instructions and pay attention to the expiry date. If your dog already eats a therapeutic diet enriched with omega-3s, include that amount before adding more.
2. Vitamins B and D: only with a clear reason
I do not recommend routine vitamin B or D supplementation for every dog.
B vitamins are water-soluble, while vitamin D is fat-soluble. Their risks are not identical, but both should still be used for a defined reason. Vitamin D toxicity can be severe. B-vitamin requirements can change with diet, gastrointestinal disease, kidney disease and other medical conditions.
Targeted supplementation may be appropriate when blood testing has demonstrated a deficiency, a disease affects digestion or nutrient absorption, kidney or gastrointestinal disease is causing increased losses, a medication alters nutrient requirements, or the dog is eating a properly formulated home-prepared diet that requires supplementation.
A dog eating a complete commercial diet does not usually need additional B vitamins or vitamin D simply for “extra protection.” Senior dogs do not automatically need a multivitamin because they are older.
If an older dog is losing muscle, becoming weak or eating poorly, the priority is to find out why. A vitamin chew will not correct inadequate protein intake, osteoarthritis, dental pain, kidney disease or another underlying illness.
3. Joint supplements: popular does not always mean effective
Glucosamine and chondroitin are probably the best-known joint supplements for dogs. They are also a good example of why popularity and evidence are not the same thing.
Individual studies have produced mixed results, but a 2022 systematic review found a marked lack of pain-relieving effect from glucosamine–chondroitin products in dogs and cats with osteoarthritis. Collagen-based products showed only weak evidence of benefit.
Other ingredients, including undenatured type II collagen, green-lipped mussel and certain combination products, have shown some encouraging results. However, studies are often small, formulations differ and one positive study cannot automatically be applied to every product containing the same ingredient.
Collagen may be considered as an adjunct for some dogs with early stiffness or concurrent skin concerns, but owners should have realistic expectations. It is not a substitute for diagnosing pain, maintaining muscle or treating osteoarthritis properly.
A dog who is slow to rise, reluctant to climb stairs or no longer comfortable on walks needs a mobility assessment. Appropriate movement, muscle preservation, physiotherapy, home modifications and effective pain relief generally matter more than the joint chew chosen at the pet shop.
4. Probiotics and prebiotics: strain and purpose matter
Probiotics are live microorganisms intended to provide a health benefit. Prebiotics are substances used by beneficial gut microbes. A synbiotic combines both.
These products are not interchangeable. A probiotic is identified by its genus, species and strain, and the result seen with one strain cannot simply be assumed for another. The number of viable organisms, storage conditions and ability to remain viable until the expiry date also matter.
Some strains and organisms, including Saccharomyces boulardii, have shown benefits in particular canine gastrointestinal studies. However, a 2024 systematic review and meta-analysis found that gastrointestinal nutraceuticals, including probiotics, did not produce a clinically meaningful reduction in the duration of acute diarrhoea overall.
There is good reason to be interested in the gut microbiome. A large amount of immune activity occurs within and around the gastrointestinal tract. But changing the organisms detected in a stool sample is not automatically the same as making a dog healthier or extending its life.
I may consider a carefully chosen probiotic for a dog with a specific gastrointestinal problem, during recovery from some illnesses or after medication that has disrupted the microbiome. I would not assume that every healthy dog needs a daily probiotic indefinitely.
Diet, fibre intake and the underlying cause of gastrointestinal signs are often more important. If your dog repeatedly has soft stools, vomiting, poor appetite or weight loss, do not keep changing supplements. Those signs need to be investigated.
5. Brain health and cognition
Nutrition can play a useful supporting role in some senior dogs with cognitive dysfunction.
Research published in 2018 found improvement in dogs fed a therapeutic diet containing medium-chain triglycerides together with a specific brain-protection nutrient blend.
The distinction is important. This evidence applies to a studied formulation, not to adding an arbitrary spoonful of coconut oil to your dog’s meals.
Coconut oil is calorie-dense and contains a different mixture of fats from the MCT preparations used in research. It should not be treated as a general brain or longevity supplement.
If an older dog is pacing at night, becoming disorientated, forgetting familiar routines or having new toileting accidents, cognitive dysfunction is one possibility. Pain, sensory decline, kidney disease, hormonal disease and other medical problems can cause similar changes.
A supplement should come after an assessment, not instead of one.
6. Heart supplements: for diagnosed heart disease
Heart supplements should be matched to the type and stage of heart disease. They do not replace prescribed cardiac medication, echocardiography or ongoing monitoring.
Coenzyme Q10
Coenzyme Q10, or CoQ10, is involved in cellular energy production and has antioxidant activity. It is a reasonable adjunct to discuss for some dogs with diagnosed heart disease, but the canine evidence remains limited.
