OBJECTIVE:Simmondsia chinensis is a well-known commercially popular plant from which jojoba oil is extracted. Jojoba cake is a sustainably produced, intractable by-product of the jojoba seed oil extraction currently used principally as a fertilizer or burned as fuel. Fermentation work conducted with various microorganisms, including Lactobacillus plantarum, Saccharomyces cerevisiae and Streptococcus thermophilus, sustainably grown on aqueous jojoba cake fermented the cake, liberating jojoba-based amino acids, peptides and proteins. The ferments have been examined chemically and via in vitro cell and tissue studies to develop new skin and scalp care targeted ingredients. METHODS:The jojoba cake contained nutrients (proteins, sugars and lipids) that self-sustain aqueous bacterial fermentation. The ferments were examined on 3D tissue models in vitro via human genomic microarrays. A ferment produced by Lactobacillus plantarum was further tested in vitro using ELISA protein assays on skin cell cultures. A 56-day clinical study on 46 individuals examined the influence of 1.0% of the Lactobacillus ferment on collagen expression using Diffuse Reflectance Spectroscopy (DRS). RESULTS:Gene responses were measured on 244+ genes known to have skin functions. It was found that the Lactobacillus ferment showed the greatest upregulation of skin-associated genes, and three highly upregulated proteins were examined more closely in vitro using ELISA protein assays: collagen-1A1, protocadherin-18 and opioid growth factor receptor. Each protein was upregulated in a dose-dependent fashion. The collagen analysis by DRS demonstrated a statistically significant increase in collagen fluorescence on Day 28 and Day 56 compared to baseline and placebo cream. Further mapping of the collagen fluorescence was done on the individuals using the active formulation at Days 0, 28 and 56. CONCLUSION:Jojoba cake presents a new source of sustainably grown biomass, but the cake is not suitable for topical applications. Fermentation produces components more suitable for topical care. In vitro studies demonstrated upregulation of three skin proteins associated with healing skin. Further studies also employed a newly emerging spectroscopic technique to measure collagen fluorescence in the skin in vivo, the results supporting in vitro work indicating the ferment made with Lactobacillus was able to stimulate collagen synthesis in the skin.
OBJECTIVE:Type III collagen plays a key role in maintaining skin elasticity and dermal resilience, yet its decline is associated with visible signs of skin ageing. This study aimed to establish a data-driven approach to identify cosmetic peptides with potential to enhance type III collagen through multi-target regulation. METHODS:A combined strategy integrating natural language processing (NLP) and knowledge graph (KG) analysis was applied to systematically identify targets associated with type III collagen regulation. Peptides listed in the Inventory of Existing Cosmetic Ingredients in China (IECIC) were screened based on structure-based molecular docking with multiple targets. Candidate peptides were selected for experimental evaluation using human dermal fibroblasts and ex vivo skin models. RESULTS:By integrating large-scale literature mining with NLP and KG-based gene interaction analysis, we constructed a comprehensive network of genes involved in type III collagen regulation, covering processes such as collagen synthesis, degradation and extracellular matrix (ECM) organization. Based on this network, candidate peptides with predicted multi-target interactions were prioritized through structure-based screening. In vitro, four selected peptides-palmitoyl tetrapeptide-7, acetyl hexapeptide-8, palmitoyl tripeptide-1 and palmitoyl tetrapeptide-10-significantly increased type III collagen levels following UV exposure, without detectable cytotoxicity. The combination of these peptides exhibited a greater effect than individual components. In ex vivo skin tissues, the peptide combination further enhanced the levels of type I, III and IV collagens, indicating a broader modulatory effect on dermal ECM components. CONCLUSION:This study provides a practical framework for the identification of cosmetic peptides targeting collagen regulation. The findings support a multi-target approach and suggest that peptide combinations may enhance collagen-related outcomes relevant to skin ageing applications.
