Beauty expert Sara Corleison unpacks the science behind SPF ingredients.
WORDS SARA CORLEISON
Beauty expert Sara Corleison unpacks the science behind SPF ingredients and looks at di erences between mineral versus chemical sunscreen. Plus, her recommendations for which sunscreens to try.
Are all chemical SPF filters bad? Should I only use a natural mineral SPF? I want a safe sunscreen for my baby, help!
It’s a minefield trying to find the best SPF for you and your family. Here I unpack the science behind SPF ingredients and make a few product recommendations.
In 2019 the American FDA proposed only two SPF ingredients be classified as GRASE (generally recognised as safe and e ective): zinc oxide and titanium dioxide, classed as mineral SPF filters. Paraaminobenzoic acid and trolamine salicylate, two chemical SPF filters, were labelled as not GRASE, because “the risks associated with use of these active ingredients in sunscreen products outweigh their benefits”.
The FDA also wanted more safety data on 12 other chemical SPF filters (cinoxate, dioxybenzone, ensulizole, homosalate, meradimate, octinoxate, octisalate, octocrylene, padimate O, sulisobenzone, oxybenzone and avobenzone).
In 2020, the FDA released a safety testing update for six of the 12 proposed dangerous active ingredients. They found all six (avobenzone, oxybenzone, octocrylene, homosalate, octisalate and octinoxate) absorbed into the bloodstream. The FDA ended with a disclaimer saying that “absorption does not equal risk”. What about the other six? Who knows!
I prefer to use a SPF which does not have soluble chemical SPF filters that absorb into my blood, because there’s always the potential that these chemicals can disrupt
my body’s balance and wreak havoc with my hormones, regardless of high or low risk. That said, this does not mean I’m saying no to all chemical SPF filters.
THE DIFFERENCE BETWEEN MINERAL AND CHEMICAL SPF
Mineral (physical) SPF like zinc oxide or titanium dioxide acts as a physical mask or shield to defend your skin against sun damage. Traditionally these ingredients produce a white appearance upon application. But recent scientific advances have produced micronised, ionised and tinted versions of these ingredients which have a less visible appearance on the skin.
Chemical SPF filters act like a sponge: they absorb the sun’s rays, converting them into heat and reducing the risk of skin damage. The main chemical SPF filters recognised by the American Academy of Dermatology are oxybenzone, avobenzone, octisalate, octocrylene, homosalate and octinoxate – all absorbed into the bloodstream. But it’s not as simple as chemical = bad, mineral = good. You can also further classify SPF filters.
INORGANIC VS ORGANIC; SOLUBLE VS INSOLUBLE
In the context of SPF filters, organic does NOT mean organically farmed. Watch out for brands claiming they have organic SPF, but their filters are ‘organic’ as in ‘organic chemistry’. Organic chemistry is the study of carbon-containing compounds, inorganic chemistry is the study of non-carbon-containing. For example, zinc oxide is an inorganic, insoluble mineral SPF filter which is considered ‘natural’, whereas oxybenzone is an organic, soluble chemical SPF filter which is synthetically made. Just because a SPF filter is an organic compound does not mean it’s natural, and certainly does not mean it’s safe. Filters are safer not because of natural vs chemical, but because they are insoluble in water and therefore do not sink into the skin, reducing the risk of producing negative impacts on health. nd
A couple of chemical SPFs worth noting are hydroxybenzoyl hexyl benzoate, which is synthetically made, organic and insoluble in water. Environmental Working Group (EWG) considers this chemical filter relatively benign along with isoamyl p-methoxycinnamate, a naturally derived, organic, oil-soluble SPF filter.
The tinosorb range of insoluble synthetic chemical filters is also worth looking into as they are synthetic, organic and insoluble, many of which have good safety ratings. Tinosorb M (methylene bisbenzotriazolyl tetramethylbutylphenol) has a rating of 1 on the EWG database, as does Tinosorb S (bis-ethylhexyloxyphenol methoxyphenyl triazine). The insolubility and large size of these filters prevents entry into the bloodstream, reducing the risk of hormone disruption.
The moral of the story is, not all chemical SPF agents are created equal. Just because an ingredient is synthetically made does not make it unsafe – which makes it that much more complicated to choose the right SPF for you and your family. At the same time, it’s nice to know there are some benign chemical SPFs which don’t make you look like a ghost.
MY SPF PRODUCT RECOMMENDATIONS
If you want a genuinely natural mineral SPF containing zinc oxide and titanium dioxide, I’d choose Frankie Apothecary’s new SPF. It’s perfect for little ones and gentle on sensitive eczema-prone skin.
For those wanting a near-natural SPF without too much whiteness, My Sunshine is the perfect blend of mineral and chemical SPF protection. Zinc oxide is the primary ingredient and it also contains isoamyl-p-methoxycinnamate, an organic, chemical SPF filter, naturally derived from Indian ginger. Its one synthetic SPF filter, hydroxybenzoyl hexyl benzoate, rates low on the EWG guide.
For a reef-safe SPF developed for surfers by surfers, I’d go with Sol and Sea. Their product base is all-natural and the primary filter is natural inorganic mineral zinc oxide. They’ve boosted the e icacy to SPF 50+ with three EWG green-rated chemical filters for full spectrum protection.
For a high-end facial SPF that blurs the line between skincare and sun cream, try Emma Lewisham’s SPF 30, with an inorganic yet natural mineral filter of zinc oxide as the primary SPF and a newly developed organic yet synthetic secondary filter from the tinosorb range. (Bear in mind this cutting-edge ingredient is not yet FDA approved and there is currently no safety rating by EWG.)
Ultimately, it’s important to do your own research when choosing the best SPF for you and your family. Two helpful sites are:
• The Skin Deep Database by EWG (ewg.org/skindeep), who provide helpful safety ratings after reviewing scientific literature.
• INCI Decoder (incidecoder.com), who provide helpful summaries of cosmetic ingredients.
Be sure to check your SPF for broad spectrum UVA and UVB protection and stay sun smart this summer. Take advantage of old-fashioned sun protection like a good hat and spending time in the shade is always a good idea!
But it’s not as simple as chemical = bad, mineral = good. You can also further classify SPF filters.”