How do I apply a sun stick?

Sunscreen sticks are very popular because they offer a convenient sun protection solution, especially during travel. However, many people are not familiar with optimal application techniques that ensure full SPF coverage with these products. Most of these sunscreens often have very small packing footprints that arguably render it difficult for the average user to know exactly how much sunscreen has been applied on their skin. Sunscreens hold the key to sun protection under one most important rule - the right application. The requirement for a sun stick is that it should be applied in a much more careful manner than some lazy swipe across skin.

An approximate one ounce (about 28 grams) measure is recommended for the application of the sunscreen to cover the entire body, with around a nickel-sized amount for the face alone. With that, it is assured that the amount of application provides the protection warranted by the SPF level. For a sunscreen stick, the difficulty is that it's very much possible to underestimate how much would be required for covering everything properly. Each pass of the stick doesn't necessarily equal a layer of full coverage, and there's a real risk of incomplete coverage, especially along those tricky boundaries, like hairline and eyebrows.

It is also essential to know that not just a few swipes are needed for complete coverage. This manner of application is important in attaining how effective the sunscreen will be on the skin. From studies about sunscreen use, it has been noted that typically at least four passes of the sunscreen stick into the surface of the skin will guarantee coverage, but this cannot be generalized, as it mostly depends on the formula of the sunscreen and the texture of the skin.

To use the sunscreen stick correctly, you should apply the stick over the skin gently, in strokes, covering the most highly exposed areas of the skin such as the forehead, cheeks, nose, and chin. Also, don't forget the often-ignored areas - ears, neck, eye contour and under the chin. With each area of application, build up additional coverage. Overlapping strokes are a good idea because they guarantee that no area will be missed while ensuring even coverage over the skin.

Stick formulation usually vary from drier to thicker. If the stick feels dry or drags on the skin, then less product might be picked up, even with multiple passes. Some formulas cut through the skin so easily that generous applications can be given in one single pass. An extra edge in coverage can come from remembering to press down on the skin after each pass, helping the product sink in and spread evenly. 

It is also very important to reapply the sunscreen stick every two hours or immediately after swimming or sweating. The sunscreen stick is resistant to water, but with towel rubbing or in-water exposure, it wears off sooner. The proper reapplication of sunscreen should be considered important the same way as the first application is. A quick swipe here and there will not cut it when it comes to maintaining adequate sun protection throughout the day - you need to apply the stick patiently and carefully in the same way as the first time. The same rule applies if people decide to use sunscreen stick for reapplication, after applying some other cream or lotion before swimming or going outside. With this approach, you should get the most out of your sunscreen stick in protecting your skin from harmful UV rays.

The differences in the sun protection that different application techniques give have also been discussed in a recent study published in the International Journal of Cosmetic Science. It is an in vitro study that looks at the influence of application methods on the effectiveness of sunscreen sticks. Due to their waxy solid parts, sunscreen sticks require different techniques of application from creams or sprays. This complicates uniform and sufficient coverage. The study showed that the amount of product deposited on the body surface depends on the number of front-and-back passes applied during use. One stroke failed to ensure a uniform protective film and resulted in SPF figures that were significantly below those marked on the product. A minimum of four back and forth strokes for a layer equivalent to about 0.75 mg/cm² were required before a more accurate comparison could be made with the conditions of the laboratory SPF tests. 

In addition, application pressure determined film thickness and uniformity. To facilitate the examination of the efficacy of a product by end users in the outdoors, the researchers proceeded to develop and validate a protocol of several passes in different directions with SPF measured using a hybrid diffuse reflectance spectrometry (HDRS). The findings emphasized that the behavior of users is essential for the effectiveness of photoprotection using sunscreen sticks and suggested that directions for application should state how many strokes users need to make in order to apply enough product to achieve intended UV protection at recommended levels.

• COIFFARD L. J. M. & al. Adaptation of the protocol for determining in vitro the sun protection factor of anti‐solar sticks. International Journal of Cosmetic Science (2008).

• UNICE K. & al. Factors that influence sunscreen application thickness and potential preservative exposure. Photodermatology, Photoimmunology & Photomedicine (2015).

• ARAÙJO E. M. & al. Analysis and characterization of stick sunscreens available in the Brazilian market. 6th Electronic Conference for the Faculty of Pharmacy Graduate Program – UFF (2024).

• NEHA P. & al. Formulation and development of sunscreen stick by calendula oil. Journal of Biotechnology and Food Engineering (2024).