How to Choose the Best Dog Supplements

Knowledge is key: Do your homework to do no harm and see the amazing benefits supplements have to offer dogs.

Key Takeaways

  • Veterinarians recommend supplements for dogs to help prevent issues, help manage body condition, and to extend quality of life.
  • Supplements help dogs who need them in many ways. Veterinarians who practice integrative medicine have extra training and/or experience in botanicals and herbal medicines and can help you understand which supplements might support your dog.
  • There is no universal best supplement to add to your dog’s food or daily life, because every dog is different. However, if your dog needs extra support, you and your veterinarian might find a gentle, safe supplement to help.
  • If your dog is healthy, supplements might support her vigorous health. If she has cancer, you might use supplements to support her body in its fight.

Research and Consult Your Veterinarian

As an integrative veterinarian with extra training in herbal medicine, I routinely recommend supplements for dogs. There is no such thing as universal “best supplements for dogs” — but there are things to know as you do your research and make careful choices with your veterinarian.

What Are Your Goals for Your Dog?

Supplements are beneficial for any dog no matter if they are for preventive care, or for a specific illness.

The goal of supplements can be to help prevent issues, help manage body condition, and to maintain a longer quality of life.

What supplement(s) to add depends on if your dog is healthy and you want to support her body or if she has health issues like cancer you need to help fight.

A healthy dog with no issues may only need supportive/preventive supplements like:

  • an Omega 3 Fatty Acid supplement
  • a joint supplement
  • milk thistle
  • whole food supplement(s)
  • Vitamin D supplementation (only if Vitamin D levels based on bloodwork are low)

A dog battling cancer will need far more support than a healthy dog.

Supplements for Dogs Are Not Straightforward for Your Veterinarian

At the first appointment with a new client, I go through every single supplement and medication that your dog is getting.

I have come to understand that many times, I am the first veterinarian who is told the whole truth of everything a dog lover is giving their dog. There is a reason that I need to know the whole truth, though.

Adding supplements to any condition, especially cancer, is not as simple as pharmaceuticals (medications) can be.

Pharmaceuticals have very specific uses, doses, and lots of information about potential side effects from the manufacturer. We also know from our practices how they behave in real dogs.

In a way, we can use pharmaceuticals in a straightforward fashion. If the dog has X, give them Y pharmaceutical in Z dose.

It is not like that with supplements. There is no X=Y scenario.

Choosing Supplements Can Be Overwhelming

There are overwhelming amounts of supplement options to choose from.

I see the amazing effects of carefully chosen and properly dosed supplements on a daily basis.

I also see dogs on toxic supplements, or on dangerous combinations of supplements.

By far, the most common problem I see is loving dog parents doubling and even tripling up ingredients by using multiple different products. This can cause potentially serious side effects.

This is not to scare you off of using supplements. I have seen results using herbs and supplements that were beyond my own expectations allowing dogs to live a healthy life.

It’s just important to think carefully about what you give your dog, how much you give, and when to use it (or stop using it).

The Best Supplements for Dogs with Cancer

In practice, once I have completed a medical history, western medical exam, and eastern medical exam, I start to formulate a plan. My plan is tailored to each dog, and I pick the most effective supplements and herbs for that dog out of the vast sea of supplements.

Some of the supplements I may use for a dog with cancer include:

  • Omega 3 Fatty acids to help with inflammation, as long as there are no bleeding issues
  • Hemp to help with pain, inflammation, and nausea
  • Vitamin A and D to help with the immune system (note: these are fat soluble vitamins so overdose can happen; you should only give your dogs these supplements under the direction of a veterinarian)
  • Vitamin C to help the immune system
  • Mushrooms to help with the immune system
  • Milk Thistle to help protect the liver
  • Chinese and Western herbs
  • Whole food supplements to support the body

The world of supplements can be overwhelming with tens if not hundreds of supplements, all of which can help with cancer, including supplements that are not on the list above.

My goal is to pick the supplements which will help that specific dog the most, and dose them accordingly.

There are only so many supplements each dog will tolerate, so sometimes we cannot use every supplement. We have to set priorities based on urgency, budget and what the dog will tolerate.

It’s also true that not all products and brands are created equal. Before you buy that bottle or dig into that online search there are things you need to know/understand.

Let’s start with the federal regulation of pharmaceuticals versus the regulation of supplements.

