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Rapamycin, mTOR, and Possible Anti-Aging Effects in Dogs

Linda Crampton is a former biology teacher, a writer, and a long-time pet owner. She has or has had dogs, cats, and birds in her family.

Sam is tired after a day of hiking and swimming on our camping trip.

Sam is tired after a day of hiking and swimming on our camping trip.

The Goal of Anti-Aging Strategies

Rapamycin is a chemical produced by soil bacteria. In lab experiments, the chemical has significantly lengthened the lifespan of yeasts, worms, fruit flies, and mice. It's currently being tested in pet dogs. If this trial is successful, rapamycin may then be tested in humans. Rapamycin seems to work by inhibiting a protein known as mTOR.

The goal of anti-aging techniques varies. For some researchers, the main objective is to prolong life. For others, the aim is not so much to extend life but instead to ward off problems and diseases that are more common in old age. If these conditions are avoided or delayed, an individual should be able to remain healthy and active for a longer portion of their life. An added benefit is that avoiding certain diseases may lead to increased lifespan. Rapamycin could be useful because it appears to counteract some of the processes involved in aging.

An Important Note

The information in this article is intended for general interest. Anyone who is interested in anti-aging tactics for a dog should consult a veterinarian. A doctor or other health professional should be consulted about anti-aging strategies in humans.

A species of Streptomyces with branching filaments and chains of spores

A species of Streptomyces with branching filaments and chains of spores

Streptomyces: The Source of Rapamycin

Rapamycin is produced by a soil bacterium named Streptomyces hygroscopicus. The "Rapa" part of the drug's name comes from Rapa Nui, the original name for Easter Island. The island is located in the southeastern part of the Pacific Ocean and is a territory of Chile. Rapamycin was discovered in soil collected from the island in 1965.

The suffix "mycin" is often used to name medicines made by species of Streptomyces. Many of these medicines have been discovered. They include antibiotics as well as immunosuppressive drugs. Not all antibiotics made by Streptomyces have "mycin" in their name, however. For example, chloramphenicol was found in Streptomyces venezuelae. It's an important antibiotic that is used to treat some serious diseases. The genus Streptomyces is very useful for humans.

The Rapamycin Investigation

Inhibition of mTOR and Immune System Suppression

Rapamycin is already used as an FDA-approved drug in humans. (The Food and Drug Administration, or FDA, is a federal agency that approves medicinal drug use in the United States.) The medicine is sometimes known as sirolimus or by the brand name of Rapamune. At high doses, it suppresses the activity of the immune system. This ability is very useful in preventing the body's rejection of tissue and organs transplanted from other people's bodies. The drug is frequently given to people who have undergone a kidney transplant.

Rapamycin is believed to inhibit the immune system by interfering with the action of T cells. T cells are a vital component of our immune system. The system protects us from invaders such as bacteria and viruses. Unfortunately, the body considers medically transplanted tissue from another person to be an invader, too, and attempts to destroy the tissue.

Once inside the body, rapamycin inhibits mTOR. The abbreviation "mTOR" stands for "Mechanistic Target of Rapomycin". The protein plays an important role in T cell activation and reproduction. When mTOR is prevented from doing its job, T cells are hindered and transplanted organs are safer.

More Facts About the mTOR Protein

The mTOR protein was first described in 1991. At that time, it was of interest mainly because it was affected by rapamycin. Scientists have since discovered that it's a very important signaling molecule in cells and is involved in many processes, including (apparently) aging.

Enzymes are a type of protein. mTOR is an enzyme that acts as a kinase. Kinases are enzymes that transfer phosphate groups from high-energy molecules to other substances. Researchers are trying to discover more details about mTOR because it seems to be involved in some critical processes in the human body.

Exploring the mTOR Pathway

Rapamycin is a bioactive chemical. A bioactive substance is a non-nutrient chemical that produces an effect (or effects) inside the human body.

Rapamycin as a Cancer Treatment

Rapamycin can fight at least some types of cancer via its action on mTOR. The mTOR protein stimulates the growth and reproduction of other cells besides T cells. It's often mutated (changed) in cancer cells. This mutation leads to increased reproduction of the cells. Since rapamycin inhibits mTOR, it can be helpful in stopping cancer cell reproduction and in treating the disease. The "hyperactive" mTOR in some types of cancer seems to be especially sensitive to the presence of rapamycin.

There are two versions of mTOR—mTORC1 and mTORC2. mTORC1 is the version involved in most research and is the type that seems to be most closely related to cancer development. It’s sometimes referred to as a master growth regulator. It promotes both the growth of cells and their proliferation.