OBJECTIVE:Human skin is a highly dynamic organ capable of sensing and responding to mechanical stimuli through tightly regulated communication between the epidermis and dermis. Daily mechanical forces-such as stretching and compression-modulate skin structure and function via mechanotransduction pathways. Central to this process are the mechanosensitive Piezo channels, which convert mechanical tension into electrochemical signals. While the role of Piezo channels in epidermal keratinocytes has been established, it remains unclear whether mechanical tension at the skin's surface can influence deeper dermal responses. METHODS:In this study, we examined whether Piezo-mediated mechanotransduction in keratinocytes affects fibroblast activity and extracellular matrix (ECM) remodelling in the dermis. We applied controlled mechanical tension to the skin surface by the application of cosmetic products on the stratum corneum and measured key features of fibroblast activity and dermal matrix composition. RESULTS:We showed that generating surface tension-induced mechanotransduction in keratinocytes is consistent with the activation of Piezo channels and molecular changes in markers from distinct compartments, including the epidermal protein E-cadherin and dermal ECM proteins such as fibronectin and collagen III. These alterations suggest activation of downstream signalling pathways that may influence dermal fibroblasts, leading to remodelling of key ECM proteins including fibronectin and collagen III, while elastin levels remained unchanged. CONCLUSION:Our findings support the hypothesis that mechanical cues at the epidermal level, sensed via Piezo channels, may participate in interlayer communication and be associated with ECM remodelling in the dermis, supporting the hypothesis of a potential epidermis-to-dermis mechanotransduction axis in human skin.
OBJECTIVE:This study evaluates room-temperature dual asymmetric centrifugation (DAC) as an R&D scale alternative mixing technology for cosmetic oil-in-water emulsions and structured creams (200 g), compared with high-shear rotor-stator and thermo-mechanical processes, with a focus on product properties and energy requirements. METHODS:Formulations were characterized by visual assessment, conductivity and pH monitoring over 30 days. Physical stability was analysed by multiple light scattering. Flow and oscillatory measurements were performed, complemented by texture analysis. Specific energy consumption was evaluated at both scales. RESULTS:All systems exhibited homogeneous oil-in-water structures with no significant differences in pH evolution or physical stability. Shear-thinning behaviour was observed for all formulations, while creams showed dominant elastic behaviour (G' > G″), indicating structured networks independent of the mixing process. Texture properties were similar across technologies. Energy analysis revealed a scale effect: rotor-stator was more efficient for 30 g samples, while DAC became competitive at 200 g due to the absence of heating. Final product properties remained comparable across processes. CONCLUSION:DAC is a robust and energy-efficient alternative for cosmetic emulsions and creams, enabling comparable product properties while offering potential energy savings at larger scales, supporting more sustainable processing strategies.
To accurately identify early destabilization signals in emulsions, this study employed multiple light scattering (MLS) technology combined with microscopic observation, particle size analysis and long-term macroscopic stability tests to perform a multi-scale evaluation on a series of emulsions. By comparing the migration of the transmission light inflection point, the average rate of change of backscattered light intensity (BSMRC) and the uniformity index (U) of samples under different temperatures, the intrinsic correlation between MLS signals and emulsion stability was systematically analysed. The results indicated that three typical destabilization phenomena can be predicted based on the characteristics of the inflection point changes. Further dynamic tracking of BSMRC and U revealed that for stable samples, both BSMRC and U remained at low levels. During destabilization at high temperature (45°C), a significant increase in BSMRC served as a precursor indicator of phase separation. During destabilization at low temperature (-16°C), the U value markedly increased while BSMRC changed gradually, reflecting mechanical damage induced by freezing. In conclusion, multiple light scattering technology can capture destabilization signals in emulsions in advance, with sensitivity superior to traditional visual observation, thereby providing an efficient and reliable technical approach for formulation screening and long-term stability prediction of emulsions.
