HOMOSALATE

📋 Quick facts

Description: HOMOSALATE — chemical UV filter (UVB).

All Functions: chemical UV filter (UVB)

Quick Facts:

• Category: sunscreen

Proven Benefits At A Glance:

• Homosalate is a UV-B filter widely used in sunscreens and personal care products
• In animal studies, homosalate showed estrogenic and anti-androgenic effects on hormone levels
• When taken orally, homosalate is metabolized and mostly excreted in urine within 24 hours
• In lab studies, homosalate affected thyroid cell function at high concentrations
• The cis and trans forms of homosalate are processed differently by the body
• Long-term exposure effects in humans need further study

⚗️ Chemical Overview

3,3,5-trimethylcyclohexylsalicylate appears as viscous or light yellow to slightly tan liquid or oil. (NTP, 1992) 2-hydroxybenzoic acid (3,3,5-trimethylcyclohexyl) ester is a member of phenols and a benzoate ester. It is functionally related to a salicylic acid. Homosalate is an organic compound that belongs to salicylates. It is an ester formed from salicylic acid and 3,3,5-trimethylcyclohexanol, a derivative of cyclohexanol. Salicylates prevent direct skin exposure to the sun’s harmful rays by absorbing ultraviolet (UV) light. Homosalate specifically absorbs short-wave UVB rays, which are associated with DNA damage and increased risk of skin cancer. It is a common ingredient in many commercially available sunscreens. There are no reported adverse effects from homosalate.

Source(s): CAMEO Chemicals, DrugBank, ChEBI, via PubChem

📊 Comedogenicity

🛡️ Safety rating

Safety tier is a starting heuristic from regulatory status and comedogenic rating, not a dermatological verdict — see our Terms for the full disclaimer. Research confidence reflects how many real cited studies back this ingredient, not the strength of their findings.

🤰 Pregnancy Safety Note

EU SCCS flagged endocrine disruption concerns. Use mineral alternatives during pregnancy.

🌍 Regulatory Status

💧 Skin Type Compatibility

Derived from this ingredient’s irritancy potential and comedogenicity rating against the needs of each skin type — e.g. oily and acne-prone skin are marked down for pore-clogging ingredients, sensitive skin for irritants. A starting heuristic, not a dermatological verdict.

⚠️ Don’t Combine With

📚 Research & Evidence

🔬 The Science

Homosalate is a salicylate-based UV filter that protects against UV-B radiation and is commonly added to sunscreens and cosmetic products. Here’s what current research shows:

#1: Hormone-related effects — In male zebrafish exposed to homosalate, researchers observed decreased testosterone levels, changes in genes involved in hormone production (hsd3b2, cyp17a1, hsd17b1), and increased estrogen levels (Chemosphere, 2023). The same pattern appeared in human adrenocortical cells in a lab setting. These findings suggest homosalate may interfere with the body’s steroid hormone system through what scientists call the “steroidogenic pathway.” When homosalate was combined with another sunscreen ingredient (avobenzone), the anti-androgenic effects—meaning effects that block male hormone activity—were amplified in fish (Chemosphere, 2023).

However, these studies were conducted in animal models and lab cells, not humans, so the relevance to typical sunscreen use remains unclear. #2: How the body processes it — When volunteers took a single oral dose of homosalate, the compound was broken down into multiple metabolites (breakdown products), with peak levels appearing in urine 1.5 to 6.3 hours after ingestion (Environ Int, 2022). More than 80% of the metabolites were excreted within the first 24 hours. Importantly, homosalate exists in two different molecular forms (cis and trans isomers), and the body handles them very differently: trans-homosalate was absorbed at much higher levels and excreted in greater amounts than cis-homosalate (Environ Int, 2022).

This distinction matters for assessing exposure risk, since commercial sunscreen products contain mixtures of both forms. #3: Effects on thyroid cells — In laboratory studies using thyroid cells, homosalate reduced cell viability (the cells’ ability to survive) at very high concentrations—starting at 250 microMolar in rat thyroid cells and 2000 microMolar in human thyroid cells—after 48 to 72 hours of exposure (Environ Pollut, 2024). The compound also increased expression of genes related to thyroid function (TPO and thyroglobulin), though it did not increase oxidative stress or affect cell proliferation (Environ Pollut, 2024). Researchers noted that effects differed depending on which type of thyroid cell was tested, suggesting the response may vary by cell type.

