Zylkene(®) is a natural remedy which helps to create a feeling of calm and relaxation in dogs. It is useful for reducing the anxiety felt during stressful situations (e.g. thunderstorms or visits to the vet) and is preferred by many owners over synthetic medicines. Zylkene is derived from casein, a type of protein often found in the milk of mammals which has been proven to have anti-anxiety effects. Despite being derived from milk, it is lactose free, so lactose-intolerant pets can take it without any issue.

Recommended Dosage

Note: Even though Zylkene is a safe supplement, please check with your vet before giving it to your dog.

The capsules come in 75 mg, 225 mg and 450 mg strengths to treat different sized dogs. See the table below to find the correct dosage for your pet.

Capsule StrengthWeight of DogCapsules to Give Daily
75 mg0 – 11 lbs1
11.1 – 22 lbs2
225 mg22 – 33 lbs1
33.1 – 66 lbs2
450 mg33.1 – 66 lbs1
66.1 – 132 lbs2


To administer the supplement you can feed the capsules directly or pop them open and sprinkle the contents either your pet’s food or in with their water. It is free from preservatives and lactose.

When to begin treatment: It’s recommended that you give the first dose at least 24 hours before anxiety is expected. If possible you should begin to use it a few days before the stressful event, which is what the manufacturer recommends. Keep in mind that certain cues can trigger anxiety in your pet, for example, if you are going on holiday the act of packing the suitcase can cause nervousness. Using that example you would administer the supplement for three days before packing the suitcase.

Example: A dog weighing 50 lbs could be given either two 225 mg capsules or one 450 mg capsule per day.


Is It Safe For Dogs?

Yes, it is a natural product considered to be very safe without any known side effects. Even in cases of overdose, there will rarely be any problems because it just contains natural protein molecules (casein). Some owners have reported their pet swallowing 6 or more 225 mg tablets without bad reactions.

Of course, this doesn’t mean you should purposefully administer too much medicine. Remain cautious and stick to the recommended dosage.

Guidelines For Use

We recommend following these guidelines when using this medicine:

  • Ideally begin treatment a few days before stress is expected
  • Discuss other options with a vet if a more powerful treatment is required
  • Consider adjunctive therapy with pheremones and other calming remedies

If this remedy does not provide adequate relief you can try Benadryl with the active ingredient diphenhydramine (an over-the-counter antihistamine) at 1 mg/lb 30 minutes before the anxiety-causing event, or talk to your vet about SSRIs such as Reconcile®. Because SSRIs and even Benadryl have a larger list of potential sides it’s a good idea to try Zylkene first and only look into these alternatives if it does not work.

Adjunctive therapy with “pheremones”, a special type of scent, can increase the calming effect. There are “DAP diffusers” (Dog Appeasing Pheremone diffusers) available for this purpose which emit pheremones to induce relaxation. DAP diffusers are available as both plug-in devices, much like an air freshener you might have in your home, or as a spray. You can pick up a good plug-in diffuser here. Keep in mind that while they can work great, they are also expensive to replace if you need to use it frequently.

What Is It Used For?

Zylkene is a natural calming aid used to relieve anxiety and reduce stress in household pets. It may be useful for the following situations:

  • Veterinary visits
  • You have a new person living in your house (a baby for example)
  • When your dog is staying home alone for an extended period
  • When your dog will be staying in the kennels
  • If you will be travelling with your dog
  • If you have a new pet in your house
  • When you are having a party
  • If you’re going on holiday
  • When you’re moving house
  • On fireworks night

Remember to anticipate cues your dog will pick up on which may stress them out before the actual event itself, and give the first dose of medicine up to three days before that trigger is expected.

Side Effects

There aren’t any adverse effects expected when using this product. It’s non-drowsy unlike most other anxiety remedies which means there should not be any fatigue or lethargy. Theoretically the following are possible:

  • Diarrhea
  • Vomiting

But this is extremely unlikely.


Official Zylkene information page