This is a T cell, or T lymphocyte, obtained from a healthy person. The photo has been colourized.

This is a T cell, or T lymphocyte, obtained from a healthy person. The photo has been colourized.

Rapamycin and Life Extension in Mice

Multiple experiments have shown that rapamycin increases the lifespan of mice by about 20%, depending on the conditions of the experiment. The chemical is exciting because its anti-aging benefit has been shown in different studies performed by different people. This indicates that the claim that it lengthens the life of mice is very likely true.

At the moment, it's unknown how rapamycin increases the lifespan of yeasts and lab animals. There are several theories, but they haven't been proven. It's thought that the inhibition of mTOR is somehow involved in the process.

How Does Rapamycin Fight Aging?

There are two leading theories for rapamycin's method of action, as described in the first two sections below. There is also a third possibility for its method of action. The chemical may extend life in more than one way.

Reducing the Amount of Protein Synthesis

One way in which mTOR triggers activity and growth in cells is by stimulating the process of protein synthesis. It's suspected that the buildup of misfolded proteins in our body is one cause of aging. It's been suggested that by reducing the number of proteins that are made, rapamycin also reduces the number of misfolded proteins produced as well as the resources needed in the attempt to repair them. This may be part of the answer to the anti-aging puzzle, but the evidence doesn't support it in all cases.

Promoting Autophagy

mTOR is involved in a chain of chemical reactions that inhibits autophagy. Autophagy is the breakdown of organelles and proteins in cells. Inhibiting this process is useful under normal circumstances, but autophagy has some benefits. The breakdown of damaged structures and the recycling of their components for new construction can be helpful for a cell. Autophagy is also helpful when a cell isn't receiving enough nutrients.

Rapamycin inhibits mTOR and promotes autophagy. Various researchers have observed that promoting autophagy can have rejuvenating and life extension benefits for yeasts, worms, flies, and mice, so this may be one way in which rapamycin reduces aging. The worm used in life extension research is usually Caenorhabditis elegans, often known as C. elegans. The fly is frequently Drosophila melanogaster, or the fruit fly.

Inhibiting Health Problems

Rapamycin may also extend life by inhibiting cancer and reducing inflammation. The immune system launches an inflammatory response to attack invaders. This inflammation is normally temporary. Increased and chronic inflammation is believed to be a contributor to the aging process.

Misha as a young dog

Misha as a young dog

I would have loved to have extended Misha's lifespan as long as I was confident about his safety under the treatment regimen.

Aging in Dogs

The research into the effects of rapamycin on dog aging is being performed by scientists at the University of Washington. They call their research the Dog Aging Project. The researchers suspect that the drug may increase the lifespan of dogs by two to five years. Only some of the dogs being studied are being given the substance, however. The project is investigating multiple ways to increase the lifespan and the "healthspan" of dogs.

I wouldn't allow my dog to be treated with rapamycin at the moment due to the uncertainty about its effects. I certainly understand the attraction of the drug for dog owners, though. Dogs have such short lives compared to ours. They are intelligent animals that make wonderful companions and often become much loved members of the family. Sadly, their lifespan is only around twelve to fifteen years, although some dogs die at a younger or older age. It's heartbreaking for a dog lover to say goodbye to multiple pets as the person goes through life.

A small number of interventions have been shown to reproducibly and robustly extend lifespan in mice. Among these, the best candidate for working similarly in dogs and people is a drug called rapamycin.

— The Dog Aging Project at the University of Washington

This is Dylan as a puppy. I hope he has a long and healthy life.

This is Dylan as a puppy. I hope he has a long and healthy life.

Another Important Note

Organizations and their websites can change over time. The Dog Aging Project website has changed its design and perhaps the operation of the project since I wrote the first edition of the article. Anyone thinking of nominating their dog for the project should explore the current website and use the "Contact Us" menu item if they have questions.

The Dog Aging Project at the University of Washington

Researchers at the University of Washington have organized two studies in their Dog Aging Project. One is called the "Longitudinal Study of Aging in Pet Dogs". This is a nationwide study of dogs throughout their life. The goal is to discover why some dogs succumb to diseases such as cancer, dementia, and kidney failure in old age while others don't.

