Change of Hair Color in Cats

Post Published on January 25, 2012 | Last Updated on July 15, 2021 by Jenny

I consulted Serge Martinod, DVM, PhD of ArcaNatura about Charlie’s coat color change as well.  Here is what he had to say about cats changing hair color.

Charlie - fat and dark on dry food 2-12-11
Charlie – fat and dark on dry food 2-12-11
Charlie slim and trim and light on wet food only 10-29-11
Charlie slim and trim and light on wet food only 10-29-11

Thank you for sharing those nice pictures of Charlie. Changes in hair color in cats is not very common but it does happen from time to time. Although I am not sure I have enough of Charlie’s history to thoroughly answer specifically; here is a summary of what I do know on changing hair color in cats.

Hair color is mostly genetically controlled but several factors can influence the color of hair:

1- The Diet:

Diet deficient in the amino acid thyrosine and/or phenylalanine causes the hair color to change from black to reddish color with a reduction of the pigment melanin in the hair. The requirement is 18 mg thyrosine + phenylalanine/kg diet.

Copper deficiency or zinc excess may also cause achromotrichia; a complicated word that means loss in hair color. Liver, kidney or thyroid deficiency can also cause the same change in color.

2- The Environment:

Lightening of the coat can occur with excessive exposure to chlorinated water (cat spending too much time around the pool) sunlight or if the hair growth is very slow.

3- The Skin Temperature:

Skin at a higher temperature has lighter colored hair and cooler areas have darker hair. So for example if an area is clipped, it is cooler and therefore hair re-growth is darker. Different outside temperatures and hair density could have similar effects.

In the case of Charlie, one thing to determine is what was his normal color: The lighter colors in the beginning (in this case, the question has been solved by his change of diet) or is his coat the darker color now? Please also keep in mind that several causes may exist at the same time.

Omega-3, although certainly helpful with maladies, it will not do much for the color of the hair. Charlie has other good reasons to be supplemented with Omega-3 but not this one! (You can read more info on ArcaNatura’s blogs.)

Let me know if I have answered your question.

Serge Martinod, DVM, PhD

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18 thoughts on “Change of Hair Color in Cats

  1. Irena Weygold says:

    On the Catsite (Black Cats Only) there is a pic of a longhairedcat in Japan that was all black when it was born and during its first year its fur changed to blondish/brown all but the whole head which stayed black. A new pic has just been posted showing the cat (named Carpet) with its blond/brown fur darkened to dark brown and the head is still black. None of the parents and grandparents are brown or black but grey with white. The other kittens in the litter also were not black. They all have the bobtail gene which is common in Japan. This cat seems to change color with the season although it is unclear at this time if it will turn light again or go to all black as it is snowing there right now and the cat is only 1 1/2 years old now. These cats are semi feral, Carpet is now domesticated, they all live in a rural area with a very large piece of property surrounded with a catproof fence, trees and all.

  2. B^!!^J says:

    Nathan, I posted this on Facebook, then read Jenny’s instructions about replying here! I did some reading about the black color pattern in Maine Coon cats (see FaceBook page Maine Coon Nation) and the readers there reported some Coonies with black coats can show shades of brown when they spend a lot of time lying in the sun. My black smoke Coon-mix shows tinges of brown now and then. Now, after a summer in South Florida, he’s got brown “highlights”. Thinking back, Cody’s brown furs do seem to come and go, like, with the seasons? I hope that’s the case with your little dollface.

  3. Julie says:

    Hi Nathan,
    So sorry to hear this…I can only speak from my own experience regarding the “reddish brown fur”. My SpikeKitty…a stray black med haired kitten i found 19 years ago started to turn reddish/brownish at around 14…same time he was diagnosed as a diabetic. I had him on insulin & when he lost enough weight…they took him off & found his diabetes to be gone…but the reddish hair stayed until he left at the 18.

    • Nathan says:

      Hi, thanks for the help. I’m not too worried about the reddish fur, as long as Beavis is OK y’know? I’m taking her to the vet tomorrow just to make sure she’s OK. Thanks again for the help.

  4. Nathan says:

    Hi, could somebody please help? I have a black moggy cat called Beavis who is now 13 years old. Her hair has started to turn reddish brown, as said with the information at the top of this page. I assume this is due to a lack of Thyrosine. Two questions: 1) Is it dangerous if left for a long time? 2) Is it age – related? Any help would be much appreciated.

  5. andrea says:

    it was dark out and every time i flashed the light on it it would run away so i couldnt take a pic of the cat ..the kitten, i will have my son upload the pics for u tmrw.i am going to go over to the house i saw him wandering around in the morning and ask them where they got him but i already did all this in the summer and didnt get anywhere w my neighbors..this cat had no collar but looked well fed and clean so i know it is living indoors somewhere close around here..thanks for your help in my detective work

  6. andrea says:

    can someone please help me?? kitten ran away in the begining of the family was devistated..i was just walking down the street and saw a cat that looks just like my kitten but bigger as it has been 3 months since he question is can cats fur change colors because when he was small he had alot of white fur around his neck and feet..this cat that i saw didnt have almost any traces of white fur..what was white was very minimal it looked like it had once been white but is now changing to gray like the rest of his body…Am i crazy or could this be my kitten?

    • Jenny says:

      What kind of cat was it as a kitten – if it was a pointed cat like a Ragdoll, then it is possible that it has lost it’s white-ness.

      • andrea says:

        im not exactly sure what kind of cat he was..the girl i got him from said his mother was a hymilayan and his dad was a street cat so she doesnt know what exact breed it is..but it responded to us by name, let us pick him up and feed him but he wouldnt come in the son believes in his heart it is his cat but what is throwing me off is that he had white fur boots in the pictures we have of him..this cats feet were all gray..he also had a white patch near his mouth and again now that was also confused

  7. paige says:

    i have a black cat that is getting gray stripes. the fur started changing around his neck first and now has expanded to his back. the change is rapidly happening. he is two years old. i have never seen this before. anyone else?

  8. Geri Rolfe says:

    I had a ragdoll, named Smudge, that was mostly white/cream color with his points and tail a chocolate with a little black … his back was completely white when he was a baby. He had a few other spots but light colored …oh and a dark “smudge” by the side of his nose.. and a full mask around his eyes.. By the time he was a year his back had gone dark and mixed down into the tail which was also the dark chocolate brown… His mask expanded a bit… He was beautiful… I thought I read on a Ragdoll site that this is common for this breed…

    • Jenny says:

      Hi Geri, yes what you described is VERY normal in Ragdolls. However, Charlie’s color change is happening in the opposite way! He got dark until he was 2 and then started lightibg up. Id Love to See a photo of Smudge!


  9. Donna & Morgan says:

    Really interesting! I wonder what Willow would have looked like if she had stayed in Puerto Rico – with the climate difference.

    Another great one Jen!

  10. michelle says:

    hmm i wonder if it may be shadow’s diet as he is a very very picky eater and only nibbles on dry food through-out the day.

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