UVB and UVA rays make up our earthly atmosphere. UVB rays represent just 5% of the entire spectrum, and they stay near the skin’s surface. UVA rays make up the remaining 95% of the spectrum, and they penetrate deeper into our skin, going far below the surface. We absorb them whether it’s sunny or cloudy, whether we’re out in the open or under a beach umbrella or next to a window. We receive UVA radiation every single day.

When UVB rays hit our skin, they can produce a short-term and visible effect, and damage to our skin more often than not is mild. We can get sunburned, and then our skin peels. UVA rays, on the other hand, can cause long-term, not immediately visible effects – and damage can be much greater. UVA rays provoke oxidative stress below the surface of our skin. This can produce lesions in skin cell DNA. The lesions can lead to premature ageing and the risk of skin cancer. 

Sun rays effect

UVB rays play an important role in skin’s self-defence mechanisms when exposed to the sun. As skin reddens, this is a signal for it to turn on its own biological defences:

Skin produces melanin, which gives us our tan and protects against burning.

The epidermis thickens to protect inner layers.

A number of internal processes are launched to reduce oxidative stress, repair DNA lesions and generate an immune system response to remove compromised cells.

In other words, skin’s reaction to UVB rays is how it defends itself from the far more serious effects of UVA rays.


A high SPF sunscreen doesn't provide full protection

That’s what we thought for a long time, that a high Sun Protection Factor (SPF) provided an ample shield from the sun. SPF, however, refers to UVB protection only.

Except that… UVB rays represent just 5% of our sun exposure. Sunscreens block 98% of those rays. Meaning that 2% of UVB reach the skin. And the other hand 95% of our sun exposure are composed by UVA rays and sunscreens let between 11 and 15% of them reach the skin.

Not only that, but when sunscreens block all UVB rays, they prevent skin from receiving the signal to protect itself. This leaves skin prone to long-term damage from further sun exposure.

  • Professor Sergio Schalka, Dermatologist and Photoprotection expert in Brazil.

    When sunscreens were first developed, they were designed to protect against sunburn , meaning they protected against UVB. And they still provide better UVB protection than UVA protection, even though we now know the effects of UVA on the skin. 

    Professor Sergio Schalka, Dermatologist and Photoprotection expert in Brazil.

So, your sunscreen also needs to provide UVA protection... What about traditional sunscreens on the market? Traditional sunscreens provide this protection in two ways:

In Europe, this is indicated on the label with ‘UVA’ in a circle. To be able to use this symbol, the UVA protection must be equal to at least one third of the UVB protection, in accordance with European regulations. This means protection against UVA rays is not optimal, and this create an imbalance between UVB and UVA rays protection. 

Typically, others traditional sunscreens that want to reach a higher UVA index include a high number of filters at higher concentrations to be able to block UVA rays effectively. With the higher number of ingredients, skin is overloaded and there is also a higher risk of skin being irritated by the sunscreen. Which means it won’t be used, and that’s the worst option of all.

To summarise, sunscreens with near-complete UVB protection are providing short-term protection – no sunburn – without taking into account the long-term protection that is needed – preventing premature ageing and the risk of skin cancer. This creates an imbalance in the skin’s defence mechanisms. Maintaining an equilibrium in all parts of the skin’s ecosystem is important for long-term health.

Furthermore, a sunscreen that is formulated using just those ingredients that are necessary and at the right dose is more likely to be tolerated by skin, making it pleasant to use as often as needed. 

Sunscreen with UVA protection

Sun active defense

As a NAOS brand, Laboratoire BIODERMA considers the skin as part of an ecosystem that is in constant interaction with its environment. A number of internal and external factors can impact this ecosystem. Taking inspiration from skin’s natural biology to preserve and restore the ecosystem’s balance, Bioderma responds to skin’s needs while also strengthening its own defence mechanisms. Skin is better able to lastingly preserve its health.

Bioderma collaborated closely with dermatologists and photobiologists to create high-technology sun protection SUN ACTIVE DEFENSE. Combining fewer filters with advanced patented biological protection, it offers a UVB block and a reinforced UVA shield, and strengthens the skin’s antioxidant defence and immune systems.


Rather than overloading skin by multiplying filters, Laboratoire BIODERMA works with only eight among the 32 that are authorised by the European Union. These filters were specifically chosen because : 

  • They respect the body, and are not endocrine disruptors.
  • They respect skin. According to an exclusive NAOS study, they are recognised as neither irritants nor pollutants.
  • They respect the planet, being neither toxic nor bioaccumulative.
  • They have the lowest environmental impact, as measured on aquatic ecosystems.



Complementing the filters is a patented method of providing antioxidant and immune system protection, inspired by skin’s biology. Damage that could result from UV exposure is limited, helping to prevent premature ageing and skin cancer from developing.

SUN ACTIVE DEFENSE is included in the formulation of all of BIODERMA’s Photoderm products and is one of the four pillars of the range. Photoderm is therefore the first sunscreen range to stimulate the skin’s natural defence mechanisms and prevent skin’s cell alteration and oxidative stress.

+26% protection against oxidative stress1

+24% protection of skin immune defenses1

By keeping all parts of the skin’s ecosystem in balance and stimulating the skin’s own biological defence mechanisms, Photoderm boosts the skin’s own protection and lowers the risk of skin cancer developing.

1Clinical study on 10 subjects, phototypes II and III, under sun exposure. Evaluation of several biomarkers to assess the complementarity of filters and ectoin + mannitol on the antioxidant and immunosuppression protection. Poland, 2021.

Good to Know

The Photoderm range provides very high protection for skin, shielding both UVA and UVB rays. With fewer rays absorbed by skin, there is less oxidative stress at deeper layers of the epidermis. Skin cell DNA is therefore better protected from developing lesions. And skin cell immune response is maintained.

Choose from a wide selection of dermatological sun care products that are tailored to all members of the family, from the youngest to the oldest, and to needs as diverse as sensitive skin, acne-prone skin, redness and hyperpigmentation problems.