Inked Up: How Do Tattoos Work?

Introduction

Tattoos have only gained popularity in recent years.  Nowadays, 32% of American adults have at least one tattoo.  Do 32% of Americans understand how their ink came to be, or why most tattoos will last a lifetime?  Unlikely.  Whether you have a full sleeve or you’re just curious about the science, this article is for you!

Tattoos & Skin

The skin is made up of three distinct layers: the epidermis, dermis, and hypodermis.

• The epidermis is the part you see, the part that acts as a barrier between the world and your insides, the part that makes new skin.

• The dermis grows hair and houses nerves, contains oil and sweat glands, supplies blood toward the epidermis, and contains tissue that gives skin its flexibility.  This is also where tattoo ink belongs.

• The hypodermis, or fat layer, cushions your bones, connects your skin to the rest of your body, and regulates body temperature.

If you are being tattooed professionally, the artist is likely going to use a tattoo machine.  The machine consists of many small needles that, after being dipped in ink, pierce through the epidermis to reach the dermis at rapid intervals, over and over again.  The dermis, unlike the epidermis, does not shed dead skin cells, which is why tattoos are permanent.  

Although permanent, tattoos do fade.  UV rays from sun exposure can break down the ink, which reduces sharpness and color intensity.  Aging skin loses flexibility, causing it to sag, which can change the appearance of a tattoo.  

Risks 

Although most people experience no more than soreness and itchiness during the healing process, being tattooed does come with a set of real risks.

• Some people experience allergic reactions to the ink used, which causes itchiness and inflammation.  An allergic reaction can happen years down the line, and is most likely to occur with red ink tattoos.

• Skin and blood  infections (think hepatitis and MRSA) may occur due to contaminated ink or unsterilized tools.  Therefore, it is important to work with an artist who follows proper cleaning procedures.

• Keloids and granulomas may form at the site.  Keloids are caused by patches of overgrown scar tissue, and granulomas are areas of general inflammation that can occur months or even years after the tattoo was applied.

Conclusion

Tattoos and the culture that surrounds them are wonderful ways to immerse oneself in art and self-expression.  However, as with any procedure, it’s important to understand the associated risks. 

References

Mayo Foundation for Medical Education and Researc

h. (2024, March 2). Thinking of getting a tattoo? know what to expect. Mayo Clinic. https://www.mayoclinic.org/healthy-lifestyle/adult-health/in-depth/tattoos-and-piercings/art-20045067

professional, C. C. medical. (2025b, March 19). Skin: Layers, structure and function. Cleveland Clinic. https://my.clevelandclinic.org/health/body/10978-skin

Riggs, J., Fiorentino, N., & Synapse. (2025, April 22). Why tattoos stay put. UCSF Synapse. https://synapse.ucsf.edu/articles/2024/05/28/why-tattoos-stay-put

Schaeffer, K. (2023, August 15). 32% of Americans have a tattoo, including 22% who have more than one. Pew Research Center. https://www.pewresearch.org/short-reads/2023/08/15/32-of-americans-have-a-tattoo-including-22-who-have-more-than-one/

Skipper, L. (2020, August 10). How ink evolved: The history and science of tattoos. Science ATL. https://scienceatl.org/awesome-science-tattoos/

Tattoo. Tattoo - an overview | ScienceDirect Topics. (n.d.). https://www.sciencedirect.com/topics/medicine-and-dentistry/tattoo

The worldwide history of tattoos. (n.d.). https://www.smithsonianmag.com/history/tattoos-worldwide-history-144038580/

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