When the sun is out, many of us reach for sunscreen, but myths and misinformation have left some people confused about when and how to use it, and how to ensure we still get enough vitamin D. , a skin cancer expert at QIMR Berghofer Medical Research Institute in Australia, has led clinical trials looking at the link between sun exposure and skin cancer, and sunscreen use and vitamin D. She also recently led the development of a new that considers how to balance the risks and benefits of sun exposure. Here, she lists five things that everyone should know about sunscreen.

Sunscreen should be used as a last line of defence

Many people think it鈥檚 OK to lie on the beach all day in a tiny bikini as long as they rub sunscreen all over their exposed skin and reapply it every 2 hours. They think sunscreen makes them bulletproof. But even if you apply the best sunscreen perfectly, it still lets some ultraviolet (UV) radiation through. If you鈥檙e out in the sun for hours, that gradually adds up to a dose that is big enough to cause skin damage. At that point, it doesn鈥檛 matter if you apply more sunscreen; the damage is already done.

People often assume that if they reapply sunscreen every 2 hours, they鈥檙e sort of starting the protection again, but that鈥檚 not how it works. You also need to protect yourself with a hat, sunglasses, rash shirt or other protective clothing, and stay in the shade in the middle of the day. Sunscreen should be considered a last line of defence for the parts of your skin that you can鈥檛 easily cover while you鈥檙e outdoors, like your hands and neck.

There is good evidence that sunscreen protects against skin cancer and wrinkles

The largest, longest-running study of sunscreen was conducted in the Australian town of Nambour. In 1992, 1600 people in the town were randomised to apply daily sunscreen or continue with their normal sunscreen use, which tended to be minimal. It found that those who applied the daily sunscreen were years down the track.

The researchers also created moulds of the backs of the study participants鈥� hands to look at damage to the surface of the skin. Those in the daily sunscreen group had compared with those who didn鈥檛. When they were followed up on in 2014, they also had .

The sunscreen to choose is the one you like wearing

It鈥檚 no good having sunscreen that sits in your cupboard and doesn鈥檛 end up on your skin because you don鈥檛 like the feel of it. If you鈥檙e going on a hike and you鈥檙e going to be out all day, it鈥檚 better to wear sunscreen with a high sun protection factor (SPF) of 50+. But it鈥檚 harder to get a high-SPF sunscreen that feels really nice, so if you鈥檒l be popping out for only short periods throughout the day, you can choose an SPF 15 or 30 sunscreen. Tinted sunscreens can offer the same protection as normal sunscreens, but only if you apply them thickly. But because these often make the skin look overly tinted, people tend to apply them too thinly. One option is to first put on a thick layer of normal sunscreen, then apply the tinted sunscreen on top of it.

Free newsletter

Sign up to Eight Weeks to a Healthier You

Sign up to newsletter

Chemical sunscreens, meaning those that contain organic ingredients such as octocrylene and avobenzone, work by absorbing UV radiation from the sun and converting it to harmless heat. Inorganic sunscreens, also known as mineral or physical sunscreens, contain zinc oxide or titanium dioxide particles. They are often reported to work by reflecting or scattering UV radiation, but they actually , like chemical sunscreens.

The only four skincare ingredients that have been proven to work

In the quest for better skin, we are faced with an overwhelming choice of creams and serums to enhance our appearance. Here's what works 鈥� and what doesn't

Wearing two layers of sunscreen helps to achieve adequate coverage

You get the SPF listed on the bottle only if you apply 2 milligrams of sunscreen per square centimetre of skin, which is around in an average adult. But it鈥檚 really hard to apply this amount of sunscreen in one go. One day, I decided to measure it out exactly, and I couldn鈥檛 rub it all on; it was too much. So now, I apply one layer, let it sink in while I brush my teeth and do other things, and then a second layer, so I can apply the full recommended amount.

I was born in Armidale, Australia, in the late 1960s and didn鈥檛 wear sunscreen as a child, despite my pale skin. I鈥檝e since had three skin cancers removed, the first of which appeared when I was just 29. So now, I am careful to protect my skin.

If you鈥檙e diligent with sunscreen, you might need to take a vitamin D supplement

We recently conducted a trial called the Sun-D Study to see whether applying SPF 50+ sunscreen every day affects people鈥檚 vitamin D levels. We randomly assigned 639 people to apply SPF 50+ sunscreen as part of their daily morning routine on days when the UV index was forecast to reach 3 or higher, or to use it at their own discretion. After about a year, a 鈥� about 46 per cent compared with 37 per cent in the control group. If you wear sunscreen every day, I would advise taking a vitamin D supplement so that you don鈥檛 become deficient, especially in winter. I take one myself 鈥� they are cheap, safe and effective.

