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Research · Medication

Sunscreen

In one Australian trial, daily sunscreen cut squamous cell skin cancers about 40%, slowed skin aging and was followed by half as many melanomas, a borderline result. Observational studies of melanoma disagree. FDA trials found chemical filters reach the blood above its screening threshold, a measure of exposure, not harm. Vitamin D effects in real use were small.

Add to Bio HackChecked 2026-11-14
Status
Regulated in the US as an over-the-counter drug under FDA's sunscreen monograph (M020). FDA's 2019 proposed rule, carried into a 2021 proposed order, found zinc oxide and titanium dioxide generally recognized as safe and effective, and asked for more safety data on 12 chemical filters, including oxybenzone and avobenzone. A 2026 final order removed PABA and trolamine salicylate. Another added bemotrizinol.
Also called
sunblock, sun cream, SPF, broad spectrum sunscreen, mineral sunscreen, physical sunscreen, zinc oxide, titanium dioxide, chemical sunscreen, organic UV filters, oxybenzone, benzophenone-3, avobenzone, octocrylene, homosalate, octisalate, octinoxate, ensulizole, ecamsule, bemotrizinol, PABA, reef safe sunscreen
Taken for
preventing sunburn, preventing skin cancer, melanoma prevention, squamous cell carcinoma, actinic keratoses, preventing wrinkles and skin aging, fewer moles in children, dark spots

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help4

Reported risks5

What people take it for, and what was found

Shown to help4

Limited

Sunburn

Small trials found sunscreen applied at the tested thickness almost prevented sunburn on a sunny holiday, and SPF 100+ left fewer people burned than SPF 50+.

Compared with usual sunscreen use without instruction [1]; SPF 50+ sunscreen [2]

The numbers and sources
Effect
During a week in Tenerife, people using their own sunscreen without instruction had daily erythema and epidermal DNA damage, while erythema was virtually absent in those applying SPF 15 at 2 mg/cm2 or more. People typically apply about 0.8 mg/cm2 [1]. In a split-face trial after about 6 hours in the sun, 55.3% were more sunburned on the SPF 50+ side and 5% on the SPF 100+ side [2]. FDA proposed capping labeled SPF at 60+, citing a lack of data that values above 60 add meaningful clinical benefit [3].
Population
62 holidaymakers [1]; 199 adults in Colorado [2].
Sources
[1], [2], [3]
Caveats
The SPF 100+ trial was funded and largely written by Johnson & Johnson Consumer staff [2]. Single-day exposure [2].
Limited

Actinic keratoses (precancerous spots)

One trial found daily SPF 17 sunscreen over one summer led to fewer new solar keratoses and more remissions than a base cream without filters.

Compared with vehicle base cream without the active ingredients [12]

The numbers and sources
Effect
Solar keratoses rose by 1.0 per person on the base cream and fell by 0.6 on sunscreen (difference 1.53, 95% CI 0.81 to 2.25). The sunscreen group had fewer new lesions (rate ratio 0.62, 95% CI 0.54 to 0.71) and more remissions (OR 1.53). More sunscreen used went with fewer new lesions [12].
Population
588 adults aged 40 or older in Australia, one summer [12].
Sources
[12]
Caveats
One trial over 7 months.
Limited

Skin aging (photoaging)

One trial found daily broad-spectrum sunscreen led to 24% less skin aging over 4.5 years than discretionary use, in adults under 55.

Compared with discretionary sunscreen use [13]

The numbers and sources
Effect
The daily sunscreen group showed no detectable increase in skin aging, measured by skin surface microtopography. Aging from 1992 to 1996 was 24% less than in the discretionary group (relative odds 0.76, 95% CI 0.59 to 0.98) [13].
Population
903 adults under 55 from the Nambour trial [13].
Sources
[13]
Caveats
Some outcome data were missing, and power was modest [13].
LimitedStudied in children

Moles in children

One trial found children given SPF 30 broad-spectrum sunscreen developed slightly fewer new moles over 3 years, mostly in freckled children.

