Tis the season ya’ll! Sun’s out, screens out. Let’s talk about natural face SPF. How to read sunscreen labels, what to look for, how to apply and more. I love re-addressing this topic every year because there are a couple of standard points to emphasize around buying natural face SPF but then there is the x-factor of new regulations and new products as well. Speaking of that, here’s my top face SPF picks for 2022. So let’s get down to it. Here’s what to look for in 2022 on sunscreen labels.
Reviewed by Kate Noonan, Molecular Biologist and Cosmetic Chemist
How to read sunscreen labels: defining “natural” face SPF
First things first. Let’s talk about what qualifies as an “organic” or “natural” or “nontoxic” or “clean” sunscreen.
To do this point, there are two main things to look for on labels when choosing clean. The sunscreen’s “active ingredients” and its “inactive ingredients”.
Active vs. inactive ingredients
Active ingredients are what each formula employs to block UVA/UVB rays. Inactive ingredients are carrier ingredients (like what makes a lotion a lotion or a spray a spray. These are ingredients like shea butter, coconut oil, sunflower seed oil, etc).
The best way to vet a sunscreen is to first look at the active ingredients. Here, you really only want to see one thing; non-nano zinc oxide. This is considered a mineral-based, broad-spectrum, nontoxic barrier and it’s the best at what it does.
Some brands will also use titanium dioxide as a mineral barrier but titanium dioxide does not provide as much broad-spectrum protection as zinc oxide does so you either want to see zinc oxide alone OR zinc oxide and titanium dioxide in tandem for the best protection (1 – 4).
Check out this graph Kate Noonan made to help visually show broad spectrum coverage broken down by barrier.
What’s the big deal with broad spectrum SPF protection?
As you can see, most of the UV barriers above are better at providing UVB than UVA protection. UVA protection should not be ignored ya’ll. UVA penetrates the skin deeper than UVB. It also makes up 95% of total UV and is around all day. In addition, both UVA and UVB cause DNA damage in skin cells, which increases skin cancer risk (5-7). UVA also causes melanin oxidation, oxidative stress, collagen and elastin damage, and photoageing (3-8).
READ: Broad-spectrum protection is important to protect from cancer, sunburn, dark spots, hyaluronic acid loss, and fine lines.
How to read sunscreen labels: why zinc oxide rules
Here are a few reasons why zinc oxide rules when it comes to sunscreens barriers…
- Zinc oxide is a true broad-spectrum and photostable sun blocker that can help prevent all types of UV-induced damage (1-3, 6, 7).
- Zinc oxide is a mineral or “inorganic” sunscreen physical sun blocker that reflects radiation whereas chemical sunscreens are “organic” filters that absorb radiation.
- Zinc oxide does not cause any free-radical production whereas chemical UV absorbers (avobenzone, oxybenzone, octinoxate, homosalate, and octocrylene) do (9-12).
- Zinc oxide protects skin from the damaging effects of blue light, which are not nearly as damaging as UVB and UVA but shouldn’t be ignored (13).
- Zinc oxide helps protect skin from environmental pollutants like burnt carbon sources (car exhaust, cigarette smoke, and campfires) (14).
Not all zinc oxide is created the same…
A couple additional things to consider when it comes to zinc oxide. Zinc oxide should also be non-nano and non-coated.
Non-nano zinc oxide offers the best UV protection and it’s the kind supported by Ecocert and the Ecocert Cosmos certification. All of the zinc oxide remains on top of the skin’s surface to reflect UV radiation. This has been proven with a study that used tape. The tape applied to the skin was able to recover all topically applied zinc oxide in sunscreens (15, 16).
Zinc oxide can also be coated with different materials like silicone and silicone derivatives (17). Some companies will include “non-coated” on the label and some won’t. If it’s not included on the label it doesn’t mean it’s assumed coated. This is often something I recommend either checking the brand’s website for or asking the brand directly for clarification.
