DHA for Dogs: What It Does for the Aging Brain

By Caroline Buck, Co-founder of Petaluma

DHA is one of the most studied nutrients for the aging brain, in both dogs and people. The strongest dog evidence comes from puppies, and studies in older dogs are promising but still small. This guide walks through what the research shows and what it means for your senior dog.

What DHA is and where it works in the body

DHA, or docosahexaenoic acid, is a long-chain omega-3 fatty acid. It is a building block of cell membranes, and it is especially concentrated in the retina and brain, according to the National Institutes of Health Office of Dietary Supplements.

DHA often travels with EPA, or eicosapentaenoic acid, another long-chain omega-3. EPA is better known for its role in joint comfort and inflammation. DHA gets most of the attention for the brain and eyes.

The aging dog brain goes through changes that look a lot like those in aging people. They include a buildup of amyloid protein, more oxidative damage, and a drop in how well the brain uses glucose for energy (Pan, 2021). Those similarities are one reason dogs are studied as a model of human brain aging.

How dogs get DHA from their food

Dogs make very little DHA on their own, so most of it needs to come from food. Plant foods like flaxseed supply ALA, a shorter omega-3. Dogs convert less than 5% of ALA into EPA and very little into DHA (Bauer, 2016).

The two direct sources of DHA are fish oil and algal oil. Algal oil comes from microalgae such as Schizochytrium, which researchers have studied as a dietary DHA source for dogs (Hadley et al., 2017). Our post on why we use marine algae instead of fish oil compares the two.

DHA and brain development in puppies

The clearest dog evidence for DHA comes from growing puppies. In a 2012 study, 48 beagle puppies ate foods with low, moderate, or high DHA from fish oil from 8 to 52 weeks of age. The high-DHA group did better on reversal learning, visual contrast tests, and early navigation through an obstacle course.

The high-DHA puppies also made more antibodies after a rabies vaccine. Their food also had more vitamin E, taurine, choline, and carnitine, so DHA was not the only difference. The authors concluded that DHA-rich fish oil, possibly along with these other nutrients, improved learning, memory, and retinal function in growing dogs.

What studies in older dogs show

Studies in older dogs point in a promising direction, with some mixed results. Most were small and many tested DHA together with other nutrients. Here are four of the best-known trials.

These studies also have limits. Both Pan trials came from Nestlé Purina researchers, and the 2022 sphingolipid study was funded by the supplement maker. The 90-day trial relied on owner reports, and its control diet also contained many of the test nutrients.

A 2025 systematic review pulled these threads together. It included 29 trials of enriched diets and supplements in aging dogs and cats, and 10 of them used omega-3s. The authors reported clear positive results at high doses of DHA and called for more standardized, controlled trials.

Our guide to canine cognitive dysfunction covers the signs of cognitive decline and how vets diagnose it.

What human research adds

Human trials suggest DHA may help most when memory changes are still mild. In the MIDAS trial, 485 adults aged 55 and older with mild memory complaints took 900 mg of algal DHA or a placebo for 24 weeks. The DHA group improved on tests of learning and memory.

Results in later stages have been less encouraging. In a 2010 trial in people with Alzheimer's disease, DHA did not slow cognitive decline. The lead author suggested DHA might work better if given earlier, before the disease progresses.

The NIH Office of Dietary Supplements sums up the wider research this way. Omega-3 supplements do not appear to change cognitive function in healthy older adults, and they may improve some aspects of thinking in people with mild cognitive impairment. Dog studies of this kind are still limited, so these human findings help fill in the picture.

How much DHA does a senior dog need?

The National Research Council sets a recommended allowance for EPA and DHA combined, scaled to a dog's metabolic body weight. For a 40-pound adult dog, that works out to about 264 mg of EPA and DHA per day. Several of the older-dog studies above used more than this, and the 2025 review found the clearest benefits at higher DHA doses.

If you are considering a DHA supplement, talk with your vet first, especially if your dog takes other medications or eats a food that already contains DHA. Your vet can help you choose a dose that fits your dog's size and health.

At Petaluma, we formulated our senior recipe with brain health and healthy aging in mind. It guarantees at least 450 mg of DHA per cup from marine microalgae. Our lab analysis measured about 460 mg per cup, nearly four times the DHA in our Adult recipe.

Supporting your older dog's brain beyond DHA

DHA is one piece of brain health, and daily habits matter too. The 2023 AAHA Senior Care Guidelines note that diets for cognitive decline showed the most benefit when combined with enrichment such as exercise, new toys, cognitive games, and agility. The guidelines also say treatment works best when started early.

