Sunscreens are the summer cosmetics par excellence and should always be present at home during the summer and, above all, in any beach bag. Sunscreens help us, together with sensible sun exposure, to protect our skin from ultraviolet radiation emitted by the sun.

What is a sunscreen?

Technically, a sunscreen is "any preparation, cream, oil, gel or spray, intended to be placed in contact with human skin for the exclusive or main purpose of protecting it against UV radiation, by absorbing, scattering or refracting it."

As is also clear from the EU definition, not all sunscreens are the same: the differences can concern many aspects, but the most substantial concerns the mechanism of action. In other words, whether they protect the skin by "absorption" and "dispersion" or by "refraction", in other words, whether they act through chemical or physical filters.

How to choose a sunscreen?

What are UV rays?

What is the difference between chemical and physical sunscreens?

What are physical sunscreens and what are they?

- Nano filters: how to know if a cosmetic contains nanoparticles

What are chemical sunscreens and what are they?

- The latest studies on chemical filters

- What are the most commonly used chemical filters?

What are booster ingredients and why do they improve the effectiveness of a sunscreen?

Physical and chemical sunscreens: which sunscreens to choose

- Why is it preferable to choose sunscreens that contain physical filters?

In Palau and Hawaii: Bans on chemical sunscreens are in place

What are UV rays?

Ultraviolet radiation is the most "energetic" radiation in the solar spectrum that we come into contact with and, therefore, it is also the most dangerous for our skin. UV radiation is divided into UVC, UVA and UVB.

• UVC has a wavelength that varies between 100 and 280 nm. They are very dangerous, but as they are absorbed by the gases in the stratosphere, they do not reach the Earth's surface unless the ozone layer undergoes further changes.
• UVA rays have a wavelength of 315 to 400 nm. They are very penetrating and, as such, can reach the dermis and alter the structure of collagen and elastin fibers, thus causing premature aging of the skin and also favoring the appearance of other skin diseases.
• UVB rays, on the other hand, with a wavelength of 280 to 315 nm, are less penetrating than UVA and affect the most superficial layer of the skin, the epidermis. They are responsible for sunburn, erythema and other skin diseases.

What is the difference between chemical and physical sunscreens?

"Sunscreens" are the skin's most important defense weapon against the sun. The effectiveness and safety of sunscreen cosmetics are based on the type and quantity of anti-UV molecules they contain. But adding filters to a cream is not enough to make a good sunscreen; there are many ingredients and formulation and production tricks that contribute to creating an effective, quality sunscreen.

In any case, regardless of the formulation and type of filters used in sunscreens, we must remember one thing: all sunscreens on the market (sold by reputable companies and through official channels!) must comply with precise legal requirements and pass a series of tests that guarantee protection against UVA and UVB rays and that serve to determine the declared sun protection factor. The different types of possible formulations (with chemical filters, with physical filters or with combined filters) are therefore not distinguished by their greater or lesser effectiveness, but by their mechanism of action and formulation characteristics.

Like all other cosmetic products, sunscreens are also regulated by the European Cosmetics Regulation 1223/2009. In particular, Annex VI lists all the UV filters authorized in cosmetic products and their maximum usable concentration. Formally, sunscreens are subdivided according to their nature and mechanism of action. But in practice, what are the differences between physical and chemical sunscreens?

What are physical sunscreens and what are they?

Physical filters, also known as inorganic filters, have protective properties. These are substances that, due to their opacity, provide a true shield against UV radiation. They are made up of small mineral particles that reflect the sun's rays so that they cannot reach the skin. Unlike chemical sunscreens, they do not retain heat or penetrate the skin. Furthermore, they do not decompose, interact with or be damaged by solar radiation. They are capable of repelling both UVA and UVB frequencies.

In practice, they are like mirrors and protect us from harmful radiation through a reflection/diffusion mechanism.

Solar radiation is reflected or scattered and not absorbed by the surface of the skin. Therefore, they do not cause the skin to overheat; on the contrary, they effectively protect it. They are inert, photostable substances and particularly safe for skin health.