Sometimes we will see zinc oxide listed as “micronized” which means all the zinc oxide particles have been smoothed out and they are uniform in shape and size. There are three particle sizes; nano (small), micronized (not as small as nano) and large particle. The takeaway here is micronized is not nano.
Active ingredients to avoid on sunscreen labels
Likewise, be sure to avoid the following chemical barriers: Avobenzone, Oxybenzone, Octinoxate, Homosalate, Octocrylene.
These will be listed under the active ingredients section on an ingredient label. There are several considerations here. These chemical filters often break down when they absorb radiation. AND, several of these chemicals have been identified as health risks.
- Avobenzone is phototoxic, photoallergenic, and highly photo-unstable with as much as 90% photodegradation in most formulas (9, 18-20).
- Avobenzone increases free-radical production in UV-exposed skin, which is highly damaging, and its reactivity continues after exposure to the sunscreen has ended (21-23).
- Avobenzone cannot be combined with certain ingredients like octinoxate or capric/caprylic triglyceride because it will lose its efficacy (1, 24, 25).
- Oxybenzone is a phototoxicant and America’s most common cause of photoallergic contact dermatitis (PACD) (26-29).
- It’s also a known endocrine disrupting chemical (EDC) and genotoxic (9-12, 30, 31).
- Oxybenzone is made from carcinogen benzophenone and sunscreens with oxybenzone have been found to contain 75.95 ppm of residual benzophenone (32).
- Oxybenzone is banned along with octinoxate in Hawaii and Key West because these are not safe for the reef (33-35).
- In the FDA’s recent study to measure blood levels of oxybenzone after a single use, oxybenzone accumulated at 339-419 times the FDA limit for systemic absorption of sunscreen agents (36).
- Pregnant women are advised to practice caution while using homosalate because this UV absorber has been found to affect the survival of the placental cells that nourish the embryo (37, 38).
- Homosalate has been found to induce oxidative stress and damage the membrane around cellular mitochondria (37, 39).
- Octocrylene in a sunscreen is a photoallergen and it does not protect against UVA1 (39-42).
- It generates considerable free-radical singlet oxygen production in skin, enhancing UVA-induced damage (41-45).
These chemical filters absorb into our skin. Period.
How well are the chemical sunscreen absorbers absorbed into the skin? Unfortunately very well after just a single-use. According to the FDA, “results showed that all six active ingredients were absorbed into the body’s bloodstream – even after a single-use.
Additional findings from this new FDA study is that once absorbed, these active ingredients can remain in the body for extended periods of time. This study evaluated the absorption of the active ingredients avobenzone, oxybenzone, octocrylene, homosalate, octisalate, and octinoxate” (36).
The FDA has proposed their final rule where only zinc oxide and titanium dioxide sunscreens are still on the approved sunscreen monograph and they will require every chemical sunscreen to go through the new drug safety and efficacy approval process. (HALLA!)
These guidelines were supposed to go into effect this year but have been postponed to 2021 due to Covid-19 delays. What hasn’t changed is the FDA still strongly recommends zinc oxide sunscreen use, protective clothing, and seeking shade to prevent skin cancer.
Choose SPF with zinc oxide
And use a lot of it!
First of all, most people do not use enough sunscreen. SkinCancer.org says to actually get the full SPF factor listed on the bottle you need to apply a nickel-sized dollop to the face alone. If you apply less than that then all of a sudden your SPF 30 is now an SPF 25 or 20 or 15 so LOAD UP ladies.
What’s the Difference between SPF 15, 30, 50, etc?
The SPF on a product tells you how much longer your skin can withstand sunlight before a change in color occurs (47-49). If you normally have 5 minutes of unprotected UVB exposure before this occurs, an SPF 30 product will give you about 150 minutes. Within this time frame, sunscreen blocks UV to prevent DNA damage in skin cells (49-51).
You should always reapply any sunscreen after 2 hours, possibly sooner if you’re sweating heavily or in the water.
Sunscreen with an SPF of at least 30 that contains zinc oxide is recommended for protecting skin from UVA and UVB overhead and bouncing off concrete, sand, and water according to the American Academy of Dermatology.
