C-Tetra® Eye

DESCRIPTION

What It Does: Provides the defining intense lemon-citrus fragrance note.

Why It's Used: The lemon scent compound – citral defines the fresh lemon scent in lemon essential oil and lemongrass with potent antimicrobial activity.

How It Works: Mixture of e-isomer (geranial) and z-isomer (neral). antimicrobial via michael addition to thiol enzymes. inhibits nf-kb for anti-inflammatory activity. antioxidant via allylic aldehyde.

Typically Found In: Citrus fragrances,antibacterial products,lemon-scented cosmetics

TECHNICAL DETAILS

Primary Category: Fragrance component – lemon aldehyde

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.001%–0.5%

SOURCING & ETHICS

Vegan Status: Yes – from lemon, lemongrass, melissa oils

Halal Status: Yes

Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Well-tolerated by most skin types.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Eu cosmetics regulation: declared fragrance allergen. high sensitisation potential from alpha,beta-unsaturated aldehyde structure. ifra strict limits.

Works Well With: Standard skincare actives

Avoid Combining With: No known significant incompatibilities

SCIENTIFIC NOTE

Citral's high sensitisation potential (llna ec3 ~0.11%) is a consequence of its alpha,beta-unsaturated aldehyde structure providing a highly reactive michael acceptor for skin protein covalent binding. the e/z mixture (geranial/neral) in natural citral means both isomers contribute to the sensitisation burden – explaining why lemongrass oil (very high citral content, ~60-80%) is one of the more common essential oil allergens.

Last Verified: Cosing database,ifra standards

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides volatile silicone delivery with longer contact time than d5 for extended active delivery.

Why It's Used: Longer-evaporation volatile silicone for formulations requiring extended delivery contact time vs d5's rapid evaporation.

How It Works: Larger ring (6 silicone units) provides lower vapor pressure than d5 (5 units). slower evaporation rate (2-3× longer than d5) provides extended delivery window. same dry-touch after complete evaporation.

Typically Found In: Longer-duration volatile vehicles,serum formulations

TECHNICAL DETAILS

Primary Category: Functional ingredient – volatile cyclic silicone

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 1%–30%

SOURCING & ETHICS

Vegan Status: Yes – synthetic

Halal Status: Yes

Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Well-tolerated by most skin types.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Eu restrictions on d5 do not apply to d6 – d6 may be used in rinse-off products without restriction.

Works Well With: Standard skincare actives

Avoid Combining With: No known significant incompatibilities

SCIENTIFIC NOTE

The different evaporation rates of d4 (methylcyclosiloxane), d5, and d6 provide formulators with a toolkit of volatile silicone delivery windows: d4 evaporates in ~1 minute, d5 in ~5 minutes, d6 in ~15 minutes. blending these provides precisely tunable evaporation kinetics for specific delivery timing requirements.

Last Verified: Cosing database,dow silicone technical data,cir safety assessment

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides a dry, weightless application vehicle that evaporates cleanly leaving actives and non-volatile silicones deposited on skin — eliminating the residual heaviness of conventional liquid carrier solvents.

Why It's Used: Cyclosiloxanes are the unique volatile silicone solvents that dissolve non-volatile silicones (dimethicone, cyclomethicone), organic uv filters, and lipophilic actives, providing the sensory-superior dry-touch application experience in premium formulations.

How It Works: Cyclosiloxane vapour pressure (d5 cyclopentasiloxane ~0.3 mmhg at 25°c) provides clean evaporation at body temperature. the cyclic ring structure provides lower boiling point than equivalent linear dimethicone, enabling faster evaporation while the ring conformation maintains the silicone's low surface energy for smooth application.

Typically Found In: Primers,antiperspirants,sunscreens

TECHNICAL DETAILS

Primary Category: Functional ingredient – emollient

Secondary Functions: Barrier sealing,softening

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 1%–50%

SOURCING & ETHICS

Vegan Status: Yes

Halal Status: Yes

Source Notes: Plant-derived, synthetic or animal-derived. verify source.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 1/5 – low; formulation-dependent

Sensitivity Concerns: Non-irritating.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Excellent safety profile. ewg score: 1.

Works Well With: Humectants,ceramides,actives as carrier

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Cyclopentasiloxane (d5) and cyclohexasiloxane (d6) are under eu regulatory review for potential environmental persistence (pbt assessment) — formulators should monitor eu regulation 2018/35 implementation for restrictions in wash-off products.

Last Verified: Cosing database,eu cyclosiloxane regulatory review

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides fresh rose-geranium floral scent with antimicrobial activity.