A 2022 randomised controlled study in dogs with myxomatous mitral valve disease found changes in some inflammatory and immune markers after CoQ10 supplementation. It did not establish that CoQ10 delays disease progression or improves survival.
Taurine and L-carnitine
Taurine and L-carnitine are particularly relevant in selected dogs with dilated cardiomyopathy, especially where diet or a documented deficiency may be involved. Some taurine-deficient dogs can show meaningful cardiac improvement after diet correction and supplementation.
They should not be added blindly to every dog with a murmur. Most heart murmurs in older small dogs are caused by degenerative mitral valve disease, which is different from taurine-responsive dilated cardiomyopathy.
L-arginine and herbal ingredients such as hawthorn also appear in cardiac combination products, but canine clinical evidence is much less established. Herbal products can interact with medication, so “natural” does not make them automatically safe.
A 2025 assessment of canine combination cardiac supplements found wide variation between products, including ingredients with potential safety concerns, possible drug interactions, suboptimal doses and limited supporting evidence. This is another reason to choose individual supplements for a defined purpose instead of relying on a broad “heart health” blend.
7. Kidney support: follow the bloodwork and disease stage
I reserve kidney support products for dogs with diagnosed kidney disease. They are not general preventive supplements for a healthy dog.
Once chronic kidney disease is confirmed, the foundation is usually a kidney-appropriate diet together with treatment tailored to the dog’s stage, blood pressure, urine protein, hydration, appetite, phosphorus and electrolyte results.
Depending on those findings, a veterinary plan may include omega-3 fatty acids, phosphate binders, potassium, B vitamins, and other medication or nutritional support directed at nausea, appetite, proteinuria, anemia or blood pressure.
These are not interchangeable wellness supplements. Phosphate binders and potassium can cause problems when used unnecessarily or at the wrong dose. Current IRIS recommendations base treatment on the individual dog’s stage and clinical abnormalities.
Some prebiotic, probiotic, antioxidant, fucoidan and fucoxanthin products are promoted for kidney support. The biological ideas are interesting, but evidence that these products meaningfully slow naturally occurring canine kidney disease is still limited. I would not place them ahead of an appropriate renal diet, phosphorus control and proper medical monitoring.
8. Liver supplements: useful adjuncts, not a diagnosis
SAMe and silybin or silymarin, derived from milk thistle, are commonly used in dogs with liver disease.
SAMe supports the production of glutathione, an important antioxidant within the liver. Silybin has antioxidant and anti-inflammatory properties. They may be reasonable adjuncts in selected hepatobiliary conditions or when a medication carries a risk of liver injury, but the canine clinical evidence is less extensive than the marketing often suggests.
A mildly elevated ALT does not automatically mean that your dog needs a liver supplement. ALT tells us that liver cells may be irritated or damaged, but it does not identify the cause or tell us how well the liver is functioning.
Mild ALT elevation may occur with primary liver disease, gastrointestinal or pancreatic disease, hormonal conditions, medication use and several other problems. The sensible next step is to interpret it alongside the rest of the blood results, symptoms, examination and, when appropriate, imaging or further testing.
Starting a liver supplement without investigating the pattern can create a false sense that the underlying problem has been addressed.
9. Mushroom extracts: promising, but not proven longevity medicine
Medicinal mushroom products have become popular in canine cancer and longevity plans. Turkey tail, reishi or Ling Zhi, Sang Huang and beta-glucan products are frequently promoted for immune support.
Turkey tail is the best studied of these in dogs, but the evidence needs to be kept in perspective.
A small 2012 pilot study of a standardised turkey tail polysaccharopeptide extract in dogs with splenic haemangiosarcoma reported delayed metastasis and longer survival at the highest dose. A larger 2022 study did not find an overall survival advantage from the extract over doxorubicin chemotherapy, or a clear additional benefit when it was combined with chemotherapy.
This leaves us with an interesting adjunct—not a proven replacement for surgery, chemotherapy or palliative care.
Evidence for reishi, Sang Huang and many mixed-mushroom products in dogs is much thinner. Laboratory evidence of immune activity does not prove that a product prevents cancer or extends life in pet dogs.
If a mushroom extract is being considered, look for the exact mushroom species, whether the product contains fruiting body, mycelium or both, a declared beta-glucan content rather than only “total polysaccharides,” a standardised extract rather than an unspecified mushroom powder, and independent testing or a certificate of analysis.
Discuss it with your veterinarian or veterinary oncologist, particularly if your dog is receiving chemotherapy, immunosuppressive medication or treatment for liver disease.
What about CBD?
CBD is often marketed alongside supplements, but it should not be treated as a routine wellness product.
Some canine studies have suggested a possible benefit for osteoarthritis pain, but a 2023 systematic review judged the certainty of the evidence to be very low. Product consistency, drug interactions and changes in liver enzyme activity remain practical concerns.
