If you are wondering how sunscreen is made, the answer starts with formulation science, process control, and regulatory planning. In real manufacturing, how SPF is made is not just a matter of adding UV filters to a base. A reliable sunscreen manufacturing process involves selecting the right filter system, designing stable emulsions, validating scale-up conditions, and testing the finished formula to confirm safety, performance, and label claims.

A commercial sunscreen product has to do several jobs at once. It has to provide reliable sun protection against UV rays, remain stable during production and storage, spread evenly on skin, and deliver consistent performance from batch to batch. That is why sunscreen development is not only about ingredients on paper. It is about how the full formula behaves during mixing, cooling, filling, and final quality release.

At a glance, the sunscreen manufacturing process includes selecting UV filters, preparing the oil phase and water phase, building a stable emulsion, dispersing active ingredients evenly, running SPF testing, and packaging the finished sunscreen product.

In practice, each of these stages affects the final product. The quality of dispersion, the emulsion structure, and the processing conditions all influence texture, stability, broad spectrum performance, and the consistency of sun protection across the batch.

Sunscreen is not a simple cream with one protective additive. Its performance depends on the relationship between filters, emollients, solvents, emulsifiers, polymers, preservatives, and antioxidants. The formula must stay stable in the vessel, pass testing, feel acceptable on skin, and maintain its performance through transport and storage.

Broad spectrum protection and the protection factor

The sun protection factor, or protection factor, mainly reflects protection against UVB radiation and UVB rays. By contrast, broad spectrum protection means protection against both UVA rays and UVB. That difference matters because UV radiation is associated not only with sunburn, but also with skin aging, visible photoaging, DNA damage, and increased risk of skin cancer.

Modern sunscreens therefore aim to deliver more than a high SPF rating. They are expected to provide effective UV protection, support skin health, and help protect skin during repeated sun exposure.

Why the full formula matters

The final performance of a sunscreen depends on far more than the label claim. Sunscreen’s effectiveness is shaped by the type of filters used, how evenly they are dispersed, the emulsion structure, the film the product forms on skin, and the way the formula behaves after scale-up.

That is why modern sunscreen formulations are built as systems, not as ingredient lists.

Insight: a sunscreen formula can look correct on paper and still fail if the manufacturing process is not controlled.

At the center of most formulas are active ingredients known as UV filters. These are the materials that create UV protection and define much of the finished product’s performance.

Chemical and physical filters

Many formulas use chemical and physical filters together. Chemical sunscreens rely on chemical filters, also called organic UV filters, which absorb UV radiation and convert it to heat. Common examples include avobenzone, oxybenzone, octisalate, homosalate, and octocrylene.

Mineral sunscreens use inorganic filters, primarily zinc oxide and titanium dioxide. These mineral actives are often selected when brands want a different positioning for sensitive skin, a hybrid formula strategy, or a more conservative regulatory approach in some markets.

In practice, formulators may work with certain organic UV filters, fully mineral systems, or hybrid systems, depending on the target market, texture, claims, and regulatory path.

The support system around the filters

Filters alone do not make a sunscreen successful. Commercial formulas also use:

• emollients and solvents to help disperse filters
• fatty alcohols and oils, sometimes including coconut-derived materials
• emulsifiers to combine the phases
• preservatives to support shelf life
• antioxidants such as vitamin E
• film-forming polymers to improve wear and water resistance

These inactive materials can influence spreadability, film formation, stability, and overall performance. In other words, inactive ingredients are not passive. They can affect both SPF claims and sunscreen’s effectiveness.

Most sunscreen emulsions are made from separate oil and water phases. The oil phase usually contains lipophilic filters, oils, waxes, and part of the emulsifier system. The water phase typically contains purified water, humectants, chelators, and other water-soluble materials.

Oil in water vs water in oil emulsion

Most sunscreen lotions are built as oil in water systems because they usually feel lighter and more familiar for daily use. A richer or more tenacious formula may instead use a water in oil emulsion, especially when the target is stronger substantivity or a heavier barrier feel.

Why stable and uniform emulsions matter

The objective is not just to mix two phases together. The objective is to create stable and uniform emulsions that remain smooth, visually consistent, and functionally reliable throughout the batch and throughout the product’s shelf life.

A good sunscreen should have a smooth texture, stable viscosity, and even filter distribution. Without that, it becomes harder to guarantee consistent sun protection and consistent product quality.

