The researchers surveyed peer-reviewed literature published through mid-2024, searching PubMed, Google Scholar, ScienceDirect and Wiley Online Library for studies combining cannabidiol with terms covering sunscreens, antioxidants, inflammation, UV radiation and skin biology. From that search, 19 studies made the final cut: four review articles, nine in vitro experiments, three animal studies, one human clinical trial and two mixed-method investigations. The authors are candid about the limits of their approach. Because this was a narrative review rather than a systematic one, they did not apply PRISMA methodology or formal risk-of-bias assessment, and they acknowledge the search may have missed relevant work, particularly non-English publications.

The most striking findings concern CBD’s antioxidant chemistry. Structurally, the molecule shares features with vitamins E and C: phenolic hydroxyl groups attached to aromatic rings that can donate hydrogen atoms to reactive oxygen species and free radicals, interrupting the chain reactions that damage lipids, proteins and DNA. CBD is also highly lipophilic, allowing it to accumulate in cell membranes and stabilize them in a manner reminiscent of vitamin E. In rat experiments, chronic UVA and UVB exposure distorted keratinocyte membrane phospholipid metabolism, and topical CBD partially reversed those changes, downregulating harmful lysophosphatidylcholines and phospholipase A2 activity while upregulating protective phosphatidylethanolamines and phosphatidylserines. In human keratinocytes stressed with hydrogen peroxide or UVB, CBD reduced malondialdehyde and 4-hydroxynonenal, two well-established markers of lipid peroxidation, and modulated proteostasis networks governing protein folding and redox balance in ways that increased cell survival.

Beyond these direct chemical effects, CBD appears to manipulate the skin’s own antioxidant machinery. The review highlights its interaction with Nrf2, a redox-sensitive transcription factor often described as the master regulator of cytoprotective gene expression. Under normal conditions Nrf2 is held inactive by its nemesis Keap1, which tags it for destruction by the proteasome. Oxidative stress disrupts this pairing, freeing Nrf2 to enter the nucleus and switch on genes encoding superoxide dismutase, glutathione peroxidase and heme oxygenase 1. Intriguingly, keratinocyte studies suggest CBD is only a weak Nrf2 activator but a strong inhibitor of BACH1, a transcriptional repressor that works alongside Nrf2 to control heme oxygenase 1. This positions CBD as an Nrf2-independent booster of HMOX1 expression, encouraging keratinocyte differentiation and cytokeratin production, processes critical to maintaining a skin barrier that resists UV-induced DNA damage.

The anti-inflammatory story runs through a different set of molecular switches. CBD appears to be a major inhibitor of NFκB signaling, the central hub of the inflammatory response. Normally locked in the cytoplasm by its inhibitor IκB, NFκB is released when pro-inflammatory signals such as tumor necrosis factor alpha trigger IκB’s degradation, allowing the transcription factor to activate genes for cytokines, chemokines and adhesion molecules. UV irradiation drives inflammation through exactly this pathway, and in three-dimensional human keratinocyte cultures CBD counteracted it, restoring IκB levels and suppressing NFκB. CBD also dampened the NLRP3 inflammasome and the pro-inflammatory protein PGAM5, while full-spectrum CBD extract showed high-affinity inhibition of NLRP3 and TGF-β1 responses. In human skin fibroblasts, CBD elevated PPARγ, a nuclear receptor that represses inflammatory pathways, and in an acne study it significantly suppressed TNF-α, IL-1β and IL-6 in human sebocytes.

