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34 entities found starting with S Clear filters

Sapienic acid
MolecularEntity
A C16:1 delta-6 monounsaturated fatty acid produced exclusively by human sebaceous glands. The most abundant fatty acid in human sebum.
Saturated fatty acids
ChemicalSubstance
A class of fatty acids characterised by a fully saturated carbon chain with no double bonds, making them chemically stable and resistant to oxidation.
Scalp
AnatomicalStructure
Distinct tissue where hair follicles reside, with different characteristics than facial skin requiring adjusted treatment approaches.
Sebaceous gland
AnatomicalStructure
Holocrine secretory glands distributed across most body skin, embedded in the dermis and typically connected to a hair follicle as part of the pilosebaceous unit.
Sebaleic acid
MolecularEntity
A C18:2 delta-5,8 polyunsaturated fatty acid produced exclusively in human sebaceous glands by elongation and desaturation of sapienic acid.
Sebocyte
AnatomicalStructure
The lipid-producing cells of the sebaceous gland, responsible for synthesising and secreting the components of sebum.
Sebum
ChemicalSubstance
The complex lipid mixture secreted by sebaceous glands onto the skin surface via the follicular canal.
Senescence-associated secretory phenotype
MedicalCondition
The pro‑inflammatory secretory programme of senescent cells, releasing cytokines and MMPs that degrade collagen, suppress regeneration, and drive chronic tissue inflammation.
Serine
ChemicalSubstance
Serine is a key amino acid for skin, required for ceramide synthesis via serine palmitoyltransferase and as a major NMF component that supports hydration and keratinocyte proliferation.
Serine palmitoyltransferase
Protein
The rate-limiting enzyme initiating de novo ceramide synthesis from serine and palmitoyl-CoA. SPT activity is directly suppressed by declining oestrogen and cortisol elevation.
Sex hormone binding globulin
Protein
Liver-produced glycoprotein that binds testosterone, DHT, and oestradiol with high affinity, functioning as the primary gatekeeper of sex hormone bioavailability.
Short-chain fatty acid
ChemicalSubstance
Short-chain fatty acids are microbially-derived metabolites - principally butyrate, propionate, and acetate - that serve as the primary functional output of a healthy gut microbiome.
Sirtuin
Protein
NAD⁺-dependent deacetylase enzymes found in every skin cell. SIRT1 is the most skin-relevant family member, regulating circadian clock amplitude, suppressing NF-κB-driven inflammation.
Skin
AnatomicalStructure
The body's largest organ, comprising epidermis, dermis, and subcutaneous tissue. Barrier function, structural integrity, and cellular renewal all decline through distinct but interacting mechanisms.
Skin ageing
BiologicalProcess
Skin ageing is the gradual decline of dermal structure, epidermal renewal, and barrier function, driven by intrinsic ageing and accelerated by environmental stressors.
Skin barrier dysfunction
MedicalCondition
Barrier dysfunction describes the full spectrum of stratum corneum failure, from the earliest detectable impairment of moisture retention to the self-perpetuating inflammatory cycle.
Skin Boosters
MedicalTherapy
Injectable hyaluronic‑acid formulations, sometimes with complementary actives, placed into the dermis to restore hydration, stimulate fibroblast activity and improve skin quality.
Skin circadian clock
BiologicalProcess
The circadian rhythm of the skin barrier describes the 24-hour molecular programme by which skin cells time their protective, regenerative, and repair functions.
Skin dysbiosis
MedicalCondition
A state of microbial community imbalance on the skin surface, characterised by loss of commensal species, reduced diversity, and conditions that permit pathogenic overgrowth.
Skin microbiome
BioChemEntity
The community of microbes on the skin that shapes barrier function by regulating pH, aiding ceramide production, tuning innate immunity, and preventing pathogen overgrowth.
Sodium lauryl sulfate
ChemicalSubstance
An anionic surfactant used in cleansers, shampoos, and personal care products that disrupts the stratum corneum through two sequential mechanisms.
Solar elastosis
MedicalCondition
The accumulation of disorganised, non-functional elastotic material in the upper dermis, representing the defining histological marker of photoaged skin.
Squalane
MolecularEntity
The fully hydrogenated, saturated derivative of squalene. Retains squalene's emollient properties and skin compatibility whilst offering oxidative stability.
Squalene
MolecularEntity
A triterpene lipid produced endogenously in the liver and sebaceous glands, and a significant component of human sebum. Functions as a surface antioxidant and emollient.
Staphylococcus aureus
BioChemEntity
A gram-positive, facultatively commensal bacterium that becomes the dominant skin pathogen in dysbiotic conditions.
Staphylococcus epidermidis
BioChemEntity
The dominant commensal bacterium on human skin, once regarded primarily as an opportunistic pathogen but now understood as an active contributor to barrier integrity and antimicrobial defence.
Stearic acid
MolecularEntity
An 18-carbon saturated fatty acid found in tallow, beef, and cocoa butter, and a significant component of human sebum.
Stratum basale
AnatomicalStructure
The deepest viable epidermal layer, anchored to the dermis via the basement membrane zone, housing the keratinocyte stem cell population that feeds the entire differentiation programme above it.
Stratum corneum
AnatomicalStructure
The outermost layer of the epidermis, composed of 15–20 layers of anucleate corneocytes embedded in a structured lipid matrix. Functions as the primary permeability barrier.
Stratum granulosum
AnatomicalStructure
The stratum granulosum is the granular layer of the viable epidermis immediately beneath the stratum corneum, where keratinocytes complete terminal differentiation.