Federal Regulation of Pharmaceuticals

Pharmaceuticals (medications) are a single ingredient chemical (or a combination of single ingredient chemicals) made in a factory to treat or cure a medical disease or condition. Examples include antibiotics, blood pressure, cholesterol, and cough medicine. These pharmaceuticals serve the X=Y path I mentioned above.

Medications are:

  • heavily regulated in the US by the Food and Drug Administration (FDA)1
  • go through scientific studies1
  • go through trials to ensure that they are safe and work for their intended purpose before they can be sold for both humans and animals1

The FDA also:

  • inspects the factories1
  • approves what is on the label1
  • ensures the label dosage for the medication is safe1
  • side effects of medications are required to be reported and if there are concerns the FDA will investigate1

Federal Regulation of Supplements in the U.S.

In contrast, vitamins, supplements, Chinese herbs, Western herbs, etc., in the US:

  • are not regulated by the FDA to the same degree as medications because they are in the category of dietary supplement1
  • the FDA monitors for any false label claims (like claims to curing cancer)1
  • the FDA monitors for reported adverse effects1
  • FDA does not require scientific studies before being sold1

Supplement companies are required to meet safety requirements under Dietary Supplemental Health and Education Act (DSHEA) of 1994. The DSHEA requires supplement companies to comply with current GMP (Good Manufacturing Practices).

Supplements sold prior to 1994 were grandfathered in as accepted supplements, but any new supplement ingredient is required to:

  • submit forms to the FDA to determine if it is relatively safe before being sold to the public1
  • follow label requirements1
  • provide dosages on the packaging1

Other Countries Use Different Regulatory Frameworks

Other countries have supplements regulations set up differently. India, Japan and China have a whole regulatory framework for traditional medicine and supplements, as they are part of their medical management in general.1

In Canada supplements are regulated by Natural Health Products Regulations and are assessed for safety, quality and efficacy via literature data and research before they can be sold.1

Australia regulates supplements under the Australian Therapeutic Good Act and are evaluated before they are sold for safety, quality and efficacy through scientific or evidence-based medicine.1 Australian companies also go through an audit to make sure they are practicing Good Manufacturing Processes.1

Buyer Beware: Read Supplement Labels

One way to help decide whether to use a product is by reading the label. It can tell us a lot about a product in a small amount of space.

Check for Commercially Grown or Wild Harvested Ingredients

The label may say nothing at all about where an ingredient comes from, in which case it is likely either commercially grown or “wild harvested” also known as wildcrafting (hand picking the herb from its natural or wild ecosystem).

Wild Harvested Ingredients

There is a common belief that wild harvested supplements have greater medicinal properties because these plants have to be stronger in order to survive the natural environmental stressors.

Studies have shown that the active ingredients are the same in wild harvested products verse commercially grown plants and that wildcrafting needs to be re-evaluated.3

The risks of wild harvesting are:

  • In some places it is illegal to harvest certain plants wildly because the amount harvested is not regulated, so harvesting causes depletion and risks extinction. Wild Gingseng, and Slippery Elm are examples of plants that are illegal to harvest in certain places.
  • There is a real risk that whoever is doing the harvesting collects the wrong species, which could cause toxicity, adverse effects, or ineffectiveness of the product.
  • Plants in the environment are also subject to contamination through water runoff.
  • Depending on the location, secondary pesticide contamination can happen from the spraying of nearby crops.
  • The ability to collect enough plants to keep up with supply can also be a challenge as sourcing ingredients can be seasonal.
  • Wild harvesting is also highly affected by droughts, fires and natural disasters.

Commercially Cultivated Ingredients

Commercially cultivated products allow for a reliable volume of crops as well as a correct identification of species.

The risks of conventional harvesting are:

  • The potential use of pesticides that the plant absorbs.
  • Even organic farming may not be pesticide free farming. Organic farmers grow plants without growth stimulants and artificial chemicals, but they can use approved pesticides for organic farming such as neem, pyrethrin, and lime sulfur.

Check Measurable Amounts

The label will also have any ingredients that are deemed to be a measurable amount.

Any herbs, fillers, or flavoring agents, if in high enough amounts, should be listed.

The herbs and supplements should have a percentage or ratio listed next to them. For example, “milk thistle seed extract (80% silymarin).”

Any fillers, or “extras” may be listed without percentages.

If your dog has food allergies, especially if it is a chewable supplement, make sure there is nothing listed your pet is allergic to.

