Why does my black cat turn brown???

If you’ve noticed a sudden change in your cat’s coat from black to brown or reddish-brown, many reasons could be causing it.

The good news is that most of these issues aren’t reasons to worry, and they can be easily fixed…except for one.

Keep reading to learn what it is along with other less-concerning reasons.

Why Does My Black Cat Turn Brown?

As mentioned above, the vast majority of the reasons are totally innocent and nothing to worry about.

However, in rare cases, the cause is far more concerning.

The sudden discoloration could result from a tyrosine deficiency, copper deficiency, age, or too much exposure to the sun. In a worst-case scenario, it can result from renal failure.

Now, let’s discuss each of the things that could make your black cat turn brown in more detail.

1. Deficiency in Tyrosine

A black cat coat’s color results from a genetic makeup that leads to the production of more melanin.

Besides keeping the coats black, melanin also protects the cat’s skin from damage by UC rays.

And for their coats to stay silky and black, they continuously need the amino acid tyrosine to facilitate eumelanin production.

When there isn’t enough Tyrosine in the cat’s body, the coat starts turning brown.

Proteins are formed from amino acids through translation. Cats need 22 amino acids, and 11 of these are considered essential.

Being essential means that they can’t produce them in their bodies, and they have to get them from their diet.

Cats need tyrosine and phenylalanine for pigmentation. Phenylalanine is an essential amino acid that leads to the production of Tyrosine, a non-essential amino acid.

Besides helping in the production of melanin, Tyrosine is a vital component in thyroid hormones and neurotransmitters.

While your cat can effectively produce Tyrosine from phenylalanine, it’s essential to feed them from various sources.

Some of the sources of Tyrosine for cats include meat, fish, and other animal products.

Rice may also contain Tyrosine, but cats are carnivores, and rice is not an option. You can also add tyrosine supplements to their diets.

READ MORE: Why My Cat Don’t Want to Sleep With Me?

2. Copper Deficiency

This deficiency doesn’t often occur in cats, but it’s worth considering if your cat’s coat color starts changing.

Copper facilitates the production of the pigment melanin from Tyrosine. This explains why its deficiency may cause discoloration.

Copper also helps in the intake and transport of iron through the cat’s system. And it plays an essential role in various enzymes.

Other signs of copper deficiency include a change in the fur’s texture, ataxia, and anemia.

Include liver, grains, or supplements in the diet to ensure an adequate supply of copper.

3. Zinc Toxicity

Zinc is vital for a cat’s skin and hair health. It’s also crucial in the reproductive function and other body functions.

But when a cat consumes too much zinc, it may lead to a copper deficiency, causing discoloration, including making a black cat turn brown.

This discoloration can also be accompanied by diarrhea, vomiting, lethargy, and a lack of appetite.

When you notice any of these symptoms, rush your cat to the vet as soon as possible.

4. Other Health Conditions

Health issues like liver disease, kidney problems, and thyroid problems can cause the coat’s color to change to brown.

For instance, the conversion of phenylalanine to Tyrosine takes place in the liver.

So if it’s not functioning, there may be a deficiency in Tyrosine.

Unlike mineral deficiencies, organ failures are fatal health conditions that should be treated as soon as possible.

5. Age

Grey cat with yellow eyes looking at the camera

Like in humans, a black cat’s coat turns gray with time due to aging.

But instead of going direct from black to gray hair, it starts by fading to a brownish color.

But if they’re too young to be turning gray, consider the other reasons I’ve discussed above.

6. Exposure to Sun

When your black cat spends too much time in direct sunlight, its fur may start turning brown.

If you’re not sure if it’s the reason, try taking your cat indoors for some time.

If the coat changes to black, then sun rays are the issue, and it’s nothing to worry about.

It happens to some people too, where their hair color changes to a lighter color when they’re exposed to sun rays for a long time.

The sun’s UV rays destroy the melanin, causing the black color to fade. But cats are always producing more melanin.

That’s why the black color is restored when they’re indoors.

What you should do is monitor how much time they spend basking and bring them indoors occasionally.

7. Shedding

Cat breed Devon-Rex

Black cats aren’t a breed. There are actually 22 black cat breeds, and some of them may shed their fur, and some may not.

When they’re about to shed, they may develop a slightly different coat color to the one they usually have.

But after the shedding process, the new coat will always regain the usual black color.

Some of the black cat breeds that shed their fur occasionally include;

  • Siberian
  • Selkirk Rex
  • Ragamuffin
  • Scottish Fold
  • Persian
  • Maine Coon
  • Manx

READ MORE: Reasons Why Cat Sleeps on My Chest

Can a Cat’s Fur Pattern Change?

Solid-colored cats coats will remain solid.

If they have a tabby or any other pattern, that won’t change either – only the coat color changes due to exposure to UV rays, aging, mineral deficiencies, or organ failure.

Can I feed My Cat With Tyrosine if the Fur is Turning Brown?

Burmese cat breed with black and brown fur

I mentioned that you could include tyrosine supplements in your cat’s food.

However, supplements may not be the best if your cat has another underlying condition.

Consult your vet first to make sure it’s appropriate, especially if they’re suffering from any of the medical conditions I mentioned or they’re pregnant.

What you can do is include lots of meat or proteins in a cat’s diet.

Check the ingredients on the packages to make they have a higher meat content.

Besides Tyrosine, meat also provides cysteine, taurine, arginine, and other essential amino acids.

Can a Brown Cat Turn Black?

Black cat with yellow eyes sitting on a path surrounded by greenery.

Brown cats may turn black due to an excess of proteins or amino acids in the diet.

This eventually leads to excess Tyrosine. If you notice this change, try and balance the minerals and vitamin amounts.



Long story short, there are many reasons why a black cat can turn brown, why they look different in the sun, and so on.

Nine times out of ten, that reason is absolutely nothing to worry about.

However, since that tenth time can be a potentially fatal condition, if your cat suddenly changes colors, definitely call your vet.

Brownish/black cat with text, "why does my black cat turn brown?"

Do you have other ideas why a black cat turns brown? Feel free to share them in the comment section.

Barry Stingmore
Barry Stingmore

Barry Stingmore is a British content creator living in Fuerteventura, Spain. An animal lover at heart, he shares his home with a dog and four rescue cats.

Barry works with the island’s animal charities to help manage and care for feral and abandoned animals. Alongside fieldwork, he works to support the charities with fundraising and raising awareness.

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Find more about him HERE.