How to Reapply Sunscreen: How Often, and Over Makeup
How often should you reapply sunscreen? Every two hours while you are outdoors, and immediately after swimming, towel drying or heavy sweating, whatever the bottle says about water resistance. The bigger problem is quantity, not timing. SPF is certified at 2 mg of product per square centimetre of skin, which is about a quarter of a teaspoon for the face and neck and roughly six to eight teaspoons for a whole adult body, and most people apply between a quarter and half of that. Reapplying is partly how you make up the difference.
Key takeaways
- Reapply every two hours outdoors, and straight after swimming, towelling or sweating heavily.
- Use about a quarter of a teaspoon for the face and neck, and six to eight teaspoons for the whole body.
- Under application is the main reason real world SPF falls far short of the number on the bottle.
- Water resistant is a timed claim, not a permanent one, so reapply after time in the water regardless.
- Over makeup, a stick, a cushion compact or a pressed sponge layer delivers more product than a quick dusting of powder.
- The parting on your scalp burns easily and is the single most missed spot on the body.
How often should you reapply sunscreen?
Every two hours of sun exposure is the standard interval in UK and international guidance, and it is not because the filters expire on a timer. Sunscreen comes off. It is rubbed away by clothing and towels, diluted by sweat, transferred onto phone screens and sunglasses, and thinned by the simple act of touching your face.
Reapply sooner than two hours if you have been swimming, towelled yourself dry, sweated heavily, or wiped your face. Indoors and away from windows, reapplication matters much less. If you sit beside a window all day, note that ordinary window glass blocks most UVB but lets UVA through, so a morning application is still worth having on the side of your face nearest the glass.
How much sunscreen should you actually use?
This is where most protection is lost. The SPF number on a bottle is measured in a laboratory at 2 mg of product per square centimetre of skin. Translated into kitchen measures, that is roughly a quarter of a teaspoon for the face and neck, and six to eight teaspoons, or about 35 ml, to cover an adult body in swimwear.
Studies of how people apply sunscreen in real life consistently find they use somewhere between a quarter and a half of the tested amount. Because the relationship between thickness and protection is not linear, applying half the dose does not leave you with half the SPF, it leaves you with considerably less. An SPF 50 applied thinly can perform closer to a low SPF product.
Two practical fixes. Use the two finger rule for the face, meaning a line of product along the length of your index and middle fingers. And apply twice before you go out, a few minutes apart, which is what UK dermatology guidance recommends and which reliably gets more product onto the skin than a single hurried layer.
Does water resistant sunscreen need reapplying?
Yes, and the label tells you when if you read it as a timed claim. Water resistance is tested by immersing treated skin for set periods, and products are labelled accordingly, commonly as 40 or 80 minutes of water resistance. Nothing is waterproof, and no sunscreen survives a towel.
So the rule is simple: reapply after swimming, after any water sport, and after drying yourself, even if you were only in the pool for ten minutes. Sand, seawater and friction from a towel all strip product mechanically, which no formulation can prevent.
How do you reapply sunscreen over makeup?
You have four workable options, and they are not equal. What you want is a method that delivers a meaningful amount of product without dragging your base off.
| Method | How it works | Realistic verdict |
|---|---|---|
| Sunscreen stick | Swipe several passes over each area, then press in with fingertips. | Best all round. Delivers real product, minimal disturbance, easy to carry. |
| Cushion compact SPF | Press a tinted sponge layer over makeup rather than sweeping it. | Very good, and it refreshes coverage at the same time. |
| Liquid SPF on a damp sponge | Stipple, never rub, so the layer beneath stays put. | Effective and cheap. Slower, and it needs a careful hand. |
| Brush on powder SPF | Dust from a brush tube in small circular motions. | Convenient top up only. A few seconds of dusting cannot reach the tested dose. |
| SPF setting spray | Mist held at arm's length, usually needing several passes. | Weakest option. Very hard to deposit an even, adequate layer. |
Powder deserves its own note because it is so heavily marketed as a reapplication solution. It is a genuine convenience, but manufacturers' own guidance points at something like a full minute of application, worked over the face in sections, to approach the labelled protection. Almost nobody does that at a bus stop. Treat powder as a partial top up on a day you are mostly indoors, not as the layer standing between you and a beach. We covered this in detail in our guide to whether powder sunscreen actually works, and the companion piece on applying sunscreen under makeup without pilling covers the base layer.
What is the best order for skincare, sunscreen and makeup?
Sunscreen goes on last in skincare and first before makeup. Cleanse, treat, moisturise, then sunscreen, then wait two to three minutes for the film to set before any foundation touches it. Rushing that pause is the most common cause of pilling, those little rolls of product that appear under a sponge.
Through the day, work in the opposite direction. Blot excess oil with a tissue first, then add your SPF top up, then touch up powder or blusher if you need to. Trying to reapply sunscreen onto a shiny face guarantees slipping and patchiness.
Which spots do people miss when they reapply?
The same ones, every time. Studies using UV photography show consistent gaps, and they line up with where skin cancers are commonly found.
- The scalp parting. Hair does not shield the skin where it is parted, and this is the most missed area on the body.
- Ears, and behind them. Easy to forget, frequently sunburnt.
- The eyelids and under eyes. Use a stick or a formula labelled for the eye area, applied carefully.
- Lips. They have almost no melanin. An SPF lip balm reapplied after eating and drinking is the answer.
