Body Art

Why the color of tattoos can always remain in the skin of the human body


Many young people in today’s society like tattoos, such as tattooing the name of the person they like. Once tattooed, the color of the tattoo will stay on the skin forever. Why?

Ink, no matter how hard to wash off, will eventually fade from the skin, but tattoos don’t have such a short-lived fate. The first reason, naturally, is that the ink doesn’t penetrate the skin like a tattoo needle does. Our outer layer of skin naturally sheds every 2 to 4 weeks, but the inner layer functions differently.

Skin is the second largest organ of the human body in terms of surface area, making up about 2.5% of our body weight. It’s no surprise, after all, our bodies are covered in these things! The skin consists of 7 layers that protect the underlying tissues, muscles, and other organs. To unravel the mysteries of tattoos, we need to understand two important layers: the epidermis and the dermis.

The top layer of the skin is the epidermis, and there are 5 other sublayers below it. But, let’s put that aside for now and only discuss the epidermis as a whole.

After the dead skin of the epidermis is sloughed off, healthy skin cells from the lower layers replace the dead cells. The epidermis acts like a protective covering that acts as a barrier against infection. There’s always something you don’t know, in fact, the epidermis does not contain any blood vessels.

The epidermis is dependent on the dermis for nutritional needs and waste disposal. In addition, almost 70% of protein-coding genes are embodied in the skin.

The dermis layer lies below the epidermis and consists of connective tissue. Connective tissue connects, supports, and holds together other tissues or organs. The dermis is further divided into the papillary area and the reticular area. The former is a superficial area near the epidermis, while the latter is a deeper, thicker area in the dermis. The dermis also contains oil and sweat glands, hair follicles, nerve endings, lymphatic vessels, macrophages and CD4+ T cells.


Pen marks on any part of our body will naturally fade after a few days because pen ink does not penetrate as deeply into the skin as tattoo ink. Pen marks only remain on the epidermis of the skin, whereas tattoo ink is intentionally deposited in the dermis.

The tattooing process usually involves injecting nanoparticles of ink pigments into the dermis of the skin. The tattoo needles are designed to deliver ink directly to the dermis, and the ink-coated needles can pierce the skin 100 times per second. The ink enters and accumulates in the papillary areas of the dermis. A tattoo is like an intentional injury to the skin, so the skin’s first response is to repair the wound.

The presence of foreign ink particles activates the body’s immune system, which is one of the reasons why the newly tattooed area swells. It’s just the body’s mechanism for treating the injured area.

In the human body, white blood cells act as guardians. Macrophages are white blood cells that are found in the dermis. These specialized cells detect, engulf and destroy bacteria and other foreign substances that enter the body. Macrophages are phagocytic cells that engulf ink particles trapped in vacuoles. The enzymes in the vacuoles easily degrade the bacteria, but they do not affect the ink particles.

Since macrophages are unable to mount an immune response to the nanoparticles, the macrophages inhibited the attack on the system by staying in place and retaining the ink in the vacuole. This process keeps the ink in the genuine leather almost forever!

Since it is said that tattoos achieve eternity in this way, are the macrophages that capture the ink immortal? Not really, but…

When the macrophages encasing the ink particles die, the free ink releases a signal that allows newly formed macrophages to reach the site. Dead macrophages release the ink into surrounding tissue, but the ink is quickly recaptured by new macrophages. This release, then recapture cycle will continue indefinitely, causing the tattoo to stay in place forever.

While macrophages have good mechanisms for degrading bacteria and other particles, tattoo inks are too large to be absorbed by them.

For fickle human beings, the only constant may be changing this thing forever. Some people opt for a tattoo in order to leave something permanent. Of course, laser tattoo removal can be a lot less painful for those who are impulsive than in the past, which required chemical destruction and surgical removal to remove the tattoo. The laser can break down giant ink particles in tissue, allowing white blood cells to easily engulf and destroy the ink.