Compared with no sunscreen supplied and no advice [14]

The numbers and sources
Effect
Children in the sunscreen group developed a median 24 new nevi against 28 in controls (P = .048). Modeling suggested freckled children would develop 30% to 40% fewer new nevi [14].
Population
309 white schoolchildren in Vancouver analyzed of 458 randomized [14].
Sources
[14]
Caveats
One trial, with many children excluded or lost [14]. Mole count is a risk marker for melanoma, not melanoma itself.

Mixed results2

Limited

Squamous cell skin cancer

One trial found daily sunscreen cut squamous cell carcinoma tumors about 40% against discretionary use, over 4.5 years and 8 years after. The number of people affected did not differ.

Compared with discretionary sunscreen use [4][5][6]

The numbers and sources
Why limited
This rests on one trial, of 1,621 people. Strength counts independent studies that agree, so one trial is limited at any size.
Effect
Daily SPF 15+ sunscreen on the head, neck, arms and hands lowered the rate of squamous cell carcinoma tumors (1,115 against 1,832 per 100,000, rate ratio 0.61, 95% CI 0.46 to 0.81), but not the rate of people with a first new squamous cell carcinoma (rate ratio 0.88, 95% CI 0.50 to 1.56) [4]. Over 8 more years of follow-up, tumor rates stayed about 40% lower (rate ratio 0.62, 95% CI 0.38 to 0.99) [5]. A Cochrane review of the same trial rated the evidence low quality and could not show prevention (RR 0.88) [6].
Population
1,621 adults aged 25 to 75 in Nambour, Queensland, Australia [4][5][6].
Sources
[4], [5], [6]
Caveats
One trial, in a high-UV region. The comparison group could still use sunscreen as they chose [4].
Limited

Melanoma

Mixed results: one trial found half as many melanomas after daily sunscreen, a borderline result, while observational meta-analyses found no overall association.

Compared with discretionary sunscreen use [7]; people who never or rarely used sunscreen [8][9][10]; sunscreen below SPF 15 [11]

The numbers and sources
Effect
Ten years after the trial ended, 11 new melanomas occurred in the daily sunscreen group and 22 in the discretionary group (HR 0.50, 95% CI 0.24 to 1.02), with fewer invasive melanomas (3 against 11, HR 0.27, 95% CI 0.08 to 0.97) [7]. Across 25 mostly case-control studies, melanoma was not associated with sunscreen use (OR 1.10, 95% CI 0.92 to 1.33, I2 89%), and studies before the 1980s showed a positive association [8]. A review of 28 studies found results varied by design: inverse in hospital case-control studies (OR 0.57), none in population case-control studies (OR 1.17) and positive in cohorts (HR 1.27), with adjustment for sun exposure moving estimates toward lower risk [9]. A 2025 review of 23 studies found OR 0.98 (95% CI 0.79 to 1.21) [10]. In 143,844 Norwegian women, SPF 15 or higher was linked to lower melanoma risk than SPF under 15 (HR 0.67, 95% CI 0.53 to 0.83) [11].
Population
1,621 Australian adults [7]; 29 studies, 313,717 participants [8]; 21,069 melanoma cases in 28 studies [9]; 23 studies [10]; women aged 40 to 75 [11].
Sources
[7], [8], [9], [10], [11]
Caveats
Observational studies are confounded, because people who burn easily and spend more time in the sun use more sunscreen [9][11]. The trial result was borderline, with 33 melanomas in total [7].

Not shown to help1

Limited

Basal cell skin cancer

One trial found daily sunscreen did not lower basal cell carcinoma against discretionary use over 4.5 years, and the later follow-up showed only a nonsignificant trend.

Compared with discretionary sunscreen use [4][5][6]

The numbers and sources
Why limited
This rests on one trial, of 1,621 people. Strength counts independent studies that agree, so one trial is limited at any size.
Effect
Basal cell carcinoma incidence did not differ (2,588 against 2,509 per 100,000, rate ratio 1.03, 95% CI 0.73 to 1.46), and tumor counts were also not lower [4]. In 8 more years of follow-up, rates tended to fall, not significantly [5]. The Cochrane review found RR 1.03 (95% CI 0.74 to 1.43) [6].
Population
1,621 adults in Nambour, Australia [4][5][6].
Sources
[4], [5], [6]
Caveats
One trial.