Compared to chemical filters, they have less allergenic power. In most cases, they are natural sunscreens. However, they can also be produced artificially and therefore synthetic. The most commonly used physical sunscreens are zinc oxide and titanium dioxide.

Zinc oxide

It reflects both UVB and UVA rays. It comes as a white powder and can be found in many cosmetics due to its antibacterial, soothing and barrier properties. It is very well tolerated by the skin, so much so that its most common and well-known use is in the zinc oxide paste used in diaper changing creams.

It is also found in many makeup products due to its pigmentation power.

The intrinsic characteristics of zinc oxide make it an excellent sunscreen, capable of "blocking" UV rays and their harmful effects.

The use of zinc oxide as a UV filter is permitted in both nano and non-nano forms, with a maximum concentration of 25%. Nano-zinc oxide, i.e. present in the form of nanoparticles, is potentially harmful to marine habitats, particularly coral reefs.

The Haereticus Environmental Laboratory (HEL), a non-profit scientific organization, is dedicated to increasing scientific, social and economic understanding of natural environmental habitats in order to conserve and restore them. HEL has developed a certification called "Protect Land + Sea" that certifies various sunscreens as safe, including those containing (non-nano) zinc oxide.

All La Saponaria sunscreens contain non-nano sunscreens and the zinc oxide present in the formula has undergone a study that has shown that its composition does not endanger coral reefs or the marine ecosystem in general, as the residual concentrations are much lower than those considered harmful to the aquatic environment.

Titanium dioxide

In nature, hydroxyapatite is a mineral that occurs in the form of white, prismatic crystals. It is one of the main components of bones and teeth and gives them their characteristic consistency and hardness.

In cosmetics, it is used in oral hygiene products, such as toothpaste, or in the manufacture of ecological and dermocompatible sunscreens.

Hydroxyapatite, in combination with other ingredients such as zinc oxide, plays an important role as a barrier against UV radiation, preventing the dreaded sunburn.

Safe for both the skin and the environment, hydroxyapatite is a photocatalytic ingredient, meaning it does not generate free radicals when exposed to light, making it excellent for protecting the skin from photoaging.

Finally, applied to the skin, it has a pleasant smoothing and softening effect.

Pongamia Extract (Pongamia Pinnata Seed Extract)

Pongamia oil is extracted from the seeds of the Pongamia tree, also known as Millettia pinnata . It is known for its protective action against UV radiation and is therefore particularly popular for the formulation of sunscreens.

Rich in flavonoids, antioxidants and fatty acids, Pongamia oil is the ideal ally for protecting the skin from the sun, preventing skin aging and softening the skin. Its emollient properties provide the skin with hydration, elasticity and softness. It also helps to naturally rebalance the hydrolipidic barrier.

Pongamia oil can also be used to protect hair from UV damage and keep it moisturized and shiny.

- Nano filters: how to know if a cosmetic contains nanoparticles

Nanomaterials are defined, according to the European Commission Recommendation of 18 October 2011, as "components with dimensions between 1 and 100 billionths of a meter".

When we talk about nanoparticles, we are therefore talking about extraordinarily small materials obtained in the laboratory, about whose characteristics we still know very little. They represent the last frontier, an emerging technology, but precisely for this reason we need to delve deeper and avoid a superficial attitude.

In 2004, several research institutes raised a serious alarm about the possible danger of synthetic nanoparticles to human health. Before that, other independent studies had reported toxic effects caused by the penetration of these nanoparticles into tissues and organs.

Nanomaterials have different toxicological properties and respond to different laws than the elements from which they come: it is not enough to know that titanium is a safe material to be certain that one of its nanoparticles is also safe. It is necessary to assess each case individually, as some studies indicate that these particles, precisely because of their size, are not metabolized or excreted by the human body, and can generate accumulations in various organs, with effects that are difficult to predict.

Therefore, it is good to adopt a principle of prudence.

In Europe, the Cosmetics Regulation clearly regulates the use of nanomaterials in cosmetic products, with the aim of ensuring a high level of consumer and human health protection. Manufacturers and distributors of cosmetic products are required to inform the European Commission six months before marketing a cosmetic product containing nanomaterials. Cosmetic manufacturers who decide to include them in their formulas must include them in the Cosmetic Safety Assessment (CSA) and notify their presence in the European Cosmetics Registration Portal (EPC).

