Can chemical sunscreens penetrate the blood stream?
9 May 2019
Sunscreens are your very best tool for preventing premature skin ageing. Did you know that 80% of premature skin ageing is actually caused by UV ray damage, a terrifying statistic which will have you slathering on the SPF in seconds. Exceptionally effective in minimising the risk of skin cancer, sunscreen should be an everyday product on your bathroom shelf.
There are two distinct types of sunscreens used in skincare - physical (also known as inorganic) and chemical (also known as organic). Both types of filters absorb UV rays, converting them into heat energy. Physical sunscreens can also reflect and scatter a percentage of UV rays away like a mirror. Physical sunscreens use filters such as the metal oxides; titanium dioxide and zinc oxide. Chemical sunscreens can use a variety of filters based on organic molecules.
The problem with chemical UV filters is that they are often shrouded in a cloud of confusion and rumours about their safety. There are a variety of well known chemical filters (such as avobenzone, oxybenzone and octocrylene) which are traditionally used within skincare, and many of them have negative connotations associated with them. There are concerns over their safety, and some have even been found to disrupt the delicate hormone balance in our bodies. These older forms of chemical filters have led to many misconceptions about the safety of chemical sunscreens. To add fire to the flame, a brand new clinical study has been published investigating whether these chemical sunscreen filters can penetrate into the bloodstream.
The recent study was published in the medical journal JAMA, looking at the whereabouts of four common sunscreen filters (avobenzone, oxybenzone, octocrylene and ecamsule). Focusing on a small panel of 24 participants applying 2 mg/cm2 of sunscreen over 75% of their body 4 times a day for 4 days, the study looked at blood plasma samples to assess if the sunscreen molecules had entered the bloodstream. Low levels of chemical sunscreen filters were shown to be absorbed through the skin into the bloodstream.
On the surface these results sound worrying. But we urge you to read past the headlines and look at the facts of the study.
This study’s results are based on maximal use conditions. First of all, how often do you actually apply the maximum amount of sunscreen to 75% of your body, 4 times a day for any significant period of time? We know that on holiday this might be the case, but on a rainy Sunday in England, it’s not going to be a huge issue. The results of the study do not necessarily reflect real-life sunscreen usage.
Also, bear in mind that there was no indication of negative effects. The presence of sunscreens in the blood after maximal use were not linked to safety concerns. The study merely highlights the need for larger scale clinical studies to determine the optimal dosage of sun creams for the perfect level of protection.
In reality, the benefits of wearing sunscreen 100% outweighs any uncertainty with their safety. In fact, the study even concludes;
‘These results do not indicate that individuals should refrain from the use of sunscreen.’
The small-scale clinical study results should not deter you from using proper sun protection, every single day.
The good news? Not one of the above controversial ingredients are used in Medik8 formulations. In fact, we avoid the 4 filters mentioned in the study already because the filters have other issues relating to instability and hormone disruption. Avobenzone has been found to breakdown in sunlight, oxybenzone is known to cause skin allergies and has a weak hormone-disruption effect. It has also recently been banned in Hawaii due to its effect on bleaching the coral reefs. Octocrylene has been associated with contact allergies.
Instead, we only select our chemical UV filters from a set of modern, well trusted and super-safe filters which have been extensively safety tested: Uvinul A Plus, Uvinul T150 and Tinosorb S. We believe these are the future of sunscreen filters. They are all exceptionally stable in the sun, safe for the skin and offer high level protection from UV rays. None of these filters have been found to be endocrine disruptors, all are rated well by consumer analysis watchdog, EWG, and all are known to be photostable
The take-away; wear your sunscreen every day, even when it’s cloudy.
 F. Flament et al., Effect of the sun on visible clinical signs of aging in Caucasian skin, Clinical, Cosmetic and Investigational Dermatology, 2013, 6, pp 221-232  M. Matta et al, Effect of Sunscreen Application Under Maximal Use Conditions on Plasma Concentration of Sunscreen Active Ingredients, JAMA, 2019