Experts warn people must not be discouraged from using SPF regardless
Researchers found that chemicals leach into the body and reach levels high enough to warrant further investigation, as the effects are currently unknown.
The study was published on 6 May in the Journal of the American Medical Association (JAMA), and found that the chemical concentration continued to rise during prolonged daily use, and remained in the body for at least 24 hours.
The four chemicals in question are avobenzone, oxybenzone, ecamsule and octocrylene. The FDA recently listed them in a series of ingredients commonly found in sunscreen which it believes requires further testing before they can be "regarded as safe and effective".
Results show that after just one day of sunscreen use the concentration of these chemicals in the bloodstream exceeds 0.5 nanograms per milliliter, which is the safety threshold set by the FDA set in 2016.
However, experts are adamant that this must not be taken as a reason to stop using sunscreen, which is crucial in avoiding serious damage caused by exposure to UV rays.
In an editorial accompanying the research, former FDA Chairman Dr Robert Califf reinforced the fact that there is no evidence to suggest the ingredients are unsafe.
Dr Anjali Mahto, a dermatologist consultant at the Cadogan Clinic and author of The Skincare Bible, expressed concern about the potential impact of a study like this, and pointed out that it was conducted on only 24 people.
Researchers asked the participants to apply two milligrams of sunscreen per square centimeter (0.2 square inches) of skin to 75 per cent of their body four times a day, and stayed indoors throughout the research. Dr Mahto and other experts have expressed concerns that this does not mimic real-world behaviour.
She tells The Independent: “Even if the sunscreen is found in the blood it tells us nothing about whether this has dangerous health effects. We’ve been using chemical sunscreens for years without any real reported issues to general health if we look at epidemiological data.”
She also stated that skin cancer is a real risk for those who are exposed to the sun without protection.
She says: “We know that reducing the risk of sunburns is important to prevent skin cancer and sunscreen along with other healthy behaviours in the sun such as covering up with clothing, shade seeking, staying out of the sun in peak daylight hours, hats and sunglasses are hugely important.”
The results of the study could also reinforce a general fear of chemicals which is becoming more and more popular among younger consumers, warns Dr Mahto.
Melanoma – a type of cancer which usually occurs in the skin and can be caused by sun exposure – is the fifth most common cancer in the UK, with around 15,400 new cases every year.