this post was submitted on 28 Nov 2025
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Science

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Study

The researchers discovered that once a tattoo is made, the ink rapidly travels through the lymphatic system and, within hours, accumulates in large quantities in the lymph nodes — key organs of the body’s defense system. Inside these nodes, immune cells called macrophages actively capture all types of pigment. This ink uptake triggers an inflammatory response with two phases: an acute phase lasting about two days after tattooing, followed by a chronic phase that can persist for years. The chronic phase is particularly concerning because it weakens the immune system, potentially increasing the susceptibility to infections and cancer. The study also showed that macrophages cannot break down the ink like they would other pathogens, wich causes them to die, especially with red and black inks, suggesting these colors may be more toxic. As a result, ink remains trapped in the lymph nodes in a continuous cycle of capture and cell death, gradually affecting the immune system’s defensive capacity.

The study found that tattooed mice produced significantly lower levels of antibodies after vaccination. This effect is likely due to the impaired function of immune cells that remain associated with tattoo ink for long periods. Similarly, human immune cells previously exposed to ink also showed a weakened response to vaccination.

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[–] SinAdjetivos@lemmy.world 47 points 3 days ago (4 children)

The full paper is here and, as usual, it's hardly anything and decontextualized in order to get a publishable result.

This one is so bad that it doesn't use established baselines or do any form of statistical analysis on the results instead opting for their own "baseline" measurements using very small sample sizes. It also plays a smoke and mirrors game where it shows a result for short term immunological response and then uses that to insinuate the 'slightly reduced but still likely well within the error of the poor control' long term effects are worth noting.

Other major flaws:

  • As others have mentioned, mice are a terrible model for this as their skin is very thin and proper tattooing is near impossible.
  • They mention verifying with human cadavers but don't include any data from those.
  • There was no control group, the baseline was an untreated mouse, not one with an acute foot trauma.
  • Mice age very quickly, best I can tell the immunological markers weren't age controlled. 2 months out of a <2 year lifespan is a lot of aging. Again, if there was a proper control to measure against.
  • The obsfucation of the raw data into cheesy and unreadable box and whisker plots is hella suspicious.

At best it's a very poorly communicated and poorly designed experiment but I suspect that's due to it result hunting.

[–] p03locke@lemmy.dbzer0.com 9 points 2 days ago (2 children)

What the hell? Was this even peer reviewed?

[–] P1nkman@lemmy.world 3 points 2 days ago

Probably by LLMs.

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[–] DocKarate@lemmy.world 3 points 2 days ago
[–] p03locke@lemmy.dbzer0.com 92 points 3 days ago* (last edited 3 days ago) (8 children)

There are far too many humans with tattoos that could have been researched extensively, but they chose mice. Mice do not have the same kind of skin density as humans, and I doubt a tattoo artist or researcher would have the talent to tattoo a mouse's skin.

There's just so many things wrong with using mice in this study. So many bad ratios with the size of the animal. I mean, for fuck's sake, tattoo artists already practice on pig skin. Pigs would have been a better analogue, but honestly, they should have picked the millions of humans who were already tattooing themselves.

Of course, if they did that, they wouldn't get the same result and be able to push this sensationalist science news title, now would they? Except, in this case, we've gone from research paper to straight to sensationalist news title in one step! Just let the institute PR department push the narrative for you, without having to wait for that pesky news cycle to crawl through the telephone game.

[–] Horsey@lemmy.world 51 points 3 days ago* (last edited 3 days ago) (3 children)

Human subjects are crazy to work with for a few reasons

  1. People don’t follow instructions perfectly
  2. Research subjects often don’t take the research project very seriously.
  3. It’s not uncommon to have dropouts, thus you either have to find more subjects or have less data.
  4. It’s impossible to know what the subjects are doing to cause data variability (diet, vices, etc)
  5. You can’t lock subjects in a room and force them to eat and drink the same food every day.
  6. There’s a financial (time) penalty to many research studies that can get in the way of enthusiastic participation.

Laboratory mice literally live 5 to a cage with almost no diet variability, in a controlled environment. Yes shit does happen with research mice, but it’s something that is easy to control overall.

[–] p03locke@lemmy.dbzer0.com 19 points 3 days ago (2 children)

And yet, we manage to have hundreds of thousands of studies written about humans with human subjects. This sounds like a boatload of excuses that could be summed up as "science is hard". Sure, it's hard, but it's better than putting out a flawed study that can't scale properly.

