A large increase in melanoma has been experienced in countries where chemical sunscreens are in use. This has been seen in the last decade in places such as Australia where promotion of sunscreens has been ongoing. In 1992 Queensland had more incidences of melanoma per capita than any other place on Earth.¹

Not to be joked about is the result of applying sunscreen to your skin, which as an organ absorbs chemicals. How else does a Nicotine patch work?! A study in the April 2004 Journal of Chromatography found that there is “… significant penetration of all sunscreen agents into the skin, and oxybenzone and metabolites across the skin”.²

A randomized clinical trial published results this year in the Journal of the American Medical Association found that found that several active ingredients, including oxybenzone, enter the bloodstream at levels that far exceed the agency’s recommended threshold for requiring additional safety tests. This was with application of four commercially available sunscreens according to current sunscreen labeling (apply at least every 2 hours).³

Chemical Sunscreens Include:

• Benzophenones (dixoybenzone, oxybenzone – a potential hormone disruptor) – rapidly oxidise in the presence of light and inactivates important antioxidant systems in the skin (the skin’s natural protection system)⁴
• Titanium dioxide – causes DNA damage (the cells genetic material) due to superoxide radicals, active oxygen radicals and hydroxyl radicals when exposed to light ^{5 6 7}
• PABA and PABA esters:
  • ethyl dihydroxy propyl PAB
  • glyceryl PABA
  • p-aminobenzoic acid
  • padimate-O – produces free radicals in presence of light (singlet molecular oxygen) and substantially increase indirect damage (strand breaks in DNA) when in contact with cells^{8 9}
  • octyl dimethyl PABA – produces free radicals in the presence of light⁸
• Cinnamates:
  • cinoxate causes DNA damage (sister chromatid exchanges)¹⁰
  • ethylhexyl p-methoxycinnamate
  • octocrylene
  • octyl methoxycinnamate – produces free radicals (singlet molecular oxygen) known to be toxic to cells⁸
• Salicylates (ethylhexyl salicylate, homosalate, octyl salicylate)
• Digalloyl trioleate
• Menthyl anthranilate
• Avobenzone [butyl-methyoxydibenzoylmethane; Parsol 1789] – This is the only chemical sunscreen currently allowed by the European Community. However, its safety is still questionable since it easily penetrates the skin and is a strong free radical generator.
• Dibenzoylmethane – produces free radicals responsible for direct DNA damage (strand breaks)¹¹
• Methyl sinapate – causes DNA damage (chromosome aberrations and sister chromatid exchanges)¹²
• Phenylbenzimidazole sulphonic acid and 2-phenylbenzimidazole – acts as photosensitisers of DNA damage when exposed to sunlight or UV-B radiation¹³

What about Free Radicals?

Many of the ingredients found in commercially sold sunscreens (as listed above) can have free radical generating properties which MAY increase cellular damage and changes that may lead to cancer. Details on why:

• Oxygen-free radicals are more generally known as reactive oxygen species (ROS). The cumulative production of ROS is termed oxidative stress.
• Oxidative stress induces a cellular redox imbalance which has been found to be present in various cancer cells compared with normal cells; the redox imbalance thus may be related to oncogenic stimulation (tending to cause or give rise to tumors).
• DNA mutation is a critical step in carcinogenesis and elevated levels of oxidative DNA lesions (8-OH-G) have been noted in various tumours, strongly implicating such damage in the study of causation of cancer.
• UV rays absorbed by the skin can generate harmful compounds called reactive oxygen species (ROS), which as detailed above can be related to skin cancer. Once the filters (Some of the chemical blockers listed above) soak into the lower layers of skin, they react with UV light to create more damaging ROS. Research indicates that sunscreen filters become damaging when they are soaked into the skin and another layer of sunscreen is not applied.
  • A team of researchers from the University of California found that three commonly used ultraviolet (UV) filters in sunscreen – octyl methoxycinnamate, benzophenone 3 and octocrylene – eventually soak into the deeper layers of the skin after application, leaving the top skin layers vulnerable to sun damage.¹⁴

After visiting Hawaii in 2018 I saw a movement there to ban chemical based sunscreens, not only due to health concerns but due to environmental concerns. The outcome has been that beginning Jan 1, 2021, Hawaii is one of the first places in the world to legislate banning chemical sunscreens including octyl methoxycinnamate and oxybenzone.¹⁵

Lastly – food for thought – The sunscreen myth?

Conclusion

I’m not a medical professional of any kind, and you should not rely on my information in any way shape or form. However the referenced material is sound, solid medical research in peer reviewed journals. As such you should read the references yourself and come to your own conclusion about what you are putting on your skin, and the motives behind the manufacturers.

UVA and UVB rays are still a danger if one is genetically predisposed to cancer and has over-exposure to the Sun. Maybe you should consider suplementation of Fish Oil for reduction of Sunburn and Risk of Cancer?^{16 17} There is even promising recent research indicating that the natural production of Vitamin D3 from natural sun exposure may also protect your skin.¹⁸

From reading all the medical journals and references, I’ll be sticking to a healthy level of natural sun exposure, or where that can not be achieved (for longer periods of time) a zinc based sunscreen, long sleeves, hats, sunglasses and shade from big trees. Fashion be damned.

Further reading:

• Free radicals, metals and antioxidants in oxidative stress-induced cancer
• Free radicals and antioxidants in normal physiological functions and human disease
• Role of oxygen radicals in DNA damage and cancer incidence

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