Is there a way that a sort of immortality could be achieved through genetic engineering or some other type of biological/medical technique? Not necessarily permanent immortality until the heat death of the universe, nor general invulnerability (just looking at anti-aging here, not necessarily being unkillable), nor even a one-and-done "now you're immortal" solution if that's too hard to pull off. Would it be possible to achieve immortality by stopping the aging process through a repeated "treatment"—basically continuously pausing the aging process and going back to renew whatever paused it (or to restore your "stock" of living, youthful cells/particles) any time it starts to wear down? Or what might be the effect of this on the body, especially if the user decided they were ready to move on and chose not to "renew"?

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    $\begingroup$ Can you specify what kind of fictional world you're working with? Like what kind of magic is involved, how advanced are they scientifically, etc? $\endgroup$
    – elemtilas
    Commented May 2, 2023 at 19:38
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    $\begingroup$ the phrase you are looking for is "biological Immortality" $\endgroup$
    – John
    Commented May 2, 2023 at 20:32
  • $\begingroup$ This was the premise of John Wyndham's "The Trouble With Lichen", one of his less popular but still decent books. $\endgroup$
    – user86462
    Commented May 3, 2023 at 2:54
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    $\begingroup$ @AncientGiantPottedPlant Heinlein beat Wyndham to it by two years with Methuselah's Children (1958), though I agree that "Lichen" was a good book. Joe Haldeman went into the social/economic implications in "The Long Habit of Living". Not sure what answer is expected - we obviously can't do it yet or it would be available, and we're not sure whether it can be done in the future. $\endgroup$ Commented May 3, 2023 at 3:22
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    $\begingroup$ I think an "anti-aging" shot is trope enough to just get handwaved. $\endgroup$
    – user458
    Commented May 3, 2023 at 4:32

9 Answers 9


You should learn about telomeres (from the Greek "telos" and "meros" which means the end part). Telomeres, as far as I know, are the end-part of our chromosomes. With each cell division, they get shorter and shorter until they can't get any shorter, thus the cell can't divide any further, and it thus dies. It seems that telomere research is a hot research topic, as you can see here. The research aims at reversing aging and thus immortality down the line. There is a wild claim that the first person to live for 1000 years has already been born.

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    $\begingroup$ (this probably evolved to prevent cancer) $\endgroup$ Commented May 3, 2023 at 7:45
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    $\begingroup$ @user253751 very interesting. Does this mean that telomeres stay intact in species that don't get cancer such as in whales (I believe)? $\endgroup$
    – cconsta1
    Commented May 3, 2023 at 7:50
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    $\begingroup$ no idea if whales have telomeres, but I wanted to point out it's not that cells can't divide forever, but that they don't want to. We also know of an enzyme called reverse telomerase; guess what it does. $\endgroup$ Commented May 3, 2023 at 7:51
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    $\begingroup$ yup............ $\endgroup$ Commented May 3, 2023 at 7:57
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    $\begingroup$ @user253751 I doubt you could find an eucaryote cell that doesn't have telomeres. If you have linear chromosomes you NEED telomeres. Whales definitely have them. $\endgroup$
    – Negdo
    Commented May 4, 2023 at 11:50

It's possible. Many animals are able to regrow limbs they lose.

The genes that allow them (as we've identified so far) seem to be suppressed in apes (including us) as a control on cancer.

Also, one of the big factors in aging is telomere reduction as we we age; this also likely a cancer control; the telomeres are end-caps on the genes that slowly get cut down as cells divide, and at a certain point the lack of telomeres will cause the cells to stop dividing, and just die in place.

If enough cells do that, we develop wrinkles and dark spots and other age related problems we recognize as a "lack of youth."

In a SciFi setting, somebody might invent a way to control these natural biological mechanisms. Some kind of gene therapy to restore telomeres, and some way to trigger organ replacements with new younger tissue, and yet another way to clean out the dead cells and make room for new cells.

