When it comes to sunscreen and skin health, there's a lot of misinformation that can make choosing the right SPF confusing. Here, we clear up some common misconceptions and get to the facts about "physical" and "chemical" sunscreens.
Myth 1: "physical" and "chemical" sunscreens are completely different
Fact: The terms "physical" and "chemical" are misleading. All sunscreens are chemicals. The main difference is that "physical" sunscreens (with zinc oxide and titanium dioxide) don't have carbon in them, so we call them inorganic. Other sunscreens do have carbon, making them organic. Both types absorb UV radiation, but inorganic (physical) sunscreens also reflect some UV rays. These tend to leave a white cast (especially if they have titanium dioxide), whereas organic (chemical) sunscreens leave less white cast.
Myth 2: physical sunscreens are natural and therefore better.
Fact: "Natural" vs. "synthetic" doesn't define sunscreen quality or safety. Many physical sunscreens undergo processing and include synthetic additives for better performance. The effectiveness and safety of a sunscreen should be based on scientific evidence, not on whether it's deemed natural or synthetic.
Myth 3: chemical sunscreens heat up the skin.
Fact: The heat generated by the absorption of UV radiation by sunscreens is minimal and not a cause for concern. Both chemical and physical sunscreens absorb a significant portion of UV rays (around 95%), converting it into an insignificant amount of heat.
Myth 4: physical sunscreens don't absorb into the skin.
Fact: Both chemical and physical sunscreen particles can penetrate the upper layers of the skin, depending on their size and the overall formula. However, this doesn't necessarily mean they're harmful. Sunscreen formulators work to minimise skin penetration to keep the protection on the skin's surface.
Myth 5: physical sunscreens provide instant protection; chemical need time to activate.
Fact: Both types of sunscreens start protecting your skin as soon as they're applied. The waiting time that’s recommended for sunscreens is to allow the formula to dry and form a protective layer, not for activation.
Myth 6: you can use less physical sunscreen.
Fact: All sunscreens, regardless of type, should be applied at the same density to achieve the protection indicated on the label: 2 milligrams per square centimetre of skin. Using less will reduce the effectiveness of both types of sunscreen.
Myth 7: physical sunscreens don't need to be reapplied.
Fact: All sunscreens should be reapplied throughout the day to maintain protection, especially after sweating, swimming, or towel drying. While it's true that physical ingredients like titanium dioxide and zinc oxide are stable in sunlight, reapplication is necessary due to the sunscreen being rubbed or washed off.
Myth 8: chemical sunscreens are hormonal disruptors.
Fact: Concerns about chemical sunscreens acting as hormonal disruptors are based on studies of specific ingredients, like oxybenzone, which have shown potential hormonal activity in laboratory and animal studies. However, the evidence from these studies cannot be directly extrapolated to human use due to differences in exposure levels and biological responses. Current research, including in vitro and animal studies, suggests that the concentration of these ingredients used in sunscreens is far below the levels required to cause a noticeable hormonal effect in humans. Regulatory agencies and scientific reviews have deemed these sunscreens safe for regular use, considering the low risk of systemic absorption and the protective benefits against UV radiation.
Myth 9: physical sunscreen nanoparticles are harmful.
Fact: Studies have shown that nanoparticles in sunscreen do not penetrate beyond the dead outer layers of the skin and are considered safe for use. Concerns about potential reactions in the body, particularly under UV exposure, have not been substantiated in human studies.
How to Choose Sunscreen
When selecting your preferred type of UV protection, focus on finding a formula that suits your skin type, touch and feel factor, and lifestyle. Whether chemical or physical, the best sunscreen is the one that offers broad-spectrum protection and most importantly that you will use consistently and correctly.