Doses studied

SPF is assessed with sunscreen applied at 2 mg/cm2, and people typically apply about 0.8 mg/cm2 [1]. The Nambour trial used an SPF 15+ sunscreen applied daily to the head, neck, arms and hands for 4.5 years [4]. The solar keratosis trial used SPF 17 daily over one summer [12], and the moles trial SPF 30 when children would be in the sun 30 minutes or more [14]. FDA's absorption trials applied 2 mg/cm2 to 75% of the body 4 times a day for 4 days [16][17]. FDA's labeling states that regular use of a Broad Spectrum SPF 15 or higher sunscreen, with other sun protection measures, decreases the risk of skin cancer and early skin aging [3].

Risks

Reported risks4

ModerateHow often is not known

Chemical filters absorbed into the blood

FDA trials found all six chemical filters tested reached blood levels above FDA's 0.5 ng/mL screening threshold after one day of use. They measured exposure, not harm.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Under maximal use, geometric mean peak plasma levels were 1.8 to 4.3 ng/mL for avobenzone, 169.3 to 209.6 ng/mL for oxybenzone, 2.9 to 7.8 ng/mL for octocrylene and 1.5 ng/mL for ecamsule, all above 0.5 ng/mL after 4 applications on day 1 [16]. A second trial found all six filters tested, avobenzone, oxybenzone, octocrylene, homosalate, octisalate and octinoxate, exceeded 0.5 ng/mL after a single application, with oxybenzone peaking at 258.1 ng/mL from the lotion [17]. FDA set 0.5 ng/mL as the level below which a carcinogenicity study might not be needed, not as a level of harm [3]. Both trials state the results "do not indicate that individuals should refrain from the use of sunscreen" [16][17].
Population
24 healthy adults [16]; 48 healthy adults [17].
Sources
[16], [17], [3]
Caveats
Small pharmacokinetic trials under heavier than usual use. They did not measure any health outcome.
ModerateHow often is not known

FDA safety data gaps and removed ingredients

FDA found too little safety data to call 12 chemical filters generally recognized as safe and effective, and removed PABA and trolamine salicylate in 2026.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
FDA's 2019 proposal classed zinc oxide and titanium dioxide, up to 25%, as generally recognized as safe and effective. It found the record lacked data for cinoxate, dioxybenzone, ensulizole, homosalate, meradimate, octinoxate, octisalate, octocrylene, padimate O, sulisobenzone, oxybenzone and avobenzone, noting oxybenzone is absorbed more than previously understood and has been found in breast milk and amniotic fluid. It proposed PABA and trolamine salicylate as not generally recognized as safe and effective, citing allergic reactions for PABA [3]. The 2021 proposed order under the CARES Act set out requirements FDA called substantively the same as the 2019 proposal, and stated that the two absorption studies reinforced the need for the data it had requested [18]. A 2026 final order removed PABA and trolamine salicylate [19]. FDA proposed adding bemotrizinol up to 6% in December 2025 [20] and finalized it in June 2026 [21].
Population
Regulatory reviews of the US sunscreen market [3][18][19][20][21].
Sources
[3], [18], [19], [20], [21]
Caveats
A request for more data is not a finding of harm.
LimitedHow often is not known

Rash, contact allergy and photoallergy

Rash was the most common adverse event in FDA's absorption trials, in 14 of 48 people. In people tested for suspected reactions, 10% had photoallergy to a sunscreen chemical.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Rash developed in 14 of 48 participants under maximal use [17], and in 1 participant on each of 4 sunscreens in the earlier trial [16]. In a European photopatch test study, 13 of 132 participants (10%) reacted to sunscreen chemicals, most often avobenzone and oxybenzone [22]. Photocontact allergy to octocrylene is seen mainly in adults previously sensitized to the anti-inflammatory gel ketoprofen, and contact allergy to it mostly in children [23]. The Cochrane review lists skin irritation and contact allergy among reported adverse events [6].
Population
72 healthy adults in FDA trials [16][17]; 132 patients photopatch tested in 10 European centers [22]; case series reviewed in [23].
Sources
[17], [16], [22], [23], [6]
Caveats
The FDA trials had no comparison group, and the photopatch study tested people already suspected of a reaction, so neither gives a rate for ordinary users.
LimitedHow often is not known

Longer time in the sun with higher SPF

One trial found young adults given SPF 30 sunbathed longer than those given SPF 10, with no difference in sunburn.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Cumulative sun exposure was 72.6 hours with SPF 30 and 58.2 hours with SPF 10 (P = .011), and daily sunbathing 3.1 against 2.6 hours. Sunburn did not differ [15].
Population
86 French and Swiss adults aged 18 to 24 on summer holidays [15].
Sources
[15]
Caveats
One small trial. Participants did not know which SPF they had [15].