The endocannabinoid system adds yet another layer. CB2 receptors, found in immune and peripheral tissues including skin, can restrain pro-inflammatory cytokine release, and CBD’s modulation of CB2, along with its desensitization of TRPV1 channels activated by oxidative stress and its activation of adenosine A2A receptors, may collectively calm overactive immune responses in UV-damaged skin. One study of patients with psoriasis, atopic dermatitis and scarring found that a CBD-enriched ointment improved disease severity, quality of life, skin hydration and elasticity with no adverse effects. The review also flags a fascinating effect on melanocytes: CBD can activate p38 and p42/44 MAPK signaling and independently upregulate MITF, tyrosinase and related proteins, enhancing melanogenesis, the production of the pigment that naturally scatters and absorbs UV radiation. This raises potential applications for hypopigmented disorders and hints at melanin-mediated photoprotection.

But here is where the enthusiasm must be tempered, and the review is refreshingly blunt about it. Spectral analyses show that CBD absorbs UV light predominantly between roughly 220 and 280 nanometers, a range overlapping UVC, which is filtered out by the atmosphere, and only minimally touching the UVB band that sunscreens must block. In one comparative study, CBD showed the strongest cytoprotection against UVA-associated injury while cannabinol performed best against UVB, but neither CBD nor its relatives demonstrated direct photoprotective absorption at the wavelengths that matter. The authors emphasize that the observed cytoprotective effects should not be interpreted as sunscreen activity. CBD’s benefits, if real, would be indirect, working beneath the filter layer to help skin cells survive whatever radiation gets through.

Safety questions also complicate the picture. Most systematic safety data come from oral CBD, where randomized trials have identified increased risks of diarrhea, somnolence, decreased appetite and abnormal liver function tests, though the hepatic and sedation signals were concentrated in high-dose childhood epilepsy studies using drugs like clobazam and valproate. CBD is metabolized by CYP450 liver enzymes and can be a potent dose-dependent inhibitor of their activity, a concern that depends heavily on how much of a topical dose actually reaches the bloodstream. Evidence on that front is mixed: in a 17-day study of 46 healthy adults, CBD was detectable in blood after repeated use of three of five commercial topical products, though concentrations were far below those from oral or inhaled use and no cognitive or physiological effects appeared. Topical tolerability data remain thin and formulation-dependent, with patch-testing studies showing selected CBD products were non-irritating and non-sensitizing in healthy adults, while a transdermal gel trial saw application-site dryness, pain and one case of irritant contact dermatitis.

There is one tantalizing human data point. A small pilot randomized trial of nanoparticle-encapsulated topical CBD, involving just 19 participants, found less erythema on treated skin after UVA irradiation, along with reductions in epidermal hyperplasia and cellular stress and aging markers. But the study measured no SPF and included no active sunscreen comparator, so it cannot speak to whether CBD would add anything to a real product. The review also raises a subtle photochemical concern: when CBD oxidizes, it can form the cannabinoid quinone HU-331, which absorbs UV near 270 and 409 nanometers and has shown topoisomerase-II inhibition and endothelial-cell apoptosis induction in non-skin experimental systems. CBD and its hydroxyquinone have also generated reactive oxygen species during mouse liver microsomal metabolism. None of this demonstrates phototoxicity in human skin, but it marks genuine toxicologic uncertainties that demand study before CBD rides around in a sun-exposed bottle.

The regulatory landscape adds a final layer of complexity. In the United States, sunscreens are regulated as over-the-counter drugs, and only zinc oxide and titanium dioxide currently meet the FDA’s Generally Recognized as Safe and Effective standard, while the 2022 Modernization of Cosmetics Regulation Act has tightened scrutiny of cosmetic ingredients, with new 2026 legislation targeting full-spectrum CBD products specifically. Any manufacturer hoping to add CBD to a sunscreen would face registration, human safety substantiation and adverse event surveillance requirements. The review’s bottom line is measured: CBD may eventually earn a role as an adjunctive, non-filter component of photoprotective skincare, but the evidence base, dominated by in vitro and rodent work with enormous variability in models and doses, is nowhere near supporting claims of sun protection. Until standardized SPF, stability, photostability and human safety testing say otherwise, your sunscreen’s active ingredients should remain the ones with proven track records.

