Introduction
Sunscreens remain a frontline intervention in the prevention of skin cancer and premature skin aging. Despite its importance, misconceptions about sunscreen ingredients and safety continue to circulate. To provide informed recommendations for patients, pharmacists and dermatologists must remain up to date on the evolving evidence concerning sunscreen. The growing complexity of sunscreen products, including the rise of nanoparticle technology and heightened scrutiny of chemical filters, necessitates informed, evidence-based guidance for clinical recommendations and patient education.
Background: Sunscreen Classification and Mechanism
Sunscreens are divided into two main types: chemical filters and physical (mineral) filters, each with distinct mechanisms and clinical implications.
Chemical filters, such as avobenzone, oxybenzone, octinoxate, and octocrylene absorb ultraviolet (UV) radiation (primarily UVA and UVB) and convert it to thermal energy, thereby protecting the skin from damage [1]. Chemical sunscreens are popular due to their lightweight consistency and cosmetic appeal, leaving little to no residue. However, certain ingredients such as oxybenzone have raised safety concerns related to absorption into the body, endocrine disruption, and environmental toxicity, particularly for their role in coral bleaching [2, 3].
Physical (mineral) filters, notably zinc oxide (ZnO) and titanium dioxide (TiO₂), primarily absorb UV radiation but also reflect and scatter light [4]. These agents are photostable and hypoallergenic, making them suitable for pediatric and sensitive-skin formulations [5]. Traditional formulations left a white cast on the skin, which limited their widespread acceptance. However, new technology has made this a problem of the past.
Nanoparticle Mineral Sunscreens: Clinical and Pharmacologic Context
To address cosmetic limitations of mineral sunscreens, manufacturers utilize nanoparticle formulations of ZnO and TiO₂. These ultrafine particles reduce the characteristic white cast of traditional mineral sunscreens while maintaining broad-spectrum UV protection. However, aerosolized nanoparticle formulations present inhalation risks, particularly for children and individuals with respiratory conditions. As a result, mineral-based stick or lotion formulations are a safer choice over sprays when advising patients on safe sun protection [6].
Regulations and Labeling: What Was Recommended?
In its proposed 2021 administrative order, the FDA reviewed sixteen active sunscreen ingredients and designated only zinc oxide and titanium dioxide as GRASE (Generally Recognized as Safe and Effective). PABA and trolamine salicylate were determined to be non-GRASE and are proposed to be excluded from sunscreen use due to safety concerns. All other ingredients remain under review pending additional data, though they are still permitted in U.S. markets.
The FDA also proposed important updates to sunscreen labeling and claims, including:
Capping SPF labels at “60+” to avoid overstated protection claims.
Requiring broad-spectrum sunscreens to offer UVA protection at one-third of the labeled SPF value.
Mandating that water resistance claims be supported by validated testing and specified for 40 or 80 minutes of protection.
Meanwhile, European regulations allow the use of additional UV filters (like Mexoryl SX and XL) and impose stricter limits on ingredient concentrations. These differences explain why sunscreen options vary between regions [7].
Environmental Impact: Protecting Skin and the Planet
Sunscreen safety is not only about people, but also about the planet. Chemical ingredients, especially oxybenzone and octinoxate, have been linked to coral reef damage and are banned in environmentally sensitive areas like Hawaii [8]. In contrast, ZnO and TiO₂ pose less demonstrated ecological risk, though their long-term environmental accumulation remains under investigation [9]. Clinicians should encourage broad-spectrum mineral sunscreens, especially in environmentally conscious or special patient populations.
Patient Counseling
Healthcare providers play a key role in translating technical sunscreen knowledge into everyday skin protection strategies. Effective counseling should go beyond product recommendations to include guidance on correct application and complementary sun protection behaviors.
Recommend SPF 30+ broad-spectrum mineral sunscreens, particularly for patients with sensitive skin, children, pregnant women, and those concerned about endocrine-disrupting chemicals [5, 10, 11].
Discourage the use of aerosolized nanoparticle formulations due to inhalation risk; advocate for lotions or sticks [6].
Instruct on proper application techniques: apply 1 oz (about a shot glass) 15 minutes before sun exposure and reapply every two hours or after water/sweat exposure [11].
Reinforce sun safety habits: seeking shade, wearing sun-protective clothing, and avoiding peak UV exposure times (10 a.m. to 4 p.m.) [10].
For additional evidence-based information, consider helpful online resources such as the Environmental Working Group (EWG) and the FDA’s sunscreen safety updates, which provide accessible guidance on ingredient safety and product selection.
Future Directions and Continuing Research
The sunscreen field continues to evolve with efforts focused on identifying new UV filters with improved photostability, minimal systemic absorption, and reduced environmental impact. As public interest in sunscreen safety grows and misinformation spreads online, healthcare professionals play a critical role in translating evidence into clear, practical recommendations for patients.
Sunscreen is a cornerstone of modern preventive skincare. By choosing the right formulation, applying it properly, and complementing it with other sun-safe habits, patients can confidently enjoy the outdoors while reducing their risk of skin damage. Armed with knowledge, healthcare professionals can ensure their sunscreen counseling is both scientifically sound and personally relevant to those they serve
References:
- NIH – Introduction to Sunscreens and Their Filters
- NIH – Benzophenone-3
- NIH – Environmental impacts due to the use of sunscreen products: a mini-review
- NIH – Metal oxide sunscreens protect skin by absorption, not by reflection or scattering
- Contemporary PEDS Journal – Sun-safe practices in different pediatric patients
- NIH – A review of inorganic UV filters zinc oxide and titanium dioxide
- FDA – Sunscreen Drug Products for OTC Human Use
- Hawaii.com – Your Reef Safe Sunscreen Guide
- ScienceDirect – Ecotoxicological effects of zinc oxide nanoparticles (ZnO-NPs) on aquatic organisms: Current research and emerging trends
- AAFP – Behavioral Counseling to Prevent Skin Cancer: Recommendation Statement
- AAD – How to apply sunscreen