However, Cancer.org explains the difference between SPF 15 and SPF 30 is just a 4% difference in coverage.
- SPF 15 sunscreens filter out about 93% of UVB rays
- SPF 30 sunscreens filter out about 97%
- SPF 50 sunscreens about 98%
Another finding is there was 1% less DNA damage with SPF 30 vs SPF 15 (50). So DNA damage at SPF 30 is 12% vs. SPF 15 at 13%. The DNA damage in sunscreen-free volunteers’ skin was very high and 100% of cells were positive for p53 DNA damage.
The takeaway being that consistency rules over the debate between what’s better: SPF 15, 30, 45 or 50.
Is a higher % of zinc better?
When we see zinc oxide on a sunscreen label, it’s usually followed by how much % zinc is used.
So in Josh Rosebrook’s Nutrient Day Cream SPF 30, the active ingredient is zinc oxide, 12%. Or in Fitglow Beauty’s Vita Active Shield SPF 30 it’s zinc oxide, 13%. Or in Kari Gran’s Essential SPF 28 it’s zinc oxide, 17%. Does more zinc oxide = better protection?
Here’s the deal. A formula’s SPF factor is measured using several inputs including; the percent of zinc used, the size of the zinc particles, the emollients used, the formulation technique and the antioxidants that are also present (52-55). As a general rule; 12% zinc will regularly achieve SPF 30.
That being said I wanted to give some more examples here because you will see different combinations of percentages on labels.
SPF 30 is generally the highest amount of SPF that can be achieved using zinc oxide alone (40 SPF unofficially if you stretch it with antioxidants) (56 – 58) So to get 40 SPF like we see in the Babo Daily Sheer Facial Sunscreen SPF 40, titanium dioxide is added in with zinc oxide to boost the SPF factor above 30. The same is true for Coola’s Baby SPF 50. OR, SPF 30 can be achievable with a combination of zinc oxide and titanium dioxide like the 5% zinc and 5% titanium dioxide like we see in Erin’s Faces Peptide SPF 30.
Okay, we are halfway there. After we vet the “active ingredient” section, we move on to the “inactive ingredient” section.
This is basically everything else that’s in the sunscreen. This takes a little bit more savviness to weed through but you’ve totally got this. Major things you want to avoid are fragrance, parfum, parabens, PEGs.
Here is an example of a sunscreen label that I would put back. You don’t even have to be a pro label reader to know this is a no-go. I see the word fragrance? Deal breaker.
On the contrary, below is an example of “inactive ingredients” that look good to me. Can you see the difference between example #1 and example #2?
For more, I recommend checking out my Easy Label Reading Checklist. Keep this on your phone and use on-the-go!
And if you are up to snuff on the basics, check out 12 hidden ingredients on labels for some next-level vetting.
Why is this sunscreen not USDA Certified Organic?
Once you’ve identified that the active ingredient is non-nano zinc oxide and there are no offenders in the inactive ingredients, you’ve most likely got yourself, what I would consider to be, a “clean beauty” or “organic” sunscreen.
Although “USDA Certified Organic sunscreens” do exist (like this one) the USDA Organic Certification is a limited tool when it comes to vetting sunscreens in general. It’s not an all-encompassing certification and it identifies only a small niche in the market. Many smaller, indie beauty brands are formulating over-the-top “skincare first” sunscreens and are not prioritizing the USDA Certification. Therefore we won’t see these indie brands included under the USDA Certified sunscreen umbrella.
But also, and maybe the bigger point is, the FDA does not define or regulate the term “organic,” as it applies to cosmetics, body care, or personal care products. “USDA certified organic” as a verification process applies to agriculture only. And because sunscreens rely heavily on non-agricultural ingredients like zinc oxide, getting a sunscreen USDA Certified Organic is, in some ways, like trying to fit a square peg into a round hole.
A better certification to look for is the ECOCERT Cosmos Natural (shown above) which you will see on brands like this.
Inactive ingredients matter
At a minimum, we want safe inactive ingredients however if you want to max out your sunscreen’s performance, look for SPFs formulated with antioxidants.