Subject of Research: Preclinical evidence on cannabidiol's effects against ultraviolet-induced skin damage and its potential as a sunscreen additive

Article Title: Cannabidiol and ultraviolet-induced skin damage: a narrative review of preclinical evidence and translational considerations for sunscreen additive development

Article References: Papadeas, G. G., Szeto, M. D., Reed, M. J., Paul, A., Runion, T. M., Anderson, J., & Dellavalle, R. P. (2026). Cannabidiol and ultraviolet-induced skin damage: a narrative review of preclinical evidence and translational considerations for sunscreen additive development. Archives of Dermatological Research, 318(1), Article 430. https://doi.org/10.1007/s00403-026-04888-x

Image Credits: AI Generated

DOI: 10.1007/s00403-026-04888-x

Keywords: cannabidiol, CBD, sunscreen, UV radiation, photoprotection, skin cancer, antioxidant, anti-inflammatory, keratinocytes, melanocytes, Nrf2, dermatology

The research, led by Tia El Kazzi of the Lebanese University with co-authors Nazek Mansour and Mirna N. Chahine, set out to measure knowledge, attitudes, and practices related to sunscreen use, sun-protective behavior, and skin cancer among the country’s medical trainees. The team surveyed 1,063 participants between April 29 and June 15, 2023, drawing respondents from all eight medical faculties in Lebanon: the seven private schools, the American University of Beirut, Beirut Arab University, the Lebanese American University, Saint George University of Beirut, Holy Spirit University of Kaslik, the University of Balamand, and Saint Joseph University, along with the public Lebanese University. Because the sample spanned every medical school in the country, the authors argue it offers an unusually broad picture of how Lebanon’s next generation of doctors approaches photoprotection.

Participants were recruited through an English-language online questionnaire distributed via WhatsApp and Instagram using snowball sampling, a technique in which early respondents forward the survey to their peers. The instrument was designed around established behavioral frameworks. Sun-protective behavior was assessed using the stages-of-change construct from the Transtheoretical Model, which classifies individuals along a continuum from not considering a behavior to maintaining it consistently. Attitudes were captured with two validated instruments: the Decisional Balance Scale, which weighs the perceived pros and cons of adopting sun protection, and the Self-Efficacy Scale, which measures confidence in one’s ability to perform protective behaviors across different situations. Knowledge of sunscreen and skin cancer was tested with dedicated items, and the team used multivariate linear regression to identify independent predictors of the three main outcome scores.

The headline numbers reveal a paradox. On one hand, 75.2 percent of participants said they used sunscreen, a figure that might seem encouraging at first glance. On the other hand, 78.6 percent reported having experienced a prior sunburn, the single best-documented behavioral risk factor for later melanoma and other skin cancers. In other words, the majority of these future doctors had already sustained the kind of acute ultraviolet injury that dermatologists warn the public about, despite knowing precisely how such injury occurs and how to prevent it. The authors describe this as a clear disconnect between knowledge and preventive behavior, one that persists even in a group with privileged access to medical education.

The quantitative scores reinforce that impression. Participants demonstrated moderate knowledge, averaging 53.23 percent with a standard deviation of 14.31. Decisional balance scores averaged 14.15 out of a possible 20, and self-efficacy scores averaged 26.39 out of 45, both indicating middling rather than strong attitudinal readiness. Notably, the three measures were positively correlated with one another, with correlation coefficients ranging from 0.219 to 0.547 and all reaching statistical significance at p less than 0.001. This interdependence matters theoretically: it suggests that knowing more about skin cancer, feeling more confident about sun protection, and perceiving greater benefits from it tend to travel together, forming a psychological cluster that could be targeted as a whole rather than piecemeal.

