Octocrylene Safety: Stabilizer With a Contamination Problem

Last updated October 27, 2026

Absorbed into blood at 15x the FDA threshold, and it breaks down into benzophenone as the bottle ages.

2/5 protection rating
UVB + some UVA II

Octocrylene is a UVB filter primarily used to stabilize avobenzone in chemical sunscreens. Recent research revealing benzophenone contamination, high systemic absorption, and photoallergy reports concentrated in ketoprofen-sensitized adults have raised significant safety concerns.

Is Octocrylene Safe? The Short Answer

It is legal in the US, the EU, Canada, Australia and Japan at up to 10% (9% in EU propellant sprays), and the EU and Australian reviews judged it safe at those levels. It is banned in the US Virgin Islands and Palau over reef damage. What keeps the question open is what happens after it is applied, and what it turns into in the bottle.

Two measurements are behind the caution. In the FDA's 2020 maximal-use trial, octocrylene reached 7.8 ng/mL in blood from a lotion, about 15 times the FDA's 0.5 ng/mL threshold, and stayed above that level through day 10 in two-thirds of participants. And a 2021 study found that octocrylene sunscreens averaging 39 mg/kg benzophenone off the shelf averaged 75 mg/kg after six weeks of accelerated aging; the one product without octocrylene had none.

The practical point follows from the second finding: if you use an octocrylene sunscreen, use fresh stock and do not keep last year's bottle.

⚠️ Benzophenone Contamination

Studies show octocrylene degrades into benzophenone, a suspected carcinogen and endocrine disruptor. Benzophenone levels increase over time, making older sunscreens potentially more hazardous.

Chemical Properties and UV Protection

Octocrylene is a cyanoacrylate that absorbs UVB and short-wave UVA radiation (280-320 nm). Approved at up to 10% in the US and EU (9% in EU propellant sprays), it serves dual purposes as a UV filter and photostabilizer for other ingredients, particularly avobenzone.

UV Absorption Profile

Peak absorption occurs at 303 nm with some UVA II coverage. While providing moderate SPF contribution, octocrylene's primary value lies in preventing the photodegradation of avobenzone, making it nearly ubiquitous in chemical broad-spectrum sunscreens.

Benzophenone Formation

Degradation Study (2021)

Research published in Chemical Research in Toxicology found octocrylene degrades into benzophenone over time. Sixteen octocrylene-containing sunscreens bought off the shelf averaged 39 mg/kg benzophenone; after six weeks of the FDA's accelerated aging protocol the same products averaged 75 mg/kg, and the worst reached 435 mg/kg. The one product in the set without octocrylene had none, before or after.

Benzophenone concerns include:

This degradation means sunscreens become more toxic over time, with older products posing greater risks than fresh ones - a unique concern among sunscreen ingredients.

Systemic Absorption Research

FDA Absorption Studies (2019-2020)

Clinical trials found octocrylene plasma concentrations reached 7.8 ng/mL - over 15 times the FDA safety threshold of 0.5 ng/mL. The chemical accumulated in the body with repeated use over 4 days.

Absorption characteristics:

Increasing Photoallergic Reactions

Octocrylene Allergy Review (2014)

A 2014 review in Contact Dermatitis brought together the published reports of octocrylene allergy, most of them from France, Belgium, Spain and Italy:

  • The most frequent photoallergen among UV filters. In a 2008-2011 European study, 1,031 patients referred for photopatch testing (sun-exposed rashes or past reactions to sunscreens or anti-inflammatory gels) were tested in 30 centres across 12 countries; octocrylene gave 41 positive reactions (4%), more than any other UV filter, behind only the anti-inflammatory painkillers ketoprofen and etofenamate. Rates ranged from 0% in some countries to an estimated 32% in France.
  • Usually follows ketoprofen. 83% of the patients photoallergic to octocrylene in that study also reacted to ketoprofen, an anti-inflammatory drug sold as a topical gel. The authors estimate that probably more than 80% of octocrylene photoallergy results from earlier sensitization to ketoprofen, though whether this is true cross-reactivity cannot yet be stated.
  • Adults and children differ. Sun-triggered (photoallergic) reactions, about 80% of the 131 octocrylene reactions notified to a French allergy-vigilance network in 2007-2012, are seen mainly in adults; plain contact allergy is far less frequent and is seen mostly in children, from sunscreens.
  • Linked reactions to oxybenzone. 44-72% of patients photoallergic to octocrylene also reacted to benzophenone-3 (oxybenzone).

Reference: de Groot AC, Roberts DW. Contact and photocontact allergy to octocrylene: a review. Contact Dermatitis. 2014;70(4):193-204. doi:10.1111/cod.12205.