In order to make the presence or absence of nanoparticles clear to consumers, the regulation requires that the presence of nanomaterials be indicated on the label, in the list of ingredients: the name of the substance must be followed by the word "nano" in brackets. When the word NANO is not indicated, it means that filters larger than 100 billionths of a meter have been selected.

While we await evidence on whether or not this new technology is dangerous, it is preferable to use other protection systems that are still valid and have no negative effects, such as microencapsulated filters, which are also capable of ensuring a certain level of glide over the skin.

What are chemical sunscreens and what are they?

Chemical or organic filters are synthetic substances that capture the energy of UV radiation to prevent it from reaching and damaging the cells of the epidermis and dermis. They selectively absorb UVA and UVB radiation, acting at different wavelengths. Some absorb only short UVA rays, others only UVB, and still others both long and short UVA.

These molecules, once absorbed, break down solar radiation, retaining the energy and releasing it in the form of heat and/or fluorescence. This, in effect, increases the sensation of heat felt on the skin. In short, chemical filters absorb part of the solar radiation and release the energy in the form of heat.

The energy they absorb leads to the formation of compounds that slowly release energy in the form of fluorescence or heat, returning to their original structure and altering the absorption wavelength. This is why the ideal sunscreen should not only be broad-spectrum, but also have photostable filters, i.e. resistant to the action of the sun.

Chemical sunscreens have the advantage of being cheaper, easier to work with and allowing the creation of cosmetics that are more comfortable for the user, lighter and easier to spread. The main limitation of these chemical filters is precisely the fact that they can cause irritation, phototoxicity and sensitization, as they absorb solar energy and can, in fact, initiate photochemical reactions and, in some cases, a reduction in effectiveness.

Chemical sunscreens are certainly critical ingredients and the subject of in-depth study by the competent authorities, as they appear to be associated with endocrine or biochemical damage.

For example, the acid filter para - aminobenzoic acid ( PABA), which was for a long time one of the most widely used chemical filters, has been banned since 2009, precisely because it was considered carcinogenic and highly sensitizing.

Other commonly used filters include benzophenone, which has been found to be an endocrine disruptor, or octinoxate, an ingredient found even in breast milk, with serious effects on human health and the environment.

Chemical filters are heavily polluting fish, molluscs, algae and corals, as they can generate genetic modifications, altering the neurological and reproductive behavior of different species.

- The latest studies on chemical filters

An American study (2019) mentioned the risk that substances contained in chemical filters could be absorbed through the skin and enter the bloodstream.

- What are the most commonly used chemical filters?

You need to be very careful when choosing the right sunscreen. Several scientific studies have shown that there are many brands of sunscreens on the market that contain ingredients that are harmful to the skin and many other ingredients that are pollutants and whose presence can compromise the balance of beaches and seas.

Buying sunscreen therefore becomes a responsible gesture towards ourselves and our planet.

Octinoxate

Also known as octyl methoxycinnamate or (OMC), it is a UV filter. It is photo stable only when used alone or in combination with Octocrylene and DrometrizoleTrisiloxane. It is readily absorbed through the skin and has been detected in human urine, blood and breast milk, indicating that humans are routinely exposed to this compound and that its bioaccumulation is readily observed. It is an endocrine disruptor that mimics estrogen and may interfere with thyroid function. Several studies show a significant negative effect on marine flora and fauna.

Octocrylene

Octocrylene protects primarily against UVB and, to a lesser extent, also against short UVA. It is used alone or in combination with other filters.

When in contact with oxygen, it creates reactions that can interfere with cell signaling, cause mutations, lead to cell death and may be involved in cardiovascular diseases. It can cause allergies and photosensitization. Harmful to the aquatic environment, several studies show that it interferes with animal reproduction.

DrometrizoleTrisiloxane

This is a very photo-stable chemical sunscreen that protects against both UVB and short UVA rays. For broad-spectrum action, it must be combined with other long UVA filters. It appears to be very toxic to the environment and very toxic to the respiratory system.