• Keep them learning: Short training sessions, new tricks, and food puzzles give an older dog's brain regular practice.
• Keep them moving: Daily walks at a comfortable pace bring exercise and new smells to explore.
• Rotate toys and games: New toys and simple games give your dog fresh problems to figure out.
• Keep up with vet visits: Tell your vet about changes in sleep, confusion, house training, or how your dog interacts with family.

Related reading: Canine Cognitive Dysfunction in Senior Dogs, Inflammaging in Dogs, and our Q&A with Dr. Blake Hawley DVM on our Senior formula.

Frequently asked questions

Is DHA good for dogs?

Yes. DHA is an omega-3 fatty acid concentrated in the brain and eyes, and dogs get most of it from food. In a 2012 study of 48 puppies, a high-DHA diet improved learning, memory, and retinal function compared with lower-DHA diets.

Does DHA help older dogs' brains?

Early research is promising. A 2025 systematic review of trials in aging dogs and cats reported clear positive results at high doses of DHA. Many studies were small or tested DHA with other nutrients, so more controlled trials are needed.

Can dogs get DHA from flaxseed?

Flaxseed supplies ALA, a shorter omega-3 that dogs convert poorly. Dogs convert less than 5% of ALA into EPA and very little into DHA (Bauer, 2016). Fish oil and algal oil provide DHA directly.

Is algal DHA as good as fish oil for dogs?

Algal oil is a direct source of DHA, the same compound found in fish oil. Researchers have tested algal DHA from Schizochytrium in aged dogs, and it improved learning on a visual task (Hadley et al., 2017).

How much DHA should I give my senior dog?

The National Research Council recommended allowance for EPA and DHA combined works out to about 264 mg per day for a 40-pound adult dog. Check what your dog's food already provides, and ask your vet before adding a supplement.

What else helps a senior dog's brain stay sharp?

The 2023 AAHA Senior Care Guidelines note that diets for cognitive decline worked best when combined with enrichment such as exercise, new toys, and cognitive games. Training games, food puzzles, and daily walks all give an older dog's brain regular practice.

References

1. National Institutes of Health Office of Dietary Supplements. Omega-3 Fatty Acids: Fact Sheet for Health Professionals. Link.
2. Pan Y. Nutrients, cognitive function, and brain aging: what we have learned from dogs. Med Sci. 2021;9(4):72. Link.
3. Bauer JE. The essential nature of dietary omega-3 fatty acids in dogs. J Am Vet Med Assoc. 2016;249(11):1267-1272. Link.
4. Hadley KB, Bauer J, Milgram NW. The oil-rich alga Schizochytrium sp. as a dietary source of docosahexaenoic acid improves shape discrimination learning associated with visual processing in a canine model of senescence. Prostaglandins Leukot Essent Fatty Acids. 2017;118:10-18. Link.
5. Zicker SC, et al. Evaluation of cognitive learning, memory, psychomotor, immunologic, and retinal functions in healthy puppies fed foods fortified with docosahexaenoic acid-rich fish oil from 8 to 52 weeks of age. J Am Vet Med Assoc. 2012;241(5):583-594. Link.
6. Araujo JA, Segarra S, Mendes J, et al. Sphingolipids and DHA improve cognitive deficits in aged beagle dogs. Front Vet Sci. 2022;9:646451. Link.
7. Pan Y, Kennedy AD, Jönsson TJ, Milgram NW. Cognitive enhancement in old dogs from dietary supplementation with a nutrient blend containing arginine, antioxidants, B vitamins and fish oil. Br J Nutr. 2018;119:349-358. Link.
8. Pan Y, Landsberg G, Mougeot I, et al. Efficacy of a therapeutic diet on dogs with signs of cognitive dysfunction syndrome (CDS): a prospective double blinded placebo controlled clinical study. Front Nutr. 2018;5:127. Link.
9. Blanchard T, Eppe J, Mugnier A, et al. Enhancing cognitive functions in aged dogs and cats: a systematic review of enriched diets and nutraceuticals. GeroScience. 2025;47:2925-2947. Link.
10. Yurko-Mauro K, McCarthy D, Rom D, et al. Beneficial effects of docosahexaenoic acid on cognition in age-related cognitive decline. Alzheimers Dement. 2010;6(6):456-464. Link.
11. Quinn JF, Raman R, Thomas RG, et al. Docosahexaenoic acid supplementation and cognitive decline in Alzheimer disease: a randomized trial. JAMA. 2010;304(17):1903-1911. Link.
12. National Research Council. Nutrient Requirements of Dogs and Cats. Washington, DC: National Academies Press; 2006. Link.
13. American Animal Hospital Association. 2023 AAHA Senior Care Guidelines for Dogs and Cats: managing cognitive dysfunction and behavioral anxiety. Link.