FDA Label Requirements

To help guide consumers, the FDA has requirements of what can and cannot be on a human supplement label.

  • A descriptive name of product
  • A statement that it is a dietary supplement
  • The name and place of business
  • The manufacturer, packer or distributor
  • A list of ingredients
  • The set contents of products
  • For human supplements, a disclaimer that it has not been reviewed by the FDA

Watch out for marketing ploys on labels trying to attract your attention with appealing fonts, colors, and designs. Lots of money goes into figuring out what triggers our brain to pick one product over another.

Red Flags

There are certain things that are red flags when it comes to supplements. Look for the following on labels:

  • The phrase “no side effects” (every supplement could potentially have side effects).
  • The “highest strength” (higher potency is not always better. Some folks believe “a little bit is good so a lot must be better,” but that is just not true).
  • “Cures X” (I would love a cure in a bottle, but I haven’t come across one).
  • “Quick fix” (This is rarely true).
  • Something else that seems too good to be true.
  • No list of ingredients because of claims being a “proprietary/secret formula.”
  • No third-party testing.
  • Endangered species in the product (if a manufacturer is willing to break the law and use an endangered species, they are more likely to be willing to break other laws, too).

Green flags

There are also things that are green flags when it comes to choosing the best supplements. Look for the following:

  • The words “cGMP” on the label. This stands for current Good Manufacturing Processes. It is illegal for cGMP certified to be listed on a label if the manufacturer is not following cGMP.
  • “Certified Organic” on the label. A product that is Certified Organic is likely to be organic. However, if it claims to be organic without certification, it may or may not be organic.
  • Third party certification.
  • A listing of ingredients and percentages or ratios on the label.
  • More information on scientific evidence and studies on their website as well as supplemental facts.

Pet supplement manufacturing is not regulated under DSHEA, so you might not see everything on these lists. However, if a supplement intended for dogs is manufactured to human-grade standards, you can rely on the list above.

Deciding If a Supplement is Right for Your Dog

By following the suggestions above you may be able to eliminate supplements that have dubious claims or seem suspicious. Once you have determined that the supplement you are considering is worth investigating further, I suggest doing the following:

Read the Ingredients

It is common for supplements to be more of a blend and have more than one herb in them. Blends can be useful, but there are some things to keep in mind.

If you are giving several different supplements individually it might be okay, but when you double or triple the same ingredients, it can cause unwanted and even toxic side effects.

For example, fat-soluble vitamins like Vitamin D or A may be included in different blends. These vitamins are already present in the diet, and giving supplements (especially multiple supplements) with these vitamins might cause them to accumulate and create toxicity. Only give supplemental Vitamin A or D if your veterinarian has checked your dog’s levels and thinks they would be helpful.

Another example is licorice, which can have a steroid like effect and cause problems if excessive amounts are given.

Check the Names of Ingredients

The same ingredient can come from a plant with multiple names, which can lead to double or triple dosing for your dog.

For example, let’s say I pick Boswellia, to help with some arthritis. Next, I choose Ru Xiang, because the label says it will help with intestinal issues. I’ve just unknowingly bought two supplements that are the same ingredient, because Ru Xiang is the Chinese name for Boswellia, the western herbal name. (Another name for this herb is the common name, Frankincense.)

Know the Chinese, western, botanical, and common names to avoid doubling up on the same product.

Is It a Whole Plant, or Single Ingredient Supplement?

Plants are made up of many different molecules and chemicals, each of which can be a single ingredient in a supplement. Using the whole plant means you are using more than a single active ingredient.

Whether this is a good idea or not is a huge area of debate and could be a whole article itself. To sum up the debate:

  • The “single ingredient is best” philosophy is the basis of the pharmaceutical industry, that there is only one ingredient that does the job, and the rest is not needed. It’s also easier to control what is in the supplement if a single ingredient is used.
  • The belief that “the whole plant is better” is generally the more integrative/holistic philosophy that there are synergistic interactions between the nonactive and active ingredient making the active ingredient essentially more potent without increasing the dosage as well as providing additional benefits to the body.

Dosage Recommendations

As tempting as it is, unless directed by a veterinary medical professional only use the labeled dosage for your dog.

Giving too much can cause gastrointestinal upset as well as more serious unwanted side effects. More is not better.

If it is a human product, it does not mean that the label dosage is the same for your pet, so check with your veterinarian about dosing for your own dog.

