How much sun cream you’re actually meant to use

Every summer the arguments about sun cream are about the ingredients. The thing that actually decides whether yours works barely gets a mention, so let's start there.

SPF is tested with a generous layer. Most of us apply a quarter of it, maybe half. Researchers at King's College London found people using SPF 50 the way people really use it were getting roughly 40% of the protection printed on the bottle. The product didn't fail. There just wasn't enough of it on.

In teaspoons, for an adult:
Face and neck: half a teaspoon
Each arm: half a teaspoon
Each leg: one teaspoon
Front of body: one teaspoon
Back of body: one teaspoon

Six to eight teaspoons for a whole body — around 30–40ml — every time. A 200ml bottle is about five full applications. If yours lasted the whole holiday, it wasn't really working.

Then again every two hours, and after swimming or towelling off. Towelling is the one everyone skips.

What makes a good one

Two things you can check standing in the aisle.

The UVA logo in a circle. In the UK that's a regulated standard — UVA protection is at least a third of the SPF on the front. Most words on a sun cream bottle mean nothing in law. That circle does.

The word (nano) in the ingredients. UK law requires it to be printed when the particles are nano-sized. No bracket means non-nano. Two seconds, done.

And while you're there — SPF 30 or 50 is plenty. Higher numbers give less back than the label suggests, and can make people feel invincible.

Mineral or chemical

Mineral filters — zinc oxide and titanium dioxide — are a genuinely good choice. Kind to sensitive skin, good for small children and rosacea, and they work the moment they're on.

Chemical filters aren’t the villains they’re painted as. You’ll see oxybenzone, octinoxate, homosalate and octocrylene named on plenty of “avoid these” lists online — but every filter has to be approved before it can be used here at all, and the restrictions that do exist come from precautionary safety-margin calculations, not evidence of harm at the levels used. Britain runs a positive list, a stricter starting point than most people assume.

So if a mineral one suits your family, choose it because it suits your family, not out of fear of the other.

One thing worth knowing: a mineral sun cream can never be fully organic. Zinc oxide is a mineral — it was never alive, so it can't be organically farmed. Around half organic is the ceiling, not a shortcoming.

Two I checked properly

Not from their websites — from the Soil Association's public register.

Green People, West Sussex. Certified COSMOS Organic, licence CS07907. Non-nano zinc oxide. One trap: they sell two similarly-named products, and only the Mineral Sun Cream is fully mineral — read the product name, not just the brand.

Odylique, Suffolk. Certified COSMOS Natural, licence CN08954. 20% non-nano zinc oxide, around 53% organic.

Both licences belong to the company, not a single product. I can tell you the brand holds them — I won't tell you a specific bottle is certified unless I've seen that in writing.

Two scares you can put down

Hidden phthalates in fragrance. The chemicals behind this warning are already banned in UK cosmetics. The one still allowed in fragrance is a different substance, reviewed twice by safety assessors and cleared both times.

Benzene in sun cream. In 2021, testing found contamination in a batch of American aerosol sprays, traced to the propellant rather than the sun cream itself, and those specific products were recalled. Lotions don’t use a propellant, so the issue never applied to them at all. It was a manufacturing problem in one part of the market, caught and dealt with, not something to watch for in what’s on UK shelves today.

Most alarming sun cream advice online is written for a different country, with a different approved list and different problems.

Where this leaves us

The real, common risk is too little sun protection — not the filters in it.

Pick one your family will actually tolerate. Buy a bigger bottle than feels necessary. Put more on than feels necessary.

Wear it, and wear more of it than you think.