Behind formulas - Why do some SPF 50+ products only deliver SPF 4?

Sunscreens have faced scrutiny recently. Earlier this year, testing conducted by the consumer organization Choice revealed that several sunscreens failed to deliver the expected sun protection. One product, labeled as SPF 50+, tested as low as SPF 4. This revelation triggered a cascade of responses: some manufacturers paused or recalled their products, and additional recalls followed. Media investigations have since highlighted issues with sunscreen testing and formulation. This week, the Therapeutic Goods Administration (TGA) reported that several sunscreens share a “base formula” from a single manufacturer. Preliminary tests indicate that some of these products may offer as little as SPF 4 protection. Understandably, consumers are confused about whether their sunscreens are effective. Here’s what we know about the TGA’s announcement and the potential issues behind it.

Why the concern about sunscreen SPF?

The Sun Protection Factor (SPF) is a key indicator of a sunscreen’s protective ability. However, testing SPF is complex. The standard method involves applying sunscreen to human skin, exposing it to ultraviolet (UV) light, and measuring redness over time. Because skin reactions vary and testing labs differ, results can be inconsistent. A product may test as high SPF in one lab but offer significantly less protection when evaluated elsewhere. A sunscreen with a lower-than-claimed SPF may still provide some protection, but it increases the risk of sunburn, DNA damage, and skin cancer.

What is a base formula?

The TGA’s concerns center on a “base formula” shared by multiple sunscreens. This base, also known as the core or vehicle, forms the foundation of a sunscreen and typically includes solvents or carrier liquids such as water, oils, and silicones, as well as emulsifiers, surfactants, and stabilizers to ensure ingredients blend and remain stable. The base also contains thickeners or gels, preservatives, antioxidants, and pigments, tints, fragrances, or texture enhancers. UV filters, the active ingredients that block UV rays, are added to this base. Some bases are sold to third parties with UV filters already incorporated, while others include additives like photostabilizers to extend the filters’ effectiveness under sunlight.

The base formula must perform multiple roles effectively: it should distribute UV filters evenly without clumping or separating, remain stable over time, protect filters from degrading in sunlight, and feel pleasant on the skin by spreading easily and adhering well. Many brands use the same base formula, customizing it with minor variations like color or scent. While UV filters are critical, their performance relies heavily on a well-designed base. A flawed base can compromise a sunscreen’s effectiveness, impacting multiple products and brands. The TGA has identified at least 21 products using the same problematic base formula.

How might a base formula fail?

The TGA has not specified why this particular base formula is concerning, but potential issues with base formulas generally include several factors. Poor dispersion or aggregation can occur when UV filters clump or settle, leaving areas of skin unprotected. Photodegradation may happen if stabilizers are inadequate, causing UV filters to break down in sunlight. Chemical incompatibility can arise when additives like pigments or fragrances interact negatively with UV filters. Dilution by inert ingredients may reduce the concentration of active UV filters if excessive fillers are used. Physical instability can cause the formula to separate, change viscosity, or crystallize over time. Manufacturing or packaging issues, such as inadequate mixing, exposure to heat or light during production, or poor packaging, can also degrade the base. Not every product using the same base will necessarily fail. Performance can vary depending on ingredient tweaks, manufacturing care, batch differences, or storage conditions.

How can I check if my sunscreen is affected?

The TGA and Choice provide lists of affected brands and products on their websites. Manufacturers may also issue recall notices, refund offers, or batch details. To confirm if your sunscreen is affected, check the batch number and contact the manufacturer directly.

What should I do if my sunscreen is affected?

If your sunscreen is part of the recall, avoid relying on it for sun protection, especially during prolonged exposure. Return it to the point of purchase for a refund or replacement, as some brands are offering refunds or vouchers. Monitor TGA updates, as additional products may be added to recall lists as investigations continue. Consult a healthcare professional if you’re concerned about skin damage or past sun exposure.

Key takeaways

Recent issues do not mean all sunscreens are unreliable, but they underscore the importance of robust design, formulation, and regulatory oversight. The TGA’s investigations may lead to improved testing protocols, stricter formulation standards, and clearer consumer guidance. Until the full scope of affected brands is clear, consider choosing sunscreens from trusted manufacturers that publish test results, maintain transparent practices, and have strong reputations. Sunscreen is just one part of sun safety. Complement it with other protective measures: wear protective clothing, hats, and sunglasses, seek shade, and avoid prolonged sun exposure whenever possible.