Huge Concern: Medication Interactions

Even though they are not pharmaceuticals, supplements still have an effect. Medication interactions is one of the biggest areas of concern for veterinarians, and with good reason.

Drug and supplement interactions can cause a decreased or increased clearance of an herb or medication. This in turn causes a decrease or increase effect of the medication or supplement. In other words, interactions can lead to potential toxicity or ineffectiveness of the medication or supplement.4

Cytochrome 450 Interactions

Most of these interaction issues are caused by competition at an enzyme called Cytochrome 450. The most common issue at this enzyme is with medications for:

  • heart issues5
  • blood pressure5
  • anti-clotting and clotting5
  • anxiety6
  • pain medications6

Herbs That Commonly Interact with Medications

Other common interactions occur with certain herbs. The most common herbs that cause contraindications are:

  • Dan Shen7
  • Gingko4
  • Ginseng6
  • St. John’s Wort4,6


Other medication interactions can be caused by antacids. Antacids cause a change in the stomach pH level, which can mean herbs are not broken down normally, and thus not absorbed properly, and thus not having the desired effect.

Medications That Speed Up or Slow Down Digestion

Medications that increase or decrease intestinal motility cause increased or decreased transit time, resulting in decreased or increased herbal absorption.

Diseases That May Cause Interactions

Another high-risk category is being treated for any of the following diseases:

  • asthma6
  • heart issues6
  • diabetes6
  • epilepsy6
  • hypothyroidism6
  • hypertension6
  • auto-immune6

This high-risk group is partly due to the medications used to treat these conditions, which might cause drug interactions. But it’s also due to the effect of herbs on some of these conditions.

For example, a pet getting insulin for diabetes, then starting a Corn Silk and Gymnema supplement can have their blood sugar drop too low.

Chemotherapy and radiation therapy in combination with supplements and herbs has to be planned on an individual basis, depending on what medications, herbs and therapies are being provided.

Why Oncologists May Discourage the Use of Supplements and Herbs

Generally veterinary oncologists have concerns with the combination of supplements, herbs and oncology due to the lack of formal safety studies.

Most herbs and supplements that may have human safety studies don’t have safety studies on the veterinary side. The evidence-based medicine approach is taken from human medicine.

The general rule of thumb in oncology is to stop supplements and herbs that would be of concern during the week of chemotherapy or radiation. However, this is highly variable and is done in a case-by-case scenario.

Your integrative/holistic veterinarian or oncologist may not have as many qualms about safety, because they use supplements regularly and share knowledge with each other. They are very helpful in determining what needs to be done for your pet.

Veterinarians collaborate, and rely upon their colleagues for information, guidance, and insight. If you are consulting with a licensed veterinarian about supplement use, they will be able to explain the reasons for their recommendations and address their oncologist colleague’s questions.

Food Interactions

Food and herb interactions are much less likely in animals, but certain combinations of food and herbs can result in gastrointestinal upset or acid reflux, especially if they are eating any tomatoes, or potatoes.6


Anesthesia and herb interactions can cause slower clearance of medications, supplements and anesthesia.6

Let your veterinarian know what supplements you are giving before a procedure to know if any need to be stopped prior to anesthesia.

If it is an emergency procedure, let your veterinarian know all supplements your dog is taking, so they can adjust medications if needed.

My Best Tips for Choosing the Best Dog Supplements

Choosing supplements is not easy or straightforward. Here are some of my best tips to help you on your supplement journey.

  • If your pet has health issues or is on medications please consult with an integrative or holistic veterinarian, to help you navigate which supplement(s) will be the most valuable to your pet. You can look on the American Holistic Veterinary Medical Association (AHVMA) website for a provider near you.
  • Keep a list of supplements, medications and dosages your pet is getting on your phone or a paper list in your wallet/purse for veterinary appointments. Taking a picture of the front of the bottle as well as the ingredients list is especially helpful.
  • Do your homework so you know the medication(s) your pet is already on, how his supplement(s) work in the body, and if there are known interactions, in humans or animals. What is safe in people is not always safe in animals, but animal herbal interactions studies are limited, so it’s a good place to start.
  • If using a human supplement watch out for xylitol snuck into human products which is toxic in dogs. There is a vast array of supplements geared just for pets that can help avoid this issue, as well as provide appropriate dosing.
  • Start with one supplement at a time so you know if your pet has any gastrointestinal upset or other issues you can narrow down what they are not tolerating.

