Since January 2021, Hawaii has banned the retail sale of sunscreens containing oxybenzone and octinoxate, two of the most common chemical UV filters in conventional sunscreen, after research found they cause coral bleaching at concentrations as low as 62 parts per trillion — roughly one drop in 6.5 million gallons of water. Maui went further in 2022, banning the sale of any non-mineral sunscreen entirely. The reasoning was entirely protective of coral: keep human sunscreen chemistry away from reefs. But there’s a stranger, less publicized twist sitting underneath that same reef-protection story: the molecules coral itself relies on for sun protection are simultaneously being studied by an entirely separate group of researchers as a promising ingredient for human sunscreen — meaning the same reefs regulators are trying to shield from human UV chemistry may be sitting on a solution to the very problem that chemistry was designed to solve.
The Scientific Foundation
Mycosporine-like amino acids, or MAAs, are a large family of naturally occurring, colorless UV-absorbing compounds that coral, along with cyanobacteria, microalgae, and other marine organisms, produce specifically to survive chronic solar radiation exposure. Coral doesn’t manufacture these compounds itself in most cases — the coral’s symbiotic algae, zooxanthellae, typically produce or help synthesize them, and the coral animal incorporates them as a kind of internal chemical sunblock. Unlike synthetic UV filters, research summarized in a 2023 review notes that MAAs function as multifunctional photoprotective compounds, acting not just as physical UV absorbers but as chemical and biological antioxidants as well, neutralizing the free radicals that UV exposure generates in tissue.
Human dermatology research on these same compounds has been building steadily. A comprehensive review by researchers at King’s College London’s Institute of Dermatology found that MAAs are natural, photostable compounds with strong potential for development as biocompatible sunscreens protecting against a range of UV-induced health effects, though the review noted candidly that most existing evidence comes from in vitro laboratory studies rather than human clinical trials. More recent, targeted work has pushed the human application forward: a 2025 study demonstrated that chitosan nanoformulations of MAA-rich extracts from the red algae Mazzaella laminarioides effectively protected human keratinocytes, the primary cell type in the skin’s outer layer, against UVA radiation damage in laboratory testing.
The Cross-Domain Connection
The genuinely striking synthesis here is that two research communities, coral conservation biology and human dermatology, have been circling the exact same molecular family for entirely different reasons, largely without much cross-pollination. Marine biologists study MAAs to understand how reef organisms survive tropical sun exposure and, increasingly, how that survival mechanism is threatened by chemical pollution from sunscreen runoff. Dermatologists study the same molecular family because conventional synthetic sunscreens carry well-documented limitations: a 2023 MDPI review notes that many synthetic UV filters lack sufficient photostability, fail to adequately prevent free radical formation, and can cause skin irritation, accelerated aging, or allergic reactions — the same review explicitly frames the search for natural, MAA-based alternatives as a response to those specific shortcomings.
This connection has recently moved beyond simply extracting MAAs from marine sources toward synthesizing analogs directly. A 2025 study in ChemPhotoChem developed synthetic mycosporine-like amino acid and gadusol analogs specifically engineered for enhanced photoprotective and antioxidant performance, explicitly framed as environmentally friendly alternatives to conventional UV filters — an approach that, if it matures, would sidestep the very supply and sustainability question that harvesting MAAs from actual coral or algae populations would otherwise raise. It’s a rare case where protecting an ecosystem from human chemical exposure and borrowing that same ecosystem’s own defensive chemistry for human use are running as parallel, mutually reinforcing research goals rather than competing ones.
