Sun protection when sunscreen is not enough

Section 01

Why this half gets ignored

Sunscreen is a product with a margin, so it gets advertised, reviewed and argued about. Shade and long sleeves are not products anyone needs to sell you, so they get a sentence at the end of an article.[3][4]

That distribution of attention is backwards relative to the evidence. Sunscreen protection depends entirely on applying enough, everywhere, and reapplying, which is exactly where people fail. A sleeve does not have that failure mode.[4][1]

Section 02

Clothing, and what the ratings mean

Fabric is rated by how much ultraviolet light it lets through. A rating of 50 means roughly one fiftieth gets past. Unlike sunscreen, that protection does not depend on how thickly you applied it or how long ago.[2]

The caveats are worth knowing. Ratings are measured on new, dry, unstretched fabric. Wet cloth protects less, stretched cloth protects less, and worn cloth protects less. A white cotton t-shirt is around a rating of five when dry and considerably worse when wet.[2]

You do not need to buy specialist clothing. Tight weaves, darker colours and looser fits all help, and holding fabric up to a light tells you most of what you need to know.[2][3]

Section 03

The trial worth knowing about

Across Australian childcare centres, children were dressed in sun-protective clothing covering at least half the body, every day, for several years. Researchers then counted moles.[1]

The clothed group developed meaningfully fewer moles than the comparison group. Mole count tracks cumulative childhood sun exposure and is associated with later melanoma risk, so this is a concrete result rather than a surrogate measurement of skin redness.[1]

Very little in sun protection has evidence of this quality. It is a cluster randomized trial with a hard outcome, run over years, and its conclusion is that covering children up works.[1][2]

Section 04

Shade and timing

Shade helps and it is not a wall. Ultraviolet light scatters through the atmosphere and bounces off sand, water, snow and pale concrete, so you can burn under an umbrella on a bright beach.[3][2]

Timing is the cheapest intervention available. Ultraviolet intensity peaks around the middle of the day and falls away sharply either side, so shifting a walk or a swim to the early morning or later afternoon cuts exposure at no cost.[3][5]

• Check a ultraviolet index forecast rather than judging by temperature; cool bright days can be high.[3]
• Treat shade as reducing exposure, not removing it, especially near water or pale surfaces.[2]
• A wide-brimmed hat covers ears and neck, which caps and visors leave exposed.[3]
• Sunglasses that block ultraviolet protect the eyes and the thin skin around them.[2]

Section 05

Putting it together

The sensible arrangement is layered. Timing and clothing carry most of the load, shade adds to it, and sunscreen covers what is left uncovered: face, neck, hands and anything a sleeve does not reach.[3][2]

Used that way, sunscreen has to do far less work, which conveniently makes its known weaknesses matter far less too. That is the real answer to the year of recalls and label doubts.[4][1]