Antioxidants in skincare further significantly reduce the risk of UV damaging skin cells–this benefit was measured by histologically examining skin exposed to UV with and without topically applied antioxidants (59-62).
Antioxidants may be depleted when the body works to fight off the harmful effects of UV radiation so having them formulated into sunscreens can help boost your SPF protection.
Look for antioxidant ingredients like ferulic acid, oryzanol, vitamin c and more.
What’s your favorite clean/natural SPF?
RELATED: Check out my top picks for eco-friendly sunscreens here.
- Beasley DG, Meyer TA. Characterization of the UVA protection provided by avobenzone, zinc oxide, and titanium dioxide in broad-spectrum sunscreen products. American journal of clinical dermatology. 2010 Dec 1;11(6):413-21.
- Pinnell SR, Fairhurst D, Gillies R, Mitchnick MA, Kollias N. Microfine zinc oxide is a superior sunscreen ingredient to microfine titanium dioxide. Dermatologic surgery. 2000 Apr;26(4):309-14.
- Hojerová J, Medovcíková A, Mikula M. Photoprotective efficacy and photostability of fifteen sunscreen products having the same label SPF subjected to natural sunlight. International journal of pharmaceutics. 2011 Apr 15;408(1-2):27-38.
- Mitchnick MA, Fairhurst D, Pinnell SR. Microfine zinc oxide (Z-cote) as a photostable UVA/UVB sunblock agent. Journal of the American Academy of Dermatology. 1999 Jan 1;40(1):85-90.
- Seebode C, Lehmann J, Emmert S. Photocarcinogenesis and skin cancer prevention strategies. Anticancer research. 2016 Mar 1;36(3):1371-8.
- Agarwal N. Photocarcinogenesis and Molecular Mechanism. InPhotocarcinogenesis & Photoprotection 2018 (pp. 29-44). Springer, Singapore.
- Rünger TM, Farahvash B, Hatvani Z, Rees A. Comparison of DNA damage responses following equimutagenic doses of UVA and UVB: a less effective cell cycle arrest with UVA may render UVA-induced pyrimidine dimers more mutagenic than UVB-induced ones. Photochemical & Photobiological Sciences. 2012;11(1):207-15.
- Amar SK, Kumar D. Chemiexcitation of Melanin and Melanoma Pathogenesis. InSkin Aging & Cancer 2019 (pp. 79-86). Springer, Singapore.
- Abid AR, Marciniak B, Pędziński T, Shahid M. Photo-stability and photo-sensitizing characterization of selected sunscreens’ ingredients. Journal of Photochemistry and Photobiology A: Chemistry. 2017 Jan 1;332:241-50.
- DiNardo JC, Downs CA. Why Evaluate the Sunscreen Active Oxybenzone (Benzophenone-3) for Carcinogenicity and Reproductive Toxicology or Consider it Unsafe for Human Use. Dermatol Res. 2019;1(1):1-3.
- Siller A, Blaszak SC, Lazar M, Harken EO. Update about the effects of the sunscreen ingredients oxybenzone and octinoxate on humans and the environment. Plastic Surgical Nursing. 2019 Oct 1;39(4):157-60.
- Santovito A, Ruberto S, Galli G, Menghi C, Girotti M, Cervella P. Induction of chromosomal aberrations and micronuclei by 2-hydroxy-4-methoxybenzophenone (oxybenzone) in human lymphocytes. Drug and chemical toxicology. 2019 Jul 4;42(4):378-85.
- Cohen L, Brodsky MA, Zubair R, Kohli I, Hamzavi IH, Sadeghpour M. Cutaneous Interaction with Visible Light: What Do We Know. Journal of the American Academy of Dermatology. 2020 Apr 11.
- Richard F, Creusot T, Catoire S, Egles C, Ficheux H. Mechanisms of pollutant-induced toxicity in skin and detoxification: Anti-pollution strategies and perspectives for cosmetic products. InAnnales Pharmaceutiques Françaises 2019 Sep 25. Elsevier Masson.
