Social media is full of claims that everyday habits can harm your skin. It’s also full of recommendations or advertisements for products that can protect you.

Now social media has blue light from our devices in its sights.

So can scrolling on our phones really damage your skin? And will applying creams or lotions help?

Here’s what the evidence says and what we should really be focusing on.

Remind me, what actually is blue light?

Blue light is part of the visible light spectrum. Sunlight is the strongest source. But our electronic devices – such as our phones, laptops and TVs – also emit it, albeit at levels 100-1,000 times lower.

Seeing as we spend so much time using these devices, there has been some concern about the impact of blue light on our health, including on our eyes and sleep.

Now, we’re learning more about the impact of blue light on our skin.

How does blue light affect the skin?

The evidence for blue light’s impact on skin is still emerging. But there are some interesting findings.

1. Blue light can increase pigmentation

Studies suggest exposure to blue light can stimulate production of melanin, the natural skin pigment that gives skin its colour.

So too much blue light can potentially worsen hyperpigmentation – overproduction of melanin leading to dark spots on the skin – especially in people with darker skin.

2. Blue light can give you wrinkles

Some research suggests blue light might damage collagen, a protein essential for skin structure, potentially accelerating the formation of wrinkles.

A laboratory study suggests this can happen if you hold your device one centimetre from your skin for as little as an hour.

However, for most people, if you hold your device more than 10cm away from your skin, that would reduce your exposure 100-fold. So this is much less likely to be significant.

3. Blue light can disrupt your sleep, affecting your skin

If the skin around your eyes looks dull or puffy, it’s easy to blame this directly on blue light. But as we know blue light affects sleep, what you’re probably seeing are some of the visible signs of sleep deprivation.

We know blue light is particularly good at suppressing production of melatonin. This natural hormone normally signals to our bodies when it’s time for sleep and helps regulate our sleep-wake cycle.

By suppressing melatonin, blue light exposure before bed disrupts this natural process, making it harder to fall asleep and potentially reducing the quality of your sleep.

The stimulating nature of screen content further disrupts sleep. Social media feeds, news articles, video games, or even work emails can keep our brains active and alert, hindering the transition into a sleep state.

Long-term sleep problems can also worsen existing skin conditions, such as acne, eczema and rosacea.

Sleep deprivation can elevate cortisol levels, a stress hormone that breaks down collagen, the protein responsible for skin’s firmness. Lack of sleep can also weaken the skin’s natural barrier, making it more susceptible to environmental damage and dryness.

Can skincare protect me?

The beauty industry has capitalised on concerns about blue light and offers a range of protective products such as mists, serums and lip glosses.

From a practical perspective, probably only those with the more troublesome hyperpigmentation known as melasma need to be concerned about blue light from devices.

This condition requires the skin to be well protected from all visible light at all times. The only products that are totally effective are those that block all light, namely mineral-based suncreens or some cosmetics. If you can’t see the skin through them they are going to be effective.

But there is a lack of rigorous testing for non-opaque products outside laboratories. This makes it difficult to assess if they work and if it’s worth adding them to your skincare routine.

What can I do to minimise blue light then?

Here are some simple steps you can take to minimise your exposure to blue light, especially at night when it can disrupt your sleep:

• use the “night mode” setting on your device or use a blue-light filter app to reduce your exposure to blue light in the evening
• minimise screen time before bed and create a relaxing bedtime routine to avoid the types of sleep disturbances that can affect the health of your skin
• hold your phone or device away from your skin to minimise exposure to blue light
• use sunscreen. Mineral and physical sunscreens containing titanium dioxide and iron oxides offer broad protection, including from blue light.

In a nutshell

Blue light exposure has been linked with some skin concerns, particularly pigmentation for people with darker skin. However, research is ongoing.

While skincare to protect against blue light shows promise, more testing is needed to determine if it works.

For now, prioritise good sun protection with a broad-spectrum sunscreen, which not only protects against UV, but also light.

Michael Freeman, Associate Professor of Dermatology, Bond University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

One of the earliest descriptions of someone with cancer comes from the fourth century BC. Satyrus, tyrant of the city of Heracleia on the Black Sea, developed a cancer between his groin and scrotum. As the cancer spread, Satyrus had ever greater pains. He was unable to sleep and had convulsions.