The regression models, which adjusted for multiple variables simultaneously, identified who scored highest on each dimension. Higher knowledge was independently associated with being further along in medical training, having experienced a prior sunburn, higher self-efficacy, higher household income, attendance at a private university, and being at an advanced stage of sunscreen adoption; this model explained 21.4 percent of the variance in knowledge scores. Higher decisional balance scores were linked to higher self-efficacy, sunscreen use, female gender, higher knowledge, and advanced behavioral stage, with the model accounting for 40.5 percent of the variance. Higher self-efficacy, in turn, was predicted by higher decisional balance, sunscreen use, and advanced behavioral stage, explaining 36.6 percent of the variance. The pattern is consistent: behavioral readiness, attitudinal confidence, and factual knowledge reinforce one another in a loop, and academic progression only partially breaks through.

Several of these predictors deserve closer attention. The association between higher academic year and greater knowledge is reassuring in one sense, since it suggests that medical education does incrementally deliver content about skin cancer and photoprotection. But the fact that knowledge remained only moderate even among senior trainees hints that this content is thin, fragmented, or delivered too late. The link between prior sunburn and higher knowledge is equally double-edged: it may reflect heightened awareness after a personal scare, but it also means that the educational system is being outpaced by ultraviolet exposure itself. Socioeconomic gradients, visible in the independent effects of household income and private university affiliation, point to structural inequities in access to both information and protective products, a reminder that sun safety is not only a matter of individual willpower.

The role of self-efficacy emerges as perhaps the most actionable finding. In behavioral science, self-efficacy, the belief that one can successfully carry out a behavior in real-world conditions, is often the strongest lever for change, because knowledge alone rarely translates into action. Here, self-efficacy was independently tied to both knowledge and decisional balance, and it clustered tightly with advanced stages of sunscreen adoption. Participants who believed they could apply sunscreen before class, reapply it during hospital shifts, or seek shade during long outdoor commitments were far more likely to actually do so. This suggests that interventions should go beyond lecturing about ultraviolet radiation and instead build practical confidence: rehearsing routines, addressing barriers specific to hospital life, and normalizing sun protection as part of professional identity.

The authors argue that the findings carry implications well beyond Lebanon. Medical students and residents occupy a dual role in skin cancer prevention: they are future counselors who will advise patients on sunscreen, protective clothing, and skin checks, and they are role models whose own behavior shapes what patients perceive as normal. A physician who preaches daily sunscreen but arrives at clinic sunburned undermines the message before saying a word. The study’s conclusion is that preventive competencies are strongly associated with academic progression, behavioral readiness, and self-efficacy, and that integrating structured, stage-specific sun protection education early in medical training could improve trainees’ own behaviors while strengthening their capacity to guide patients. Stage-specific means matching the intervention to where the learner sits on the Transtheoretical Model continuum, nudging precontemplators toward awareness and helping maintainers sustain their habits.

For a country with abundant sunshine and a Mediterranean climate, the stakes are concrete. Lebanon’s medical trainees will spend decades working under high ultraviolet conditions and treating a population similarly exposed. The study, which received no external funding and was approved by the Institutional Review Board of Al-Zahraa Hospital University Medical Center, offers a baseline that other countries in the region could replicate. Its core message is deceptively simple: knowing about skin cancer is not the same as preventing it, even for people trained to do exactly that. Closing that gap, the authors contend, requires embedding sun protection into the earliest years of medical curricula, treating it not as an optional dermatology footnote but as a core preventive skill that future physicians must first practice on themselves.

Subject of Research: Knowledge, attitudes, and practices regarding sunscreen use, sun protection, and skin cancer prevention among medical students and residents in Lebanon

Article Title: Knowledge, attitude, and practice towards sunscreen use, sun protective behavior, and skin cancer among Lebanese medical students and residents

Article References: El Kazzi, T., Mansour, N., & Chahine, M. N. (2026). Knowledge, attitude, and practice towards sunscreen use, sun protective behavior, and skin cancer among Lebanese medical students and residents. BMC Cancer. https://doi.org/10.1186/s12885-026-17074-z