OBJECTIVE:The aryl hydrocarbon receptor (AHR) is a regulator of epidermal homeostasis and a promising target for cosmetic and dermatological ingredients aimed at improving skin barrier function and reducing inflammation. This study investigated the potential of the natural polyphenol trans-resveratrol (RSV), a compound of cosmetic interest, to modulate downstream AHR signalling and restore epidermal integrity in a model of skin compromised by a pro-inflammatory environment. METHODS:A reconstructed human epidermis (RhE) was exposed to a cytokine cocktail (IL-4, IL-13, TNF-α) to induce a phenotype mimicking some aspects of atopic eczema, namely inflammation, oxidative stress and barrier disruption, features also prevalent in sensitive and reactive skin conditions. The effects of RSV were evaluated by assessing inflammatory mediators, oxidative stress-related markers, aryl hydrocarbon receptor signalling and epidermal barrier-associated proteins using molecular, biochemical and histological analyses. RESULTS:Cytokine exposure induced a pronounced inflammatory response, activation of aryl hydrocarbon receptor signalling, oxidative stress-related gene expression and dysregulation of barrier-related markers. Treatment with RSV attenuated the inflamed phenotype by reducing IL1A mRNA expression and IL-1α secretion, attenuating oxidative stress-associated AHR target gene responses through downregulation of CYP1A1 and CYP1B1, while maintaining AHR and HMOX1 expression and modulating barrier-associated gene expression, particularly by downregulating CASP14 and upregulating the tight junction protein occludin (OCLN). CONCLUSION:These findings provide mechanistic evidence in a human epidermis model that RSV can counteract inflammation, mitigate oxidative stress and support epidermal barrier homeostasis, actions mediated, at least in part, through modulation of AHR downstream signalling. This supports the potential of resveratrol as a multifunctional active ingredient in cosmetic and dermatological formulations designed to strengthen the skin barrier and calm sensitive or compromised skin.
BACKGROUND:Blemish-prone skin is driven by follicular hyperkeratinization, excessive sebum production, microbial dysbiosis and inflammation, often accompanied by post-inflammatory erythema and hyperpigmentation. Retinal and azelaic acid are established topical actives with complementary mechanisms of action, yet no clinical study has evaluated their combination in a single formulation. OBJECTIVE:To evaluate the efficacy and tolerability of a minimalist anhydrous concentrate combining retinal (0.1%) and azelaic acid (10%) in improving objective and self-perceived features of blemish-prone skin over 8 weeks. METHODS:In a prospective randomized, vehicle-controlled split-face study, participants applied the active concentrate to one side of the face and a vehicle concentrate to the contralateral side, mixed with a moisturizer immediately before application. Assessments were performed at baseline and week 8 using standardized photography, Antera 3D imaging and consumer questionnaires. Statistical comparisons were performed within subjects and between treatment conditions. RESULTS:Twenty-three participants completed the study (age 16-49 years; mean 28 years; Fitzpatrick skin types I-IV). After 8 weeks, the active formulation demonstrated statistically significant improvements versus baseline and vehicle. Skin texture improved by 10.9% versus baseline (p < 0.0001) and 5.6% versus vehicle (p = 0.0016). Skin volume (surface irregularities/pits) decreased by 24.8% versus baseline (p < 0.0001) and 12.7% versus vehicle (p = 0.0053). Overall redness was reduced by 13.2% versus baseline (p = 0.0009) and 18.1% versus vehicle (p = 0.011), while maximum redness intensity decreased by 8.8% versus baseline (p < 0.0001) and 5.2% versus vehicle (p = 0.029). The pore parameter showed a 22.3% improvement versus vehicle (p = 0.015) and 15.9% versus baseline (p = 0.051). Self-assessments indicated improvements in overall skin condition (87%), pimple size/severity (78%), number of pimples (74%), calmer skin feel (95%) and reduced oiliness (82%). Visible improvements within 4 weeks were reported by 65% of participants. Adverse events were few, mild and transient. CONCLUSION:An anhydrous six-ingredient concentrate combining retinal 0.1% and azelaic acid 10% significantly improved texture, surface irregularities, redness and pore appearance in acne-prone skin over 8 weeks with good tolerability. The formulation provides a stability-optimized approach for combining two evidence-based actives in a minimalist system.
