(Photo : Pexels/ Mikhail Nilov)

The amount of sunscreen ultraviolet filters (UVF) rinsed off while swimming in the ocean varies based on the product's formula, a new study has found.

Neutrogena parent company Kenvue conducted a study, in collaboration with nonprofit applied science and technology organization Battelle, on the rinse-off levels of certain sunscreens to determine how much product seawater removes from the skin while users are in the ocean.

For the study, published in the International Journal of Cosmetic Science, Kenvue looked into the difference between oil-in-water sunscreens and water-in-oil and waterless formula types to test which ones have more rinse-off.

Kenvue's research found that water-in-oil and waterless sunscreens had 5% or less of the applied UVF rinsed from the skin after 40 minutes of bathing in the seawater during simulated tests.

On the other hand, oil-in-water sunscreens were found to have up to 20% rinse-off during testing.

The findings suggested that sunscreens made without water or are water-in-oil-based are expected to last longer while swimming in the ocean.

Kenvue said the 22 combinations of UVF and sunscreen formulations it tested did not exhibit more than 20% rinse-off. Of the total, 19 had less than 10% of the applied UVF rinsed from the skin.

Previous research had suggested that 25% to 100% of applied UVFs may rinse into seawater.

The new study can help identify what sunscreen makers need to improve in their products' formulas to bring less rinse-off and what ingredients to keep to make sure consumers are getting long-lasting sunscreen.