People with dark-coloured skin are at greater risk of developing a vitamin D deficiency. I recently led the development of a new that looked at how to balance the various risks and benefits of sun exposure. It brought together experts from many Australian universities and medical organisations, and it concluded that people with dark-coloured skin need to put on sunscreen only if they plan to spend more than 2 hours outdoors on days with high UV radiation levels. This is in recognition of the fact that melanoma incidence is 30 times lower in people with dark-coloured skin than in those with light-coloured skin, and that vitamin D deficiency poses a greater risk.

A first-of-its-kind cream that targets the underlying cause of vitiligo will be made available on the National Health Service in England. In clinical trials, the cream significantly increased pigmentation in the white skin patches caused by the condition, but the treatment , as vitiligo isn鈥檛 painful or dangerous.

鈥淯sually, people [with vitiligo] are asymptomatic in terms of physical symptoms, but it can cause a lot of emotional hardship,鈥� says at Indiana University, who led two trials of the new ruxolitinib cream treatment.

The cream, which is already available in the US, is sold under the name Opzelura. It treats non-segmental vitiligo, which occurs when symmetrical white patches appear on both sides of the body. This is thought to be caused by the immune system attacking melanocytes, the cells that make the pigment melanin, which gives skin colour.

The treatment is the first drug to be robustly tested that acts directly on the pathway that causes vitiligo, says at Vitiligo Support UK. 鈥淭hat鈥檚 why this [decision] is such a landmark,鈥� she says.

Ruxolitinib works by inhibiting two enzymes that cause . Existing treatments, like steroid creams, can restore some pigment, but suppress immune function more broadly.

, published in 2022, found that the drug increased pigmentation and reduced the noticeability of vitiligo patches compared with a placebo cream. This occurred (vitiligo is more noticeable on darker skin), and in more than a third of those who came off the drug after the trial.

Free newsletter

Sign up to Health Check

Sign up to newsletter

The National Institute for Health and Care Excellence (NICE) weighed up these results in the past, but judged ruxolitinib to for use on the NHS. Now, it says the cream should be made available to people aged 12 and older with non-segmental vitiligo when other topical treatments haven鈥檛 worked or are unsuitable.

Vitiligo, which , varies in severity. Some people have just a few small patches, while for others they can be large, red, inflamed or discoloured.

鈥淧atients and clinicians sometimes think we shouldn鈥檛 treat vitiligo, [because] it doesn鈥檛 kill you [and] it鈥檚 not painful,鈥� says at the British Association of Dermatologists. But vitiligo can have serious complications, such as a higher risk of .

The only four skincare ingredients that have been proven to work

In the quest for better skin, we are faced with an overwhelming choice of creams and serums to enhance our appearance. Here's what works 鈥� and what doesn't

Natalie Ambersley 鈥� a vitiligo ambassador for the charity , which supports people with physical differences 鈥� says that people shouldn鈥檛 feel judged for treating the condition, but adds that after spending years using existing treatments, she won鈥檛 be seeking out ruxolitinib. 鈥淚鈥檝e learned to accept my skin,鈥� she says. 鈥淲e鈥檙e [all] unique and we can embrace what we look like.鈥�

鈥淚t鈥檚 great that there are people who love the skin they鈥檙e in, but that鈥檚 not for everyone,鈥� says Rush.

An oral version of ruxolitinib, which is used to treat some cancers and rheumatoid arthritis, , including lymphoma, heart problems and serious infections. But these have not been reported with the topical version. In the two vitiligo trials, ruxolitinib caused only mild side effects, including acne and itchiness. 鈥淭here is super minimal systemic absorption,鈥� says Eleftheriadou.

Ruxolitinib is also thought to be safer than steroid creams, which can cause skin thinning with long-term use. People with severe vitiligo may also be offered ultraviolet therapy, but this isn鈥檛 widely accessible.

Sex, or even just intimate touch, could help speed up wound healing 鈥� but perhaps only if combined with a nasal oxytocin spray.

Often called the 鈥渓ove hormone鈥� or 鈥渃uddle chemical鈥�, oxytocin stimulates uterine contractions during childbirth, and then lactation, but has also been associated with social bonding and sex. Previous research suggests it also speeds up the healing of , possibly due to its anti-inflammatory effect.

What鈥檚 more, has been linked to the slower healing of blisters, which prompted at the University of Zurich in Switzerland and her colleagues to wonder if a lack of oxytocin during these interactions could at least be partly mediating this effect.

To learn more, the team conducted a trial with 80 healthy heterosexual couples, whose average age was 27, who all received four small wounds on their forearms from a suction device.

The couples were then split into four groups, all of which experienced different interventions over the following week. The first group took a twice-daily oxytocin nasal spray and completed a 10-minute Partner Appreciation Task (PAT) 鈥� a structured discussion where they expressed gratitude for each other and paid each other compliments 鈥� up to three times a week.