The Supplement Decision Tree

It can be overwhelming to decide what supplement to use, and you do not want to over-supplement your dog.

Here is a good decision tree to use.

What’s the Most Crucial Issue?

Focus on helping with the most crucial issue first. Make a list of all of your dog’s problems and pick the most crucial one.

For example, is your dog not eating because she is nauseous, or is she in so much pain she won’t get up? If she’s not eating because she can’t get up to go to her bowl, addressing her pain might be the first priority. You can address nausea, if necessary, later on.

Does One Supplement Help More Than One Issue?

As you research herbs, you may find one supplement will help more than one issue on your list. If that’s the case, you may be able to address both issues with one supplement, which cuts down on potential interactions and side effects.

Is Your Dog Already on Medications?

If your dog is already on medications, check to see if it is on the high-risk list for interactions. Research how the medication is cleared from the body, and if there are supplement interactions to be aware of.

Is Your Dog Already on Supplements?

If your dog is already on supplements, you will have to check to see if there is doubling up on ingredients.

Start with the Most Helpful Supplement First

Start researching the supplement likely to give your dog the most help right away.

As tempting as it is to “get started on everything,” please don’t start several supplements at the same time. Everything you put in your dog’s mouth could potentially cause gastrointestinal upset including nausea, vomiting, or diarrhea.

If you start with one supplement and see that your dog tolerates it well, you can proceed to the next most important supplement with confidence and see how your dog tolerates that one.

Research Companies

Research companies as well as products. Does the company seem like it has “real people” working for it? Is it big, small, mid-size? Testimonials can be made up, so calling the company or emailing and seeing if you like the responses you get is always a good way to evaluate them.

Go to their website to see if they have an analysis of their product and more information on uses. See if they have been certified by ConsumerLabs, the U.S. Pharmacopeial Convention, or NSF (which used to be called NSF International, and before that National Sanitation Foundation).

Other Things to Consider

Is there a specific animal product version of a human product? A company that makes supplements for both humans and animals may be more interested in and committed to getting dosing right and safety. Preferably use a product for animal as some human safe products are toxic to pets.

Watch for fillers or flavoring agents if your pet has allergies.

If possible, use a brand that has been used in a veterinary scientific study which may give more peace of mind for efficacy, although there are not many of these studies available.

What form is going to be easiest to get into your dog? Supplements are only useful if your dog will take them. Powders, capsules, chewables may be available; what will work for your dog?

The Bottom Line on Choosing the Best Supplements for Dogs

I have personally seen the amazing benefits of herbs and supplements on a daily basis where patients live a longer, quality of life. But there is no shortcut to this kind of success.

Take your time, do your research and digging, and consult with your veterinarian so you can make the best-informed decision for your pet.

  1. Dwyer JT, Coates PM, Smith MJ. Dietary Supplements: Regulatory Challenges and Research Resources. Nutrients. 2018;10(1):41. Published 2018 Jan 4. doi:10.3390/nu10010041
  2. Charen E, Harbord N. Toxicity of Herbs, Vitamins, and Supplements. Adv Chronic Kidney Dis. 2020;27(1):67-71. doi:10.1053/j.ackd.2019.08.003
  3. Assinewe VA, Baum BR, Gagnon D, Arnason JT. Phytochemistry of wild populations of Panax quinquefolius L. (North American ginseng). J Agric Food Chem. 2003;51(16):4549-4553. doi:10.1021/jf030042h
  4. Rombolà L, Scuteri D, Marilisa S, et al. Pharmacokinetic Interactions between Herbal Medicines and Drugs: Their Mechanisms and Clinical Relevance. Life (Basel). 2020;10(7):106. Published 2020 Jul 4. doi:10.3390/life10070106
  5. Zuo HL, Linghu KG, Wang YL, et al. Interactions of antithrombotic herbal medicines with Western cardiovascular drugs. Pharmacol Res. 2020;159:104963. doi:10.1016/j.phrs.2020.104963
  6. Hussain MS. Patient counseling about herbal-drug interactions. Afr J Tradit Complement Altern Med. 2011;8(5 Suppl):152-163. doi:10.4314/ajtcam.v8i5S.8
  7. Fugh-Berman A. Herb-drug interactions [published correction appears in Lancet 2000 Mar 18;355(9208):1020]. Lancet. 2000;355(9198):134-138. doi:10.1016/S0140-6736(99)06457-0


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