There’s a lot of misinformation out there about sunscreen, so here’s a myth-busting post answering some of the most frequently asked questions and myths. Missed anything? Let us know!
“If I wear sunscreen every day, will I become Vitamin D deficient?”
The Science: Clinical studies show that regular, everyday sunscreen use rarely impacts normal Vitamin D levels.
Sunscreen is designed to filter out the majority of ultraviolet radiation, but no formula blocks 100% of UV rays – an SPF 30, for example, lets through about 3% of UVB light. The body requires only a small amount of UVB exposure (often just 10 to 15 minutes of indirect exposure on small areas of bare skin) to synthesize adequate Vitamin D.
Dermatologist Take: Trading unprotected UV exposure for Vitamin D dramatically raises your risk of cellular DNA damage, premature aging, and melanoma. If your blood tests indicate low Vitamin D, the safest and most reliable solution is dietary intake (fortified foods, oily fish) or an oral supplement.
“Are ‘chemical’ sunscreens toxic or dangerous if absorbed into the bloodstream?”
The Science: Chemical (organic) filters such as avobenzone, octisalate, and homosalate absorb UV energy and convert it into negligible heat. While recent laboratory and FDA studies have demonstrated that minute traces of some chemical filters can be absorbed into the bloodstream, absorption does not equal harm.
Regulatory agencies worldwide—including the European Commission’s Scientific Committee on Consumer Safety (SCCS) and the US FDA—continue to review filter toxicology data. To date, there is no conclusive scientific evidence that standard topical sunscreen application causes hormonal disruption or systemic health issues in humans.
Dermatologist Take: What is undeniably proven through decades of empirical data is that unprotected UV radiation causes mutations leading to basal cell carcinoma, squamous cell carcinoma, and melanoma. If you are pregnant or prefer zero absorption, mineral sunscreens formulated with non-nano zinc oxide and titanium dioxide remain strictly surface-level barriers.
“All physical/mineral sunscreens leave a heavy, chalky white cast.”
The Science: This was largely true a decade ago, but modern mineral formulations have evolved significantly.
The traditional white cast comes from large particles of zinc oxide and titanium dioxide sitting on top of the skin. Modern cosmetic chemistry utilizes micronized particles, surface coatings, and tinted iron oxides to solve this:
- Micronized & Non-Nano Minerals: Smaller particle sizes disperse light more efficiently without the stark opacity of older formulas.
- Tinted Formulations: Iron oxide pigments are added to match a variety of skin undertones and deep complexions, neutralizing any ashy appearance while simultaneously offering proven protection against high-energy visible (HEV) blue light.
“People with darker skin tones don’t need sunscreen.”
The Science: Melanin does provide natural protection against sunburn (acting roughly equivalent to a natural SPF of 2 to 4, depending on skin phototype), but it does not make deeper skin tones immune to sun damage.
While melanoma incidence is lower in skin of color, it is frequently diagnosed at significantly later stages, leading to poorer survival outcomes. Furthermore, UV radiation exacerbates chronic pigmentary conditions common in darker skin, such as:
- Post-inflammatory hyperpigmentation (PIH)
- Melasma
- Persistent dark spots and uneven tone
Daily broad-spectrum sunscreen helps stabilize melanocytes, preventing pigment flares and protecting deep dermal collagen from degrading.
“I work indoors, so I don’t need to apply SPF unless I go outside.”
The Science: Standard window glass blocks UVB rays (the burning rays), but it lets through up to 50% or more of UVA rays (the aging and deep-damage rays).
UVA wavelengths have longer frequencies that penetrate clouds, commercial office windows, and vehicle windshields, reaching the deeper dermis where they generate reactive oxygen species (ROS) and DNA mutations. If your workspace is within several feet of a window, daily application remains essential.
“My foundation/moisturizer has SPF 30, so I’m already covered.”
The Science: While makeup or daytime moisturizers with SPF offer a helpful secondary layer, they are rarely applied in sufficient quantities to achieve the label’s protection rating.
To attain the certified SPF on a bottle, you need 2 milligrams of product per square centimeter of skin—roughly 1/4 to 1/2 teaspoon (or two full finger-lengths) for the face and neck alone. Applying that volume of foundation or tinted moisturizer results in an unnaturally heavy cake of makeup.
Best Practice: Apply a dedicated broad-spectrum sunscreen as the final step of your skincare routine, allow it to dry down for 2 to 3 minutes, and then apply makeup over it.