Sun protection · Expert care

SPF is not the whole story: how to read PA++++ and choose a filter that truly protects the skin

The SPF number on the label tells only half the truth. We explain the difference between UVB and UVA protection, when mineral filters make sense, and when they lose out to hybrid ones — and why after treatment, PA++++ is non-negotiable.

Expert care·read 10 min·J'ADORE INSTYTUT

Most clients choose a filter based on one number — SPF. Meanwhile, the label of a good sunscreen tells more: the type of filter, the spectrum of protection, the PA symbol. Ignoring this second half of the information is the most common reason why skin continues to discolor, loses firmness, and ages faster despite a "high SPF". We break down the label into its components — without marketing simplifications, clearly distinguishing what each number and letter really means.

SPF and PA are two different counters — for two different radiations

SPF (Sun Protection Factor) describes protection solely against UVB radiation — the waves responsible for sunburn and direct damage to the epidermis. The index is calculated by comparing the time it takes for skin to redden with and without the filter. SPF 50 does not mean "50 times stronger protection" — it means an extended time to burn in a specific, laboratory test.

The problem is that UVB is only part of the radiation that reaches the skin. UVA — longer waves, present all year round, penetrating even through car windows or office glass — penetrate deeper, into the dermis. They are responsible for photoaging, loss of firmness, and, crucially for many clients, for exacerbating discoloration and melasma. SPF practically does not measure them.

This is where PA (Protection Grade of UVA) comes in — a Japanese-Korean labeling system, increasingly present on cosmetics available in Europe, based on the PPD (Persistent Pigment Darkening) test, which measures the time to permanent skin darkening under UVA. The scale ranges from PA+ to PA++++ — the more pluses, the higher the level of UVA protection. PA++++ is the highest category available in this system. A cream with a high SPF alone, but without a PA designation or with low PA, may protect against burning while not protecting against discoloration.

Chemical, mineral, and hybrid filters — how they differ in practice

The type of filter determines how the product works on the skin, how it wears under makeup, and whom it may irritate. These are three different physical mechanisms, not a question of "better versus worse".

• Chemical (organic) filters — absorb UV radiation and convert it into heat. Lightweight, imperceptible consistency, no white residue, easy to spread under makeup. They start to work fully only after about 15–20 minutes after application and may cause irritation in some people with reactive skin.
• Mineral (physical) filters — zinc oxide and titanium dioxide reflect and scatter radiation on the skin's surface. They work immediately upon application, are usually better tolerated by sensitive, vascular skin and skin post-treatment — but can be thicker in texture and may leave a white residue, especially on darker skin tones.
• Hybrid filters — combine chemical and mineral filters in one formula. This solution is what most professional Korean brands, including the Cell Fusion C sunscreen line available in our store, are opting for today: the chemical part ensures lightness and invisibility on the skin, while the mineral part ensures gentleness and a broad spectrum. The effect is protection without cosmetic compromise, without the "mask" effect characteristic of pure mineral filters.

Note when reading labels: in the names of some lines — like Aquatica Sunscreen 100 or Derma Relief Sunscreen 100 — the number "100" is the name of the manufacturer's cosmetic series, not the SPF value. The actual, tested protection of these products is SPF 50+/PA++++, in accordance with the EU labeling limit — in the European Union, the highest allowable declaration on the packaging is "50+", regardless of how high the formula would score in the test.

How to choose a filter for your skin

Choosing a filter is not a matter of fashion, but a response to one skin problem:

• Sensitive and vascular skin — hybrid or mineral formula, without alcohol and intense fragrances, with soothing ingredients (e.g., centella extract, panthenol).
• Discoloration and melasma — the priority is maximum PA++++, because UVA (and partially visible light) drives melanin production. SPF alone is not enough — without high PA, discolorations will return despite regular use of the cream.
• Acne-prone and oily skin — lightweight, mattifying formulas without comedogenic oils, labeled as non-comedogenic.
• Skin post-treatment from the clinic (laser, peeling, microneedling, microneedling radiofrequency) — this is a situation where PA++++ stops being an option and becomes a necessity. The skin barrier is weakened, melanocytes are overactive, and even short exposure to UVA can cause post-inflammatory hyperpigmentation (PIH), which will permanently undermine the effect of the treatment.

Laser UV SunscreenPost-laser and microneedling — skin requiring regenerationSee product → Advanced Clear SunscreenAcne-prone and oily skin — lightweight, mattifying formulaSee product → Aquatica Sunscreen 100Daily protection, lightweight consistency, no white residueSee product →

Derma Relief Sunscreen 100Very sensitive and vascular skin — soothing formulaSee product → Sunyses Protect & RepairProtection with a regenerating component — support after aesthetic medicineSee product →

How much to apply and when to reapply

The effectiveness of the filter on the label was measured at a dose of 2 mg per cm² of skin — in practice, most people apply even three times less, which realistically lowers the declared SPF to several times lower than what is written on the packaging. A simple way to measure the right amount is the two-finger rule: two lines of cream squeezed along the index and middle fingers is the dose for the face and neck. This is more than most people intuitively apply.

Reapplication is just as important as the first layer. The filter — regardless of type — loses effectiveness after about 2 hours of sun exposure, and earlier if sweating, bathing, or rubbing against clothing or a mask occurs. During the day in an office by a window or in a car, the risk of UVA is lower, but not zero — therefore, during longer exposure, reapplication remains a rule, not a suggestion.

SPF and makeup — how to reconcile it without extra steps

Foundation or powder with SPF is a nice addition, but in practice, it does not replace a separate filter — to achieve the declared protection from makeup alone, you would have to apply it in an amount that would look like a mask on the face. The proper order is: skincare → filter as the last step of skincare → only on top of it the base for makeup and foundation. Reapplication during the day is most conveniently done in the form of a mineral powder with SPF or a mist applied over finished makeup — without the need to remove cosmetics.

Three myths about filters worth debunking

"SPF in my day cream is enough"

Skincare creams with filters usually have lower SPF (15–20) and are designed for incidental, short exposure — not for real protection throughout the day. Additionally, they are applied in a thin layer, like a regular cream, not in a test dose. A dedicated filter, a separate step in skincare, in the right amount — is the only way for protection to actually work as the label claims.

"On a cloudy day, I don't need to apply"

Clouds block part of the visible light, but even up to 80% of UV radiation penetrates through cloudy skies. UVA is present all year round, regardless of the weather and time of day, and also penetrates through glass — which is why a filter is also required in winter and in an office by a window, not just on the beach in July.

"Mineral filter is always safer for sensitive skin"

This is only partially true. A well-designed hybrid formula — like the professional Cell Fusion C lines used in clinics — can be equally well tolerated, while being lighter to wear and without the whitening effect. Tolerance depends on the entire formulation and soothing additives, not just the type of UV filter.

Frequently asked questions

This material is educational and does not replace a cosmetic consultation or medical advice. The SPF and PA designations are standardized laboratory indicators provided by manufacturers in accordance with applicable labeling standards. Choosing a filter, especially after treatments from the clinic or with a tendency to discoloration, should be consulted with a specialist. The images depict original products available in our store.