Mixed results1

ModerateHow often is not known

Vitamin D

Mixed results: sunscreen blocked vitamin D production under artificial UV light, but field trials and real-life studies found little or no drop in vitamin D levels.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
In 4 experimental studies with artificial UV, sunscreen largely abrogated vitamin D3 or 25(OH)D production. Two randomized field trials of SPF about 16 found no effect of daily use, and most of 69 observational studies found no association or higher 25(OH)D in sunscreen users [24]. On a week-long sunny holiday, 25(OH)D3 rose by 19.0 and 13.0 nmol/L on two SPF 15 sunscreens applied as directed and by 28.0 nmol/L with discretionary use, while it fell 2.5 nmol/L in people who stayed home [25].
Population
76 studies reviewed [24]; 79 Polish adults, 62 on holiday [25].
Sources
[24], [25]
Caveats
No trial has tested the high-SPF sunscreens now common [24].

Checked, no increase found3

Limited

Hormone levels with chemical filters

One small study found two weeks of whole-body oxybenzone, octinoxate and 4-MBC did not change LH or FSH, and minor testosterone and estradiol differences were unrelated to exposure.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
After a week of base cream and a week of cream with 10% each of benzophenone-3 (oxybenzone), octyl-methoxycinnamate (octinoxate) and 4-methylbenzylidene camphor at 2 mg/cm2, peak plasma levels reached 200 to 300 ng/mL for oxybenzone. FSH and LH were unchanged. Minor differences in testosterone, and in estradiol and inhibin B in men, were not related to sunscreen exposure [26].
Population
32 healthy volunteers, 15 young men and 17 postmenopausal women [26].
Sources
[26]
Caveats
Small, two weeks, single-blinded. 4-MBC is not an FDA monograph ingredient.
Limited

Nanoparticle zinc oxide entering the skin

One volunteer study found zinc oxide nanoparticles stayed on the skin surface and in furrows and did not enter or harm the living epidermis over 5 days.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
With repeated application over 5 days, zinc oxide nanoparticles accumulated on the skin surface and in skin furrows but did not enter the viable epidermis or cause cell toxicity there. Zinc ion levels in the viable epidermis of excised skin rose slightly [27].
Population
Human volunteers and excised human skin [27].
Sources
[27]
Caveats
One small study. FDA's 2019 proposal discussed nanomaterial forms and still classed zinc oxide as generally recognized as safe and effective [3].
Limited

Death from any cause

One trial found 4.5 years of daily SPF 16 sunscreen did not change deaths from any cause, heart disease or cancer over 21 years.

The numbers and sources
How common
How often is not known: the sources give no rate.
Effect
Deaths numbered 160 in the daily group and 170 in the discretionary group (HR 0.94, 95% CI 0.76 to 1.17). Cardiovascular deaths were 59 against 76 (HR 0.77) and cancer deaths 63 against 58 (HR 1.09) [28].
Population
1,621 adults from the Nambour trial, followed 1993 to 2014 [28].
Sources
[28]
Caveats
One trial, not designed to measure mortality.

Claims tested and not found

  1. That sunscreen prevents basal cell carcinoma. In the only randomized trial, basal cell carcinoma did not differ between daily and discretionary use (rate ratio 1.03) [4].
  2. That ordinary sunscreen use causes vitamin D deficiency. Randomized field trials found no effect of daily use on 25(OH)D, and vitamin D rose on a sunny holiday even with sunscreen applied as directed [24][25].
  3. That regular sunscreen use shortens life. Deaths over 21 years did not differ between daily and discretionary users (HR 0.94) [28].