OBJECTIVE:Extrinsic, lifestyle stressors can increase oxidative stress and induce premature aging characteristics of the skin. We studied the effects of oxidative stress at the biomolecular level to gain insights into effective stress-resiliency strategies for skincare. We also investigated if Galactomyces ferment filtrate (GFF) pretreatment could enhance stress resiliency in keratinocytes in vitro. METHODS:In vitro single cell Raman spectroscopy was performed to identify an oxidative stress phenotype in keratinocytes exposed to hydrogen peroxide (H2O2) stress. The gene expression and functional consequences of acute stress were also determined by performing RNA sequencing, mitochondrial metabolism assays, and proliferation assays 24 h after H2O2 stress exposure. All experiments were performed with and without GFF pretreatment. RESULTS:Raman spectra revealed a novel stress phenotype which includes the formation of cysteic acid with increasing doses of H2O2, likely from the breaking of disulfide bonds in keratins. GFF pretreatment significantly mitigated this stress phenotype; GFF-pretreated cells were 11.9 times more likely to exhibit healthy spectra compared to control cells when exposed to high stress. RNA sequencing conducted 24 h after H2O2 exposure also demonstrated a stress-related phenotype characterized by enhanced regulation of apoptosis and reduced keratinocyte differentiation. Conversely, GFF pretreatment increased multiple pathways of skin development at baseline and prevented the stress-induced dysregulation of gene expression. Keratinocytes pretreated with GFF also had increased stress resiliency in mitochondrial stress and wound healing assays. CONCLUSION:Our data establishes that oxidative stress induces a distinctive biomolecular stress phenotype in keratinocytes. GFF pretreatment enhances the resilience of keratinocytes, as demonstrated by increased expression across various gene pathways related to keratinocyte differentiation, cell-cell junctions, and lipid metabolism. Following oxidative stress, GFF-pretreated cells exhibited substantial protection from the stress-induced biomolecular alterations identified in Raman spectra. Furthermore, GFF pretreatment effectively mitigated the downstream consequences of stress, supporting maintenance of keratinocyte gene-expression programs, mitochondrial activity, and wound-closure capacity after oxidative stress.
OBJECTIVE:To clarify the efficacy of Tuberose Polysaccharide (TPS) as a skin moisturizer and to elucidate its mechanism of action. TPS is known to form a long-lasting, smooth film that protects the stratum corneum (SC) from external stimuli. METHODS:A 12-week randomized, double-blind, vehicle-controlled, split-face study was conducted using a lotion containing 0.08% TPS combined with an emulsion containing 0.10% TPS, compared to a placebo lotion and emulsion. Skin features, SC components and panelist awareness were evaluated. Additionally, 3D-culture epidermal models treated with 0.50% TPS or vehicle were analysed to determine cytokine levels in the medium and epidermal composition before and after exposure to sodium dodecyl sulfate (SDS). RESULTS:The surface texture of the skin improved faster with TPS treatment compared to the placebo. The capacitance value of the skin increased more from the baseline only in the TPS-treated group. Panelists reported a significantly greater awareness of the efficacy and improvement with TPS compared to the placebo. Cytokine levels in the skin were lower, while intercellular lipids in the SC were higher in the TPS-treated sites compared to the baseline. The ratio of ceramide NP to NS was lower in the placebo-treated sites than in the baseline. Cytokine levels in the medium of the TPS film plus SDS-treated 3D epidermal model were lower than in the vehicle plus SDS-treated epidermal model. CONCLUSION:TPS supports normal epidermal keratinization by suppressing the cytokines release due to external stimuli by forming a long-lasting smooth film.
The sensory performance of cosmetic emulsions is a critical determinant of consumer acceptance. While it is understood that emulsifiers are the main sensory contributors, systematic investigations that isolate the sensory contribution of emollients within emulsions remain scarce. This study presents the first comprehensive sensory analysis in a large dataset, specifically examining the impact of emollient cascades on the sensory perception of skin creams while maintaining a fixed emulsifier system. A total of 32 oil-in-water emulsions were formulated with the same emulsifier system at different loads (2.5% vs. 5%), while emollients were systematically varied in type and blend composition (4 blends), ratio (4/3/2 vs. 3/3/3) and total load (9% vs. 18%). Sensory evaluation was conducted using a Check-All-That-Apply (CATA) survey with 50 untrained panellists. The resulting dataset was investigated by univariate parametric and non-parametric statistical tests, as well as multivariate multiple factor analysis (MFA) to assess product discrimination and perceptual structuring. While emulsifiers established the prevailing sensory profile of the emulsions, untrained panellists could differentiate primarily based on visual appearance and static afterfeel attributes, driven by the emollient cascades. MFA revealed that appearance (47.73%) and afterfeel (24.66%) were the principal dimensions driving perception. Conversely, descriptors associated with dynamic application (pick-up, rub-out and immediate skin feel) contributed marginally to discrimination, primarily reflecting the comparatively minor influence of emollients during dynamic sensory stages. The results demonstrate that emulsifiers govern the foundational sensory characteristics of emulsions, while emollients play a decisive role in shaping static afterfeel and visual cues perceptible to untrained users. These findings underscore the sensory relevance of emollients and provide formulation-relevant insights into how controlled emollient selection can meaningfully influence consumer-perceived skin feel beyond emulsifier-driven effects.
