Dermatologist warns most people use far too little sunscreen

Most people apply far less sunscreen than needed, according to dermatologist Carl Kyrklund of Helsinki’s Skin Hospital, speaking to Yle.

For the face and neck alone, the correct amount is two finger-widths of product. For an adult’s entire body, the recommended dose is two tablespoons.

Applying too little means the stated SPF rating will not be achieved. Reapplication is also essential: official guidance is every two hours, and immediately after swimming or sweating. Higher SPF products like 50 offer longer protection if applied sufficiently, but lower SPF ratings such as 30 require especially careful reapplication.

Kyrklund advises applying two layers in the morning to avoid unprotected patches. The amount is correct when the skin appears slightly white before the product absorbs.

Spray oils and aerosols are often under-applied. Kyrklund recommends spraying the product into the palm first, then spreading it evenly, ensuring the same quantity as with cream-based sunscreens.

He cautions against new serum sunscreens in dropper bottles, as the small doses can mislead users into applying too little.

All skin types should use high SPF, he says. While fair-skinned individuals are more prone to melanoma, darker skin also benefits from strong protection, including for even pigmentation.

Sunscreen can be layered with other skincare products, applied after moisturiser has absorbed. It can also replace moisturiser for normal skin types. Makeup is typically applied over sunscreen, though some products allow sunscreen to be applied on top of makeup.

Sunscreen expires 12 months after opening. Kyrklund recommends buying a new product each year, as heat exposure—such as leaving a bottle in a hot car—degrades effectiveness. An expired product is still better than none, but may not deliver the stated protection.

In Finland, UV levels reach 3 or higher from May onward, meaning sunscreen should be used throughout the summer months. The UV index can be checked via the Finnish Meteorological Institute’s website.