The second study is called the "Rapamycin Intervention Trial in Pet Dogs". There have been two phases in this study. The first involved a small group of pet dogs living in Seattle. All were older than six and were middle-aged. They were given a low dose of rapamycin for ten weeks. During this time, their blood chemistry, heart function, and microbiome was monitored by veterinarians. The "microbiome" is the community of predominantly helpful bacteria and other microscopic organisms that lives in the gut of dogs and humans.

The second phase in the rapamycin intervention trial is still in progress. It involves dogs from a wider area and is a long-term project. Its goal is to discover the effects of rapamycin on lifespan and health. The dogs will be monitored closely and frequent tests will be performed to assess aspects of their health.

The goal of the Dog Aging Project is to understand how genes, lifestyle, and environment influence aging. We want to use that information to help dogs and people increase healthspan, the period of life spent free from disease.

— The Dog Aging Project Website

Dog Safety and Side Effects of Rapamycin Treatment

At the high doses used to treat kidney transplants and cancer, there may be major side effects of rapamycin treatment in humans. These include increasing the risk of diabetes, hindering wound healing, and suppressing the immune system in cases where this isn't desirable. Only a low dose of the drug is needed to extend the lifespan of mice, however. The potential side effects of rapamycin use as well as the potential anti-aging benefits are of great interest to researchers.

The risk of side effects from a medicinal rapamycin treatment is probably acceptable for someone with a life threatening disorder. It may not be acceptable for relatively healthy people. The University of Washington researchers say that the anti-aging doses of rapamycin used in mouse experiments have caused few to no side effects in the mice, however. They suspect that the low doses of the drug used in their dog aging project will cause no significant problems, either.

Benefits of Anti-Aging Research in Pet Dogs

The Dog Aging Project may have important benefits for both dogs and humans. It would be wonderful if our pets had an increased lifespan while remaining healthy. Using dogs in the research instead of mice and simpler animals could be beneficial for humans beyond giving us a longer time with our pets, however.

Confirmation of rapamycin's effects in dogs is likely to take several years. Although dogs live for a short time compared to humans, they live much longer than the mice and other animals tested in lab experiments. The wait for the research results may be very worthwhile. Dogs are more similar to humans with respect to physiology and behaviour. Discoveries in dogs may therefore be more applicable to humans than those already made in lab animals. Another advantage of dog research is that results will be obtained more quickly than the equivalent research in humans due to the shorter lifespan of dogs.

At the moment, it's unknown whether rapamycin has anti-aging benefits in humans. If it does and if it's widely used, problems may arise. Most people would probably consider living for longer a great idea, as long as they stayed healthy and reasonably happy. If life extension strategies become routine, however, we may experience overpopulation and changes to the structure of society.

Potential Benefits of Understanding mTOR

The research at the University of Washington is personally interesting to me. Sam (the dog in my first photo) died of cancer, which is unfortunately common in golden retrievers. Cancer in dogs is a topic that is being investigated in the Longitudinal Study of Aging at the university. Dylan is still healthy and active but is showing a few signs of aging. Like all dogs, he will live for a much shorter time than most humans. Increasing his lifespan or at least maintaining his health as he ages would be wonderful.

Hopefully, the anti-aging potential of rapamycin will be very successful in dogs. If not, we should have at least learned more about mTOR. It's a fascinating chemical and its effects appear to be far-reaching. We know more about mTORC1 than mTORC2 at the moment. Both chemicals seem to be very important. Our research and knowledge of the substances could help us in many other ways besides extending lifespan.


This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2015 Linda Crampton


Linda Crampton (author) from British Columbia, Canada on July 18, 2019:

Thank you very much, Sara.

Sara on July 18, 2019:

Very well written article. It clarifies the issues perfectly.

Linda Crampton (author) from British Columbia, Canada on May 07, 2018:

Thank you very much, Natalie. I appreciate your visit and your kind comment.

Natalie Frank from Chicago, IL on May 07, 2018:

I am always impressed by your ability to take complex subjects and relate them in an easily understandable format for the rest of us who aren't science geniuses! Thanks again for another well researched, well written article.

Linda Crampton (author) from British Columbia, Canada on May 07, 2018:

Thank you very much, Darla.

Darla from Camas,Wa on May 07, 2018:

Great research and compassion.

Linda Crampton (author) from British Columbia, Canada on March 31, 2018:

I'm unaware of any research that compares life extension in dogs produced by rapamycin administration and by calorie restriction. It's an interesting idea (as long as the dogs in each group continue to enjoy life).

Skip Skipper on March 26, 2018:

Hasn’t calorie restriction (which also triggers autophogy) been just as effective as this drug?

