The Sense of Smell

Cats and dogs, and many other pets have a powerful sense of smell, much better than humans.  This leads to lots of questions surrounding all to safely use essential oils around animals.

Metabolism

When essential oils are inside an animal or a human body, they sometimes have to go through metabolism before they can be excreted.  Metabolism is nothing more than a change, a chemical process that occurs within a living organism in order to maintain life.

There are Three Basic Types of Metabolic Processes

There are three types of metabolism: Phase 1, 2, and 3.

Phase 1 is basic chemistry: oxidation, reduction, and hydrolysis.  Humans and pets can easily perform these basic chemistry operations. Byproducts of phase 1 metabolism may be immediately eliminated from the body, or may undergo further transformation in phase 2 metabolism.

Phase 2 metabolism uses an enzyme to add a group to the existing molecule and ensures that the group is water soluble.  This means that it can now be easily excreted from the body via the urine or feces. After this step most byproducts are excreted, but some may proceed to phase 3 reactions.

Phase 3 takes the conjugation products from phase 2 reactions, removes the added group and then adds a different group and prepares them for excretion.

Many of these metabolic reactions are dependent on liver enzymes and specifically on the cytochrome P450 system.

The Difference in Metabolism

Humans, dogs, horses, goats, sheep, cattle and other herbivores and omnivores have the ability to complete a wide variety of Phase 1, 2, and 3 metabolic reactions.

Cats on the other hand have a uniquely carnivorous diet. They are not usually exposed to many plant-based chemicals such as those found in essential oils. Therefore, throughout evolution, they have lost the ability to complete all Phase 2 reactions. Specifically, they lack the enzyme UDP-glucuronosyltransferase, and therefore cannot add glucuronide groups to essential oil molecules in Phase 2 metabolism. While cats have some of the P450 system, it doesn’t function as well as it does in humans, dogs, and other omnivores. When pets do not metabolize well, this leads to an increased risk of toxicity.

Use Caution

While I am never a purveyor of gloom and doom, there are certainly some reasonable points of caution to use around pets.

  1. Dilute essential oils before applying to pets, especially cats who do not have a strong P450 system.
  2. Space out dosing for cats as well. Instead of applying each day, apply every 2-3 days.
  3. Always be sure the animal can leave the room while diffusing essential oils. Dogs and cats absorb essential oils through their fur, so even diffusing may result in topical administration. Because dogs and cats have so much more fur than humans, this can lead to a large indirect application. Do not trap a pet in a confined space while diffusing.
  4. Never over use essential oils.  Less is more. Moderation is wise. While the headlines about poisonings in dogs and cats may be alarming. Remember that in some of these case reports up to 85 mL of an oil was used at once. Use small amounts, spaced out.
  5. Quality matters. Choose essential oils that are 100% pure, unadulterated, free from synthetics and other fillers. Know and trust the company that you choose to use around pets.
  6. Use additional caution in any animal with kidney or liver disease, or very old or very young animals. Just like in humans.
  7. Consult an animal healthcare provider skilled in essential oils before starting any routine.

Specific Essential Oils

  1. Phenols must be metabolized by cytochrome P450. Use additional caution when using essential oils high in phenols such as basil, anise, clove, oregano, thyme, cinnamon, or cassia. Many pet parents choose to avoid essential oils high in phenols around animals that lack a strong cytochrome P450 system such as cats, reptiles, and birds.
  2. Some essential oils high in monoterpenes may cause harm to cats. Tea tree is likely the most well known, and limonene (which is converted to the phenol carvacrol in the body) and alpha-terpene have also been implicated.  Some pet parents use caution with citrus oils (excluding yuzu), pine, spruce, celery seed, and fir.
  3. Ketones also many accumulate in cats increasing the risk of ketoacidosis. Use caution with dill, peppermint, rosemary, fennel and lavender.
  4. Animal skin is different than humans. While not a true toxicity risk essential oils high in aldehydes may carry an increased risk of irritation. Dilute oils like cinnamon, cumin, and citronella.

How to Introduce an Oil to an Animal

When I introduce a new essential oil to an animal:

  1. First, never introduce an essential oil in times of stress or duress.
  2. To introduce, leave the cap on the bottle and hold in front of their nose. Watch for the animal’s response. If the animal sneezes or snorts at the aroma of the oils, I usually will not further expose them.
  3. Next, add the essential oil to your skin approximately 15-20 minutes before entering the room with an animal. This will reduce the initial impact to the animal. Watch for the animal’s response.
  4. Then, I add 1 drop of essential oil to my hands and rub my hands together.  I hold my hands about 4-6 inches in front of the animal’s nose.  Watch for the animal’s response. If they draw in closer, then we have a winner.
  5. After that, I will either add the essential oil to a diffuser, or dilute and apply to a dog’s paw or on the ears. Many pet parents choose to avoid applying essential oils directly to cats.
  6. For rodents such as gerbils, hamsters and guinea pigs, I add no more than one drop of a mild essential oil to fresh bedding. Watch the animal closely, change bedding if any signs of distress arise. Be sure they have free access to water.

Observe Your Animal

  1. Whenever you introduce an essential oil to your animal, be sure to observe for signs of distress or discomfort. Look for excessive yawning, scratching, backing away, lip licking, lifting a paw, excessive sleeping, excessive water consumption, excessive urination, or aggression.
  2. Be sure animals have free access to water and fresh air. Never confine an animal around essential oils. Never force an essential oil on an animal.

Bottom Line

It is up to you as a pet parent how you choose to use essential oils.  Start low, go slow, and closely observe your animal. Remember your science, and use common sense.

Want more oily education?  Let’s go!

References