OBJECTIVE:To evaluate changes in scar appearance and tolerability associated with 8 weeks of use of a test product comprising a topical dexpanthenol-containing silicone gel with an integrated massage ball in individuals with existing immature hypertrophic scars. METHODS:This was a prospective monocentric, open-label, exploratory, single-arm, in-use study with intra-individual comparison, which enrolled 55 participants with hypertrophic scars aged 1-12 months. Participants massaged the scar with the test product's integrated massage ball prior to applying the dexpanthenol-containing silicone gel twice daily for 8 weeks. Scar appearance was assessed at baseline and at Day 57 using the Patient and Observer Scar Assessment Scale (POSAS), supported by clinical photography, instrumental skin measurements and a participant questionnaire. RESULTS:After 8 weeks, a statistically significant improvement in overall scar appearance was observed, as reflected by a reduction in the total POSAS score. Improvements were reported by both observers and participants across multiple scar parameters, including thickness, pliability and relief. Instrumental assessments supported these findings, including a reduction in scar thickness. The product was well tolerated, with no product-related adverse reactions, and participants reported high overall satisfaction. CONCLUSION:Under the study conditions, the test product was associated with improvements in the appearance of existing immature hypertrophic scars and was well tolerated in a population comprising both adults and children. These findings support its potential utility in topical scar management, including in pediatric populations.
Skin continually faces stresses that compromise its structure and barrier quality, impacting skin appearance and comfort. By sustaining the main biological process of epithelisation, we could improve skin repair, thus correcting skin appearance or discomfort. A stronger barrier will ultimately lead to improvement of the skin surface smoothness, fine lines and radiance. To bolster barrier function, the cohesion of the stratum corneum involving keratinocyte transglutaminase (TGK) and filaggrin (FLG) and the stratum granulosum via tight junction proteins, is critical. Carboxymethyl beta-glucan (CM-BG), a water-soluble derivative of β-glucan, has shown promise in skin repair and anti-ageing applications. This study investigates its wound repair potential using in vitro assays and a 3D human full-thickness wounded skin model. The effects of CM-BG on various skin biological processes, including inflammation, differentiation and extracellular matrix remodelling, were investigated using a range of in vitro assays. Its potential to promote wound healing, epidermal recovery and barrier function was further assessed in a 3D reconstructed skin model. These comprehensive investigations revealed CM-BG's multifaceted actions in skin biology. Findings showed CM-BG selectively activates Dectin-1 receptors in a concentration-dependent manner. Furthermore, CM-BG exhibited anti-inflammatory properties by inhibiting key pro-inflammatory mediators (PGE2, IL-12/IL-23p40, IL-1β) while promoting the release of anti-inflammatory cytokines IL-10. Additionally, CM-BG significantly enhanced the expression of TGK, tight junction proteins (Claudin-1, Zonula occludens-1 and Occludin) and collagen type I. A 3D skin wound healing model confirmed these findings. CM-BG accelerated wound repair, reduced Transepidermal Water Loss and increased epidermal/dermal thickness in the wounded area. Additionally, post-injury, CM-BG also showed increased expression of key markers on the 3D reconstructed skin model. These results suggest CM-BG is a valuable topical ingredient for promoting wound healing, skin repair and mitigating skin ageing by interacting with Dectin-1 receptors, modulating inflammation, improving skin barrier function and boosting collagen production. Further clinical studies are warranted to confirm these promising findings.