[–] olafurp@lemmy.world 17 points 3 days ago (1 children)

Sure, the study would be best if we did a randomised double blind study on a sample of 100 people that all are going to get a tattoo anyway but that doesn't make the mouse study irrelevant.

Mice and humans, although very different in appearance have biomechanics that are very similar. For every human study you could make a 20 mouse studies with the same funding so you could do a lot more exploration.

This study found something, notably that ink in the blood affected the immune system. This just means that future studies are needed like injecting people with tattoo ink and blood samples diagnosis after tattoo to see how much ink is in the blood. If confirmed this will push tattoo ink manufacturers to develop a new ink that eliminates the effect and we can all enjoy safer more effective tattooing.

This study is not flawed, it's pushing human knowledge forward like it always does.

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[–] bonenode@piefed.social 7 points 3 days ago

You don't need to sum it up as science is hard but also as science is expensive. They might simply not have gotten funding for something as that.

[–] grey_maniac@lemmy.ca 4 points 2 days ago (1 children)

If only there was a place where humans who have a tendency to get tattoos are in cages for an exrended period of time with a relatively consistent, trackable food intake, and constantly tracked behaviour. Humans who might even be motivated by privileges to volunteer for such studies.

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[–] bonenode@piefed.social 29 points 3 days ago (1 children)

You are generally not wrong but where can you find people who are tattooed, not yet vaccinated, but happy to get vaccinated for this study? It is wrong to say this definitely works the same in humans, but it is not easy to setup such a study.

[–] p03locke@lemmy.dbzer0.com 24 points 3 days ago

Within a single city, hundreds of people get tattoos each day. A large cross-section of those probably haven't refreshed their COVID vaccine, but only because they haven't gotten around to it.

[–] EtherWhack@lemmy.world 18 points 3 days ago* (last edited 3 days ago)

I think it's more the news article that's upselling it and with it being "groundbreaking", it is likely only at the initial stages.

Mice are usually the first phase are they do have a similar immune response (systemically), have a fast metabolism and quick to mature. They're also clones, which helps eliminate external factors that could contribute to what they're studying. More or less, mice are just a quicker litmus test to just show that something is possible and if it warrants a study on a closer analogue.

[–] voodooattack@lemmy.world 10 points 3 days ago

Unless we dissect the original paper in its entirety, I don’t think we should dismiss their methods out of hand.

I’ll reserve judgement until peer-reviews can confirm or rebuke the results.

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[–] vatlark@lemmy.world 102 points 3 days ago* (last edited 3 days ago) (1 children)

In the study the longest they waited after tattooing the mouse before giving the vaccine was 2 months.

They made some connections with people that had tattoos for a much longer time. But I can't tell how meaningful those connections are.

This is well outside of my field.

Edit:

Also, it sounds like the tattooed mice were less responsive to the covid vaccine but more responsive to the Influenza vaccine.

[–] SendMePhotos@lemmy.world 12 points 3 days ago (2 children)

... This is the internet. You can always be like the rest and pretend you know everything and are multi discaplined, instead of taking the proper, less fun, honest route.

[–] gusgalarnyk@lemmy.world 28 points 3 days ago (3 children)

Why make this comment encouraging bad behavior? This feels like injected negativity for negativity sake. Idk man, be the change you want to see in your community.

[–] derek@infosec.pub 15 points 3 days ago

I agree with you in sentiment, however; I believe the comment you're replying to was intended as a joke.

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[–] pglpm@lemmy.ca 41 points 3 days ago* (last edited 3 days ago) (1 children)

Why not be a professional scientist by:

  • adding "in mice" to the title;
  • using modern statistical methods instead of continuously discredited procedures like p-values?
[–] MonkderVierte@lemmy.zip 7 points 3 days ago (1 children)
  • adding "in mice" to the title;

Similarly, human immune cells previously exposed to ink also showed a weakened response to vaccination.

[–] p03locke@lemmy.dbzer0.com 6 points 2 days ago

In a Petri dish!

[–] Jhex@lemmy.world 23 points 3 days ago* (last edited 3 days ago) (4 children)

how low? weakened by how much?

I think they leave that out on purpose so they can make these sensational claims… if your immune system takes a 0.02% hit, nobody would care

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[–] Realspecialguy@lemmy.world 1 points 1 day ago

I have a jail tat, I wonder if thats worse.

[–] Tollana1234567@lemmy.today 19 points 3 days ago* (last edited 3 days ago) (1 children)

thats why some people get a rash at the tattoo sites, or it triggers shingles. make sense since macrophages clean up melanin pigment produced by post-inflammatory hyperpigmentation, a brown spot after a severe pimple or something.