The legal position also varies significantly. In Singapore, CBD and other products derived from Cannabis sativa are controlled substances. They must not be imported, possessed or used as pet supplements.
A useful comparison
Consider two nine-year-old dogs whose owners want to start a longevity supplement plan.
The first dog is healthy, active and eating a complete diet. Her plan may be simple: an appropriate omega-3 supplement, followed by monitoring rather than automatically adding anything else. If stiffness develops, the next step is a mobility assessment—not a cupboard full of joint chews.
The second dog has recently been diagnosed with early chronic kidney disease. Her plan looks different. A renal diet and monitoring form the foundation. Omega-3 intake, phosphorus control, potassium and other support are then chosen according to her diet, bloodwork, urine results and disease stage.
Both dogs are the same age. Their supplement plans should not be the same, because age alone does not tell us what the body needs.
How to choose a dog supplement
Before starting anything, ask these questions:
- What specific problem am I trying to address? “General health” is too vague to judge whether a product works.
- Is there evidence for this exact ingredient and formulation in dogs? Research in people, rodents or laboratory cells is not the same as a clinical benefit in dogs.
- Does the label state the amount of each active ingredient? Be cautious with proprietary blends that give one total amount but hide the amount of each component.
- Can the manufacturer provide quality-control information? Look for a batch number, expiry date, clear storage instructions, independent testing and a certificate of analysis where available. The NASC quality seal may be useful for products sold in the United States, but it does not prove that the supplement is clinically effective.
- Is the dose appropriate for my dog? The right amount may depend on weight, diet, diagnosis, medication and other health conditions.
- How will I know whether it is working? Choose a measurable outcome, such as stool consistency, scratching frequency, ability to rise or comfortable walking time.
Regulation differs between countries, and a supplement should not be assumed to have undergone the same pre-market assessment for effectiveness as a veterinary medicine.
Commercial product quality cannot be assumed either. A 2020 analysis of kefir products marketed for dogs and cats found poor label accuracy, illustrating why the contents of a supplement may not always match the impression given by its packaging.
Introduce one new product at a time. Otherwise, if your dog improves—or develops vomiting, diarrhoea or another problem—you may have no idea which product was responsible.
Frequently asked questions
Can I give every supplement mentioned here to cover all the bases?
No. I would actively discourage it. Most of these products are intended for a specific problem, not general use. Combining unnecessary supplements adds cost and potential interactions without proven additional benefit.
Are human supplements safe for dogs?
Not automatically. The active ingredient may be suitable while the product itself is not. Human gummies, chewable tablets and powders may contain xylitol, flavourings, sweeteners or very high concentrations that are unsafe for dogs. Doses cannot be converted reliably by simply giving a fraction of the human amount.
Is fish oil safe with prescription medication?
Often, but your veterinarian still needs to know that your dog receives it. This is particularly important when a dog takes medication that affects clotting or is preparing for surgery.
My dog’s ALT is mildly elevated. Should I start liver supplements?
Not automatically. A mild ALT increase has many possible causes. It should be interpreted alongside the rest of the bloodwork and your dog’s clinical history before deciding whether liver support or further investigation is appropriate.
Are mushroom supplements backed by strong evidence?
No. The canine evidence is promising in a few narrow areas, but it is not yet strong enough to treat mushroom extracts as proven cancer prevention or longevity supplements.
Can supplements prevent cancer or extend my dog’s life?
There is currently no over-the-counter supplement proven to prevent cancer or reliably extend lifespan in pet dogs. Longevity is more likely to be supported by a nutritionally complete diet, maintaining muscle and a healthy body condition, regular movement, dental care, early investigation of changes and appropriate medical screening. Supplements may support one part of that work, but they cannot replace it.
Final thoughts
A longevity supplement plan does not need to be complicated.
For many adult and senior dogs, omega-3s at an appropriate dose can form a sensible foundation. Everything else works best when it is matched to something specific—a diagnosed heart, kidney or liver condition, a confirmed nutrient deficiency, a gastrointestinal problem, cognitive changes or an emerging mobility issue.
Start with the dog in front of you. What is the goal? Is there reasonable evidence that this product can help? Is the dose appropriate, and how will you measure the result?
One carefully chosen supplement is more useful than six added just in case.
Supplements support, but never replace, the Academy’s approach to healthy ageing.
About the Author
Dr Kelly Yeo graduated from the University of Melbourne in 2009 and has extensive experience in companion animal medicine, with a special interest in geriatric care, chronic disease management, palliative care and canine longevity.
Her work focuses on helping dogs live longer, healthier and more comfortable lives through early detection, thoughtful nutrition, practical preventive care and compassionate support for owners.
This article is for educational purposes only and does not replace professional veterinary advice. If your dog is unwell, please consult your veterinarian.
