Sunscreen is the product category where a cosmetic manufacturer's technical capability is tested most directly, because almost nothing about it behaves like a normal skincare product. The performance number on the front of the pack is a measured quantity rather than a marketing description, the ingredient list is governed by a short positive list in most markets, and the same formula can be a cosmetic in one country and a drug or a therapeutic good in the next.
For a brand planning a sunscreen launch, this means the formulation brief and the market strategy have to be written together. A formula that hits SPF 50 with an elegant texture but uses filters that are not permitted in the target market is not a formula, it is a prototype.
This guide covers how SPF and UVA protection are actually measured, how filter approvals differ between the major markets, how water resistance and photostability claims are substantiated, and what a brand should put in a sunscreen brief so that the first sample is already pointed at the right market.
Why sunscreen is a regulated product before it is a cosmetic
In most markets a sunscreen sits in a special category with its own approval route. In the European Union it remains a cosmetic under Regulation 1223/2009 but is subject to additional recommendations on efficacy and labelling. In the United States it is an over-the-counter drug. In China it is a special cosmetic requiring registration rather than filing. In Australia a product whose primary purpose is sun protection is regulated as a therapeutic good. In Canada a sunscreen is a drug.
The practical consequence is that the SPF value is not a claim the brand chooses. It is a test result, produced by an accredited laboratory under a defined protocol, and the label carries it as a factual statement. Two products can both say SPF 30 and mean exactly the same measured thing.
This is also why sunscreen development timelines are longer than skincare timelines. The formulation work may take two to three weeks, but the efficacy testing, the photostability work and the regulatory submission run on their own clocks, and none of them can be compressed by starting later.
How SPF is measured
The international reference for in vivo SPF is the ISO 24444 method, which determines the minimum erythemal dose on protected and unprotected skin in human volunteers and expresses the ratio between them. The number that appears on the pack is derived from that ratio, averaged across a panel of subjects and rounded down to the permitted labelling values.
Two features of the method drive most of the practical planning. First, the panel size and the individual sensitivity of the subjects mean that the result carries a statistical spread, so a formula developed to land exactly on SPF 50 may test below it. Formulators therefore build in headroom, targeting a measured value comfortably above the label grade they intend to print.
Second, the test is expensive and the sample must be a finished, stable, filled product, not a laboratory beaker. That means the sequence is: settle the formula, confirm stability and pack compatibility, fill the test samples, then test. A formula change after the SPF test invalidates the result.
In vitro methods exist and are used for screening during development, because they are faster and cheaper and can compare candidate formulas against each other. They are not a substitute for the in vivo result where the market requires one, but they are extremely useful for narrowing a set of options before committing to a full study.
UVA protection: PA, PPD and the ratio rules
SPF describes protection against UVB, which is what causes burning. UVA penetrates more deeply, and in the European Union and several other markets a sunscreen cannot simply claim broad spectrum protection without evidence.
The two common UVA metrics are the in vivo persistent pigment darkening method under ISO 24442, which produces the PA rating used widely in Asia, and the in vitro method under ISO 24443, which produces a UVA protection factor and a critical wavelength. The critical wavelength is the point at which 90 percent of the total absorbance curve has been reached; a value of 370 nanometres or above is the threshold for a broad spectrum claim in the United States.
The European approach adds a proportionality requirement: the UVA protection factor must be at least one third of the labelled SPF. This is the rule that catches brands who build a high SPF with a UVB-heavy filter system, and it is the single most common reason a formula that passes SPF testing fails to reach the market as designed.
| Requirement | What it does | Typical method | Practical consequence |
|---|---|---|---|
| SPF value | Sets the UVB number printed on pack | ISO 24444 in vivo; in vitro screening during development | Build headroom above the target grade; test the finished, filled product |
| PA rating | UVA protection grade used in many Asian markets | ISO 24442 in vivo persistent pigment darkening | Panel-dependent; plan the test alongside the SPF study |
| UVA protection factor | Numeric UVA value for European labelling | ISO 24443 in vitro with pre-irradiation | Must be at least one third of the SPF value in the EU |
| Critical wavelength | Breadth of the absorbance curve | ISO 24443 in vitro | 370 nm or above supports a broad spectrum claim in the US |
| Water resistance | Retention of protection after immersion | Immersion protocol with post-immersion SPF determination | Claim wording must match the immersion time actually tested |
UV filter approvals differ by market
This is the constraint that shapes sunscreen strategy more than any other. The list of permitted UV filters is a positive list in every major market, and the lists are not the same.
