Alternatives to Lysine for Cats

Did you know that whenever your cat leaves your home, it may be susceptible to Feline Herpes Virus (FHV)? This virus can cause problems in the cat’s bodies and is usually treated by an amino acid supplement for cats called lysine. But sometimes, cat owners may prefer to use some other supplement, in which case, there are many alternatives to lysine for cats.

If you are looking for a substitute for lysine for your cat, look no further, because we have compiled all the information you need in this article.

alternative to lysine for cats

FHV and Lysine

Feline Herpes Virus or FHV works like any other virus; it needs to multiply itself so it can spread and activate in the host’s body.

Cats that are affected by FHV may have the following symptoms:

  • Runny Nose
  • Eye discharge
  • Breathing Problems
  • Laziness
  • Some flu symptoms

Lysine is one such medicine that fights against FHV and protects the body from being affected by this virus. It also helps reduce the symptoms and provide comfort to your cat when its symptoms are at their peak.

For many years, lysine has been the go-to medication for FHV, but recent research has shown that it may not be the best option for some cats, and can even cause major side effects, which outweigh the positives.

Hence, many people prefer to look for other alternatives, in case lysine does not suit their cat.

Below we have mentioned the different alternatives you can utilize if you don’t want to use lysine.

Alternatives to Lysine for cats

These alternatives may or may not work for your cat. Make sure you talk to your vet before giving them to your cat in case it causes any allergic reactions.


Probiotics are living bacteria that help cats grow their own “good” bacteria to improve their immunity and help fight against FHV.

They also improve digestion of food in cats, but before feeding any type of probiotic, consult a vet because many cats are allergic to them, and fall victim to vomiting and diarrhea.

Some examples that are proven to work better than lysine for cats are the SF68 and Fortiflora. These supplements help decrease symptoms of FHV and the side effects are manageable as well (they differ for every cat).

However, if your cat is showing increased symptoms after the supplement, do not hesitate to go to the vet.


Famciclovir is an antiviral drug that is usually prescribed to humans but is very effective in fighting against Feline Herpes Virus in cats.

Famciclovir is FDA-approved in humans, but it is not approved for treating feline-related diseases. You can still use it if your cat has a lot of side effects using other medications.

This supplement helps reduce symptoms such as breathing problems and decreases the damage caused to the respiratory organs after the disease.

However, keep in mind that famciclovir also has its own set of side effects, this can include diarrhea, fever, and sometimes even vomiting.

Therefore, before you begin proper usage of the medicine, you should consult your veterinarian thoroughly so you are aware of the possible problems your cat could encounter.

Thymus Extract

The thymus gland is a common organ in both cats and humans and is responsible for producing lymphocytes and other types of white blood cells to aid in immunity.

Because of this function, thymus extract is also seen as a useful hormone in medicine. Extracted from a cow’s thymus gland, this helps felines with breathing, nausea, and allergic symptoms from FHV.

It should also help reduce physical FHV symptoms like eye discharge and runny nose which we discussed at the beginning of the article.

The best part is that thymus extract does not have any side effects, and suits most cats just fine. However, if you find your cat showing any symptoms, talk to your vet about it. It is also best to ask the proper dosage for your cat based on its breed, age, and severity of symptoms.

Keep in mind, most vets do not recommend using thymus extract regularly, it is best to use it occasionally when the symptoms of Feline Herpes Virus arise.

Bovine Lactoferrin

Cow milk contains a protein called Bovine Lactoferrin and this is found in the colostrum, which is the first milk produced after the birth of a baby. This means it has loads of immune properties and can also be used in medicine.

Bovine Lactoferrin helps treat the Feline herpes Virus by controlling respiratory problems, and other FHV symptoms.

Vets recommend using this with an appropriate lysine dosage, many cat owners have seen a vast improvement in cats’ health after using this combination.

Not only for FHV, but Bovine Lactoferrin also improves immunity in the cat for other illnesses like viral flu, cancer, and influenza as well.

It also reports no side effects in cats with FHV, so it is a great option for those looking for alternatives.

Changes in lifestyle

This factor is underrated because having a healthy lifestyle can put a lot of things on the right path in your life. The same goes for cats, if they have a healthy environment around them, they are more likely to feel healthier and heal at a faster pace.

Besides this, having a properly balanced diet is very important. Cats need a diet with the right proportion of fats, carbs, and proteins, as well as dry or wet cat food based on their age and preference.

If you can give your cat a healthy and nutrient-filled diet, it will thank you in the future for its good health.

Moreover, cats should have a good relationship with their owners and have plenty of playtime throughout the day. This helps them stay active and prevents laziness, which can take longer to heal.

Taking your cat on a walk in nature regularly also helps.

Other Changes

Besides using the supplements and techniques mentioned above, there are other alternatives to lysine for cats, based on whether the vet has approved of them.

Other options to tame Feline Herpes Virus include nebulizing the cat using saline water and using strong antibiotics if the symptoms are too bad.

Nebulizing will help clear up congestion in the cat’s respiratory airways and allow it to breathe with ease.

If you decide to use antibiotics, make sure you ask the vet about what dosage you should give your cat and the duration of the medication.


Before using these supplements, you should ask your vet and discuss any possible side effects that your cat may face after usage.

If not taken seriously, the side effects can cause even more damage to the cat than Feline Herpes Virus.

For example, Famciclovir is found in the mother’s milk, and the mother’s milk is given to the kitten. If a pregnant cat or a new mother is given Famciclovir, it can transfer from the mother to the kitten. This can be harmful, as it is not meant for the kitten, and they may be allergic to it.

Also, try to avoid letting your cat go outside your home very often. You can’t completely stop it, because cats need their fair share of nature and walks, but limiting them is a good option.

This way, they are less likely to acquire the Feline Herpes Virus from other stray cats and organisms.


In conclusion, if lysine is not working to treat Feline Herpes Virus in your cat, there are other alternatives you can look towards.

Supplements such as probiotics, famciclovir, thymus extract, and bovine lactoferrin are all substitutes for lysine, though some of these may call for mixing some parts lysine for best results.

While using other supplements may eliminate the side effects of lysine, each of these medications may have its own set of drawbacks, depending on how your cat reacts to it.

Lastly, there are some precautions you should keep in mind while using each medication, and if your cat shows strong symptoms even after treatment, take a vet’s opinion immediately.

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