Image Credits: AI Generated

DOI: 10.1186/s12885-026-17074-z

Keywords: skin cancer, sunscreen, sun protection, medical students, residents, self-efficacy, Transtheoretical Model, melanoma, Lebanon, health behavior, cancer prevention, dermatology

The study was driven by a question at the heart of the emerging circular bioeconomy: can microorganisms with useful traits replace petrochemical and synthetic ingredients in everyday consumer products? Sunscreens are an obvious target. Many conventional UV filters, such as oxybenzone and octinoxate, have come under scrutiny for their environmental persistence and suspected effects on coral reefs and aquatic ecosystems. A biologically produced, biodegradable alternative that can be fermented from renewable feedstocks would fit neatly into the sustainability goals of the cosmetics industry. Mycosporine-like amino acids, the family of compounds to which mycosporine-glutaminol belongs, are already prized in biotechnology because they absorb harmful ultraviolet radiation efficiently while remaining photostable, meaning they do not degrade after repeated exposure to sunlight.

To explore this potential, the researchers isolated and characterized two P. laurentii strains, designated FBU001 from urban São Paulo and FBU003 from the Atacama Desert. Confirming the identity of a yeast strain is not a trivial matter, since misidentified organisms have derailed many biotechnological projects. The team used two complementary approaches: sequencing of ribosomal DNA, the standard molecular barcode for fungal identification, and MALDI-TOF mass spectrometry, a technique that fingerprints the protein profile of a microorganism within minutes. Both methods agreed on the taxonomic assignment, giving the researchers confidence that they were indeed working with P. laurentii and could compare their results against the growing body of literature on this basidiomycetous yeast.

Safety came next, and it is arguably the most consequential part of the work. Any organism proposed for large-scale cultivation must be shown to pose minimal risk to workers, consumers, and the environment. The team assessed biosafety through several independent lines of evidence. They measured the temperature range at which the yeasts can grow, since fungi capable of thriving at mammalian body temperature are inherently more concerning as potential pathogens. They also screened the strains for common fungal virulence factors, the molecular weaponry that pathogenic species use to invade host tissue and evade immune defenses. Finally, they turned to in vivo infection models, experiments in living organisms that provide a direct test of pathogenic potential rather than relying solely on genetic inference. The combined results indicated that both strains have low pathogenic potential, supporting their classification as suitable for industrial applications.

With safety established, the researchers probed the physiological hardiness of the two isolates, and here the contrast between their origins became vivid. Both strains proved resistant to UVC radiation, the shortest and most damaging band of ultraviolet light, which is largely filtered out by the ozone layer but is a formidable stressor for any microorganism that encounters it. The Atacama strain, however, carried additional extremophilic adaptations, most notably tolerance of osmotic stress, the cellular strain imposed by high salt or sugar concentrations that would normally dehydrate and kill less hardy microbes. This makes evolutionary sense: the Atacama Desert subjects its inhabitants to intense solar radiation, extreme aridity, and saline soils, so a yeast surviving there must be a biochemical generalist. The São Paulo strain, adapted to a milder but still sun-exposed urban niche, shared the UVC resistance but not the full suite of desert survival tools.

The centerpiece of the study was the detection and characterization of mycosporine-glutaminol itself. Both yeasts produced the compound, a small molecule that functions simultaneously as a UV filter and an antioxidant, neutralizing the reactive oxygen species that ultraviolet radiation generates inside cells. The researchers then went beyond simple chemical detection and interrogated the genomes and transcriptomes of the two strains. They found that the genes responsible for synthesizing mycosporine-glutaminol are not scattered randomly across the genome but are organized into a cluster, which the team designated the MYC biosynthetic gene cluster. Gene clustering is a hallmark of microbial secondary metabolism and makes both the evolution and the engineering of such pathways more tractable, because the entire production line sits in one contiguous stretch of DNA.