- Back of the neck and hands. Both accumulate a lifetime of exposure.
- Tops of the feet. Ignored on every beach in Britain.
See a doctor about changing moles. Any mole that changes in size, shape or colour, itches, bleeds, or looks different from your others should be checked by a GP. Sunscreen advice is prevention. It is not a substitute for having something looked at, and skin cancer is far more treatable when it is found early.
Does sunscreen matter on a cloudy UK day?
Yes, when the UV index is 3 or above, which in the UK happens on plenty of overcast days from roughly April to September. Cloud scatters visible light more than it filters ultraviolet, so a grey day can still carry meaningful UV. The practical habit is to check the UV index in your weather app rather than judging by how bright it feels.
Below UV 3, most people do not need daily sunscreen for burn protection, though those with a history of skin cancer, photosensitivity or pigmentation concerns are often advised to wear it year round. That is a conversation for your GP or dermatologist rather than a blanket rule.
What about your hair and scalp in the sun?
Two separate problems get bundled together here, and they need different answers. Your scalp is skin and it burns. Your hair is not living tissue, so it does not burn, but it does degrade.
For the scalp, the honest options are a hat, a parting that you move from day to day, or a sunscreen designed for use in hair, usually a spray or a light fluid. Ordinary facial sunscreen works on an exposed parting if you can tolerate the texture, and it is far better than nothing.
For the hair itself, ultraviolet light degrades keratin and strips colour, which is why hair feels drier, rougher and more brittle after a summer holiday. Salt water and chlorine compound it by swelling and roughening the cuticle. None of that is dangerous, it is a cosmetic problem, and it is largely preventable: rinse hair with fresh water before swimming so it absorbs less pool or sea water, tie it up, and deep condition afterwards. Our guide to protecting hair from sun, salt and chlorine goes further, and our piece on what causes hair damage covers the repair side.
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A deep conditioning treatment with argan oil, provitamin B5 and rosemary for hair left dry and rough by sun, salt and chlorine. Use once a week after a holiday, or weekly through the summer.
To be clear: this is a conditioning mask with no SPF. It does not protect your skin or scalp from UV, and it is not a substitute for sunscreen or a hat.
A simple reapplication routine for a day out
- Before you leave: apply generously, then apply a second layer a few minutes later. Include ears, neck, parting and the tops of your feet.
- On arrival: top up anything you rubbed off in the car or on the train, especially forearms and the back of your neck.
- Every two hours: reapply properly, using a stick or cushion on the face if you are wearing makeup.
- After every swim or towel dry: reapply immediately, no matter what the label promised.
- Peak hours, roughly 11am to 3pm: add shade, a hat and a shirt. Sunscreen is one layer of protection, not the only one.
- That evening: cleanse thoroughly, rehydrate the skin, and deep condition hair that has been in sea or pool water.
Frequently asked questions
How often should you reapply sunscreen?
Every two hours while you are outdoors, and immediately after swimming, towel drying or heavy sweating. Indoors and away from windows the need drops sharply. The interval exists because sunscreen is physically removed by friction, sweat and water, not because the filters stop working.
How much sunscreen should I use on my face?
About a quarter of a teaspoon for the face and neck, which matches the two finger rule, a line of product along your index and middle fingers. That is considerably more than most people apply, and under application is the main reason real world protection falls short of the SPF on the label.
Do I need to reapply sunscreen if I am indoors all day?
Usually not, unless you sit beside a window. Ordinary window glass blocks most UVB but transmits UVA, which contributes to ageing and pigmentation. If you work next to glass, a morning application is worthwhile, and people managing melasma are often advised to be stricter.
Is powder sunscreen enough on its own?
No. Brush on powder is a top up, not a base layer. Reaching the labelled SPF requires far more product and application time than a quick dusting delivers, so powder works best over an existing liquid layer on days you are mostly indoors.
Does SPF in makeup or moisturiser count?
Only partly. Foundation and moisturiser with SPF are applied far too thinly to reach their tested protection, and they are rarely reapplied. Treat them as a bonus on top of a dedicated sunscreen rather than as your protection for the day.
How do I put sunscreen on my scalp?
Use a spray or light fluid designed for use in hair, or apply ordinary sunscreen along an exposed parting. A wide brimmed hat is the easiest option of all. The parting is the single most commonly missed area on the body and it burns readily.
Does sunscreen expire?
Yes. Check the expiry date and the period after opening symbol, usually twelve months for sunscreen. Heat degrades formulas, so a bottle that has spent a summer in a hot car is best replaced. If the texture has separated or the smell has changed, discard it.
Can sunscreen cause hair loss?
No evidence links sunscreen to hair loss. Product build up on the scalp can cause irritation or flaking, which is a washing frequency issue rather than a shedding one. Persistent, sudden or patchy hair loss should be assessed by a GP or a trichologist.
The bottom line
Reapplication is the least glamorous part of sun protection and the part that decides whether the number on the bottle means anything. Apply enough, apply twice before you leave, top up every two hours and after water, and choose a stick or a cushion for topping up over makeup. Then remember your parting, your ears and your lips.
For hair that has taken a summer of sun, salt and chlorine, the fix is conditioning rather than protection. Masque Me® Hair Mask is a vegan, UK made deep conditioning treatment for dry, roughened lengths. Watermans has sold over 5 million bottles since 2012.