Related

SunlightVitamin D

Sources

  1. Narbutt J, Philipsen PA, Harrison GI, et al. Sunscreen applied at ≥ 2 mg cm-2 during a sunny holiday prevents erythema, a biomarker of ultraviolet radiation-induced DNA damage and suppression of acquired immunity. British Journal of Dermatology. 2019. https://doi.org/10.1111/bjd.17277
  2. Williams JD, Maitra P, Atillasoy E, et al. SPF 100+ sunscreen is more protective against sunburn than SPF 50+ in actual use: Results of a randomized, double-blind, split-face, natural sunlight exposure clinical trial. Journal of the American Academy of Dermatology. 2018. https://doi.org/10.1016/j.jaad.2017.12.062
  3. U.S. Food and Drug Administration. Sunscreen Drug Products for Over-the-Counter Human Use. Proposed rule. Federal Register 84 FR 6204. 2019. https://www.federalregister.gov/documents/2019/02/26/2019-03019/sunscreen-drug-products-for-over-the-counter-human-use
  4. Green A, Williams G, Neale R, et al. Daily sunscreen application and betacarotene supplementation in prevention of basal-cell and squamous-cell carcinomas of the skin: a randomised controlled trial. The Lancet. 1999. https://doi.org/10.1016/s0140-6736(98)12168-2
  5. van der Pols JC, Williams GM, Pandeya N, Logan V, Green AC. Prolonged prevention of squamous cell carcinoma of the skin by regular sunscreen use. Cancer Epidemiology, Biomarkers & Prevention. 2006. https://doi.org/10.1158/1055-9965.epi-06-0352
  6. Sánchez G, Nova J, Rodriguez-Hernandez AE, et al. Sun protection for preventing basal cell and squamous cell skin cancers. Cochrane Database of Systematic Reviews. 2016. https://doi.org/10.1002/14651858.cd011161.pub2
  7. Green AC, Williams GM, Logan V, Strutton GM. Reduced melanoma after regular sunscreen use: randomized trial follow-up. Journal of Clinical Oncology. 2011. https://doi.org/10.1200/jco.2010.28.7078
  8. Silva ESD, Tavares R, Paulitsch FDS, Zhang L. Use of sunscreen and risk of melanoma and non-melanoma skin cancer: a systematic review and meta-analysis. European Journal of Dermatology. 2018. https://doi.org/10.1684/ejd.2018.3251
  9. Rueegg CS, Stenehjem JS, Egger M, et al. Challenges in assessing the sunscreen-melanoma association. International Journal of Cancer. 2019. https://doi.org/10.1002/ijc.31997
  10. Brunner AS, Haddad S, Weise JJ, et al. Malignant Melanoma: The Relationship Between Sunscreen Use and Cancer Risk. A Systematic Review and Meta-analysis. Anticancer Research. 2025. https://doi.org/10.21873/anticanres.17724
  11. Ghiasvand R, Weiderpass E, Green AC, Lund E, Veierød MB. Sunscreen Use and Subsequent Melanoma Risk: A Population-Based Cohort Study. Journal of Clinical Oncology. 2016. https://doi.org/10.1200/jco.2016.67.5934
  12. Thompson SC, Jolley D, Marks R. Reduction of solar keratoses by regular sunscreen use. New England Journal of Medicine. 1993. https://doi.org/10.1056/nejm199310143291602
  13. Hughes MC, Williams GM, Baker P, Green AC. Sunscreen and prevention of skin aging: a randomized trial. Annals of Internal Medicine. 2013. https://doi.org/10.7326/0003-4819-158-11-201306040-00002
  14. Gallagher RP, Rivers JK, Lee TK, et al. Broad-spectrum sunscreen use and the development of new nevi in white children: A randomized controlled trial. JAMA. 2000. https://doi.org/10.1001/jama.283.22.2955
  15. Autier P, Doré JF, Négrier S, et al. Sunscreen use and duration of sun exposure: a double-blind, randomized trial. Journal of the National Cancer Institute. 1999. https://doi.org/10.1093/jnci/91.15.1304
  16. Matta MK, Zusterzeel R, Pilli NR, et al. Effect of Sunscreen Application Under Maximal Use Conditions on Plasma Concentration of Sunscreen Active Ingredients: A Randomized Clinical Trial. JAMA. 2019. https://doi.org/10.1001/jama.2019.5586