Advanced cancers in that part of the body were regarded as inoperable, and there were no drugs strong enough to alleviate the agony. So doctors could do nothing. Eventually, the cancer took Satyrus’ life at the age of 65.

Cancer was already well known in this period. A text written in the late fifth or early fourth century BC, called Diseases of Women, described how breast cancer develops:

hard growths form […] out of them hidden cancers develop […] pains shoot up from the patients’ breasts to their throats, and around their shoulder blades […] such patients become thin through their whole body […] breathing decreases, the sense of smell is lost […]

Other medical works of this period describe different sorts of cancers. A woman from the Greek city of Abdera died from a cancer of the chest; a man with throat cancer survived after his doctor burned away the tumour.

Where does the word ‘cancer’ come from?

The word cancer comes from the same era. In the late fifth and early fourth century BC, doctors were using the word karkinos – the ancient Greek word for crab – to describe malignant tumours. Later, when Latin-speaking doctors described the same disease, they used the Latin word for crab: cancer. So, the name stuck.

Even in ancient times, people wondered why doctors named the disease after an animal. One explanation was the crab is an aggressive animal, just as cancer can be an aggressive disease; another explanation was the crab can grip one part of a person’s body with its claws and be difficult to remove, just as cancer can be difficult to remove once it has developed. Others thought it was because of the appearance of the tumour.

The physician Galen (129-216 AD) described breast cancer in his work A Method of Medicine to Glaucon, and compared the form of the tumour to the form of a crab:

We have often seen in the breasts a tumour exactly like a crab. Just as that animal has feet on either side of its body, so too in this disease the veins of the unnatural swelling are stretched out on either side, creating a form similar to a crab.

Not everyone agreed what caused cancer

In the Greco-Roman period, there were different opinions about the cause of cancer.

According to a widespread ancient medical theory, the body has four humours: blood, yellow bile, phlegm and black bile. These four humours need to be kept in a state of balance, otherwise a person becomes sick. If a person suffered from an excess of black bile, it was thought this would eventually lead to cancer.

The physician Erasistratus, who lived from around 315 to 240 BC, disagreed. However, so far as we know, he did not offer an alternative explanation.

How was cancer treated?

Cancer was treated in a range of different ways. It was thought that cancers in their early stages could be cured using medications.

These included drugs derived from plants (such as cucumber, narcissus bulb, castor bean, bitter vetch, cabbage); animals (such as the ash of a crab); and metals (such as arsenic).

Galen claimed that by using this sort of medication, and repeatedly purging his patients with emetics or enemas, he was sometimes successful at making emerging cancers disappear. He said the same treatment sometimes prevented more advanced cancers from continuing to grow. However, he also said surgery is necessary if these medications do not work.

Surgery was usually avoided as patients tended to die from blood loss. The most successful operations were on cancers of the tip of the breast. Leonidas, a physician who lived in the second and third century AD, described his method, which involved cauterising (burning):

I usually operate in cases where the tumours do not extend into the chest […] When the patient has been placed on her back, I incise the healthy area of the breast above the tumour and then cauterize the incision until scabs form and the bleeding is stanched. Then I incise again, marking out the area as I cut deeply into the breast, and again I cauterize. I do this [incising and cauterizing] quite often […] This way the bleeding is not dangerous. After the excision is complete I again cauterize the entire area until it is dessicated.

Cancer was generally regarded as an incurable disease, and so it was feared. Some people with cancer, such as the poet Silius Italicus (26-102 AD), died by suicide to end the torment.

Patients would also pray to the gods for hope of a cure. An example of this is Innocentia, an aristocratic lady who lived in Carthage (in modern-day Tunisia) in the fifth century AD. She told her doctor divine intervention had cured her breast cancer, though her doctor did not believe her.

From the past into the future

We began with Satyrus, a tyrant in the fourth century BC. In the 2,400 years or so since then, much has changed in our knowledge of what causes cancer, how to prevent it and how to treat it. We also know there are more than 200 different types of cancer. Some people’s cancers are so successfully managed, they go on to live long lives.

But there is still no general “cure for cancer”, a disease that about one in five people develop in their lifetime. In 2022 alone, there were about 20 million new cancer cases and 9.7 million cancer deaths globally. We clearly have a long way to go.

Konstantine Panegyres, McKenzie Postdoctoral Fellow, Historical and Philosophical Studies, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.