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[–] answersplease77@lemmy.world 28 points 3 days ago (3 children)

followed by a chronic phase that can persist for years.

how many years? am I doomed for life because what I did to my body when I was 18 :(

[–] DarkCloud@lemmy.world 50 points 3 days ago (2 children)

I think if these effects were universal and as serious as the paper makes out,, we'd have noticed them waaay sooner.

[–] scytale@piefed.zip 27 points 3 days ago

To be fair, it’s possible it has been a significant factor to weakend immune systems all along; it was just now that the connection/link with tattoo ink was identified. Not a scientist obviously, just spitballing.

[–] jacksilver@lemmy.world 18 points 3 days ago (2 children)

And yet things like asbestos, lead, and smoking all took way longer than you'd expect (given they were a lot more universal).

[–] azertyfun@sh.itjust.works 15 points 3 days ago

All three of your examples were known to cause ill effects for centuries. The ancient Romans knew the asbestos mines were killing their slaves. Their overuse during the 20th century was not due to ignorance but corporate lobbying and political complacency.

The lobbyist play is to fund counter-studies to sow FUD even though the scientific consensus that [X Bad] is well established, because it gives an easy out for bought out politicians. However the tatoo lobby is certainly not one that I expect to be have the pull to fund FUD scientific studies to delay legislation, and if they are doing that it should be pretty easy to point to.

[–] Confused_Emus@lemmy.dbzer0.com 15 points 3 days ago

And yet humans have been tattooing themselves since the dawn of recorded history - significantly longer than any of those other things were around before their harm became evident.

[–] tuff_wizard@aussie.zone 38 points 3 days ago

Yes but that applies to almost everything you did when you were 18.

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[–] Wubwub@lemmy.zip 24 points 3 days ago (9 children)

The anti tatto crowd licking their lips over this one.

[–] UnderpantsWeevil@lemmy.world 19 points 3 days ago (2 children)

It's just tiresome to hear these hyperventilating articles without any real measure of the degree of risk or long term consequences.

[–] faythofdragons@slrpnk.net 8 points 3 days ago (1 children)

Honestly, I think that shitty science reporting like this is fuel for the normie to science skeptic pipeline.

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[–] DozensOfDonner@mander.xyz 20 points 3 days ago (2 children)

Ah pretty interesting. Good to clarify that its in mice, not humans.

[–] thejoker954@lemmy.world 28 points 3 days ago (2 children)

The study found that tattooed mice produced significantly lower levels of antibodies after vaccination. This effect is likely due to the impaired function of immune cells that remain associated with tattoo ink for long periods. Similarly, human immune cells previously exposed to ink also showed a weakened response to vaccination

[–] Onomatopoeia@lemmy.cafe 24 points 3 days ago* (last edited 3 days ago) (1 children)

"Human immune cells", not cells in humans.

That's not to say this doesn't happen in humans, it very well may. It's intriguing research, but it's still only demonstrated in mice. Important to always keep that in mind until we get better information (which this research is at least leading us to).

Lots of stuff happens in mice (or pigs, or a petri dish) and we find doesn't replicate to homo sapiens.

[–] FlexibleToast@lemmy.world 18 points 3 days ago* (last edited 3 days ago) (1 children)

It's also important to keep on mind that the burden of proof is on something to prove it is safe, not that something is unsafe. It happening to human cells in mice would have me assume it happens to human cells in humans until proven otherwise (that's the null hypothesis in this situation). But also I don't have a tattoo or any interest in getting one so I'm not too bothered by this.

[–] ada@piefed.blahaj.zone 13 points 3 days ago (1 children)

Humans have been tattooing each other for over 5000 years. I would argue that it's not really a case of "they need to be proven to be safe". That ship has sailed. If they are unsafe, we should know, but I think the burden of proof has definitely shifted on tattoos given their extensive history without obvious negative repercussion

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[–] salacious_coaster@infosec.pub 16 points 3 days ago (2 children)

Well, then. That could explain a lot about why I always feel like I'm dying.

[–] bjoern_tantau@swg-empire.de 24 points 3 days ago (1 children)

I have the opposite problem, my immune system is in overdrive. I should get a tattoo to reign it in.

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[–] supersquirrel@sopuli.xyz 15 points 3 days ago (1 children)

What is your opinion on how much this applies to humans?

[–] Kyle_The_G@lemmy.world 34 points 3 days ago

I spent a career in translational medicine (research). Its not a perfect 1:1 but most of the time these models are very good.

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