You might need some medical support for things like heart replacement. And for other brain elements with limited capacity, like long term memory, you might need some way to edit what you would discard to make room for fresh cells. Or maybe you don't get to really choose; incrementally "forgetting" your parents or loved ones, little by little, may be the sacrifice you accept in return for functional immortality. (And really, we do it now; I recall very little of my childhood before adulthood, for example, more than half a century ago.)

I don't think these are outside the realm of plausible future science; some of it is seriously proposed as science to work towards.

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    $\begingroup$ There is a known enzyme, reverse telomerase. Telomeres aren't some intrinsic limitation of DNA - it seems they just evolved to prevent cancer. $\endgroup$ Commented May 3, 2023 at 7:45
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    $\begingroup$ @user253751 If they evolved to prevent cancer, then we need some alternative to prevent cancer if we restore the telomeres. Perhaps some sort of genetic engineering can provide a more reliable solution to prevent cancer instead of telomere reduction. $\endgroup$
    – Amadeus
    Commented May 3, 2023 at 10:35

Mind Uploading + Cloning + Mind Downloading does it

Step 1: Make a test tube clone of yourself.

Step 2: Upload your brain to a computer model (destructive process is okay).

Step 3: Download your computer modeled brain into the cloned body.

Step 1 is doable with today's technology; step 2 is certainly possible, though the how is not within the ability of current science; step 3 is the natural next step after step 2 and is the biggest stretch for believable science.

  • $\begingroup$ The question is asking about purely biological methods of immortality within a single body that would require regular treatments to maintain; this is a common approach in fiction, but it doesn't really fit that very well? $\endgroup$
    – Idran
    Commented May 3, 2023 at 18:34

Let's look at an interesting graph

enter image description here
Chart Courtesy Disabled World

From 1900 to 2008 the life expectancy of the average U.S. citizen increased from age 47 to age 78. That's no small thing! There was that nasty blip due to the Spanish Flu in 1917-1918, but still, it's a nearly doubling of our life expentency. Why did that happen?

  • Improved pharmaceuticals
  • Improved medical treatment
  • Improved sanitation
  • Improved food

And that's really undrscored by how the graph smooths out after World War II. Huge advances in science — especially in terms of vaccination and innoculation — removed a lot of the variability year-to-year.

But what's really amazing is the U.S. could pull this off since the 1980s despite increasing political tension, greater work stress, and lowering food quality due to processed food consumption. Let's ignore these. With the possible exception of the consequences of processed food (which some think is the cause of average weight increases among U.S. citizens), we'll probably always have stress in our lives.

What's my point?

The idea that improving medical science (e.g. genetic engineering) and other factors could lead to reasonable immortality (perhaps hundreds of years?) is, in my opinion, completely believable.

Would there be consquences?

You bet!

  • Overpopulation
  • New diseases due to increased population density
  • Crime...
  • War... if only due to stress on limited resources

But all that is beyond the scope of your question. But it is interesting to ask the question, at what point does it no longer make sense to save everyone? We're facing the beginnings of that question today as we (at least in the U.S.) deal with questions like what rights people have to health care? When you consider the implications of your question, what rights should people have to the kind of health care that would extend lifespans that far?

But I'm rambling. Sorry.