Why It's Used: The rose fragrance terpene – geraniol defines the fresh, sweet rose-geranium note found in more than 60 essential oils and is essential for recreating natural floral fragrance profiles.

How It Works: Monoterpene alcohol inhibits bacterial membrane integrity for antimicrobial activity. activates trpv1 for anti-nociception. inhibits nf-kb for anti-inflammatory activity. antioxidant via allylic radical scavenging.

Typically Found In: Rose-scented products,floral fragrances,natural cosmetics

TECHNICAL DETAILS

Primary Category: Fragrance component – acyclic monoterpene alcohol

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.001%–1%

SOURCING & ETHICS

Vegan Status: Yes – from rose, geranium, palmarosa oils

Halal Status: Yes

Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Well-tolerated by most skin types.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Eu cosmetics regulation: declared fragrance allergen. ifra guidelines apply.

Works Well With: Standard skincare actives

Avoid Combining With: No known significant incompatibilities

SCIENTIFIC NOTE

Geraniol's isomers (geraniol, nerol, citronellol) provide subtly different scent characters despite identical molecular formulae (c10h18o): geraniol provides the sweet, fresh rose note while its z-isomer nerol has a more delicate, neroli-like character. these isomeric scent differences arise from different spatial presentation of the hydroxyl and double bond groups to the olfactory receptor – demonstrating the extraordinary structural sensitivity of olfactory perception.

Last Verified: Cosing database,ifra standards

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides the defining fresh citrus fragrance note alongside solvent and antimicrobial properties.

Why It's Used: The citrus industry's primary fragrance compound and the most abundant terpene in essential oils – limonene provides the clean, universally appealing fresh citrus scent character.

How It Works: D-limonene activates trpv1 mildly at high concentrations. antimicrobial via membrane disruption. solvent for oils and lipophilic compounds. cleaning via emulsification of lipid soils.

Typically Found In: Citrus-scented products,cleaning products,fragrance compounds

TECHNICAL DETAILS

Primary Category: Fragrance component – cyclic monoterpene

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.001%–3%

SOURCING & ETHICS

Vegan Status: Yes – from citrus peel essential oils

Halal Status: Yes

Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Well-tolerated by most skin types.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Eu cosmetics regulation: declared fragrance allergen. oxidises to sensitising compounds (limonene hydroperoxides) on air exposure – use with antioxidant stabilisers. ifra guidelines apply.

Works Well With: Standard skincare actives

Avoid Combining With: No known significant incompatibilities

SCIENTIFIC NOTE

Limonene's sensitisation risk arises not from limonene itself but from its autooxidation products (limonene-1,2-epoxide and limonene hydroperoxides) formed on air exposure. fresh limonene has low sensitisation potential, but air-oxidised limonene's hydroperoxide products are potent skin sensitisers. this explains why oxidation-stabilised formulations (with bht or other antioxidants) are required to manage limonene safety.

Last Verified: Cosing database,ifra standards,bråred christensson et al. limonene oxidation study

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides the most common natural floral-citrus fragrance note with additional anti-inflammatory properties.

Why It's Used: The most abundant fragrance terpene in nature – linalool forms the primary scent character of lavender, responsible for lavender's documented aromatherapy calming effects.

How It Works: Monoterpene alcohol activates gaba-a receptors for anti-anxiety activity (same receptor as benzodiazepines). inhibits glutamate-induced excitotoxicity. antimicrobial via membrane disruption. anti-inflammatory via nf-kb inhibition.

Typically Found In: Virtually all fragranced cosmetics

TECHNICAL DETAILS

Primary Category: Fragrance component – tertiary terpene alcohol

Secondary Functions: Skin conditioning

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.001%–3%

SOURCING & ETHICS

Vegan Status: Yes – from lavender, coriander, bergamot

Halal Status: Yes

Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Well-tolerated by most skin types.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Eu cosmetics regulation: declared fragrance allergen on label when >0.001% (leave-on) or >0.01% (rinse-off). ifra guidelines apply.

Works Well With: Standard skincare actives

Avoid Combining With: No known significant incompatibilities

SCIENTIFIC NOTE

Linalool's gaba-a receptor activation provides a pharmacological basis for lavender aromatherapy's documented anxiolytic effects. the same receptor modulation used by benzodiazepine drugs (such as diazepam) is activated by inhaled linalool vapor, providing receptor-mediated calming without the tolerance and dependence associated with pharmaceutical gaba-a modulators.

