Research explorer
Every record states its study design, sample size where reported, key finding and limitations. Where an identifier could not be verified, the entry links to a Europe PMC title search instead of asserting a PMID.
56 matching records
Notes that public independent data on hydroxypinacolone retinoate are limited relative to retinol and retinoic acid.
Limitations — Review highlighting an evidence gap rather than reporting new results.
Pooled analysis reported increased hair count versus placebo across multiple randomised trials.
Limitations — Regulated medicine; outcomes measured over 16-48 weeks; discontinuation reverses gains.
Reported comparable improvement in wrinkle and pigmentation scores between bakuchiol and retinol, with less scaling and stinging reported for bakuchiol.
Limitations — Single centre, 12 weeks, no vehicle arm, so both may reflect regression to the mean.
Pooled analysis reported reductions in melasma severity scores, with substantial heterogeneity between studies.
Limitations — High heterogeneity, varied vehicles and concentrations, mostly small trials.
Summarises the NAD salvage route in which nicotinamide is converted by NAMPT and NMNAT enzymes to NAD+, supporting redox and signalling functions.
Limitations — Review of mechanism, largely non-cutaneous; does not evaluate topical delivery.
Summarises concentration-dependent behaviour of urea, humectant at low percentages and keratolytic at higher percentages.
Limitations — Narrative review without quantitative synthesis.
Summarises evidence that skin expresses melatonin-pathway enzymes and receptors, and that melatonin scavenges reactive species in cutaneous models.
Limitations — Review; controlled cosmetic endpoints in humans are sparse.
Reported faster transepidermal water loss recovery with a ceramide-dominant formulation compared with a control emollient.
Limitations — Short duration; identifier not verified during curation.
Found supporting evidence only in cases of underlying biotin deficiency; no evidence of benefit in non-deficient individuals.
Limitations — Review of a small literature; few controlled trials exist.
Establishes linoleate as required for omega-O-acylceramide formation, with PNPLA1 mediating the transfer step.
Limitations — Review of genetic and animal evidence; topical repletion effects less characterised.
Summarises long-standing topical use with limited modern controlled data on mechanism.
Limitations — Sparse controlled evidence; mechanism partly unresolved.
Summarises RAR/RXR heterodimer signalling as the transcriptional mechanism of retinoid action in epidermis and dermis.
Limitations — Narrative review; mechanistic focus without effect-size synthesis.
Summarises reported effects of GHK and GHK-Cu on matrix protein and antioxidant gene expression in cell and animal models.
Limitations — Review with substantial single-group authorship; human cosmetic endpoints sparse.
Describes squalene as readily oxidised in sebum, whereas the saturated squalane form is oxidation-resistant and functions as an emollient.
Limitations — Review; largely physicochemical rather than biological endpoints.
Summarises how hyaluronan fragment size determines CD44 signalling outcomes, with high and low molecular weight forms behaving differently.
Limitations — Mechanistic review; largely non-topical models.
Reported association between follicular SULT1A1 activity and clinical response to topical minoxidil.
Limitations — Observational association; identifier not verified during curation.
Reported rapid oxidative degradation of L-ascorbic acid at neutral pH, mitigated by low pH and antioxidant co-formulation.
Limitations — Formulation chemistry only; no biological endpoints.
Reported small improvements in wrinkle depth versus vehicle, with overlapping confidence intervals on several endpoints.
Limitations — Small effect size; identifier not verified; peptide not isolated from other actives in the formulation.
Reported increased anagen hair ratio and thick hair rate compared with control lotion.
Limitations — Small sample; industry-sponsored; identifier not verified during curation.
Reported no detectable increase in skin ageing over 4.5 years in the daily sunscreen group compared with discretionary use.
Limitations — Sunscreen formulation was not zinc-oxide-specific; outcome assessed by microtopography of the hand.
Reported reduced plasmin-dependent signalling to melanocytes in co-culture after tranexamic acid exposure.
Limitations — Cell model; identifier not verified during curation.
Reported improved formulation stability for magnesium ascorbyl phosphate but slower and variable conversion to free ascorbate in skin models.
Limitations — Formulation and ex-vivo delivery only; no clinical endpoints.
Characterises nicotinamide as a weak product inhibitor of PARP enzymes in cell-free assays.
Limitations — Biochemical assay; inhibitory concentrations far above physiological skin levels.
Reported increased corneometry-measured hydration and reduced wrinkle depth versus baseline over 8 weeks.
Limitations — Instrumental surrogate endpoints; identifier not verified during curation.
Reported reduced UV-induced MMP-9 expression in treated skin equivalents.
Limitations — Skin equivalent model; identifier not verified; human endpoints lacking.
Establishes CLEC7A/dectin-1 as the principal receptor for beta-1,3-glucans in innate immune recognition.
Limitations — Immunology review; cosmetic topical endpoints not addressed.
Describes lipophilic partitioning into sebaceous follicles and reduced corneocyte cohesion as the principal described mechanisms.
Limitations — Review; mechanistic detail at the protein level remains incomplete.
