Your skin is soft, stretchy, flaky, and hairy - but what is it made of?

It’s soft, it’s stretchy, it’s hairy, and sometimes flaky. It comes in different colors, it can change colors, and it might even tell your future.

If it wasn’t in the title, would you have guessed we’re talking about skin?

How well do you know your skin? Inside out? How would you describe it? Have you ever had your palms read? Can you predict what you’re about to learn?

Weighing in at 4 kg, and covering about 2 square meters of space, your skin is your body’s largest organ. And be grateful that it is. Without your skin’s seamless coverage and sophisticated protection, you’d literally disappear. That is to say, without skin you’d evaporate.

But what other tricks can your skin do?

Well, it protects you from impacts, earth’s elements, and deadly UV rays from outer space. At the same time, all the time, your skin is fighting against harmful bacteria, regenerating fresh skin cells, and producing vitamin D to give you healthy bones. Call it magic, call it a miracle worker, the word “biology” doesn’t seem to do it justice. Now that you’re familiar with your skin, and you know what it does, let’s see what it’s made of.

Your palm might show that you’re going to live long and prosper. But really, there are three layers of skin keeping you alive. The one that you see is called the epidermis. This outer layer of skin is made mostly of keratinocytes. These cells come from the protein keratin, which is the key structural material in not just your skin, but also in your nails and hair. Keratin is a particularly strong protein that works hard to protect other skin cells from damage or stress.

But while keratin is tough, it can’t stop everything, which is why we have other defence mechanisms on our outer layer.

Langerhans cells alert the immune system to any harmful viruses or bacteria that might’ve found their way into the body. Melanin, which determines skin color, is a pigment that is produced in the epidermis to protect against deadly UV rays from the Sun.

Below your epidermis, the second layer of skin is called the dermis. It’s thicker than the first layer, and it’s also what makes your skin strong and stretchy, thanks to fibers of collagen and elastin. Your dermis is home to a network of nerve fibers, hair follicles, and glands. Your sense of touch and your body’s internal thermostat are based in this layer.

Sebaceous glands in your dermis produce sebum, an oily substance which coats your exterior to keep bacteria from settling on your skin.

Your last, and deepest, layer of skin is the hypodermis. And it’s the one holding everything together. This subcutaneous tissue helps to bind your dermis and epidermis to your bones and organs. The hypodermis isn’t really considered true skin, since it’s mostly a layer of fat that serves to keep you warm and cushion your falls. It’s also a natural energy reserve in extreme cases of food shortage. Depending on your size, you’re made up of approximately 1.5 trillion skin cells.

And your body is constantly growing new ones to replace the nearly 40,000 skin cells that fall off of you each hour. The surface of your skin has about 1000 species of microbes living on it. About 50 million individual bacteria can be found every 6.5 square cm (1 sq. inch.)

This number can go up to 500 million on oily surfaces like your face. That may sound like a lot, but if you gathered up all the microbes living on the surface of your body, you could fit them all inside the volume of a pea. And, for the most part, these microbes keep each other in check, and are necessary for healthy skin.

You might be able to look at your hand, and see good fortune ahead of you. But don’t give fate too much credit. The fact is, we’re all pretty lucky that our bodies are the way they are.