SPF Testing for Sunscreen Products
A sunscreen's SPF value must be supported by an appropriate method applied to the finished product and connected to the label consumers will see. UVA protection, critical wavelength and any water-resistance claim each require specific evaluation.
SHAPYPRO defines the testing strategy around the formula, product format, target market and intended claims, supporting the project from method selection to result review.
More Than a Number on the Label
SPF expresses protection against erythema caused mainly by UVB radiation. It does not describe the product's full sun-protection profile on its own. To present broad-spectrum protection, the evidence must also address UVA performance and meet the criteria that apply in the market where the product will be sold.
The same product may require a different combination of methods for the European Union, the United States or another destination. The strategy should therefore be defined before claims are finalised, packaging is printed or a result generated for one jurisdiction is reused elsewhere.
Sun Protection Testing Services
The testing strategy may combine different assessments depending on the claim, target market and product characteristics. Each result should be interpreted as part of the sunscreen's overall evidence package.
SPF Determination
Protection against erythema can be determined using recognised methods such as ISO 24444 for in vivo SPF. ISO 23675 and ISO 23698 introduce newer approaches whose suitability and acceptance must be confirmed for each product and target market.
UVA Protection
UVA protection can be assessed in vivo under ISO 24442 or in vitro under ISO 24443, depending on the objective and applicable framework. The result should be interpreted together with SPF and critical wavelength.
Critical Wavelength
This parameter describes the breadth of protection across the ultraviolet spectrum. In the European Union and the FDA broad-spectrum test, the reference threshold is 370 nm, although the test methods and regulatory contexts are not interchangeable.
Water Resistance
Where a product makes a water-resistance claim, the study combines protection measurement with a controlled immersion procedure. The duration, method and final wording must match the destination market.
Choosing the Right Test Method
ISO 24444 remains the international reference method for in vivo SPF determination. ISO 23675 specifies an in vitro method for certain emulsions and single-phase alcoholic formulations, with defined format exclusions. ISO 23698 uses diffuse reflectance spectroscopy in a hybrid procedure.
These methods broaden the technical options, but their publication does not remove the need to confirm regulatory and market acceptance.
Method selection depends on the dosage form, expected protection range, photostability, target market and available data. SHAPYPRO reviews these factors before recommending a programme, helping to avoid tests that do not serve the project objective or results that cannot support the intended label.
Applicable Standards: ISO 24444:2019/Amd 1:2022 · ISO 24442:2022 · ISO 24443:2021/Amd 1:2026 · ISO 23675:2024 · ISO 23698:2024
European Union and United States Requirements
The target market determines the methods, acceptance criteria and labelling requirements. The same formula needs a market-specific review before its results are used in the European Union or the United States.
European Union
In the European Union, sunscreens are regulated as cosmetics. Recommendation 2006/647/EC states that products should protect against both UVB and UVA radiation.
As reference criteria, a product should provide at least SPF 6, a UVA protection factor of at least one third of the labelled SPF and a critical wavelength of at least 370 nm. Labelling should not imply total or unlimited protection.
United States
In the United States, sunscreens are regulated as over-the-counter drugs. Testing and labelling must follow the FDA framework, including its broad-spectrum test.
A result generated using an ISO method should not automatically be treated as sufficient for marketing in the United States.
From Formula to Claim
Filter distribution, film uniformity, viscosity and packaging can influence sunscreen performance. Testing should be conducted on a sample that represents the product to be marketed, after the formula and manufacturing process are sufficiently defined.
Formula Review
We assess the product format, UV filters, directions for use and previous data that may affect method selection.
Testing Plan
We connect SPF, UVA protection, critical wavelength and water resistance with the intended claims, without adding studies that do not answer the technical or regulatory objective.
Label Review
We compare the results with the protection category, directions for use and relevant warnings before the final artwork is approved.
Working Methodology
Market and Claims
We identify where the product will be sold and what level or type of protection will be communicated.
Technical Review
We assess the formula, format, packaging, directions for use and existing data.
Method Selection
Coordination and Follow-Up
Final Interpretation
Frequently Asked Questions About SPF Testing
Are SPF and UVA Protection the Same?
No. SPF relates mainly to protection against UVB-induced erythema. UVA protection is evaluated through specific parameters and methods and must be considered alongside SPF.
Can an In Vitro Test Be Used for an SPF Claim?
Published ISO in vitro and hybrid methods are available, but their use depends on the product type and acceptance in the target market. The strategy should be confirmed before the study begins.
When Should Water Resistance Be Evaluated?
It should be assessed when the product will communicate that benefit or when the applicable framework requires it. The final claim must match the tested procedure and immersion period.
Can a European Result Be Used in the United States?
Not necessarily. Product classification, accepted methods and labelling differ. Every result should be checked against the FDA framework before use.
When Is the Best Time to Test During Development?
Testing is most useful when the formula, manufacturing process and packaging reliably represent the commercial product. Testing too early increases the risk that the study will need to be repeated after a relevant change.
Sun Protection Testing Adapted to Your Market
Share the formula, product format, target market and intended claims with SHAPYPRO. We will prepare a strategy that connects the test methods with the label and documentation the product requires.
