16 Jan New Information Regarding OTC Cardiac Supplements
Many dogs with myxomatous mitral valve disease (MMVD) are given heart supplements for dogs, and I understand why owners are drawn to them. When a dog has a heart diagnosis, it is natural to want to do everything possible to help. However, I do not personally recommend combination cardiac supplements for dogs with MMVD.
At this time, there is no good evidence that these products provide a meaningful benefit in dogs with genetically mediated heart disease such as MMVD or dilated cardiomyopathy (DCM that is not nutritionally caused). Unlike prescription medications, these supplements are not required to prove effectiveness, appropriate dosing, or consistent quality before being sold.
Lack of Regulation and Ingredient Transparency in Heart Supplements for Dogs
A large recent review examined combination cardiac supplements sold in the United States that are marketed for dogs with MMVD. Sixty different products were evaluated, and across those products, there were at least 147 different active ingredients. Individual supplements contain anywhere from two to thirty-two ingredients.
Many labels were vague, relied on proprietary blends, or failed to clearly identify the exact ingredient or plant species used. In some cases, companies even stated that ingredients could vary between batches or throughout the year. This makes it very difficult to know what a dog is actually receiving on a daily basis.
Dosing Concerns
Dosing was one of the biggest problems identified. Most products did not provide enough information to calculate how much of each ingredient a dog was getting. Even when doses could be calculated, the majority of supplements did not provide amounts that match commonly used or studied doses of familiar ingredients such as taurine, L-carnitine, omega-3 fatty acids (EPA and DHA), or coenzyme Q10.
In other words, many products list ingredients that owners recognize and trust, but include them in amounts that are unlikely to have any meaningful physiologic effect.
Do Heart Supplements Actually Help Dogs With Heart Disease?
There is also a lack of evidence that these supplements help dogs with MMVD or non-diet–related DCM. Aside from omega-3 fatty acids in certain stages of heart disease, there is no strong, consistent research showing that cardiac supplements slow disease progression, improve survival, or replace proven therapies in dogs with genetically driven heart disease. Even for omega-3 fatty acids, the data are limited and nuanced.
There are no large, multicenter, definitive clinical trials showing improved survival or reversal of disease in dogs with MMVD from omega-3 supplementation alone, and most studies do not isolate omega-3s from other dietary factors or evaluate all stages of disease in a consistent way. Omega-3s should not be viewed as a cure or a substitute for evidence-based medical therapy.
Safety Concerns With Heart Supplements for Dogs
Safety is another important concern. Dogs with heart disease are often taking prescription medications, and many supplements contain ingredients that can affect blood pressure, heart rate, or drug metabolism. Even “natural” ingredients can have real biological effects, and combination products increase the risk of interactions between ingredients and with medications.
Because these supplements are not regulated like drugs, quality control can vary, and the amount listed on the label may not always reflect what is actually in the product.
Cardiac Care for Your Dog in Nevada
For these reasons, I do not recommend the routine use of heart supplements for dogs with MMVD, particularly combination cardiac supplements. If you are considering a supplement, or if your dog is already receiving one, please let me know exactly which product you are using. Reviewing the ingredient list, dosing transparency, potential medication interactions, and realistic expectations allows us to avoid unnecessary risks and costs and to focus instead on treatments that are known to be beneficial for dogs with heart disease.
If you have questions or concerns about your dog’s heart health, or if you’re unsure whether a supplement is appropriate, contact us. We’re happy to review what your dog is currently receiving and help you make informed, evidence-based decisions that support their long-term health and comfort.
Photo by hannah grace on Unsplash used with permission under the Creative Commons license for commercial use 01/16/2026