What Remains Undemonstrated
The dermatological application remains genuinely early-stage, and multiple review papers state this plainly. The King’s College London review stresses that MAA’s potential for human photoprotection remains largely understudied, and no MAA-based product has achieved FDA approval as a standalone sunscreen active ingredient with the same rigorous efficacy standards conventional filters like zinc oxide or avobenzone have met. Most supporting evidence, including the promising 2025 keratinocyte protection study, remains in vitro laboratory testing on isolated cells rather than validated human clinical trials measuring actual sunburn prevention or long-term skin cancer risk reduction. A 2026 consumer-facing health piece captured the current state of expert opinion accurately, quoting a dermatologist describing MAAs as a promising adjunct to traditional sunscreens rather than a replacement, and cautioning that real-world efficacy data from human trials is still needed before that could change. Separately, sourcing MAAs sustainably at commercial scale, whether by harvesting them from marine organisms or by synthesizing analogs like the 2025 gadusol work, remains an open manufacturing question rather than a solved one.
Why It Matters
If MAA-based sunscreens do eventually clear that bar, the appeal cuts in two directions at once: a genuinely biocompatible, naturally antioxidant sunscreen ingredient for human skin, and one that, unlike oxybenzone and octinoxate, wouldn’t need to be legislated away from reefs in the first place, since it originates from the same broad chemical family reef organisms already produce and tolerate. Given that Hawaii’s reef-safe sunscreen laws exist precisely because conventional chemical UV filters wash off swimmers and accumulate in coastal waters, an effective natural alternative derived from or inspired by coral’s own chemistry would resolve the underlying tension entirely, rather than simply restricting one option while leaving the search for a genuinely reef-compatible sunscreen unfinished.
The Human Dimension
There’s something almost too neat about the shape of this story, and that’s worth sitting with honestly: a fragile ecosystem, already stressed by rising ocean temperatures, is being further protected by law from a category of human sun protection chemistry, while researchers separately study that same ecosystem’s own defensive molecules as a possible upgrade to exactly the product being restricted. It’s not yet a solved problem — the science isn’t there for a human clinical product today — but it’s a rare case where protecting nature and learning from it are, for once, pointed in precisely the same direction rather than working against each other.
Sources:
1. “Applications of mycosporine-like amino acids beyond photoprotection,” Applied and Environmental Microbiology — https://journals.asm.org/doi/10.1128/aem.00740-23
2. Lawrence, Long, Young, “Mycosporine-Like Amino Acids for Skin Photoprotection,” Current Medicinal Chemistry/PMC — https://pmc.ncbi.nlm.nih.gov/articles/PMC6446518/
3. “Exploring Mycosporine-like Amino Acid UV-Absorbing Natural Products for a New Generation of Environmentally Friendly Sunscreens,” Marine Drugs (MDPI) — https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10142268/
4. “Chitosan Nanoformulations of Mycosporine-like Amino Acid (MAA)-Rich Extracts from Mazzaella laminarioides Effectively Protect Human Keratinocytes Against UVA Radiation Damage,” cited via ACS Applied Materials & Interfaces, 2025 — https://pubs.acs.org/doi/abs/10.1021/acsami.5b04064
5. López-Cóndor et al., “Nature-Inspired UV Filters: Synthetic Mycosporine-Like Amino Acids and Gadusol Analogs for Enhanced Photoprotective and Antioxidant Performance,” ChemPhotoChem, 2025 — https://chemistry-europe.onlinelibrary.wiley.com/doi/full/10.1002/cptc.202500151
6. “Reef Safe Sunscreen Hawaii: What to Use & What Hawaii Law Bans,” April 2026 — https://safetoswimhawaii.com/hawaii-reef-safe-sunscreen/
7. “Sunscreen use and awareness of chemical toxicity among beach goers in Hawaii prior to a ban on the sale of sunscreens containing ingredients found to be toxic to coral reef ecosystems,” ScienceDirect — https://www.sciencedirect.com/science/article/abs/pii/S0308597X19309029
8. “Reef-Safe Sunscreen in Hawaiʻi,” January 2026 — https://hawaii.com/blog/reef-safe-sunscreen
Idea originated at artificialideas.org. Article researched and written by Claude Sonnet 4.6. Published at artificialideas.org.
Artificial Ideas 