Rosemary extract is a common ingredient found in many dog foods, especially as food producers look to use clean and natural ingredients.
However, there is a debate online regarding whether rosemary—in its plant, oil and extract form—is safe for dogs to consume.
We decided to research this topic after noticing a handful of articles that claim rosemary is neurotoxic for dogs. None of those articles included links to research supporting their claims.
We went ahead and did our own research to confirm whether or not rosemary is safe for dogs to eat daily. Our analysis provides links to NIH studies, which are considered the most reputable source of scientific information on the Internet.
Bottom line: all research confirms that rosemary and its essential oils are completely safe for dogs to eat, and that it may in fact have benefits for dogs.
In this article, we will present the major studies that have been completed on this topic and the results scientists uncovered.
Rosemary Gave Dogs Improved Brain Function
Several studies provided significant evidence that rosemary is not a neurotoxin for dogs.
One such NIH study was a randomised, controlled clinical evaluation of 69 dogs with behavioural disorders related to anxiety and chronic stress. The dogs were fed two diets—a control diet and a nutraceutical diet including rosemary—for 45 days.
The study's results showed a significant increase in serotonin, dopamine and β-endorphins and a significant decrease in noradrenaline and cortisol for the group eating the diet with rosemary[*].
Simply put, the diet with rosemary made dogs happier and healthier across many biological markers. It had no negative effects.
Rosemary Protects Brain Cells from Stress
The rosmarinic acid in rosemary has been shown to exert neuroprotective effect against antioxidative stress and excitotoxicity, and to even possess anti-anxiety and antidepressive-like effects.
This NIH study showed that rosemary and its essential oils modulate the electrophysiological properties of recombinant TTCCs (CaV3.2) expressed in HEK-293T cells[*].
What does that biology mean for your dog?
The CaV3.2 pathway is directly tied to pain and epilepsy in canines, and the result of this study suggests rosemary oil can produce anticonvulsant-like effects, potentially reducing seizures in dogs with epilepsy. This isn't the only study that came to this conclusion, which we'll explore later in this article.
Furthermore, this study suggests rosemary may reduce stress experienced by dogs and may also help protect their brain cells from damage.
Rosemary May Extend Long Term Memory
Another NIH study showed how rosemary may extend long term memory and prevent dimensia in mammals.
This study showed that rosemary extract inhibited the AChE activity and showed a stimulatory effect on BuChE in both parts of the brain in rats. Moreover, it produced a lower mRNA BuChE expression in the cortex and an increase in the hippocampus[*].
Simply put, rosemary oil improved several biomarkers in the brain that related to memory and combating dimensia.
We hope a study will be done to replicate this experiment in dogs, but the results in rats are promising.
Rosemary May Help Slow Brain Cancer in Dogs
Brain cancer is the main cause of death for ~30% of dogs in the United States, and the incidence rate increases to a stunning 50% in dogs once they reach 10 years and older.
Scientists found that rosemary may be able to help.
The carnosic acid and carnosol contained in rosemary were shown to slow the rate of brain cancer growth in dogs.
An NIH study found that a daily 25 μg mL dose of rosemary oil (consisting of 70% carnosic acid) reduced cancer cell proliferation by 75%[*].
That is a very substantial reduction in cancer growth.
This study also found that rosemary oil had no negative effects on healthy brain cells, further supporting evidence earlier in this article that rosemary and its extracts are indeed safe for dogs.
Rosemary Is Safe for Dogs with Epilepsy
While rosemary is not a neurotoxin, there is virtually no information on whether it has positive or negative effects on dogs with epilepsy. In fact, there have been no studies done on this to date.
However, the research completed around rosemary's effects on mice with epilepsy may shed some light.
A groundbreaking study by the NIH showed that including rosemary oil in the diet of rats with epilepsy increased their survival rate from 0% to 60%[*].
Rosemary is safe—and even healthy—for dogs to consume.
Its extract and oils are safe for them too.
We found no studies supporting the theory that rosemary could be a neurotoxin for dogs, and in fact, all of the science-backed research we've found suggests otherwise.
Rosemary has a positive effect on brain function for dogs. This outcome was seen across many NIH studies. If you'd like to make sure your dog receives these benefits, here's a dog food with rosemary extract we recommend.
In summary, rosemary extract may help make your dog feel happier, protect their brain against cancer and dementia, and improve their long-term memory. It's a natural ingredient shown to support dogs' brain health.