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    $\begingroup$ People often misunderstand pre-modern life expectancy statistics. Most of the life expectancy shift is from a drop in infant mortality, and a general higher likelihood that children born will reach adulthood. It is NOT the case that adults used to rarely live to 50. $\endgroup$
    – Jedediah
    Commented May 2, 2023 at 20:48
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    $\begingroup$ @Jedediah That makes sense, but I don't think it changes my general assertions. It does remove most of the celebratory drama, though. $\endgroup$
    – JBH
    Commented May 2, 2023 at 21:56
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    $\begingroup$ The USA is not facing the beginnings of any of these questions: it has already concluded them long ago, and the answers are "only billionaires get healthcare", "only billionaires get fair trials", "you have to make over $20k a year to avoid getting murdered on the subway in the morning for complaining" etc (the assailant was released with no charges, precisely because the victim had no money and in the USA, it's de facto legal to murder people with no money) $\endgroup$ Commented May 3, 2023 at 7:47
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    $\begingroup$ @user253751 Wow, did you overpoliticize that article from the Post! Even the witness said the man was being aggressive. A group of people in an enclosed area with no exits until the next stop faced with a man who's screaming and acting violently. Do I approve of the outcome? Absolutely not! The man could have been restrained in a way that didn't take his life, obviously. But I cannot condone your belief that he died simply because he was complaining. And unless you can prove the assailant was a billionaire, (*Continued*) $\endgroup$
    – JBH
    Commented May 3, 2023 at 15:13
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    $\begingroup$ ... you're massively oversimplifying. It's normal for people to be released without charges when the situation hasn't been fully investigated or when evidence of self-defense is found or an interpretation of good samaritan laws are involved (in this case, most likely the former and the later). I cannot see your comment as an effort to improve my answer, but rather just a political rant. $\endgroup$
    – JBH
    Commented May 3, 2023 at 15:14

In my fiction, I've identified four distinct forms of immortality.

Unaging: the main race in my second book has achieved an understanding of biological processes that allows them to perform regular maintenance on the human body that basically reverses aging. You can review what they do on the Wikipedia article on Biogerontology. This also involves surgical processes for handling disease and damage.

Serial immortality: The same race also has the ability to scan a person's brain at death and re-incarnate that person into a fresh clone. The new person is considered legally identical to the previous one, but a lot of their emotional biases are "flushed." The process prevents people from making the same mistakes every time they're reincarnated.

Nigh immortality: This is a magical form of immortality, but it could be done with nanotech. There's basically an agent that has an idea of what the person should look like, and enhances biological processes to return it to that form when it's injured. You can still bleed out, and you can get your brains blown out, but if you can survive it, you will eventually return to optimal health.

True immortality: The body is just an avatar of the real self. The real self is an intelligence that runs on a substrate elsewhere, and the body is the "user interface for the world." If the body is destroyed, it can always get another. The level of effort for getting a new body makes a fun story point.


Assuming you don't want some kind of cloning with mind transfer, you need effective maintenance.

Firstly, the telomere shortening clearly has to be prevented, but just doing that is already solved or close to it.

More challenging is finding other ways to defend against unbounded mutant cell division, but there are plausible alternative mechanisms.

For example, I read a novella a while back [insert name when somebody else remembers it] in which effective immortality was achieved by adding a "checksum" to the DNA, which caused any cells with defective DNA to self destruct. (There were three problems: firstly, the higher rate of cellular replacement increased their metabolic requirements, leading to lethargy if they subsisted on a normal diet; secondly, it couldn't be retrofitted to a living person, as it had to be done immediately after fertilisation; and thirdly, the process created a new species which couldn't interbreed with normal humans. In the story there was so few produced that they didn't form a viable population, so they slowly died out, mostly from suicides.)

But that leads the second thing that needs fixing: our immune system sits on a knife edge between under-reacting and over-reacting. Dealing with invaders that lack the "self" identifying surface enzymes is easy, but dealing with tumours and certain kinds of chameleon invaders that do have the correct surface enzymes involves randomly asking cells to die, and if they fail to do so, triggering an inflammation response that kills them and all the surrounding cells as well (on the assumption that neighbouring cells are more likely to have the same defect).

Instead of asking cells to die, the immune system could in theory use some other kind of challenge-response; in the checksumming scenario, it could offer them with a protein, which the cell then sequences and "signs" with its own checksum; only if it fails to produce the right answer in a reasonable time frame then kill it.

Thirdly, even when the immune system gets it right, it won't stop non-malignant tumours; but I guess occasional surgical (likely thermoclave) intervention to remove these would be within the scope of this question.

Fourthly, defending against failures of the immune system itself is very tricky. Perhaps some kind of "best of 3".