- Leite-Silva VR, Sanchez WY, Studier H, Liu DC, Mohammed YH, Holmes AM, Ryan EM, Haridass IN, Chandrasekaran NC, Becker W, Grice JE. Human skin penetration and local effects of topical nano zinc oxide after occlusion and barrier impairment. European Journal of Pharmaceutics and Biopharmaceutics. 2016 Jul 1;104:140-7.
- Szikszai Z, Kertész Z, Bodnar E, Major I, Borbiro I, Kiss AZ, Hunyadi J. Nuclear microprobe investigation of the penetration of ultrafine zinc oxide into intact and tape-stripped human skin. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 2010 Jun 1;268(11-12):2160-3.
- Passino DR, Smith SB. Acute bioassays and hazard evaluation of representative contaminants detected in Great Lakes fish. Environmental Toxicology and Chemistry: An International Journal. 1987 Nov;6(11):901-7.
- Paris C, Lhiaubet‐Vallet V, Jiménez O, Trullas C, Miranda MA. A blocked diketo form of avobenzone: Photostability, photosensitizing properties and triplet quenching by a triazine‐derived UVB‐filter. Photochemistry and photobiology. 2009 Jan;85(1):178-84.
- Kawakami CM, Gaspar LR. Mangiferin and naringenin affect the photostability and phototoxicity of sunscreens containing avobenzone. Journal of Photochemistry and Photobiology B: Biology. 2015 Oct 1;151:239-47.
- Ceresole R, Asero MD, Han YK, Rosasco MA, Segall AI. Evaluation of Thermal Stability and Sun Protector Factor values In Vitro in O/W Emulsions Containing Benzophenone-3 and Avobenzone. Latin American Journal of Pharmacy. 2013 Jun 1;32(5):706-11.
- Ceresole R, Han Y, Rosasco MA, Orelli LR, Segall AI. Drug–excipient compatibility studies in binary mixtures of Avobenzone. J Cosmet Sci. 2013 Sep 1;64:317-28.
- Mujtaba SF, Srivastav AK, Agnihotry S, Negi S, Upadhayay J, Ray RS. Role of Personal Care Products and Phototoxicity. InPhotocarcinogenesis & Photoprotection 2018 (pp. 109-128). Springer, Singapore.
- Govindu PC, Hosamani B, Moi S, Venkatachalam D, Asha S, John VN, Sandeep V, Gowd KH. Glutathione as a photo-stabilizer of avobenzone: an evaluation under glass-filtered sunlight using UV-spectroscopy. Photochemical & Photobiological Sciences. 2019;18(1):198-207.
- Sayre RM, Dowdy JC, Gerwig AJ, Shlelds WJ, Lioyd RV. Unexpected Photolysis of the Sunscreen Octinoxate in the Presence of the Sunscreen Avobenzone¶. Photochemistry and photobiology. 2005 Mar;81(2):452-6.
- Jain P, Rahi P, Pandey V, Asati S, Soni V. Nanostructure lipid carriers: A modish contrivance to overcome the ultraviolet effects. Egyptian journal of basic and applied sciences. 2017 Jun 1;4(2):89-100.
- Szczurko C, Dompmartin A, Michel M, Moreau A, Leroy D. Photocontact allergy to oxybenzone: ten years of experience. Photodermatology, photoimmunology & photomedicine. 1994 Aug;10(4):144-7.
- Emonet S, Pasche-Koo F, Perin-Minisini MJ, Hauser C. Anaphylaxis to oxybenzone, a frequent constituent of sunscreens. Journal of Allergy and Clinical Immunology. 2001 Mar 1;107(3):556-7.
- Landers M, Law S, Storrs FJ. Contact urticaria, allergic contact dermatitis, and photoallergic contact dermatitis from oxybenzone. American journal of contact dermatitis: official journal of the American Contact Dermatitis Society. 2003 Mar;14(1):33-4.