Benzophenone-3

It belongs to the benzophenone category (also known as oxybenzone). It is a chemical filter capable of protecting the skin well against UVB and UVA rays. The maximum concentration for use is 6%. If the cosmetic contains more than 0.5%, it should be indicated as "Contains Benzophenone-3", as it may not be tolerated by some individuals.

Laboratory studies have shown that, in addition to this ingredient being able to disrupt the hormonal system, causing a weakening of estrogenic activity, it penetrates the skin, promoting an increase in free radicals that damage DNA when exposed to the sun.

Benzophenone-4

This is a chemical filter that blocks short UVB and UVA rays well. It can cause sensitization and allergy problems. There is strong evidence that it is an endocrine disruptor.

Ethylhexyldimethyl PABA or PADIMATO

Absorbs UVB radiation. Facilitates the formation of free radicals and can cause allergic reactions in some people. One of the few PABAs still permitted, it is a close relative of the PABA filter that was widely used in the past and is now banned because it is proven to be carcinogenic. Several studies demonstrate its estrogenic, radical-forming and DNA-interacting activity. Strongly allergenic.

Salicylates

The most common examples of this class are ethylhexyl salicylate and homosalate. The former is a chemical filter with low UVB absorption power and is not very photostable, so it must be combined with other chemical and/or physical filters in the formulations. It can be used in a maximum concentration of 5%.
Homosalate is a very effective filter against UVB rays, but does not protect against UVA, although these are often a source of allergies. It is suspected of being an environmental toxin and of being persistent or bioaccumulative.

PABA

It is a filter that protects us from UVB rays. It can cause photosensitivity to the point of causing photoallergic dermatitis. It is also responsible for an increase in the amount of free radicals. It is a natural chemical found in folic acid, vitamins and various foods, including wheat, eggs, milk and meat.

Its use in cosmetics was banned in the EU for several years.

Isoamyl p-methoxycinnamate

It has a good absorption power of UVB radiation. It can cause skin irritation and contact allergies.

Diethylamino Hydroxybenzoyl Hexyl Benzoate

It is a broad-spectrum filter capable of protecting the skin from short and long UVA rays, but not from UVB. For this reason, it should be combined with UVB filters. It is very photostable and compatible with other cosmetic ingredients.

What are booster ingredients and why do they improve the effectiveness of a sunscreen?

The term BOOSTER in sun protection is used to highlight a protective capacity of the finished cosmetic that is superior to that of its individual parts.

We speak of a synergistic effect in which 1+1 equals 3.

This is generally due to the action of certain polymers and emollients which, when added to a cosmetic with a certain mixture of sunscreens, amplify its SPF, or to the combination of certain soluble and/or insoluble sunscreens, which provide a higher SPF than the individual filters.

There are, however, several techniques used to obtain a BOOSTER effect in cosmetic sun protection:

1. Emollients and polymers (silicone elastomers) allow for an optimal distribution of the filtering substances. A multilayer filter effect can be achieved with layers of substances with different refractive indices.
2. Coating of filtering substances, especially metallic ones , reducing their photo-reactivity and photo-catalytic properties
3. Spheres (grains, droplets, spheres) : combine the advantage of having non-nanometric dimensions and enclose any insoluble nanofilters, reducing the risks of photo-reactivity due to nanometric dimensions
4. Quencer : non-filtering substances that break down the different states of sunscreens. They are essential for stabilizing the filtering system over time. When properly formulated, they can amplify SPF and UVA absorption. Derivatives of benzylidenecamphor and cinnamic acid can be used.
5. Natural substances : in nature, there are also oils and extracts that, although they cannot be considered true sunscreens, when used in a sun cream they improve its performance, both in terms of protection and, above all, by acting as natural antioxidants.