Crucially, transcriptional analyses showed that the MYC cluster is activated by ultraviolet exposure. When the yeasts were irradiated, the genes in the cluster switched on, ramping up production of the protective molecule in response to the threat. This inducible behavior confirms that mycosporine-glutaminol is not an incidental metabolic byproduct but a deliberate, regulated defense strategy. It also suggests a practical advantage for manufacturing: because production is triggered by a simple physical stimulus, UV light, fermentation processes could potentially be tuned to maximize yields without adding expensive chemical inducers. The fact that both the urban and desert strains carry and express the same cluster indicates that this photoprotective capacity is a conserved trait of the species rather than a local adaptation, which broadens the pool of candidate strains available for industrial screening.

The implications extend beyond a single compound. Mycosporine-like amino acids have been investigated for applications ranging from anti-aging skincare, where their antioxidant activity may protect against photoaging, to pharmaceutical formulations that require photostable excipients. A yeast platform that naturally produces one member of this family, and whose biosynthetic genes are mapped and inducible, offers a starting point for metabolic engineering: the MYC cluster could in principle be optimized, transferred to faster-growing production hosts, or modified to generate structural analogs with tailored absorption spectra. The low pathogenicity of the two strains also simplifies the regulatory pathway, since biosafety dossiers for industrial microorganisms demand exactly the kind of evidence this study assembled, from growth-temperature limits to virulence-factor screening to in vivo testing.

The work also carries a broader message about where useful biodiversity hides. A yeast thriving on tree surfaces or soil in a South American megacity and a relative surviving in the hyperarid Atacama turned out to share a sophisticated molecular sunscreen, discovered only because researchers chose to compare strains from contrasting ecological niches. As the cosmetics and chemical industries search for renewable, biodegradable ingredients, extremophilic and urban microorganisms alike are emerging as an underexplored reservoir of functional molecules. For now, the Brazilian team’s two P. laurentii strains stand as robust candidates for sustainable biotechnology, bridging the gap between microbial ecology on two continents and the sunscreen shelf, and offering a glimpse of a future in which the UV protection people wear is grown rather than synthesized.

Subject of Research: Photoprotective compound production by Papiliotrema laurentii yeasts from urban and desert environments

Article Title: Papiliotrema laurentii from two ecological niches: a possible source of next-generation photoprotective compounds

Article References: Santos, R. S., Martins-Silva, G., Barbosa, R. S., da Silva Costa de Oliveira, C. M., Vilanova, P. F., Pereira, P. T., Gianoni, I. M., dos Santos Queiroz, A. C., Padilla, A. A. A., Souza Ramos de Carvalho, A. C., Kreusch, M., Yamaguchi, L. F., Monteiro-Vitorello, C. B., Vallim, M. A., de Medeiros, L. S., & Pascon, R. C. (2026). Papiliotrema laurentii from two ecological niches: a possible source of next-generation photoprotective compounds. Applied Microbiology and Biotechnology. https://doi.org/10.1007/s00253-026-14000-y

Image Credits: AI Generated

DOI: 10.1007/s00253-026-14000-y

Keywords: Papiliotrema laurentii, mycosporine-glutaminol, ultraviolet radiation, sunscreen, Atacama Desert, yeast biotechnology, biosafety, biosynthetic gene cluster, circular bioeconomy, extremophiles, cosmetics, antioxidant

The biological rationale begins with reactive oxygen species, or ROS. These molecules, including superoxide anion, hydroxyl radical, and singlet oxygen, are unavoidable byproducts of oxidative metabolism, generated inside cells by electron leakage in mitochondria and outside them by ultraviolet radiation and pollution. At low levels, ROS act as legitimate signaling molecules in many cellular processes. But when their production outpaces the body’s antioxidant defenses, oxidative stress ensues, damaging DNA, proteins, and lipids, and driving cells toward apoptosis. The skin, as the body’s largest organ and its first line of contact with the environment, is particularly exposed. ROS accumulation triggered by ultraviolet light is considered a central event in photoaging, marked by collagen degradation, rupture of elastic fibers, and heightened activity of matrix metalloproteinases, the enzymes that dismantle the skin’s structural scaffolding.