- Veysey EC, Orton DI. Photoallergic contact cheilitis due to oxybenzone found in a lip cosmetic. Contact dermatitis. 2006 Jul;55(1):54-.
- DiNardo JC, Downs CA. Dermatological and environmental toxicological impact of the sunscreen ingredient oxybenzone/benzophenone‐3. Journal of cosmetic dermatology. 2018 Feb;17(1):15-9.
- Dinardo JC, Downs CA. Can oxybenzone cause Hirschsprung’s disease?. Reproductive Toxicology. 2019 Mar 1.
- https://www.regulations.gov/document?D=FDA- 1978-N-0018-1508
- Schneider SL, Lim HW. Review of environmental effects of oxybenzone and other sunscreen active ingredients. Journal of the American Academy of Dermatology. 2019 Jan 1;80(1):266-71.
- Downs CA, Kramarsky-Winter E, Segal R, Fauth J, Knutson S, Bronstein O, Ciner FR, Jeger R, Lichtenfeld Y, Woodley CM, Pennington P. Toxicopathological effects of the sunscreen UV filter, oxybenzone (benzophenone-3), on coral planulae and cultured primary cells and its environmental contamination in Hawaii and the US Virgin Islands. Archives of environmental contamination and toxicology. 2016 Feb 1;70(2):265-88.
- Raffa RB, Pergolizzi Jr JV, Taylor Jr R, Kitzen JM, NEMA Research Group. Sunscreen bans: Coral reefs and skin cancer. Journal of clinical pharmacy and therapeutics. 2019 Feb;44(1):134-9.
- Matta MK, Zusterzeel R, Pilli NR, Patel V, Volpe DA, Florian J, Oh L, Bashaw E, Zineh I, Sanabria C, Kemp S. Effect of sunscreen application under maximal use conditions on plasma concentration of sunscreen active ingredients: a randomized clinical trial. Jama. 2019 Jun 4;321(21):2082-91.
- Yang C, Lim W, Bazer FW, Song G. Homosalate aggravates the invasion of human trophoblast cells as well as regulates intracellular signaling pathways including PI3K/AKT and MAPK pathways. Environmental pollution. 2018 Dec 1;243:1263-73.
- Jiménez-Díaz I, Molina-Molina JM, Zafra-Gómez A, Ballesteros O, Navalón A, Real M, Sáenz JM, Fernández MF, Olea N. Simultaneous determination of the UV-filters benzyl salicylate, phenyl salicylate, octyl salicylate, homosalate, 3-(4-methylbenzylidene) camphor and 3-benzylidene camphor in human placental tissue by LC–MS/MS. Assessment of their in vitro endocrine activity. Journal of Chromatography B. 2013 Oct 1;936:80-7.
- Yazar S, GÖKÇEK Y. Assessment of in vitro genotoxicity effect of homosalate in cosmetics. Marmara Pharmaceutical Journal. 2018 Jan 1;21(3).
- de Groot AC, Roberts DW. Contact and photocontact allergy to octocrylene: a review. Contact Dermatitis. 2014 Apr;70(4):193-204.
- Avenel-Audran M, Dutartre H, Goossens A, Jeanmougin M, Comte C, Bernier C, Benkalfate L, Michel M, Ferrier-Lebouëdec MC, Vigan M, Bourrain JL. Octocrylene, an emerging photoallergen. Archives of dermatology. 2010 Jul 1;146(7):753-7.
- Bennàssar A, Grimalt R, Romaguera C, Vilaplana J. Two cases of photocontact allergy to the new sun filter octocrylene. Dermatology online journal. 2009;15(12):14-.
- Karlsson I, Persson E, Mårtensson J, Börje A. Investigation of the sunscreen octocrylene’s interaction with amino acid analogs in the presence of UV radiation. Photochemistry and photobiology. 2012 Jul;88(4):904-12.
- Hanson KM, Gratton E, Bardeen CJ. Sunscreen enhancement of UV-induced reactive oxygen species in the skin. Free Radical Biology and Medicine. 2006 Oct 15;41(8):1205-12.