The second group took the oxytocin spray twice a day, but didn鈥檛 participate in the PAT intervention, while the third group used a placebo spray and did the PAT, and the fourth used the placebo spray with no PAT intervention.

Free newsletter

Sign up to Health Check

Sign up to newsletter

Taking the oxytocin spray alone, or doing the PAT with a placebo spray, didn鈥檛 heal the wounds any faster than the rate seen in the no-spray, no-PAT group. Combining oxytocin and PAT helped a little 鈥� in terms of things like reducing the size and depth of the wounds 鈥� but the effects were most pronounced among the couples who also reported touching or having any sexual activity with each other during that week. This was also linked to lower levels of cortisol, the stress hormone that can suppress immune function, in their saliva.

鈥淲e see improved wound healing in that group that combines the [PAT] interaction and oxytocin, but that effect is much less strong than the effect for those who combine oxytocin with a naturally occurring touch behaviour, and even sexual or intimate behaviour,鈥� says Ditzen. 鈥淣ow we know we have a really strong indication that oxytocin seems to be an underlying mechanism mediating these effects of positive couple interaction.鈥�

Women have supercharged immune systems and we now know why

Being born with two X chromosomes brings a host of health benefits, and recognising this could lead to personalised medical treatments for men and women

鈥淲hat makes the findings particularly exciting is that they suggest combining oxytocin administration with positive relational behaviours may enhance physical recovery 鈥� a promising direction for future psychosocial interventions in healthcare settings,鈥� says at the University of Leeds, UK.

at the University of Stirling in the UK says that administering a higher dose of oxytocin could bring about similar benefits, perhaps particularly for older adults, who tend to have suppressed immunity.

Vaccines could one day be administered topically, with no needles required, by stretching the skin beforehand.

Our skin is an essential barrier against pathogens, and is also tied to our immune system in other ways 鈥� gentle scratching, for example, seems to activate receptors that boost immune defences.

To investigate whether stretching the skin prompts similar effects, at King鈥檚 College London and his colleagues applied a suction device to mice and human skin samples for 20 minutes, increasing the skin tension to about 6 newtons. Normally, skin is under tension of about 1.5 newtons, says Jones. Applying lotion doubles it, and a broader massage takes it to 6 newtons or more.

By watching fluorescently labelled molecules under a microscope, the researchers found that such stretching rearranges skin鈥檚 collagen fibres and opens hair follicles, increasing its permeability so the molecules could pass through. After the tension was released, the skin stayed in this state for about 15 minutes.

The stretching also triggered stromal cells, which provide structural support to the skin, to react. 鈥淭hey produce a mild inflammatory response in the stretched area, and that stimulates an immune response,鈥� says team member at INSERM, the French National Institute of Health and Medical Research.

Tests in mice revealed that the stretching increased the number of immune cells in that part of the skin, and triggered changes in the activity of genes that encode immune signalling molecules called cytokines.

Free newsletter

Sign up to Health Check

Sign up to newsletter

In another part of the experiment, the team compared the effects of injecting an H1N1 flu vaccine into mice against stretching their skin and then applying a lotion containing the same vaccine dose. 鈥淲e were very surprised to see that the strength of the immune response was similar,鈥� says Jones.

鈥淚t鈥檚 a really exciting idea that you could put a nanoparticle on the skin and then by stretching the skin, you鈥檙e able to get it in,鈥� says 聽at the University of Pittsburgh, Pennsylvania.

The researchers also found that the topical vaccine鈥檚 effect was strong with or without an adjuvant. These are molecules used in vaccines to stimulate the immune system, but some people are allergic to them. 鈥淚n this case, the stretching is providing that trigger,鈥� says Jones.

He envisages that people could self-administer topical vaccines at home by applying a small suction device to their skin beforehand. 鈥淭here鈥檚 no blood. There鈥檚 no breaking of the skin. It鈥檚 not invasive,鈥� he says.

How to nurture your microbiome to look after your skin

Our skin is host to a thriving community of bacteria, some of which help to restore and protect our epidermis. The hunt is now on for treatments that make the most of these allies

Despite finding the study 鈥渧ery interesting鈥�, at the University of Oxford says questions remain. 鈥淲hat sort of depths could you reach with this sort of treatment? And how accurately are you going to be able to hit a certain target dose?鈥�

More work is needed to see whether the approach works in people, who have a thicker outer layer of skin than mice, says Jones. But he adds that the permeability response in the first part of the experiment was similar between the two species.

鈥淎lthough in mouse skin, the hair follicles are more numerous, the ones in humans are bigger,鈥� says Jones. This means you get bigger gaps around the follicles to let molecules through. 鈥淲e actually think it might work slightly better in humans.鈥