#4: Marine ecosystem concerns — Separate research in jellyfish models suggests homosalate may interfere with developmental pathways (specifically the PI3K/Akt and ERK signaling pathways) in ways that could delay metamorphosis in marine organisms (Curr Issues Mol Biol, 2024). This finding is relevant to understanding homosalate’s environmental impact rather than its safety in topical sunscreen use. #5: Safety modeling for human use — Researchers have developed computer-based physiological models to predict how homosalate is absorbed, distributed, and eliminated in humans based on both animal data and actual measurements from a small clinical trial (Front Pharmacol, 2021). These models showed reasonable predictive accuracy for different exposure scenarios (such as typical sunscreen application) and were developed to reduce reliance on animal testing going forward.

Importantly, the sources acknowledge significant knowledge gaps: long-term human exposure effects remain understudied (Chemosphere, 2023), effects on thyroid function warrant further investigation (Environ Pollut, 2024), and the endocrine-disrupting potential of repeated, real-world sunscreen use needs clarification (Chemosphere, 2023).

📄 Related Research

Matched by search — not necessarily verified support for every statement above.

• Lee S et al. (2023). Single and mixture toxicity evaluation of avobenzone and homosalate to male zebrafish and H295R cells. Chemosphere.
• Ebert KE et al. (2022). Diastereoselective metabolism of homomenthyl salicylate (homosalate): Identification of relevant human exposure biomarkers. Environ Int.
• Coperchini F et al. (2024). In vitro study of the UV-filter homosalate effects on rat and human thyroid cells. Environ Pollut.
• Chen J et al. (2024). Homosalate and ERK Knockdown in the Modulation of Aurelia coerulea Metamorphosis by Regulating the PI3K Pathway and ERK Pathway. Curr Issues Mol Biol.
• Najjar A et al. (2021). Use of Physiologically-Based Kinetics Modelling to Reliably Predict Internal Concentrations of the UV Filter, Homosalate, After Repeated Oral and Topical Application. Front Pharmacol.

🧴 Products Containing HOMOSALATE

• La Roche-Posay Effaclar DUO (+) SPF 30
• Nivea, Nivea Sun Spray transparent protection invisible 30 haute
• Nivea crème solaire visage nivea
• Bilboa, Società Italo Britannica Manetti-Roberts Viso 50 alta
• Nivea Sun Kids Lait Protecteur Format Voyage
• Babaria Aceite protector monoi
• Coop, Io Coop Crema Solare 50+
• Cien crema solar
• Les Cosmetiques Aceite solar coco spf30 sun ultimate spray
• Les Cosmetiques Spray solar invisible sport spf30 sun ultimate
• Conad Essentiae Crema Viso con estratti di aloe vera e tè matcha
• Sun ultimate Spray solar invisible spf50 sun ultimate
• Les Cosmetiques Spray solar spf50+ sun ultimate
• Les Cosmetiques Spray solar spf30 sun ultimate
• Babaria spray protector solar
• Les Cosmetiques Bote leche solar spf50+ sun ultimate
• delab BALM TATTOO
• Nesira Gel-Crema Solar SPF30
• acofarderm Gel facial invisible fotoprotector spf 50+
• Tula TULA sun protection measures
• Mixa Solaire Brume Solaire Protection Renforcée Peau Sensible Spf50+
• Nu Skin Nutricentials, day dream protective cream
• Blistex
• Les Cosmetiques Bruma solar facial spf50 sun ultimate
• Neutrogena Ultra Sheer Dry-Touch Sunscreen with Helioplex
• Neutrogena Hydro Boost Water Gel Lotion SPF 50
• Garnier Ombrelle Ombrelle endurance sport
• Edgewell, Hawaiian Tropic Sheer Touch Oil-free Sunscreen Lotion SPF 15
• Hawaiian Tropic Hawaiian Tropic Island Sport
• Banana Boat UltraSport Faces Sunscreen Lotion UVA/UVB Broad Spectrum SPF 30
• Les Cosmetiques Protector solar facial antiedad spf 50+ sun ultimate
• Protector solar NO-AD
• Cetaphil Cetaphil Oil-Free Facial Moisturizer with Sunscreen SPF 35
• BioDerma Bioderma
• Supergoop Play Everyday Lotion SPF 50 with Sunflower Extract
• Cetaphil Cetaphil Pro Oil Absorbing Moisturizer SPF 30
• Protector solar Omnilife
• Nivea, Nivea Sonnenmilch Schutzfaktor 30, Nivea Sonnenmilch Schutzfaktor Hoch, Nivea Sun Schutz und Pflege, Nivea Sun Schutzfaktor 30, Nivea sun Sun Schutz & Pflege LSF 30
• Henkel, Diadermine Lift + Super Correcteur Soin de Jour SPF 15 anti-Rides Correcteur
• La Roche-Posay Lait solaire anthelios XL 50+