The European Union permits a relatively broad set of organic and inorganic filters under Annex VI of Regulation 1223/2009, with maximum concentrations specified per filter. Japan recognises a set of UV absorbers within its quasi-drug framework and is known for filters that are widely used in Asia. China works from its own inventory of permitted sunscreen agents, and because sunscreen is a special cosmetic there, the approved route is registration with efficacy testing. ASEAN harmonises through the Cosmetic Directive with its own annex of permitted filters.
The United States is the most restrictive of the major markets. The permitted sunscreen actives sit in the over-the-counter monograph, the list is considerably shorter than the European one, and adding a new filter follows a separate and historically slow process. A brand whose global formula depends on a filter that has no US monograph route cannot simply sell the same product in the United States.
The practical planning consequence is that a brand with ambitions in the United States, the European Union and China should ask its manufacturer early whether a single filter system can satisfy all three, or whether the range needs to be split. Splitting is common and perfectly workable, but it doubles the testing and it has to be budgeted from the beginning.
Water resistance and photostability
Water resistance is a claim about retention of protection after immersion, and it must be substantiated by a test in which the SPF is determined after the immersion protocol rather than before. Claim wording follows the immersion time: a 40 minute protocol and an 80 minute protocol are different claims, and the pack must say which one applies. A sunscreen that has not been immersion tested can still be sold, but it should not carry any water resistance wording.
Photostability is the second performance question. Some organic filters, avobenzone being the best known, degrade under UV exposure, and a formula built on an unstable filter system loses protection during use, even if the laboratory SPF value measured before irradiation is high. The in vitro UVA method includes a pre-irradiation step precisely because this matters, and a photostability study on the finished formula is the normal way to confirm that the system holds up.
Stabilisation is a formulation problem with several solutions: pairing the unstable filter with a stabilising filter, using an encapsulated or solubilised form, or choosing a filter system that does not rely on the unstable chemistry at all. Each has a texture and cost consequence, and the decision should be taken during formula design rather than discovered during testing.
Formulating to a target SPF without losing the texture
Consumers judge sunscreen on feel, and a formula that is unpleasant will be under-applied, which reduces real-world protection regardless of the number on the pack. Managing the trade-off between filter load and elegance is the core formulation task.
Several levers are available. The choice of filter system determines how much total filter mass is needed for a given SPF, so a more efficient system can hit the target with less loading. The oil phase and the emulsifier system determine how the filters are dispersed and how the film behaves on skin, which affects both measured performance and perceived texture. Volatile silicones and light esters can carry a high filter load while keeping the film dry. And the inorganic route with treated titanium dioxide or zinc oxide offers a different sensory profile that suits mineral positionings, at the cost of a whitening tendency that has to be managed with particle size and dispersion.
Two product formats dominate the OEM catalogue. A cream or lotion is the easier development and the easier test, because spreading and dosing are straightforward. A spray is harder: the film has to be uniform enough to test reliably, the delivery has to be consistent, and the inhalation question attracts regulatory attention. Brands should expect a spray to take longer and to cost more to develop.
Pack compatibility deserves specific attention. Sunscreen formulas are aggressive towards some pack materials and some decoration methods, because the solvent and filter load can extract components from plastics and soften adhesives. Testing the finished formula in the actual pack over the full stability period is not optional.
