Even if you consider yourself a skincare expert, we’re betting you don’t know every single fact about the important organ that covers your body. We’ve rounded up seven fascinating skin facts for you. So the next time you’re at trivia night and the topic is skin, you’ll be golden.
1. Skin is the largest organ of the body
Contrary to popular belief, the liver is not the largest organ of the body. While it is the heaviest and biggest internal organ, skin is actually the largest external organ and the largest organ overall. It covers more than 18.5 square feet and accounts for about 16% of your body weight.
2. There are five main types of skin
Normal, Oily, Dry, Combination and Sensitive. Skin type will often change over the course of a person’s lifetime. For example, a baby may have sensitive skin, which changes to oily during adolescence, combination during mid-life and dry in old age. Your skin type is determined by various factors, including how much water is in your skin, how easily it is triggered by irritants and how large your pores are. It’s essential to know your skin type and stick with type-appropriate products, so you don’t suffer unnecessary dryness, breakouts or irritations.
3. Skin regulates body temperature
Although skin is an external organ, it plays an important role in thermoregulation, which is the body’s ability to maintain a temperature within certain boundaries despite surrounding temperatures (as a throwback to seventh-grade science, that ability is why humans are endothermic). The skin is essentially the body’s thermostat: when body temperature rises above 98.6F, sweat glands are activated to cool the body. When it needs to keep the body warm, the skin constricts blood vessels (a process known as vasoconstriction). This reduces the flow of warm blood near the surface of the skin and overall heat loss.
4. The thickness of skin differs across the body and can change
Your skin is thinnest on your eyelids (approx. 0.2 mm) and thickest on your feet (approx. 1.4 mm). Skin can also get thicker in spots (called a callus) if it is exposed to frequent pressure or friction.
5. Skin regenerates itself
Skin is composed of several layers: the epidermis, dermis and hypodermis. When new skin cells push up to the top layer, the dead layer (called the stratum corneum) breaks away from the epidermis. A new layer is formed every 28 days, which means you have a completely new layer of skin nearly every month! Some experts estimate that almost half of the dust in your home is actually dead skin. (Gross, right?)
Since skin regenerates itself, you may be wondering why it’s important to exfoliate. It’s because some dead skin cells stick around and exfoliation unclogs the skin to make room for the fresh new cells below.
6. Pimples are not caused by hormones, stress or diet.
While these factors have long been blamed for breakouts, the truth is that acne is caused by a combination of genetics, bacteria and excess oil production. However, a poor diet, stress and a hormonal imbalance can definitely exacerbate the situation.
RELATED READ: Fact or Myth: Does Chocolate Really Cause Acne?
7. Using a higher SPF does not mean your skin is protected for a longer amount of time.
The sun protection factor (SPF) on a sunscreen bottle doesn’t indicate how long you can stay out in the sun, but rather the fraction of sunburn-producing UV rays that reach your skin. For example, SPF 15 means that 1/15 (or 7%) of the burning radiation reaches the skin. With SPF 30, 1/30 (or 4%) of the burning radiation reaches the skin. And so on.
And those numbers are only accurate if you apply enough sunscreen, which is not typically the case. Most people only use a third of the recommended amount, so the actual SPF would only be one third of its labeled value. Even with a high SPF sunscreen, it is important to spend time in the shade and drink plenty of water. Apply sunscreen 20-30 minutes before going outdoors and reapply every two hours. And don’t skimp! Slather it all over your body to ensure adequate protection.