A professional sunscreen production project begins with a product brief. Before development starts, the manufacturer has to define:

• the format, such as cream, lotion, stick, or one of the spray sunscreens
• the target SPF rating
• whether the formula must provide broad spectrum protection
• the expected level of water resistance
• the intended consumer profile, including use on sensitive skin
• the target market and related regulatory compliance details

This first stage helps align formulation work with commercial, technical, and regulatory expectations.

This is the stage where brands often ask how is SPF made. The practical answer is that SPF is created through the interaction of filters, solvents, emollients, film formation, and finished-product testing.

The formulation team selects sunscreen ingredients and builds the filter package to deliver the intended broad spectrum profile. That may involve mineral filters such as zinc oxide and titanium dioxide, combinations of organic UV filters, or hybrid systems designed to balance aesthetics and skin protection.

The process of making sunscreen starts with weighing ingredients in precise measures. Manufacturers prepare the aqueous and oil premixes separately, then heat them to the required range before combining them.

This stage requires discipline. The sequence of additions, the temperature profile, and the dispersibility of the filters all affect the final product.

Once the premixes are ready, manufacturers effectively blend them using industrial mixers, homogenizers, or rotor-stator systems. The mixing process often involves applying intense shear forces to reduce droplet size, improve filter distribution, and build a more uniform emulsion.

This is where a stable emulsion becomes a manufacturing reality rather than a formulation theory. It is also where many production risks begin if the system is not robust enough for scale.

After emulsification, the batch is cooled under controlled conditions. Cooling must be done gradually to reduce the risk of separation or destabilization. Heat-sensitive materials such as antioxidants, fragrance systems, and certain specialty ingredients are usually added after the mixture has cooled sufficiently.

This matters because sunscreen performance depends on both composition and process. A rushed cooling curve can affect viscosity, texture, and long-term stability.

Commercial sunscreen manufacturing does not end when the emulsion looks good. Before release, the batch may be checked for:

• viscosity and appearance
• emulsion stability and batch homogeneity
• microbiological quality
• packaging compatibility
• SPF testing
• filling accuracy
• coding, labeling equipment sealing, and final packing

Labeling readiness also includes accurate INCI naming and documentation aligned with the target market. The sunscreen is packed and sent to the brand only after it passes the required tests and release checks.

From a manufacturer’s perspective, one of the biggest misconceptions about sunscreen is that a successful lab sample will behave exactly the same way in full production. In reality, scale-up changes the process. Larger vessels, different shear conditions, longer hold times, and slower cooling curves can all affect viscosity, texture, filter dispersion, and ultimately SPF consistency.

This is why checking the uniform distribution of active ingredients is critical. If UV filters are not dispersed evenly, the batch may not deliver the same level of protection throughout the finished run. A sunscreen can look fine visually and still show problems in stability, fill performance, or final testing.

At Merywood, scale-up controls and release checkpoints are essential for ensuring consistent product quality across the full production run. Before release, critical checkpoints typically include emulsion stability, viscosity profile, batch homogeneity, packaging compatibility, and documentation readiness for the target market. In sunscreen manufacturing, repeatability is part of product quality.

The regulation of sunscreen varies globally, and that affects both formulation and labeling.

The United States

In the United States, sunscreen is regulated by the Food and Drug Administration as an over-the-counter drug rather than a cosmetic product. OTC Monograph M020 and the FDA’s labeling and effectiveness testing guidance set the framework for sunscreen drug products, including Drug Facts labeling, broad spectrum designation, water resistance claims, and SPF testing.

Historically, the U.S. monograph framework has recognized 16 sunscreen active ingredients, although only a smaller group is commonly used in the market. In more recent FDA review, UV filters have been discussed in categories such as GRASE, non-GRASE, and ingredients requiring further evaluation. In practical terms, zinc oxide and titanium dioxide remain especially important in the U.S. safety discussion.

Europe and other markets

In Europe, sunscreens are regulated as cosmetic products under Regulation (EC) No 1223/2009, applicable since July 2013. For sunscreen-specific compliance, brands should also review Annex VI on permitted UV filters and Commission Recommendation 2006/647/EC on sunscreen efficacy and claims.

Other regions may classify sunscreens as cosmetic or therapeutic products, which changes the regulatory route, allowed filters, and label language.

Our advice: brands should never assume that one sunscreen formula can move between markets without regulatory review. Requirements vary, and regulators can restrict or investigate UV filters over safety concerns.

