How to Make an Effective Mineral-Based Sunscreen
Wearing sunscreen is one of the most important steps in keeping skin healthy, preventing skin cancers, and fending off premature aging. The global market for sun care products was valued at over $13 billion in 2019 and is projected to reach $27 billion by 2027.
Since there are now so many products on the market, customers are becoming more and more selective about the sunscreens they buy and use. And increasingly, customers expect their everyday beauty products, from haircare to lip care, to come with sun-protective properties.
Thanks to the growing popularity of the green beauty movement, consumers are also becoming increasingly aware of some of the problems presented by chemical-based sunscreens. There is still debate over the safety of certain key ingredients in these products. Some ingredients are also known to be harmful to the planet, whether due to sourcing, manufacturing, or through the effects of toxic chemicals being released into the environment (see our article on reef-safe sunscreen for more information.)
This means that many ingredients that sunscreen manufacturers have used in the past are no longer suitable. As a result, there has been a shift in recent years away from chemical sunscreens and towards mineral-based products, which clean-conscious consumers consider more body-safe, sustainable, and environmentally friendly. However, mineral-based sunscreens also come with their own issues and complicating factors. Read on to learn what makes an effective mineral-based sunscreen.
How Do Sunscreens Work?
In this section, we will take a closer look at how sunscreen works and what that all-important SPF number actually means.
How Does Sunscreen Work?
Ultraviolet (UV) radiation is what causes sunburn and makes too much sun exposure dangerous. Sunscreen works by using physical and/or chemical particles to block and absorb UV rays, preventing them from damaging the skin. These particles form a protective film, reflecting the harmful rays and absorbing them before your skin can.
To be effective, a sunscreen must protect against both UVA and UVB rays. While UVB rays are the main cause of skin cancer and sunburn, UVA has also been linked to long-term skin damage and may play a role in some skin cancers as well.
Why SPF Is An Important Factor?
A major moment in the history of sunscreen was the creation of the SPF rating by a Swiss student named Franz Greiter.
A sunscreen’s sun protection factor, or SPF, refers to the amount of UV radiation that is required to burn the skin when using the product. In other words, the higher the SPF, the more protective the sunscreen.
Many people believe that SPF relates directly to how long the wearer can safely be in the sun while using the product. However, since the sun’s rays are not consistent throughout the day, this is not the case. An hour’s worth of solar exposure at 9am might be equivalent to only 15 minutes at noon. Other factors, such as skin type and reapplication frequency, also impact how long sunscreen is effective for an individual.
While SPF is important, it is not the only significant factor in determining a sunscreen’s effectiveness. SPF relates exclusively to the product’s UVB protection and does not tell you anything about how well the product protects against UVA rays. When choosing a sunscreen, it is essential to look for a broad-spectrum product. This means that it protects against both UVA and UVB rays.
In the last few years, the FDA has instituted new regulations on what constitutes a broad-spectrum sunscreen. Prior to these regulations, manufacturers could claim that a product was broad spectrum without it actually including any UVA protection. EU guidelines are even more stringent.
How Is Sunscreen Made?
At its most basic level, sunscreen manufacturing simply involves formulating a skin lotion with UV filtering ingredients added. But there is an art and science to choosing the correct ingredients and formulating them in the best way.
How Do You Formulate Sunscreens?
Sunscreens can be made as either oil-in-water or water-in-oil emulsions, each of which has its own properties, benefits, and drawbacks when manufacturing a mineral sunscreen. An emulsion simply refers to a mixture of two or more liquids which are usually immiscible (unmixable).
One consistent issue with oil-in-water emulsions is that streaking occurs, usually due to the high xanthan gum content. This can be addressed by replacing some of this with activated cellulose and by ensuring a proper emulsifier/co-emulsifier concentration.
In addition, for oil-in-water formulas, a large oil phase (preferably > 10% of the total formula) is needed to help mineral UV filters disperse properly and reach the target SPF.
With water-in-oil emulsions, we often see settlement at the bottom of the vessel during heat stability testing. This is because the suspension power of the emulsion is insufficient to support mineral powders at lower viscosity/high temperature, and the common solution is to add or increase the usage of suspension agents.
Other typical ingredients consist of emollients, lubricants, preservatives, emulsifying and thickening agents, perfumes, and colors in some products. UV filters and absorbers such as titanium dioxide or zinc oxide are also added. For some formulations, it is best practice to add emollients, thickeners, and emulsifiers right at the end of the process.
What Makes For a More Effective Sunscreen?
When it comes to making an effective sunscreen, the most important factor is the ingredients used. When manufacturing sunscreen products, beauty, and personal care brands look for what we colloquially refer to as the “unicorn” formulation: transparent, high SPF, low viscosity, and absolute stability.
Unlike chemical UV filters, mineral sunscreen ingredients typically come as powders. These physical particulates complicate the manufacturing process, as it is vital to ensure they are completely and evenly dispersed throughout the lotion. Otherwise, the product may not deliver on its promised sun-protective properties.
