12 Common Myths About Sunscreens – Debunked with Science
1. “There is almost no difference between SPF 50 and SPF 100 sunscreen.”
Scientifically, this is true—but not under real-life usage conditions.
When sunscreen is applied in thinner layers than recommended, its SPF value decreases, which means reduced protection.
For example, when applied at a thickness of 1 mg/cm², SPF 50 drops to SPF 26, while SPF 100 drops to SPF 55. Since people tend to apply less than the recommended amount, SPF 100 offers better protection in practice.
2. “Applying only sunscreen is enough to prevent skin cancer.”
Sunscreen is a strong layer of defense, but no product can provide 100% protection from UV rays. That’s why additional precautions are essential—such as wearing wide-brimmed hats, UV-protective clothing, sunglasses, seeking shade, and avoiding peak sun hours between 10 a.m. and 4 p.m.
3. “I have dark skin, so I don’t need sunscreen.”
Darker skin offers some natural protection due to higher melanin, but it’s not immune to UV damage. Studies have shown that even the darkest skin tones can experience DNA damage after sun exposure. No skin type is completely UV-resistant. Dark skin can still develop skin cancer, making sunscreen use necessary for everyone.
4. “Tanning protects against skin cancer.”
Tanning is actually a sign of DNA damage, not protection. It increases the risk of skin cancer and accelerates skin aging. Tanning beds are even more dangerous due to their higher UV output. One study found a 74% increase in melanoma risk in individuals aged 25–59 who used tanning beds. Avoid them altogether.
5. “Sunscreen blocks my body’s vitamin D production.”
In theory, sunscreen can reduce vitamin D synthesis, but studies show this effect is minimal in real-world conditions. Vitamin D can still be obtained through diet and supplements. Using sunscreen won’t significantly impact your vitamin D levels.
6. “My makeup has SPF, so I don’t need sunscreen.”
Most makeup products have SPF 15 or less, which is below the recommended SPF 30. Also, makeup is not applied in sufficient quantities for full coverage. You should always apply a separate sunscreen with at least SPF 30 under your makeup and reapply it throughout the day, especially when spending extended time outdoors.
7. “Sitting under an umbrella is better than sunscreen.”
Umbrellas only block direct UV rays—not the rays reflected from the ground or nearby surfaces. Shade alone is not enough. If you plan to spend time outside, make sure to use sunscreen and other forms of protection like hats and UV-filtered clothing.
8. “All sunscreens are the same.”
Sunscreens fall into two main categories: physical (mineral) and chemical.
Physical sunscreens contain zinc oxide or titanium dioxide and act as a barrier, reflecting UV rays.
Chemical sunscreens absorb UV rays and convert them into heat.
While both are effective, physical sunscreens are generally less likely to cause allergic reactions.
9. “There’s no need for sunscreen on cloudy days.”
UV rays are still present even when it’s cloudy—up to 80% of UV radiation can pass through clouds. That’s why sunscreen is necessary regardless of the weather.
10. “Since 80% of sun exposure happens before age 18, it’s too late for me.”
New research shows that only about 25% of lifetime UV exposure occurs before age 18. Sun damage continues throughout life, so sunscreen is important at any age.
11. “I work indoors, so I don’t need sunscreen.”
UV rays and high-energy visible (HEV) light can still reach you through windows, including car windows. Indoor workers are not completely safe from sun damage. Daily sunscreen use is recommended for everyone.
12. “Sunscreens are not safe.”
Physical sunscreens containing titanium dioxide and zinc oxide are considered safe. Although studies on certain chemical filters (like oxybenzone and octinoxate) are ongoing, no side effects have been found in normal human use. Toxicity concerns have only arisen in high-dose animal studies, which are not relevant to daily application amounts. If you’re still concerned, mineral sunscreens are a safe alternative.