Environmental scrutiny is now shaping sunscreen development more directly.

Why some filters face restrictions

Some sunscreen active ingredients have been associated with toxicity toward marine life and coral reefs, which has led to bans or restrictions in different states, countries, and ecological areas. In Hawaii, official Hawaii legislative materials referring to Act 104, Session Laws of Hawaii 2018 describe the restriction on the sale and distribution of sunscreens containing oxybenzone and octinoxate without a prescription and frame it as a measure to help preserve the State’s marine ecosystems. Other jurisdictions, including Key West, the U.S. Virgin Islands, Bonaire, and Palau, have also introduced restrictions on these ingredients.

Studies often cited in this discussion suggest that oxybenzone and octinoxate can damage coral DNA, induce deformities in coral larvae, and increase susceptibility to viral infection. Some findings also suggest that certain compounds may contribute to coral bleaching at very low concentrations.

The shift toward reef-conscious design

As environmental awareness grows, brands are paying closer attention to reef-conscious positioning and lower-impact formulas. This has contributed to growing interest in mineral-led systems, more sustainable ingredients, and formulas that avoid filters under particular environmental scrutiny.

At the same time, the topic should be handled carefully. Environmental impact is multi-layered, and sunscreen is only one factor affecting marine ecosystems. Good communication should be specific, evidence-aware, and market-aware.

Recent sunscreen innovation is not only about higher SPF.

Better user experience and better protection

New sunscreen formulations are being developed to improve texture, film quality, and wear, while also addressing environmental and safety concerns linked to traditional petrochemical systems. Film-forming polymers can improve water resistance and formula stability. Antioxidants can enhance protection against oxidative stress and may help reduce markers associated with extrinsic photoaging.

There is also growing interest in formulas that protect not only against ultraviolet light, but also against environmental stressors such as pollution, high-energy visible light, blue light, and even infrared-associated damage.

This is why innovation in sunscreen today focuses on three goals at once:

• stronger daily usability
• reliable effective sun protection
• more responsible formulation choices

At Merywood, we support sunscreen projects through formulation, scale-up, testing coordination, packaging, and compliance documentation. We also know that sunscreen performance depends on both formula design and process control, and that regulatory expectations vary by market.

For brands exploring private label cosmetics, sunscreen development requires more than a good concept — it requires a partner that can manage compliance, scale-up, and testing.

A strong sunscreen is built at the intersection of chemistry, process engineering, testing, and regulation. The best sunscreen manufacturing process is repeatable: choose the right filter system, prepare the phases correctly, build a stable emulsion, disperse actives evenly, validate performance, and release only when the batch supports both claims and consumer use.

For brands evaluating a contract manufacturing partner, the real question is not only how sunscreen is made, but whether the manufacturer can reproduce that performance consistently at scale and for the requirements of the target market.

How was sunscreen invented?

Modern sunscreen was developed in the 1930s and 1940s as chemists looked for ways to prevent sunburn caused by UV exposure. While people had used simple forms of sun protection for centuries, early commercial sunscreens appeared with Ambre Solaire in the mid-1930s, followed by Franz Greiter’s Gletscher Crème in 1946. Later, Greiter helped introduce the SPF rating system, which shaped how sunscreen is measured today.

Why do two sunscreens with the same SPF feel completely different?

Two products can have the same SPF and still feel very different because SPF does not describe the full formula. Filter choice, oil level, polymer system, emulsion type, and rheology all affect texture, spreadability, finish, and wear.

How do manufacturers make water resistant sunscreens?

Manufacturers make water resistant sunscreens by combining the right filter system with film-forming materials, emollients, and an emulsion structure that helps the formula remain on skin after water exposure. Water resistance depends on the whole formulation and the way the finished product performs in testing.

What is the difference between zinc oxide and titanium dioxide in sunscreen formulations?

Both zinc oxide and titanium dioxide are mineral UV filters, but they do not behave in exactly the same way. Zinc oxide is often valued for broader UVA and UVB coverage, while titanium dioxide is especially useful in UVB and short-UVA protection. Formulators choose between them, or combine them, depending on coverage goals, whitening effect, texture, and market requirements.

Can inactive ingredients affect SPF and sunscreen’s effectiveness?

Yes. Inactive ingredients can affect SPF and overall sunscreen’s effectiveness because they influence filter dispersion, film formation, spreadability, stability, and wear on skin. Even when the active ingredients stay the same, changes in the base can change performance.