Mineral-based sunscreens can also have stability issues, causing the product to separate. It is common for the particles to sink to the bottom of the bottle, dramatically reducing the product’s effectiveness.
Finally, using a powder-based ingredient can alter the sensory properties of the finished product, and balancing these concerns is an ongoing issue for manufacturers. For example, zinc oxide is a white powder that can cause a visible whitening effect when applied to the skin. Poorly made mineral sunscreens are also known for feeling “cakey.”
Formulators have a number of tools at their disposal to help them address some of these issues. Some types of thickeners and emulsifiers are more compatible with mineral ingredients than others. Suspending agents can help to reduce the amount of “settling” in a finished product. Using the right equipment is also vital. A propellor mixer, for example, is unlikely to be powerful enough to ensure even dispersions. More powerful dispersing and mixing equipment is needed.
How Applechem Improves Sunscreen Formulations
To address some of the issues highlighted in the above section, manufacturers can choose to use a pre-dispersion of mineral sunscreen ingredients. This takes much of the work and experimentation out of the equation, allowing you to bring quality, consistent products to market more quickly.
Here at Applechem, we offer two key ingredients to help our clients formulate the best mineral-based sunscreen products. Our experts have spent countless hours researching and testing to produce ingredients that offer all the vital characteristics we discussed above. This has allowed us to create a stable, reliable dispersion with no sediment whatsoever, which contains a much higher percentage of the active ingredient than any previous formulations.
Our ingredients are compliant with FDA, EU, and other global cosmetics regulations.
G-Block is a premium dispersion engineered to provide the most efficient combination of high transparency, broad spectrum protection, and SPF performance. With 100% clean ingredients, an easy-to-disperse viscosity profile, and fantastic stability, G-Block ensures that SPF and critical wavelength levels remain consistent across product batches.
G-Block is the ideal choice for clean beauty manufacturers and independent personal care brands.
S-Block is a new zinc oxide dispersion designed to meet growing consumer demand for multi-functional sun care products. It combines clinically-validated claims with cleaner ingredients to offer consistent, clinical-grade, broad-spectrum mineral SPF protection.
S-Block is ideal for dermatologists and dermaceutical manufacturers seeking clinical-grade ingredients.
Common Sunscreen Manufacturing Questions
Does Sunscreen Have to be FDA Approved?
Yes, sunscreens need to be FDA-approved. Using a very stable dispersion such as G-Block or S-Block eliminates inconsistency in your products and produces a sunscreen that has the best chance of passing in-vivo screening tests by delivering consistent SPF protection every time.
Can Mineral-Based Sunscreens be Mixed With Non-Mineral?
Yes. Hybrid sunscreens do exist, and these contain both mineral and chemical SPF-filtering ingredients. In some instances, the synergy between these ingredients can elevate a product’s SPF to greater than the sum of its parts. However, creating hybrid products can present other manufacturing and ingredient selection issues.
It is also fine for an end customer to use both mineral and chemical sunscreens together on their skin if they wish. However, ingredients can interact in ways that can undermine the product’s efficacy if left for a long time, so do not expect these mixtures to have a long and effective shelf life.
Are Sunscreens with Natural Ingredients Better?
This depends entirely upon what we mean by “better.” Thanks to advances in technology in the last few years, sunscreens with natural ingredients can now be just as effective as those with chemical ingredients. Mineral-based sunscreens tend to be more sustainable and environmentally friendly. Many also believe they are safer.
Well-made sunscreens with natural ingredients are also more than equal to those with chemical ingredients in SPF efficacy and stability.
However, there are areas in which a 100% natural sunscreen still cannot match its chemical counterparts. For example, when sensory properties are the main concern, silicone oils tend to be used, and natural ingredients cannot yet match them in this aspect.
Learn More or Request a Sample
Sun care is a tremendously competitive industry. This means that if you want to get ahead in the market, it is vital to keep on top of industry trends, such as the clean beauty movement, and make use of the best ingredients.
Here at Applechem, we have developed several sunscreen prototypes using G-Block and S-Block. These are fantastic examples of how manufacturers can develop a high-performing mineral sunscreen.
For example, our Natural Silk Sunscreen is our version of the “unicorn formula” for modern, clean mineral sunscreens. It offers the whole package: a serum-like viscosity with great transparency, SPF 50 broad spectrum protection, and 80-minute water resistance, all in a fully stable formula. Natural Silk Sunscreen uses G-Block, and details can be found here.
The Slip Shield Liquid Powder is a sunscreen that caters towards dermaceutical and clinical brands seeking an ultra-premium sensory experience with superior broad-spectrum protection. This product uses our S-Block dispersion, and details can be found here.
If you are ready to begin formulating, download these and other prototype sheets for inspiration.
If you would like any more information on G-Block, S-Block, or any other Applechem products, our highly knowledgeable team members would be pleased to hear from you. We believe in making ourselves available to support you and answer any questions you may have, so please do get in touch.