Reported that apparent SIRT1 activation by resveratrol depends on the fluorophore-labelled substrate used in the assay.
Limitations — Biochemical; cautions against over-interpretation of resveratrol as a direct sirtuin activator.
Reported increased collagen deposition and faster wound closure in a rodent model.
Limitations — Animal wound model; not equivalent to intact cosmetic use; identifier not verified.
Demonstrates that filaggrin proteolysis by caspase-14 and downstream enzymes generates pyrrolidone carboxylic acid and urocanic acid.
Limitations — Ex-vivo/in-vitro; identifier not verified during curation.
Reported reduced sebocyte lipid accumulation with zinc salts, including 5-alpha reductase inhibition in cell assays.
Limitations — Cell model; identifier not verified; concentration relevance unclear.
Reported improvement in fine wrinkling with topical retinol versus vehicle in older adults.
Limitations — Small sample; older cohort limits generalisation; identifier not verified during curation.
Reported counteraction of testosterone-suppressed hair shaft elongation in ex-vivo follicle culture.
Limitations — Organ culture; topical delivery to the follicle in vivo not established; identifier not verified.
Reported reduced UVA-induced signalling and membrane damage in ectoin-treated keratinocytes.
Limitations — Cell model; identifier not verified during curation.
Summarises hydroquinone as historically the most effective topical depigmenting agent, with dose-related irritation and ochronosis concerns.
Limitations — Review; regulatory status varies widely by jurisdiction.
Reported improvements in several appearance endpoints including fine lines and skin texture over 12 weeks of use versus vehicle.
Limitations — Manufacturer-affiliated authorship; appearance endpoints partly investigator-graded.
Reported improved formulation stability and increased measured photoprotection for a C/E/ferulic combination on human skin.
Limitations — Very small sample; surrogate photoprotection endpoints; industry-affiliated.
Reported increased collagen I and fibronectin expression in treated fibroblast cultures.
Limitations — In-vitro; identifier not verified; no dermal delivery data.
Reported dose-dependent reduction of melanin content in cultured melanocytes.
Limitations — In-vitro only; hydroquinone release in skin not quantified; identifier not verified.
Establishes the approximately equimolar ceramide/cholesterol/free fatty acid composition required for competent lamellar barrier structure.
Limitations — Review; ratio requirements derived largely from animal and ex-vivo models.
Reported modest improvement in photoaging scores versus vehicle on half-face assessment.
Limitations — Small sample; identifier not verified; subjective grading.
Reported reduced hyperpigmentation with topical niacinamide, and reduced melanosome transfer to keratinocytes in an accompanying co-culture model.
Limitations — Small sample, short duration, split-face design without long-term follow-up.
Reported improvement in investigator-assessed photoaging scores on the vitamin C treated side.
Limitations — Very small sample; identifier not verified during curation; formulation stability not reported.
Aquaporin-3 null mice showed reduced stratum corneum glycerol and impaired hydration, restored by glycerol administration.
Limitations — Animal knockout model; identifier not verified during curation.
Reported interference with SNAP-25 dependent complex formation in a cell-free system.
Limitations — Cell-free system; cutaneous penetration to neuromuscular junctions not demonstrated.
Reported faster barrier recovery measured by transepidermal water loss compared with vehicle after sodium lauryl sulfate challenge.
Limitations — Experimental irritation model; identifier not verified during curation.
Reported increased ceramide and free fatty acid synthesis in keratinocyte culture after niacinamide exposure.
Limitations — In-vitro only; concentrations may not reflect in-use exposure.
Reported increased procollagen I expression and reduced MMP-1 in biopsied retinoid-treated skin.
Limitations — Biopsy-based surrogate endpoints; identifier not verified during curation.
Reported measurable CoQ10 in epidermal layers and reduced oxidation markers after supplementation in vitro.
Limitations — In-vitro; identifier not verified during curation.
Reported reduced corneocyte cohesion and increased epidermal thickness after repeated glycolic acid application.
Limitations — Historical study; identifier not verified during curation; pH and concentration not standardised across arms.
Reported increased epidermal ceramide production after lactic acid exposure in a skin model.
Limitations — In-vitro; stereoisomer-specific effects incompletely characterised; identifier not verified.
Reported that only balanced ceramide/cholesterol/fatty acid mixtures accelerated barrier recovery; incomplete mixtures delayed it.
Limitations — Animal model; identifier not verified during curation.
Characterises kojic acid inhibition of tyrosinase through chelation of active-site copper ions.
Limitations — Enzyme assay only; no cutaneous endpoints; identifier not verified.
Establishes ascorbate as an obligatory cofactor for prolyl and lysyl hydroxylases in collagen maturation.
Limitations — Nutritional/biochemical focus rather than topical cosmetic use.
Reported competitive tyrosinase inhibition with greater effect on hyperactive melanocytes than normal melanocytes.
Limitations — In-vitro; selectivity claim not confirmed in later human work; identifier not verified.
Reported statistically significant improvement in photoaging endpoints with tretinoin versus vehicle.
Limitations — Small sample; prescription-strength retinoid, not a cosmetic retinol.