Last Verified: Cosing database,ifra standards,elisabetsky et al. linalool gaba study

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides antioxidant protection from reactive oxygen species, reduces inflammatory cytokine production in skin, and conditions skin through the plant's phytochemical complex.

Why It's Used: Natural origin narrative, traditional use heritage, and multi-functional phytochemical profile supporting concurrent skin care claims from one ingredient.

How It Works: Polyphenols, terpenoids, and alkaloids scavenge ros via h• donation, inhibit nf-kb or cox-2 inflammatory pathways, and interact with skin surface proteins for conditioning.

Typically Found In: Botanical skin care,natural products

TECHNICAL DETAILS

Primary Category: Active ingredient – antioxidant

Secondary Functions: Free radical scavenging,anti-aging

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.1%–10%

SOURCING & ETHICS

Vegan Status: Conditional

Halal Status: Yes

Source Notes: Plant-derived extract or synthetic.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Non-irritating; well-tolerated.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Excellent safety profile. ewg score: 1.

Works Well With: Vitamin c,vitamin e,ferulic acid,spf,other antioxidants

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Plant secondary metabolites evolved as photoprotectants and antimicrobials — mechanisms directly applicable to cosmetic antioxidant and anti-inflammatory activity in human skin.

Last Verified: Cosing database,simmondsia chinensis (jojoba) seed botanical review

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Delivers potent, stable vitamin c deep into skin for superior antioxidant protection and collagen stimulation.

Why It's Used: Premium anti-aging requiring proven deep penetration and exceptional stability in all formulation types.

How It Works: Four hexyl decyl chains provide lipophilicity for membrane penetration. progressive enzymatic hydrolysis releases ascorbic acid within deeper skin layers.

Typically Found In: Luxury vitamin c serums,anti-aging products,brightening formulations

TECHNICAL DETAILS

Primary Category: Active ingredient – vitamin c derivative

Secondary Functions: Superior penetration,stable vitamin c

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.5%–3%

SOURCING & ETHICS

Vegan Status: Yes – synthetic

Halal Status: Yes

Source Notes: Fully synthetic. produced by esterification of ascorbic acid with 2-hexyl decanol.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Non-irritating; suitable for all skin types.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Excellent safety profile. ewg score: 1.

Works Well With: Tocopherol,ferulic acid,niacinamide,spf

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Clinical studies confirm thd reaches the dermis more effectively than l-ascorbic acid, stimulating fibroblast collagen production at the structural skin level.

Last Verified: Cosing database,shefer et al. penetration studies

Primary Sources: 2026-03-12

DESCRIPTION

What It Does: Provides stable vitamin e delivery with antioxidant activity after esterase hydrolysis in skin.

Why It's Used: The formulation-stable vitamin e — tocopheryl acetate's ester protection prevents oxidative degradation during shelf life while releasing active tocopherol in skin for equivalent biological activity.

How It Works: Acetate ester blocks the phenolic oh group responsible for oxidation and radical scavenging. skin esterases cleave acetate bond releasing free tocopherol. released tocopherol provides lipid peroxyl radical scavenging in cell membranes. also provides direct emollient and skin conditioning.

Typically Found In: Moisturisers,sunscreens,anti-aging products — extremely widespread

TECHNICAL DETAILS

Primary Category: Active ingredient – stable vitamin e ester

Secondary Functions: Free radical scavenging,anti-aging

Application Areas:

Facial Skincare

Body Care

Hair Care

Beard Care

Color Cosmetics (Makeup)

Dietary/Oral Supplements

Typical Concentration Range: 0.1%–5%

SOURCING & ETHICS

Vegan Status: Conditional – natural from vegetable oils (soy, sunflower); synthetic dl-form

Halal Status: Yes

Source Notes: Plant-derived extract or synthetic.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Non-irritating; well-tolerated.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: The d-alpha-tocopheryl acetate (natural isomer) is biologically superior to dl-alpha-tocopheryl acetate (racemic synthetic) for skin antioxidant activity. ingredient label d- vs dl- prefix identifies natural vs synthetic origin.

Works Well With: Vitamin c,vitamin e,ferulic acid,spf,other antioxidants

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Tocopheryl acetate's conversion to active tocopherol in skin is quantitatively efficient: skin esterase activity is sufficient to cleave 60-80% of applied tocopheryl acetate within 24 hours of application. however, the conversion rate varies with skin condition (eczematous or barrier-compromised skin has reduced esterase activity), meaning tocopheryl acetate efficacy may be reduced precisely in the skin conditions that most need antioxidant support.

Last Verified: Cosing database,cir safety assessment

Primary Sources: 2026-03-12