La Roche-Posay Anthelios UVmune 400 Invisible Fluid SPF50+
Last updated: 4 October 2026
The Anthelios UVmune 400 Invisible Fluid is La Roche-Posay's SPF50+ face sun cream for sensitive skin, a thin fluid in a 50ml bottle. Its Mexoryl 400 filter is built to block ultra-long UVA rays, the longest wavelengths that most filters cover poorly. On 4 October 2026 it cost £16.79 on Amazon UK, sold and dispatched by Amazon. La Roche-Posay's own UK shop listed it at £21 but was out of stock.
Buy Anthelios UVmune 400 on Amazon UK, £16.79
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What the UVmune 400 filter does
Sunlight reaches the skin as UVB, which burns, and UVA, which goes deeper and drives tanning and skin ageing. UVA runs from 320 to 400 nanometres, and the last stretch of it, close to 400, is called ultra-long UVA.
Mexoryl 400 is La Roche-Posay's own filter for that last stretch. The brand says the fluid's UVA protection is stricter than the European recommendation. It also says the Anthelios range has been tested in 16 clinical studies.
The fluid uses what La Roche-Posay calls Netlock technology. The filters sit in tiny droplets that link together on the skin, so the film stays even and does not slide into your eyes.
How it feels on the skin
It is a runny fluid rather than a cream, so you shake it and pour a little into your palm. It sinks in quickly and dries to a non-sticky finish.
La Roche-Posay says it leaves no white marks, does not sting the eyes and is suitable for every skin type and skin tone. It has been tested on contact lens wearers and is labelled hypoallergenic. It is also water, sweat and sand resistant, so it holds up on a beach day better than a light moisturiser with SPF.
If you want a little colour, the same fluid comes in a tinted version at £22 direct.
How to use it
Apply it as the last step of your morning skincare, before make-up, and use enough to cover your face, ears and neck evenly. For comparison, the NHS says an adult needs around 6 to 8 teaspoons of sun cream to cover the whole body.
The NHS advice on sunscreen and sun safety is to reapply every two hours, and straight after swimming or towelling off. The NHS also says to stay out of the sun between 11am and 3pm from March to October. Shade and clothing still do part of the work.
Key facts
- Price: £16.79 on Amazon UK on 4 October 2026, sold by Amazon; £21 direct from La Roche-Posay UK (out of stock that day)
- Size: 50ml
- Protection: SPF50+, broad spectrum against UVA and UVB
- Filters: Mexoryl 400 plus the Mexoplex filter system, with La Roche-Posay Thermal Spring Water
- Resistance: water, sweat and sand
- Skin types: all, including sensitive skin, according to La Roche-Posay
- Rating: 4.6 out of 5 from 18,100 ratings on Amazon UK
Who it suits
- People with sensitive skin: the formula was developed and tested on it.
- Daily wearers: the light finish sits well under make-up, so it is easy to use every morning rather than only on holiday.
- Contact lens wearers: La Roche-Posay tested it on them and on the eye area.
Our self care gift guide has more skincare and wellbeing presents, if you are buying this for someone else.
The limits
At £16.79 for 50ml it costs more per millilitre than a supermarket SPF50. It is a face product, so covering your body with it would empty the bottle quickly.
The fluid is thin, which makes it easy to apply too little. A thin layer gives you less protection than the SPF50+ on the label.
Water resistant does not mean it lasts all day in the sea. Reapply after swimming, as the NHS advises.
Where to buy it in the UK
Amazon UK had it in stock at £16.79, sold and dispatched by Amazon. The La Roche-Posay UK product page lists it at £21, with free delivery over £25, and carries the full ingredients list.
Packing for a trip? Our best travel accessories guide covers the rest of the bag.
Anthelios UVmune 400 on Amazon UK
FAQs
How much is La Roche-Posay Anthelios UVmune 400?
The 50ml Invisible Fluid SPF50+ was £16.79 on Amazon UK and £21 on La Roche-Posay's UK shop on 4 October 2026.
What is UVmune 400?
It is La Roche-Posay's sun cream range built around Mexoryl 400. That filter blocks ultra-long UVA rays, at the far end of the UVA band close to 400 nanometres.
Does Anthelios UVmune 400 leave a white cast?
La Roche-Posay says the Invisible Fluid leaves no white marks and suits all skin tones.
Is it suitable for sensitive skin?
Yes. La Roche-Posay developed it for sensitive skin, tested it under dermatological control and labels it hypoallergenic.
How often should I reapply it?
Every two hours, and straight after swimming or drying off with a towel, in line with NHS advice.
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Prices and availability change. This page is general product information, not medical advice; speak to a pharmacist or GP about a skin condition. The affiliate links on this page earn a commission at no extra cost to you, and brands do not choose what we feature.
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