Linda Crampton (author) from British Columbia, Canada on March 31, 2016:

Hi, Easy Exercise. I love animals, too. I wish I could predict how long it will take to prove that rapamycin is both effective and safe. Losing a pet is certainly heart breaking. I can understand why you want to avoid getting a dog with a short lifespan. Thanks for the visit.

Kelly A Burnett from United States on March 31, 2016:


You hit it out of the park on this hub - the very core of me loves animals and you had many of favorites in your photos. The idea of extending a dog's life is amazing - simply amazing. But then the other ramifications are also of high interest which perhaps our children will have a chance to debate? Any crystal ball predictions of a time line?

Once long ago I decided I wanted a flat coated retriever. I did all the research, saved the funds, called the breeder and when I learned they had a short life span I ran as fast I could. Loosing an animal is heart breaking.

Linda Crampton (author) from British Columbia, Canada on March 11, 2016:

Thank you very much, Peggy! I hope Skippy stays as healthy as possible and lives for a long time.

Peggy Woods from Houston, Texas on March 11, 2016:

Our Skippy is around 15 and definitely showing his age. It would be wonderful to be able to prolong the lives of our beloved pets if there are no serious side effects. As to prolonging human life...the sociological impact of overpopulation would surely need to be considered. Very interesting article Alicia. You never cease to amaze me with what you write!

Linda Crampton (author) from British Columbia, Canada on March 06, 2016:

I can imagine how you feel, Audrey. Seeing signs of aging in a pet is sad. I also know what you mean about writing poetry in an effort to deal with a difficult situation. I hope you have the companionship of your dog for as long as possible. Best wishes to you.

Audrey Howitt from California on March 06, 2016:

This touched me! I have an older dog and I don't know how I will say goodbye--lately it is through poetry that I can start to write my way through

Linda Crampton (author) from British Columbia, Canada on January 21, 2016:

Hi, Carolyn. It is hopeful research. I hope it leads to good things!

Carolyn Emerick on January 21, 2016:

thank you for sharing this! I had never heard of this research! Very interesting and hopeful.

Linda Crampton (author) from British Columbia, Canada on January 13, 2016:

Hi, Jackie. I hope my cats live as long as yours! They are indoor cats, although they do get taken out at times in a cat stroller. Thanks for the visit.

Jackie Lynnley from the beautiful south on January 13, 2016:

This is something great to know and very hopeful!

My last cat lived to be almost 20 and was an outdoor/ indoor one. I think it is great your dogs get to be outdoors; I think that will always be best for their health than ones who only go for an occasional walk.

Linda Crampton (author) from British Columbia, Canada on January 13, 2016:

Thank you, Vellur. Yes, rapamycin does seem to have a lot of potential. It's a very interesting substance!

Nithya Venkat from Dubai on January 13, 2016:

Rapamycin seems to have a lot of potential, this I know now after reading your hub. Another interesting and informative article voted up.

Linda Crampton (author) from British Columbia, Canada on December 31, 2015:

Thank you for the comment, Dianna. I hope you have a very happy new year.

Dianna Mendez on December 31, 2015:

I am always amazed at the amount of research out there that could possibly change lives. Thanks for bringing this information to us in basic knowledge format.

Linda Crampton (author) from British Columbia, Canada on December 31, 2015:

Thank you, Devika. Happy New Year to you, too!

Devika Primić from Dubrovnik, Croatia on December 31, 2015:

A Happy New Year to you!

Linda Crampton (author) from British Columbia, Canada on December 25, 2015:

Thank you for the comment, Mel. Yes, I think we do have to be careful. The possibilities are intriguing, though!

Mel Carriere from Snowbound and down in Northern Colorado on December 25, 2015:

It seems like there are some very worthwhile uses for this drug, but I agree we have to be cautious, and not open Pandora's Box before we really know what is in there. You have some lovely dogs, by the way. Great hub!

Linda Crampton (author) from British Columbia, Canada on December 21, 2015:

Thank you, Flourish. I agree with your desire so much. I would love my dogs, cats and birds to live for longer. Life extension for humans would be wonderful, too, as long as both our body and our mind stayed in good condition.

FlourishAnyway from USA on December 21, 2015:

Beautiful dogs, Linda. Oh, to turn back the clock for ourselves and our pets! And hopefully the mind stays sharp as well!

Linda Crampton (author) from British Columbia, Canada on December 21, 2015:

Thanks for sharing the interesting information, Deb. You've raised some good points!

