Between SPF and chemical or mineral filters, how do you find your way around?

The sun is one of the biggest threats to skin health, especially scalp health. Exposing your shaved head to the sun on the beach or during a lunch break lasting more than an hour on a terrace requires applying sunscreen to protect your scalp. But what do you really know about your sunscreen?

Sunscreen protects against two types of UV rays, but there are actually three: UVA, UVB, and UVC. The latter, the most dangerous, are blocked by the ozone layer and are therefore not a concern for us. UVA rays penetrate the skin as far as the dermis, while UVB rays only reach the epidermis.

UVA rays accelerate skin aging, while UVB rays cause sunburn, which can lead to skin cancer even years later. Both types of UV radiation can damage cell DNA.

To fully understand everything that's in your sunscreen, first of all, what is an SPF?

What is an SPF?

SPF (or FPS) is an abbreviation for Sun Protection Factor. It's an indicator that assesses the level of protection offered by sunscreens against UVB rays , which cause sunburn. There are four levels of sun protection:

• SPF 6 to 10 (low);
• SPF 15 to 25 (average);
• SPF 30 to 50 (high);
• SPF 50+ (very high).

SPF refers to the percentage of UVB rays that the filter used in the cream blocks.

To better understand:

• SPF 15 blocks 93% of UVB rays;
• SPF 30 blocks 97% of UVB rays;
• SPF 50 blocks 98% of UVB rays;
• SPF 50+ allows you to block +98% of UVB rays.

However, there is no product that can block 100% of UV rays . That's why it's no longer permitted to write "total sunblock" on sunscreen.

Sunscreens are also supposed to protect against UVA rays. To ensure your sunscreen has passed the UVA test, look for the word "UVA" circled on the tube . For the UVA test to be valid, it must correspond to one-third of the SPF indicated on the label.

Mineral or chemical filter, what's the difference?

Whether your sunscreen contains chemical or mineral filters has no impact on its sun protection factor (SPF). As mentioned earlier, only the SPF and the UVA protection rating indicate this.

Mineral filters

Mineral filters are the only filters allowed in organic farming.

There are 2 mineral filters: titanium dioxide and zinc oxide.

These filters work like a “mirror” ; they don't penetrate the epidermis but are deposited on the skin to reflect the sun's rays. Because they are not absorbed by the skin, they are better tolerated and there is less risk of allergies.

Creams containing this type of filter are effective immediately upon application because they directly reflect the sun's rays.

Mineral filters would be less polluting for the oceans because they are resistant to water.

However, the disadvantage of using these filters is that they leave white streaks that are difficult to spread. This is why some manufacturers use nanoparticles to address this problem. And as you probably know, nanoparticles are harmful to the oceans and to our health.

Note : when filters are used in the form of nanomaterials (particle size between 1 and 100 nm), this is specified in the list of ingredients: the name of the filter is followed by [nano].

Chemical (or organic) filters

These filters penetrate the epidermis to absorb UV rays instead of the skin. However, the skin needs time to absorb the product, and the cream only becomes effective about 20 minutes after application.

Chemical filters, unlike mineral filters, do not need to be nanoparticles to have a smooth texture without white marks and most are waterproof, which limits their negative impact on the environment.

There are currently 25 chemical filters authorized in Europe. However, some are suspected of being endocrine disruptors, potentially carcinogenic, highly allergenic, or posing a potential danger to the environment.

Ex: 4-Methylbenzylidene Camphor, Benzophenone-3, Oxybenzone, Butyl Methoxydibenzoylmethane

While others are risk-free

Ex: Ethylexyl Triazone, Diethylamino Hydroxybenzoyl Hexyl Benzoate, Diethylhexyl Butamido Triazone, Bis-Ethylhexyoxyphenol Methoxyphenyl

Other active ingredients present in sunscreens

In addition to UV filters, sunscreens contain other active ingredients to complement the care given to the skin during sun exposure.

They can therefore contain a moisturizer to counteract the drying effects of UV filters, or an antioxidant or an anti-aging active ingredient to prevent pigment spots or premature skin aging.

A cream containing a lipid-replenishing agent helps to restore the skin's barrier function.

To be perfectly suited to shaved heads, BOTAK Sunscreen contains antiseptics (antibacterial and anti-inflammatory) to treat micro-lesions of the scalp damaged by clippers or razors, skin flora regulators and antioxidants to prevent premature skin aging.

BOTAK's choice

At BOTAK, for our Sunscreen, we have chosen an SPF 30 (actually 34) and our UVA protection corresponds to 2/3 of our SPF , therefore beyond the regulatory 1/3, to ensure you optimal protection.

Regarding the choice of SPF, this decision was made after observing that achieving SPF 50 or 50+ required the use of harmful, even dangerous, filters and increased concentrations. Furthermore, the difference in UVB protection percentage between SPF 30 and 50 is only 1 point. We therefore preferred SPF 30, and emphasized the importance of reapplying the product every two hours, to SPF 50, which can give the false impression of constant protection, leading users to forget to reapply sunscreen.

We have chosen 3 chemical filters.

Why chemical filters?

After several tests, this choice allowed us to obtain a pleasant texture, easy to apply and without white traces , without being nanoparticulated.

Why these three chemical filters?

Our 3 filters: Ethylhexyl Triazone, Diethylamino Hydroxybenzoyl Hexyl Benzoate and Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine

Our filters exhibit excellent photostability (meaning they retain their protective effects despite exposure to UV rays, unlike photodegradable filters which degrade in sunlight), have excellent absorption capacity, and offer broad-spectrum UVA and UVB absorption. The chemical filters we use are safe; they contain no suspected allergens or endocrine disruptors .

Why only three filters?

The more filters there are, the greasier the cream becomes and can give an “oily” effect.

We therefore opted for a cream that is effective, pleasant and non-harmful .

Our tips for summer

A tube of sunscreen should not be kept from one summer to the next. In addition to the PAO (Period After Opening) which indicates the number of months you can use the product after opening, sunscreens are generally left in the sun on the beach, which inevitably leads to bacterial growth.

It is worth remembering that even if you use a sun protection product, overexposure is a serious health threat.

Finally, it is important to reapply sunscreen every two hours to maintain optimal protection, regardless of the SPF.