From the Guidelines
Prescription sunscreens are not typically necessary for the general population, but may be recommended for individuals with severe photosensitivity conditions, history of skin cancer, or those taking medications that increase sun sensitivity, as they offer superior protection against both UVA and UVB rays with SPF 50+ protection and water resistance for up to 80 minutes. When selecting a sunscreen, it is essential to choose a broad-spectrum sunscreen that protects against UV-A and UV-B rays and has a sun protection factor (SPF) of at least 15, as recommended by the guidelines for school programs to prevent skin cancer 1. Additionally, patients with heart failure should be advised to use broad-spectrum sunscreens with a sun protection factor of 30 or higher, as certain medications such as amiodarone and thiazide diuretics can cause drug-induced photosensitivity 1.
Some key considerations when selecting a sunscreen include:
- Reading product labels to ensure the sunscreen is waterproof if you will be sweating or swimming
- Choosing a nonstinging product or one specifically formulated for your face
- Avoiding products that contain para-aminobenzoic acid (PABA) if you are sensitive to that ingredient
- Selecting a water-based sunscreen if you have oily skin or are prone to acne
- Being aware of the expiration date, as some sunscreen ingredients may degrade over time 1.
It is also important to note that more expensive does not necessarily mean better, and that the effectiveness of a sunscreen is not solely determined by its price 1. Ultimately, the choice of sunscreen will depend on individual needs and circumstances, and prescription sunscreens may be necessary for those with severe photosensitivity conditions or medical necessity, and should be applied 15-30 minutes before sun exposure and reapplied every two hours or after swimming/sweating.
From the Research
Prescription Sunscreen
- Prescription sunscreens are designed to provide protection against the Sun's damaging ultraviolet (UV) radiation, which is a recognized prime carcinogen 2.
- The effectiveness of sunscreens in protecting against skin cancers, sunburns, and skin photo-ageing has been studied extensively over the last two decades 2.
- Physical UV filters such as titanium dioxide (TiO2) and zinc oxide (ZnO) are commonly used in sunscreens, while chemical UVB/UVA filters like octinoxate (OMC) and avobenzone (AVO) are also widely used 2.
Active Ingredients
- Avobenzone and zinc oxide are two sunscreen active ingredients approved in the US that provide true broad-spectrum protection against UVA wavelengths >360 nm 3.
- Titanium dioxide is often believed to confer broad-spectrum protection but is less effective against UVA wavelengths >360 nm compared to avobenzone and zinc oxide 3.
- Iron oxides, including red iron oxide, yellow iron oxide, and black iron oxide, can effectively block high-energy visible (HEV) light and provide enhanced skin protection when combined with zinc oxide 4.
Photostability and Protection
- Microfine zinc oxide (Z-Cote) is a photostable UVA/UVB sunblock agent that attenuates throughout the UVR spectrum, including UVA I 5.
- Titanium dioxide and zinc oxide provide UV protection primarily via absorption of UV radiation, rather than through significant reflection or scattering 6.
- The use of proper formulation strategies can ensure that avobenzone losses are minimized, allowing for sustained broad-spectrum absorbance during prolonged exposure to UVR 3.