Since 2003, studies mostly from France, Belgium, Spain and Italy have reported growing numbers of patients with octocrylene photoallergy, mainly adults who had earlier used ketoprofen gel (2014 review). Anyone with a confirmed patch or photopatch test allergy to octocrylene should avoid products that contain it; the review found it in more than 20% of everyday skin-care cosmetics, not just sunscreens.

Environmental Impact

Marine Toxicity

Octocrylene demonstrates significant environmental persistence and toxicity:

Regulatory Bans

US Virgin Islands (2020): Banned alongside oxybenzone and octinoxate
Palau (2020): Included in comprehensive sunscreen ban
Under consideration: Several other regions evaluating restrictions

Safety Concerns

Endocrine Disruption

Both octocrylene and its degradation product benzophenone show hormonal activity:

Reproductive Concerns

Animal studies indicate potential reproductive effects including:

Regulatory Status

United States: Approved at up to 10% concentration. FDA has not determined GRASE status: its 2021 proposed order found the public record does not contain sufficient data to support a positive determination and requested additional safety studies.

European Union: Maximum 10%, and 9% in propellant sprays, under Regulation (EU) 2022/1176. The limits follow the SCCS's 2021 opinion (SCCS/1627/21), which assessed its potential endocrine-disrupting properties and found it safe at those levels. The regulation also requires benzophenone, as an impurity or degradation product of octocrylene, to be kept at trace level.

Industry response: Some manufacturers reformulating to remove octocrylene due to contamination concerns and consumer pressure.

Australia: Permitted at up to 10% under TGA regulation. The TGA's 2025 safety review found a margin of safety above 100 and considers it low-risk at permitted levels.

Canada: Permitted at up to 10% under Health Canada's Primary Sunscreen Monograph.

Storage and Stability Issues

The benzophenone formation issue creates unique challenges:

  1. Shelf life concerns: Sunscreens become more toxic over time
  2. Storage conditions: Heat and light accelerate degradation
  3. No expiration enforcement: Many countries don't require expiration dates
  4. Consumer awareness: Most users unaware of degradation risks

What the Studies Actually Tested

Two bodies of evidence sit behind this page, and only one of them tested commercial sunscreens at all. The FDA's maximal-use trials describe their products by formulation type — lotion, aerosol spray, non-aerosol spray, pump spray — and name no brands. The benzophenone work did buy products off the shelf, but the brand identities and the per-product figures are in supplementary material behind a paywall we have not read, so no product is named here either.

Benzophenone Contamination (2021)

Seventeen products were assayed — nine from the EU, eight from the US, including two single-ingredient octocrylene sources. The sixteen octocrylene-containing lines, bought recently, averaged 39 mg/kg benzophenone (range 6 to 186 mg/kg). After the FDA's accelerated stability protocol — six weeks of forced aging — the same sixteen averaged 75 mg/kg (range 9.8 to 435 mg/kg). The one product without octocrylene had no detectable benzophenone, before or after. Benzophenone was also present in the pure manufactured octocrylene ingredient, and the authors identify retro-aldol condensation of octocrylene as the source.

Reference: Downs CA, DiNardo JC, Stien D, Rodrigues AMS, Lebaron P. Benzophenone Accumulates over Time from the Degradation of Octocrylene in Commercial Sunscreen Products. Chemical Research in Toxicology. 2021;34(4):1046-1054. doi:10.1021/acs.chemrestox.0c00461. (Abstract read; full text and product list paywalled.)

FDA Absorption Trials (2019-2020)

In the 2020 trial, 48 participants applied 2 mg/cm² of one sunscreen to 75% of body surface area, 13 times over four days, with 34 blood samples across 21 days. Octocrylene's geometric mean maximum plasma concentration was 7.8 ng/mL from the lotion (15 times the FDA's 0.5 ng/mL level), and 6.6 ng/mL from both the aerosol and the non-aerosol spray; it was not in the pump-spray product. A single application on day 1 already gave 1.5, 1.3 and 1.4 ng/mL. Octocrylene stayed above 0.5 ng/mL through day 10 in 67% of participants (22 of 33) — longer than avobenzone, octisalate or octinoxate, shorter than oxybenzone or homosalate. The 2019 pilot, sampling only to day 7, reported 2.9 and 7.8 ng/mL for its two sprays and 5.7 ng/mL for both its lotion and its cream.

References: Matta MK, Zusterzeel R, Pilli NR, et al. JAMA. 2019;321(21):2082-2091. doi:10.1001/jama.2019.5586. Matta MK, Florian J, Zusterzeel R, et al. JAMA. 2020;323(3):256-267. doi:10.1001/jama.2019.20747.

Eleven further product claims once sat in this section, each naming a commercial sunscreen: three SPF and photostability comparisons, three more benzophenone measurements, three environmental-detection figures and two photoallergy series. None of their citations resolves to a real paper in PubMed, so all were removed in September 2026 rather than left with a figure whose source cannot be named.