Lastly, all organisms already have potential immortality but a finite expected lifespan. The limiting case for humans is above 95, where expected (remaining) lifespan remains fairly steady at around 15 months for women and 10 months for men.) Even if we increase the expected lifespan by a factor of a million, it's still finite. At some point, the expected longevity of external renewal services becomes the limit.


Such immortality already exists in the real life. Take the immortal jellyfish, as an example. It can revert from its sexually mature life-cycle stage to its larval stage. Then it proceeds through it normal development. While humans dont have such stages, there is no reason the regenerative process couldnt be replicated.


To give the most basic form of anti aging, resetting the telomeres gives basic resetting of age. People also look at transfusions of blood from young people for fresh stem cells. It won't give immortality as it doesn't solve things like cancer.

Frame Challenge

Immortality will never come from genetic engineering. Even if you solve cellular aging and regeneration, people will still die from accidents or murder.

The technological singularity is when computers reach the same level of sophistication as the human brain. If you can back up the human mind, you can achieve immortality. If someone gets killed, you download yesterday's backup into a new body and off they go.

To kill someone completely, you'd kill their body plus destroy all the backups of their mind which could be hard to do.

In the book series "Altered Carbon" minds are backed up inside the stack which is a small chip in the neck. Additional copies can also be made and stored in safe locations. Bodies are called sleeves and people can jump bodies easily into biological or mechanical ones or even just exist inside digital worlds.

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    $\begingroup$ This is not really a frame challenge, because the question already says: "Not necessarily permanent immortality until the heat death of the universe, nor general invulnerability (just looking at anti-aging here, not necessarily being unkillable)". $\endgroup$
    – kaya3
    Commented May 4, 2023 at 17:46
  • $\begingroup$ @kaya3 If you can die, you're really not immortal $\endgroup$
    – Thorne
    Commented May 5, 2023 at 0:00

Yes, and here are two solutions you should look at.


Aging of the body as a whole is due in part to the accumulation of so-called senescent cells. Normaly when our cells accumulate too much flaws, they auto-kill in a process called apoptosis. This prevent useless cells to become a burden for the body. However, it is not a 100%-reliable mechanisms, and some cells are stuck between life and death. Theses senescent cells produce a lot of inflammatory molecules which degrades the body's constitution, resulting in overall frailty.

Some research teams recently discovered that, by killing these cells with drugs (mostly re-targeted anti-oncotics), life expectancy can be increased by a few months in mice (a few years in humans). Effort is currently on the way to develop senolytics, drugs specialized in this purpose.

In your setting, you could consider that a one-month therapy with senolytics would be required every decade or so. Secondary effects would be probably similar to chemotherapy (nausea, hair loss,...) and require hospitalisation for the duration of the session. While affordable for the wealthiest, this would be a logistical nightmare if you would like to expand this to the rest of the population (just imagine the health budget and the number of medics/paramedics required). Discontinuing the treatment here would simply cause the aging process to resume at normal speed.

Gene/Cell therapy

If our cells are flawed, then you can try to replace them. Cell therapy consists in extracting a few cells, reprogramming them and reinjecting them to the patient, or, if the technique allows it in your setting, directly using a non-contagious, non-pathogenic virus as a carrier to directly edit the genetic material of the cells in the patient's body. Some of the edited gene could be implied in DNA repair and oxydation buffering to protect against aging, but you could as well increase strength through bone density or myosin packing, or cognition through improved myelin fibers and neural ionic channels.

The trick here, is that you (or your evil biomedical corporation) could make these cells depending on a proprietary drug for their survival. In practice, that would be similar to a synthetic vitamin. Hence, once you receive the therapy you'll need the drug for your new super-cells to survive. If you discontinue the proprietary drug at early stages (years after treatment) you will find yourself greatly weakened and lose your immortality (you would need a second session of cell therapy). At late stages (decades, centuries), the super-cells would have replaced most of your original cells so if you were to discontinue the drug you would simply die in days due to massive cell death - something ugly and quite similar to the radiation fever.

Of course you could make your super-cells not reliant on any drug, but from a corporation's perspective that would be a huge loss of money.


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