• These include:
• Vitamin C increases protection against UVB rays
• Vitamin E increases protection against UVB and UVA rays, while slowing down the oxidation processes initiated by free radicals generated by infrared radiation after incorrect exposure to the sun.
• Raspberry seed oil contains natural UV filters
• Carrot oil , rich in β-carotene, stimulates the formation of melanin, the skin pigment that protects the epidermis from radiation and stimulates tanning
• Turmeric , thanks to its antioxidant action, protects cells from free radicals. It contains natural sunscreens with medium-low protection (which is why it is useful for already tanned skin) and accelerates tanning.
• Pomegranate seed oil improves skin elasticity and counteracts photoaging
• Rice bran oil also improves skin elasticity and counteracts photoaging.

Physical and chemical sunscreens: which sunscreens to choose

A well-formulated sunscreen must take several aspects into account. The type of filters used is certainly a fundamental aspect, although it is not the only one.

The ideal sunscreen should meet the following requirements:

• Provide effective protection against UVA and UVB radiation
• Be well tolerated
• Be resistant to water and sweat
• Easy to apply and spread
• Be photo-stable and heat-stable
• Be safe and effective
• Does not contain allergenic substances
• Be rich in antioxidants
• Be manufactured with physical filters only

Formulas made with natural ingredients, rich in antioxidants and vitamins, are preferable, and all formulas containing irritating and potentially allergenic ingredients (such as parabens or various types of chemical filters) should be avoided. The perfumes present in some creams can also cause problems when exposed to the sun; sunscreens with mild, preferably neutral, fragrances should be preferred.

The texture of the product is equally important: it is not only an aesthetic factor, but also a functional factor. A sunscreen that spreads well and does not leave white marks will be easier to apply and will not run the risk of leaving areas of skin unprotected.

- Why is it preferable to choose sunscreens that contain physical filters?

As regards the type of filters to choose, our choice fell on physical filters.

These have the disadvantage of being more difficult to use in recipes and making it harder for the formulator to create a product with a pleasant texture. However, current research has brought us very satisfactory results, a far cry from the first sunscreens with physical filters that were on the market with the "ghost effect". Today, we can formulate creams with physical filters that are very fluid and comfortable on the skin, although they still cannot match formulations with chemical filters in this regard.

However, compared to the latter, physical filters have several advantages: they have a lighter environmental impact, are more photostable and certainly have a better toxicological profile.

The use of physical filters, compared to chemical filters, minimises the risk of allergies and skin sensitisation, which is why they are particularly suitable for sensitive and predisposed individuals who may be intolerant to chemical filters. As we have seen, some chemical filters can also be endocrine disruptors, which is why their use is not particularly recommended for pregnant women, children and adolescents.

In short, here's why we chose physical filters :

Safer toxicological profile
- They do not interact with the skin and are potentially less allergenic;
- Significantly reduced risk of individual skin sensitization;
- Highly compatible with children's delicate skin.
Environmental sustainability
- Eco-sustainable, in line with what we believe in!
- They do not have the devastating effects on aquatic flora and fauna of chemical filters

In Palau and Hawaii: Bans on chemical sunscreens are in place

The Palau archipelago, made up of beautiful, unspoilt islands between the Philippines and Papua New Guinea, has decided to ban sunscreens that contain 10 chemical agents that are super polluting for the seas and harmful to coral reefs.

We must live with respect for the environment, because it is the cradle of our very existence: otherwise we would not survive", declared the president of the small state, Tommy Remengesau. "About 340 islands, just over 450 square kilometers of land surface for less than 20,000 inhabitants, but ten times more tourists per year: hence the environmental emergency.

Located in the middle of the Pacific, the archipelago is universally recognized for the richness of its marine ecosystem, peculiarities that make it one of the most popular destinations for lovers of underwater tourism. The ban was decided in November 2019 and implemented in record time at the beginning of 2020.

They were the first state in the world to do so, but Hawaii quickly followed suit when in 2021 it formulated the now-famous Hawaii Protocol, banning the use of sunscreens containing two chemicals, oxybenzone and octinoxate. According to the bill, these chemicals “have a significant and detrimental impact on Hawaii’s marine environment and surrounding ecosystems.” Starting in 2023, a new bill, also from Hawaii, aims to ban two more ingredients, avobenzone and octocrylene.

One more reason to choose physical filters and to bathe consciously and with respect for all the animals that live in the sea, even the most delicate ones, such as corals.