Deb Hirt from Stillwater, OK on December 21, 2015:

There's a lot more in dirt that meets the eye. I grew up in dirt. I was there day and night, night and day, and am one of the healthiest specimens that you'll ever hope to meet. I also look about twenty years younger than most people that revolve around my age. I attribute this to growing up on organic food and being out in the open spaces exploring. That's why it has been said for years that kids that grow up in the country are much healthier than those in the city. Not only that, we know the source of french fries...

Linda Crampton (author) from British Columbia, Canada on December 20, 2015:

Thank you so much for the comment, Genna. I appreciate your kindness. Yes, I think that widespread extension of the human lifespan could definitely create some problems!

Linda Crampton (author) from British Columbia, Canada on December 20, 2015:

Hi, MsDora. Yes, rapamycin does sound promising. I'm a bit cautious because sometimes a substance is shown to be effective in lab experiments but not in humans. There's a lot of scientific interest in rapamycin, though. It could become a very important substance.

Genna East from Massachusetts, USA on December 20, 2015:

Linda, your articles are so well researched and presented; I always look forward to reading them, learning something new with each and every read. Rapamycin presents us with a Catch 22: It is hopeful for our canine friends that we dearly love, but with for humans, as you have pointed out, a prolonged lifespan comes with a new set of challenges.

Dora Weithers from The Caribbean on December 20, 2015:

Rapamycin sounds like a miracle product. I'm all for it fighting aging diseases; perhaps it can maintain the life it extends. Thanks for this information.

Linda Crampton (author) from British Columbia, Canada on December 20, 2015:

Hi, Bill. Thanks for the visit. Rapamycin is certainly an exciting chemical. The future should be interesting!

Bill De Giulio from Massachusetts on December 20, 2015:

Absolutely fascinating. Thank you for sharing this with us Linda. These are exciting times that we live in. Hopefully rapamycin proves to be as promising as it sounds.

Linda Crampton (author) from British Columbia, Canada on December 19, 2015:

Hi, Martie. Yes, rapamycin could be very important in our future. I hope it doesn't cause any problems, too.

Martie Coetser from South Africa on December 19, 2015:

Very interesting! Rapamycin could be the discovery of the century. I hope it will not cause problems in humans.

Linda Crampton (author) from British Columbia, Canada on December 18, 2015:

That's an excellent point, Larry. Life extension for humans sounds very attractive, but I think it could definitely cause some problems. Thanks for the visit.

Larry Rankin from Oklahoma on December 18, 2015:

I don't know what to say except just fascinating!

I often wonder when we crack the code on our bodies aging how we will deal with our brains going bad, or just running out of space.

Linda Crampton (author) from British Columbia, Canada on December 18, 2015:

Hi, RTalloni. Thanks for the visit and comment. We do live in amazing times!

RTalloni on December 18, 2015:

Thanks for sharing what you've learned on rapamycin. This is an interesting read that shows some of the potential that might come from the research. We live in amazing times to be able to explore the intricacies of this world's grand design!

Linda Crampton (author) from British Columbia, Canada on December 18, 2015:

Thanks, Bill. I think that biology is fascinating, so it's always fun for me to explore the topic.

Linda Crampton (author) from British Columbia, Canada on December 18, 2015:

Hi, Devika. Thank you very much for the comment.

Linda Crampton (author) from British Columbia, Canada on December 18, 2015:

Hi, Buildreps. Thank you for the comment. I would be so happy if dogs lived longer, as long as the life extension process was safe.

Bill Holland from Olympia, WA on December 18, 2015:

I don't know how you know all this stuff, but I appreciate the fact that you can share it with us in an understandable way.

Devika Primić from Dubrovnik, Croatia on December 18, 2015:

Hi AliciaC thank you for a very interesting hub. Dogs are amazing pets and your research taught me lots.

Buildreps from Europe on December 18, 2015:

As always very interesting and well researched, Alicia. I think it would be an ethical legitimate way to extend the lifetime of our four-legged friends. Like you state perfectly well, the life expectancies of humans and dogs are not very in sync, and is heartbreaking when they decease. Nice photo's of your dogs!

Linda Crampton (author) from British Columbia, Canada on December 17, 2015:

Thank you very much for such a kind comment, drbj. I appreciate it a great deal.

drbj and sherry from south Florida on December 17, 2015:

Thanks for sharing this exciting, and possibly anti-aging, research with us, Alicia. Rapamycin might be the new 'Fountain of Youth.' You are in a class of your own, m'dear, when it comes to sharing medical research in a manner that folks can relate to.