Labelling and claim boundaries
Sunscreen labels carry mandatory performance information, and the wording is regulated. The European labelling categories describe the protection level in words alongside the SPF number, and the UVA indicator accompanies a compliant broad spectrum formula. Directions for use, the quantity to apply and reapplication guidance are required content in most markets.
What sunscreen cannot claim is where brands most often go wrong. A sunscreen is not a treatment, and wording that implies prevention of a disease, reversal of skin damage or a therapeutic benefit moves the product into a different regulatory category. Language about anti-ageing benefit has to stay in the cosmetic register: protecting the appearance of the skin and helping to reduce the visible signs associated with sun exposure, supported by the product's measured performance, rather than any statement about disease.
Where a brand wants to publish SPF, UVA and water resistance numbers on marketing material as well as on pack, the figures must match the tested values exactly and the supporting reports must be available on request. Regulators and marketplace compliance teams do ask for them.
Compliance notes by market
In the European Union the product requires a Responsible Person, a Product Information File, a Cosmetic Product Safety Report and notification through CPNP, in addition to the efficacy evidence behind the stated SPF, UVA protection and any water resistance wording.
In the United States the sunscreen is an over-the-counter drug, which brings monograph compliance, facility registration and listing obligations, and a labelling regime that differs from the cosmetic one. Because the filter list is narrow, the formulation has to be built for the US list from the start if that market is planned.
In China, sunscreen is a special cosmetic. Registration is required rather than filing, and efficacy testing by an approved institution is part of the process. In Australia the therapeutic goods framework applies to products whose primary purpose is sun protection. In Canada a sunscreen is regulated as a drug. In Japan it sits in the quasi-drug category. In ASEAN, the Cosmetic Directive provides a harmonised route with its own annex of permitted filters.
What should a sunscreen brief contain?
State the target markets first, because the filter list follows from them. Then specify the target SPF grade and whether a UVA rating or a PA grade is required, the format (cream, lotion, gel, spray or stick), the intended use context and whether water resistance is needed, the sensory target including finish and residue, the pack type and size, any market-specific labelling requirements, the first order quantity and the target cost.
Two additional items save time later. Confirm which markets the brand intends to enter within the next two years, not only the first one, so the formula is not built into a corner. And confirm who will hold the regulatory responsibility in each market, because the notification and registration obligations sit with a person or entity, and that entity has to exist before launch.
Frequently asked questions about sunscreen OEM
Can a single formula be sold in the EU, the US and China?
Sometimes, but only within the intersection of the three filter lists. It is more common to develop a base formula and then produce market variants that share the texture and the packaging. The variants each need their own efficacy testing.
How long does sunscreen development take?
Expect the formulation and sampling stage to run several weeks, with efficacy testing, photostability and stability adding further time on their own schedule. The efficacy test can only be run on a finished, filled sample, so it sits after the formula is frozen.
Can you reduce the filter load to improve the texture?
Within limits. The measured SPF is a function of the filter system and the film, so texture improvements have to come from the choice of filters, the oil phase and the emulsifier, not from quietly reducing the actives below the level the label requires.
Do you provide the test reports?
Yes. Efficacy testing under the appropriate methods, photostability and stability documentation and pack compatibility are arranged through accredited laboratories, and the reports are supplied to the brand for its regulatory file.
Is a mineral-only formula feasible?
Yes, using treated titanium dioxide or zinc oxide. The trade-offs are the whitening tendency, which is managed through particle size, surface treatment and dispersion, and a sensory profile that differs from an organic filter system.
Next step: fix the markets, then build the formula
If you are developing a sunscreen or a sun care range, send us the target markets, the SPF grade you intend to label, the format and the pack you have in mind, and we will propose a filter system that fits those markets, a texture direction, a test plan and a costed quote. Write to capsulebiotech@163.com, message the right team on WhatsApp: Capsule Series (capsules only) +86 158-7655-5319, Cosmetics Series (serum, hair care, body care, fragrance) +86 158-7655-5319, or use the inquiry form and we will reply within one working day.
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