As the heat of summer intensifies and the amount of beachgoers increases, the authenticity of sunscreen is questioned by many. There are many common misconceptions regarding sunscreen that can significantly affect one’s health. Here’s the truth to many of the common myths about sunscreen.

1. You only need sunscreen on sunny days

Many people believe that they only need to apply sunscreen on sunny days; however, dermatologists at the Harvard Medical School have debunked this. The Harvard Medical School has proven that even on cloudy days, people who spend a large part of their day outside can still suffer from sunburns that are detrimental to their health. People also believe that clouds provide them with protection from the sun’s harsh rays, but this is also false. As the rays of the sunshine down, around 80% of UV rays reach Earth’s surface and therefore have the ability to cause sunburns. “I use sunscreen whenever I know I’m going to be outside for too long,” Senior Maryam Atique said. “Yes, [using sunscreen] is important because you don’t want to get skin cancer.”

2. You only need to apply sunscreen once

Numerous people also believe that only one application of sunscreen is sufficient for the entire day, but this is also not true. According to the Harvard Medical School, as people sunbathe, the sunscreen breaks down and does not sufficiently protect from the sun’s harmful UV rays. Instead, people in the sun should reapply sunscreen every 2 to 4 hours in order to achieve maximum protection. “I put sunscreen every day because I have very sensitive skin and need a prescribed sunscreen to prevent my skin from burning,” Senior Sarah Sahal said. “Sunscreen is an important tool to help prevent skin cancer.”

3. Using sunscreen prohibits one’s body from absorbing and producing vitamin D

Vitamin D, which is a nutrient that is produced through sun exposure, is very important to one’s health. Although many people have the misconception that wearing sunscreen prevents the body from producing vitamin D. In theory, if someone applied sunscreen all the time, this would prevent his or her body from producing vitamin D; however, when someone is in the sun, their sunscreen generally wears off, which allows vitamin D to be produced. “You may have been taught that you need sunlight for your body to make vitamin D because vitamin D is not found naturally in most foods,” Sahal said. “Today, many foods make vitamin D during the manufacturing process. Thus, sun exposure is not as important for the body’s vitamin D supply as it used to be.”

4. You do not need sunscreen if you have dark skin

Although people with more melanin in their skin may receive more protection against sunburns, they still need to apply a full layer of sunscreen. Melanin can diffuse UVB rays from the sun, which may reduce the chance of someone with darker skin receiving a sunburn. On the other hand, melanin does not shield from UVA rays, which are known to cause wrinkles and age skin prematurely. Additionally, the Harvard Medical School states that melanin does not protect one from skin cancer “Of course, being outdoors makes most people feel good, and playing tennis is better for your health than being in your room on your phone,” Sahal said. “You can still protect yourself from the sun’s damaging effects while enjoying yourself outdoors.”

5. Sunscreen is toxic

Many also believe that ingredients in certain sunscreen brands are carcinogenic, or cause cancer. Although some sunscreen brands may contain chemicals with negative effects, there is no significant link between these chemicals and any detrimental health effect. In the United States, the FDA thoroughly regulates the chemicals used in sunscreen, which makes the majority of sunscreen safe to use. Senior George Sandy also stated, “I have been sunburned multiple times within my lifetime, especially because I usually sweat the sunscreen off. The way I prevent it is by wearing a shirt when I am not in the water, wearing a hat, and most importantly applying sunscreen to my whole body.” Through the use of sunscreen, people can safely have fun in the sun without risking their health.