  17. Matta MK, Florian J, Zusterzeel R, et al. Effect of Sunscreen Application on Plasma Concentration of Sunscreen Active Ingredients: A Randomized Clinical Trial. JAMA. 2020. https://doi.org/10.1001/jama.2019.20747
  18. U.S. Food and Drug Administration. Amending Over-the-Counter Monograph M020: Sunscreen Drug Products for Over-the-Counter Human Use; Over the Counter Monograph Proposed Order; Availability. Federal Register 86 FR 53322. 2021. https://www.federalregister.gov/documents/2021/09/27/2021-20780/amending-over-the-counter-monograph-m020-sunscreen-drug-products-for-over-the-counter-human-use-over
  19. U.S. Food and Drug Administration. Amending Over-the-Counter Monograph M020: Sunscreen Drug Products for Over-the-Counter Human Use, and Related Information; Aminobenzoic Acid (PABA) and Trolamine Salicylate. Final order notice. Federal Register 91 FR 57892. 2026. https://www.federalregister.gov/documents/2026/09/11/2026-18551/amending-over-the-counter-monograph-m020-sunscreen-drug-products-for-over-the-counter-human-use-and
  20. U.S. Food and Drug Administration. Amending Over-the-Counter Monograph M020: Sunscreen Drug Products for Over-the-Counter Human Use (bemotrizinol proposed order). Federal Register 90 FR 57765. 2025. https://www.federalregister.gov/documents/2025/12/12/2025-22649/amending-over-the-counter-monograph-m020-sunscreen-drug-products-for-over-the-counter-human-use
  21. U.S. Food and Drug Administration. Amending Over-the-Counter Monograph M020: Sunscreen Drug Products for Over-the-Counter Human Use, and Related Information (bemotrizinol final order). Federal Register 91 FR 35220. 2026. https://www.federalregister.gov/documents/2026/06/10/2026-11578/amending-over-the-counter-monograph-m020-sunscreen-drug-products-for-over-the-counter-human-use-and
  22. Ralph N, Goossens A, Carrascosa JM, et al. Prospective multicentre photopatch test study of photoallergy to sunscreens and nonsteroidal anti-inflammatory drugs in Europe. British Journal of Dermatology. 2026. https://doi.org/10.1093/bjd/ljag085
  23. de Groot AC, Roberts DW. Contact and photocontact allergy to octocrylene: a review. Contact Dermatitis. 2014. https://doi.org/10.1111/cod.12205
  24. Neale RE, Khan SR, Lucas RM, et al. The effect of sunscreen on vitamin D: a review. British Journal of Dermatology. 2019. https://doi.org/10.1111/bjd.17980
  25. Young AR, Narbutt J, Harrison GI, et al. Optimal sunscreen use, during a sun holiday with a very high ultraviolet index, allows vitamin D synthesis without sunburn. British Journal of Dermatology. 2019. https://doi.org/10.1111/bjd.17888
  26. Janjua NR, Mogensen B, Andersson AM, et al. Systemic absorption of the sunscreens benzophenone-3, octyl-methoxycinnamate, and 3-(4-methyl-benzylidene) camphor after whole-body topical application and reproductive hormone levels in humans. Journal of Investigative Dermatology. 2004. https://doi.org/10.1111/j.0022-202x.2004.22725.x
  27. Mohammed YH, Holmes A, Haridass IN, et al. Support for the Safe Use of Zinc Oxide Nanoparticle Sunscreens: Lack of Skin Penetration or Cellular Toxicity after Repeated Application in Volunteers. Journal of Investigative Dermatology. 2019. https://doi.org/10.1016/j.jid.2018.08.024
  28. Lindstrom AR, von Schuckmann LA, Hughes MCB, et al. Regular Sunscreen Use and Risk of Mortality: Long-Term Follow-up of a Skin Cancer Prevention Trial. American Journal of Preventive Medicine. 2019. https://doi.org/10.1016/j.amepre.2018.11.025

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