Conventional skincare addresses oxidative stress with synthetic antioxidants and physical treatments, but these often irritate the skin, provoke photosensitivity, and deliver only temporary benefits. Natural antioxidants are generally less likely to cause irritation or allergy, and they align with the fast-growing consumer movement toward so-called clean beauty. What makes microalgae and cyanobacteria especially compelling is their evolutionary history. These are the oldest photosynthetic microorganisms on Earth, and populations living in hot springs, salt lakes, deserts, and high-irradiance intertidal zones have endured intense ultraviolet exposure, desiccation, and oxidative pressure for millions of years. Their response was to build elaborate chemical defenses, synthesizing structurally distinct antioxidants that terrestrial plants rarely produce, while also growing quickly and cultivable at scale on non-arable land.

The standout molecule is astaxanthin, a ketocarotenoid whose long chain of thirteen conjugated double bonds, capped by oxygenated ionone rings, gives it extraordinary capacity to quench singlet oxygen, outperforming other carotenoids as well as vitamins C and E. The green microalga Haematococcus pluvialis is the industrial workhorse, accumulating astaxanthin to five to eight percent of its dry cell weight, with annual production reaching tens of tons. In laboratory studies, concentrations of five to ten micromolar astaxanthin efficiently quenched UVA-induced ROS clusters in human dermal fibroblasts and lowered levels of malondialdehyde, a marker of lipid peroxidation. Mechanistically, astaxanthin also activates the cell’s own defenses: it promotes the release of the transcription factor Nrf2 from its cytoplasmic inhibitor Keap1, allowing Nrf2 to enter the nucleus and switch on genes for antioxidant enzymes such as glutathione S-transferases, glutathione peroxidase, superoxide dismutase, and NQO1.

Fucoxanthin, a polyunsaturated carotenoid with a reactive allenic bond and an epoxy group, delivers broad-spectrum radical scavenging and, in human keratinocytes, boosts glutathione through the same Nrf2 pathway. The diatom Phaeodactylum tricornutum and the haptophyte Tisochrysis lutea, which can reach nearly eighty milligrams of fucoxanthin per gram under optimized culture, are leading production candidates, and microalgae contain roughly ten to one hundred times more of the pigment than macroalgae. Beta-carotene, famously over-accumulated by the halotolerant green alga Dunaliella salina at up to fifteen percent of dry weight, quenches singlet oxygen through energy transfer and, in its 9-cis isomer form found uniquely in algae, exhibits strong antioxidant power. Lutein, currently harvested commercially only from marigold petals, could shift to algal sources that promise two to five times the per-hectare yield with eighty percent less water consumption and growth cycles as short as one to two weeks.

Beyond pigments, the review highlights polysaccharides, phycocyanin, polyphenols, mycosporine-like amino acids, and scytonemin as complementary actives. Sulfated exopolysaccharides from the red microalga Porphyridium cruentum and cyanobacterial EPS from Arthrospira and Nostoc scavenge radicals, chelate iron and copper ions that would otherwise fuel Fenton chemistry, and even form physical barriers against membrane lipid peroxidation. Phycocyanin, the brilliant blue pigment that makes up ten to twenty percent of Spirulina’s dry weight, directly eliminates ROS and reactive nitrogen species while enhancing intracellular antioxidant enzymes. Mycosporine-like amino acids, or MAAs, are especially elegant: these water-soluble molecules under four hundred daltons absorb UV-A and UV-B radiation with superb photostability, dissipating the energy harmlessly as heat rather than generating ROS, and compounds such as palythine and porphyra-334 rival ascorbic acid in radical-scavenging assays. Scytonemin, a lipophilic dimeric pigment produced in the extracellular sheaths of more than three hundred cyanobacterial species, absorbs across the UV-A, UV-B, and UV-C ranges.

