Chemicals in sunscreen are absorbed into your blood at concentrations up to 419 TIMES above ‘what is safe to avoid cancer’
- Chemical oxybenzone reaches plasma concentrations of up to 209.6ng/mL
- Food and Drug Administration in the US recommends no more than 0.5ng/mL
- Oxybenzone may also disrupt our hormones, leading to embryonic toxicities
Chemicals in sunscreen get absorbed into our blood at concentrations up to 419 times higher than what is considered safe, research suggests.
A study found the chemical oxybenzone, which absorbs UVA and UVB rays, reaches plasma concentrations of up to 209.6ng/mL.
This is despite the US Food and Drug Administration (FDA), which works to ensure medical devices and personal products are safe in the US, recommending no more than 0.5ng/mL to prevent cancer.
As well as being potentially carcinogenic, oxybenzone may also disrupt hormones, leading to embryonic toxicities, research suggests.
Researchers stress, however, the implications of their study are unknown and people should not make the ‘knee-jerk decision’ to stop using sunscreen.
Sunscreen gets absorbed at concentrations up to 419 times higher than what is safe (stock)
The research was carried out by the FDA and led by Dr David Strauss, director of the division of applied regulatory science.
Sunscreens protect against skin damage by reflecting, absorbing or scattering damaging UV radiation, the researchers wrote in the Journal of the American Medical Association.
Many people apply multiple grams of sunscreen every day, both directly and in SPF-enriched skincare or make-up.
Despite sunscreen’s proven benefits, the FDA advised ingredients with ‘safety concerns’, or those that are absorbed into the bloodstream at rates greater than 0.5ng/mL, should undergo ‘toxicology assessment’.
Under the Threshold of Toxicological Concern, 0.5ng/mL is considered the highest concentration an unknown compound can reach in the bloodstream where the cancer risk is less than one in 100,000 after a single dose.
The same principal is used to regulate food packaging in the US when there is a risk substances may migrate into food.
The FDA added sunscreen concerns may be ‘waived’ if studies reveal the ingredients of sunscreen do not consistently rise above a plasma concentration of 0.5ng/mL.
To put this to the test, the researchers analysed the active ingredients – avobenzone, oxybenzone, octocrylene and ecamsule – of four commercially-available sunscreens. Brand names were not given.
How can I keep my skin healthy?
Protect it from the sun: UV rays in sunlight are a major cause of skin ageing and skin cancer. Protect skin from sun damage by avoiding direct sunlight on sunny days or in hot countries, and by using sunscreen.
Stop smoking: Smoking causes skin to age prematurely by breaking down collagen, which reduces its elasticity, and cutting off supplies of oxygen and nutrients.
Drink less alcohol: Drinking alcohol can dehydrate your skin, leaving it looking tired and old. Drink alcohol in responsible amounts and stay hydrated.
Wash regularly: Wash skin regularly using mild soap and warm water, but too much washing or harsh soaps can dry skin out. Moisturise after washing if you have dry skin.
Source: NHS Choices
They had 23 volunteers apply either the first two sunscreens, which were both sprays, or the remaining products, which were a lotion and a cream.
Two milligrams of the sunscreen was applied per 1cm² of the participants’ skin over three quarters of their body four times a day for four days.
This regimen was chosen due to sunscreen labels instructing users to apply the product at least every two hours.
Sun cream use may also take place over several days if people are ‘outside in the sun’, the researchers wrote.
A total of 30 blood samples were also taken from each of the participants over a week.
Results revealed applying any of the four sunscreens caused the active ingredients to reach concentrations of more than 0.5ng/mL in the participants’ blood.
Oxybenzone even reached concentrations of up to 209.6ng/mL after the application of the first spray.
This chemical is found in human breast milk and has been detected in amniotic fluid. Concerns have been raised oxybenzone may affect hormonal activity that regulates pregnancy.
Levels of avobenzone, which has been linked to cancer, allergies and organ toxicity, peaked at 4.3ng/mL in the lotion.
And octocrylene, which may cause skin, eye or lung irritation, was highest in the second spray at 7.8ng/mL.
Ecamsule, which can cause dry skin, redness and acne, was only found in the cream at 1.5ng/mL.
The researchers stress their study should not discourage people from using sunscreen.
However, they add further studies should be carried out to uncover the ‘clinical significance’ of their results.
They also note their study was carried out inside away from heat, UV rays and humidity, which may alter the absorption of sunscreens’ ingredients.
And it did not take in account how absorption varies according to a user’s age or skin type, as well as if the sunscreen comes as a spray, lotion or cream.
Professor Brian Diffey, emeritus professor of photobiology at Newcastle University, said: ‘It is important to note each participant applied the equivalent of two standard bottles of sunscreen over four days.
‘This is considerably greater than typical use where it has been estimated that people who use sunscreen go through about one bottle per year per person.
‘This would mean that for three of the four agents studied here, the levels of active ingredients found in the plasma during typical usage would fall below the threshold value.
‘It is important to note there is no evidence from this study that there is any health risk.
‘And even at maximal use, any theoretical risk is almost certainly far smaller than the reduced risk of skin cancer that has been shown to be associated with sunscreen use. ‘
Dr Andrew Birnie, dermatologist at the British Association of Dermatologists, added: ‘Sunscreen has been used by a large portion of the population for a number of decades and there has not been any epidemiological data that suggests users come to harm.
‘We agree with the researchers that people should not make the knee-jerk decision to stop using sunscreen.
‘Skin cancer is the UK’s most common cancer, equalling all other cancers combined. The link between excess sun exposure and skin cancer is well documented and indisputable.’
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