- Gago-Ferrero P, Alonso MB, Bertozzi CP, Marigo J, Barbosa L, Cremer M, Secchi ER, Azevedo A, Lailson-Brito Jr J, Torres JP, Malm O. First determination of UV filters in marine mammals. Octocrylene levels in Franciscana dolphins. Environmental science & technology. 2013 Jun 4;47(11):5619-25.
- Blüthgen N, Meili N, Chew G, Odermatt A, Fent K. Accumulation and effects of the UV-filter octocrylene in adult and embryonic zebrafish (Danio rerio). Science of the Total Environment. 2014 Apr 1;476:207-17.
- DeHaven C, Hayden PJ, Armento A, Oldach J. DNA photoprotection conveyed by sunscreen. Journal of cosmetic dermatology. 2014 Jun;13(2):99-102.
- Khan AQ, Travers JB, Kemp MG. Roles of UVA radiation and DNA damage responses in melanoma pathogenesis. Environmental and molecular mutagenesis. 2018 Jun;59(5):438-60.
- Reinert G, Fuso F, Hilfiker R, Schmidt E. UV-protecting properties of textile fabrics and their improvement. Textile Chemist & Colorist. 1997 Dec 1;29(12).
- Phillips TJ, Bhawan J, Yaar M, Bello Y, LoPiccolo D, Nash JF. Effect of daily versus intermittent sunscreen application on solar simulated UV radiation–induced skin response in humans. Journal of the American Academy of Dermatology. 2000 Oct 1;43(4):610-8.
- Césarini JP, Demanneville S. Toward a genotoxic protection factor. Radiation protection dosimetry. 2000 Sep 1;91(1-3):89-91.
- Kaidbey KH. The photoprotective potential of the new superpotent sunscreens. Journal of the American Academy of Dermatology. 1990 Jan 1;22(3):449-52.
- Montenegro L, Santagati LM. Use of Vegetable Oils to Improve the Sun Protection Factor of Sunscreen Formulations. Cosmetics. 2019 Jun;6(2):25.
- Yeon JY, Seo JM, Bae JT, Lee CH, Lee SG, Pyo HB, Hong JT. A study on the factors that influence the sun protection factor (SPF) and protection factor of UV-A (PA) in sunscreen. Journal of the Korean Applied Science and Technology. 2014;31(3):422-39.
- Villalobos-Hernandez JR, Müller-Goymann CC. Sun protection enhancement of titanium dioxide crystals by the use of carnauba wax nanoparticles: the synergistic interaction between organic and inorganic sunscreens at nanoscale. International journal of pharmaceutics. 2006 Sep 28;322(1-2):161-70.
- Shaath NA. The chemistry of sunscreens. Sunscreens: Development, Evaluation and Regulatory Aspects. 1990;10:211-33.
- Cesarini JP, Michel L, Maurette JM, Adhoute H, Bejot M. Immediate effects of UV radiation on the skin: modification by an antioxidant complex containing carotenoids. Photodermatology, photoimmunology & photomedicine. 2003 Aug;19(4):182-9.
- Yim S, Lee J, Hae J, Scholten J, Willingham R, Nicoll J, Baswan SM. Chrysanthemum Morifolium Extract And Ascorbic Acid-2-Glucoside (AA2G) Blend Inhibits UVA-Induced Delayed Cyclobutane Pyrimidine Dimer (CPD) Production In Melanocytes. Clinical, Cosmetic and Investigational Dermatology. 2019;12:823.
- Rojas JO, Londoño CE, Ciro YH. The health benefits of natural skin UVA photoprotective compounds found in botanical sources. Int J Pharm Pharm Sci. 2016;8(3):13-23.
- Lorigo M, Cairrao E. Antioxidants as stabilizers of UV filters: an example for the UV-B filter octylmethoxycinnamate. Biomedical Dermatology. 2019 Dec 1;3(1):11.
- Leccia MT, Béani JC. Protection by Antioxidants Against UV-Induced Damage. Trace Elements and Free Radicals in Oxidative Diseases. 1994 May 30:233.