Alternatives and Recommendations

Given the benzophenone contamination, absorption concerns, and allergy risks:

The discovery of benzophenone formation adds a new dimension to octocrylene's risk profile. Combined with high absorption rates and its photoallergy record, consumers may want to avoid octocrylene-containing sunscreens, especially older products that may contain elevated benzophenone levels.

Recommended: Babo Botanicals Sheer Zinc Mineral Sunscreen SPF 30 — an octocrylene-free mineral alternative — non-nano zinc oxide, fragrance-free

Our Verdict: 2/5

Octocrylene is a UVB filter used mainly to keep avobenzone from breaking down in sunlight. The FDA's 2020 trial measured it in blood at 7.8 ng/mL from a lotion, about 15x the agency's 0.5 ng/mL threshold, and a 2021 study found benzophenone in octocrylene sunscreens rising from an average 39 to 75 mg/kg after six weeks of accelerated aging.

Pros

  • Photostabilizes avobenzone, which is why it is in so many broad-spectrum chemical sunscreens
  • Permitted at up to 10% in the US, Canada, Australia and Japan, and in the EU (9% in propellant sprays)
  • The EU safety committee's 2021 opinion assessed its endocrine concerns and found it safe at those levels
  • Australia's TGA 2025 review found a margin of safety above 100

Cons

  • Reached 7.8 ng/mL from a lotion in the FDA's 2020 trial — about 15x the 0.5 ng/mL threshold — and stayed above it through day 10 in 67% of participants
  • Degrades into benzophenone (IARC Group 2B): 39 mg/kg on average off the shelf, 75 mg/kg after six weeks of accelerated aging
  • The most frequent photoallergen among UV filters in a 1,031-patient European photopatch study of people with suspected photoallergy; most such reactions follow earlier sensitization to the painkiller ketoprofen
  • The FDA's 2021 proposed order found the record lacks the data to call it generally recognized as safe and effective
  • Banned in the US Virgin Islands and Palau over reef damage

Frequently Asked Questions

Is octocrylene safe?

It is permitted at up to 10% in the US, Canada, Australia and Japan, and in the EU at up to 10% (9% in propellant sprays). The EU's safety committee judged it safe at those levels in 2021, and Australia's TGA found a margin of safety above 100 in its 2025 review. Two findings keep the question open. In the FDA's 2020 trial it reached 7.8 ng/mL in blood from a lotion, about 15 times the agency's 0.5 ng/mL threshold, and the FDA's 2021 proposed order found the record lacks the data to call it generally recognized as safe and effective. And it degrades into benzophenone as a sunscreen ages.

What is octocrylene in sunscreen?

A UVB filter (peak absorption 303 nm, with some UVA II coverage) whose main job is to stabilize avobenzone, the common UVA filter, so it does not break down in sunlight. That is why it appears in nearly every chemical broad-spectrum sunscreen. Its own contribution to SPF is moderate.

Does octocrylene degrade into benzophenone?

Yes. A 2021 study in Chemical Research in Toxicology assayed sixteen octocrylene sunscreens: bought off the shelf they averaged 39 mg/kg benzophenone, and after six weeks of the FDA's accelerated aging protocol the same products averaged 75 mg/kg, the worst 435 mg/kg. The one product without octocrylene had none, before or after. Benzophenone was also present in the pure octocrylene ingredient.

Does octocrylene cause cancer?

The cancer concern is benzophenone, the compound octocrylene degrades into: IARC classifies benzophenone as possibly carcinogenic to humans (Group 2B). Benzophenone levels in octocrylene sunscreens roughly doubled, from 39 to 75 mg/kg on average, after six weeks of accelerated aging, so older products carry more of it.

Is octocrylene a chemical or physical sunscreen?

Chemical. Octocrylene is an organic filter, a cyanoacrylate, that absorbs UV radiation and is absorbed into the blood. The physical (mineral) filters are zinc oxide and titanium dioxide.

What are octocrylene's side effects?

The documented reaction is on the skin. Octocrylene was the most frequent photoallergen among the UV filters tested in a 1,031-patient European photopatch study (2008 to 2011), and a 2014 review estimates that probably more than 80% of these sun-triggered reactions follow earlier sensitization to ketoprofen, an anti-inflammatory painkiller gel. Plain contact allergy without sunlight is far rarer and is seen mostly in children, from sunscreens. Anyone with a confirmed patch or photopatch test allergy to it should avoid products containing octocrylene, including moisturizers and makeup as well as sunscreens. The systemic question is open: it reached 7.8 ng/mL in blood in the FDA's 2020 trial, about 15 times the agency's threshold.

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