What elevates these compounds above simple radical sponges is the breadth of their secondary effects on skin biology. Phycocyanin suppresses cyclooxygenase-2 and downstream prostaglandin E2, easing inflammation; fucoxanthin damps inflammatory cytokines through NF-kappaB signaling. On the anti-aging front, Spirulina polysaccharide complexes restore mitochondrial function in aged fibroblasts and spur collagen regeneration, while porphyra-334 increases procollagen, type I collagen, and elastin expression in UVA-irradiated skin fibroblasts. Several molecules inhibit the matrix metalloproteinases that degrade collagen and elastin: mycosporine-2-glycine from the halotolerant cyanobacterium Aphanothece halophytica matches the collagenase inhibitor aminoguanidine, C-phycocyanin reduces MMP-1 and MMP-9 in UVB-treated keratinocytes, and polysaccharides from Nostochopsis lobatus outperform the natural hyaluronidase inhibitor disodium cromoglycate. Microalgal polyphenols and phenolic acids also inhibit tyrosinase, the rate-limiting enzyme in melanin synthesis, offering safer alternatives to unstable or irritating whitening agents such as hydroquinone and kojic acid.

Commercial traction is already visible. Estee Lauder markets skincare lines featuring Chlorella extract for hydration and oil-water balance, while L’Oreal holds patents on marine polysaccharides for moisturizing and hair care. Astaxanthin appears in brightening serums and eye creams, and clinical trials suggest that oral doses of three to six milligrams per day reduce UV-induced wrinkles and enhance collagen synthesis. In the sunscreen space, Mibelle AG Biotechnology’s Helioguard 365, a porphyra-334 and shinorine complex from the red alga Porphyra umbilicalis, increased skin firmness by ten percent and reduced wrinkle depth by twelve percent over four weeks of application. Spirulina-derived extracts are found in anti-wrinkle and even antifungal formulations, and engineered microalgae-nanodrug delivery systems and live algal hydrogels are being explored for tissue repair, exploiting their capacity to produce oxygen through photosynthesis at wound sites.

Significant obstacles remain before these compounds reach their full potential. Extraction from tough algal cell walls is inefficient and often relies on polluting organic solvents, prompting interest in greener methods such as supercritical water extraction, ultrasound-assisted extraction, and enzyme-assisted processing. Stability is another vulnerability: carotenoids and phycobiliproteins degrade under light, heat, oxygen, and pH shifts, shortening shelf life, while hydrophilic and macromolecular ingredients struggle to cross the stratum corneum. Nanocarriers, including liposomes, nanoemulsions, and solid lipid nanoparticles, are emerging as solutions that shield actives and improve skin penetration, and the authors point to artificial intelligence-designed responsive delivery systems as a future frontier. Perhaps most critically, rigorous clinical evidence on biosafety, irritation, sensitization, and long-term effects remains thin for many novel species. The review calls for large-scale, multicenter, randomized, double-blind, placebo-controlled trials across diverse skin types and age groups, combined with omics-based mechanistic studies, to convert a promising laboratory story into the backbone of next-generation dermatological treatments and functional cosmeceuticals.

Subject of Research: Natural antioxidants from microalgae and cyanobacteria and their applications in skincare

Article Title: Natural antioxidants derived from microalgae and cyanobacteria and their applications in skincare

Article References: Natural antioxidants derived from microalgae and cyanobacteria and their applications in skincare. (n.d.). https://doi.org/10.1186/s44315-025-00050-w

Image Credits: AI Generated

DOI: 10.1186/s44315-025-00050-w

Keywords: microalgae, cyanobacteria, antioxidants, skincare, astaxanthin, phycocyanin, mycosporine-like amino acids, carotenoids, photoaging, Nrf2 pathway, sunscreen, cosmetics