OBJECTIVE:This study investigated the antioxidant activity of oil and alkaline aqueous extracts obtained from Bixa orellana seeds and evaluated their potential to modulate the in vitro sun protection factor (SPF) of a sunscreen formulation containing avobenzone (5% w/w) and ethylhexyl methoxycinnamate (10% w/w). METHODS:Alkaline aqueous extracts from whole (AAE1) and ground seeds (AAE2) were prepared, freeze-dried and chemically characterised. Extracted oil (EO) and commercial oil (CO) were also evaluated. Phytochemical screening, chromatographic analyses (GC-MS and LC-MS), carotenoid quantification and in vitro antioxidant assays (DPPH, ABTS + and CUPRAC) were performed. Sunscreen formulations containing 5% (w/w) of each sample were developed, and in vitro SPF was determined before and after UV irradiation. RESULTS:AAE1, AAE2 and EO exhibited relevant antioxidant activity (IC₅₀ < 50 μg/mL), whereas CO showed no detectable activity under the tested conditions. Formulations containing AAE1 and AAE2 demonstrated a marked increase in in vitro SPF prior to irradiation (86.7 and 86.3, respectively) compared to the base formulation (23.3). However, after irradiation, SPF values decreased substantially for AAE1 and AAE2 (11.51 and 21.36, respectively), indicating limited photostability. LC-MS analysis confirmed the presence of bixin and norbixin in aqueous extracts, while GC-MS revealed a more complex profile in EO. Notably, AAE2 exhibited greater SPF retention after irradiation, which may be associated with the presence of triterpenes. CONCLUSION:Although annatto-derived extracts enhanced in vitro SPF prior to irradiation, their limited photostability restricts their direct application as standalone photoprotective agents. These findings suggested that such extracts may be better positioned as auxiliary antioxidant ingredients in sunscreen formulations, particularly when combined with stabilisation strategies to mitigate photodegradation.
Bakuchiol was initially introduced as a functional alternative to retinol based on its ability to modulate gene expression associated with skin aging. Since that initial characterization, a substantial body of evidence has emerged, supporting a broader and more integrated biological role. This narrative review critically evaluates current genomic, mechanistic and clinical data to reassess bakuchiol within dermatological science, focusing on its functional convergence with retinol and its divergence into coordinated modulation of interconnected pathways in skin biology. Gene expression and protein-level analyses demonstrate significant overlap with retinol in the regulation of extracellular matrix remodelling, epidermal differentiation and barrier function, supporting its classification as a retinol-like functional compound. However, mechanistic studies reveal distinct and complementary modes of action, including activation of Nrf2-mediated cytoprotective pathways, selective upregulation of antioxidant enzymes such as NQO1, modulation of inflammatory and melanogenic signalling networks, regulation of endocannabinoid signalling involved in epidermal homeostasis and direct engagement of mitochondrial regulatory complexes. Bakuchiol also influences retinoid transport and metabolism, including upregulation of LRAT, suggesting enhancement of endogenous retinoid activity without direct receptor activation. These effects extend to activation of conserved longevity-associated pathways, including FOXO3 signalling, supported by in vivo evidence from Caenorhabditis elegans models. Clinical studies consistently demonstrate improvements in photoaging, pigmentation and overall skin quality, with superior tolerability relative to retinol. Collectively, these findings position bakuchiol not merely as a retinol alternative, but as a systems-level bioactive that coordinates multiple regulatory networks governing skin resilience, repair and ageing.
BACKGROUND:Plant-derived bioactive compounds are increasingly sought after in the cosmetics and pharmaceutical industries, prompting the development of sustainable production methods. This study explored the potential of Cannabis sativa adventitious root cultures to produce extracellular vesicle-like nanoparticles (CA-NPs) and investigated their protective effects against UVB-induced damage in human keratinocytes. METHODS:CA-NPs were isolated from Cannabis sativa root cultures and characterized for particle size, zeta potential and stability. HaCaT keratinocytes were used to assess the nanoparticles' ability to improve cell viability, reduce apoptosis and alleviate oxidative stress after UVB exposure. Gene expression of skin barrier components and matrix metalloproteinases (MMPs) was analysed, and underlying signalling pathways (MAPK, Nrf2) were examined. RESULTS:CA-NPs (~128 nm, -12.9 mV) showed strong physicochemical stability and effectively protected HaCaT cells from UVB-induced damage. They suppressed MMP-1, MMP-3 and MMP-9 expression while enhancing skin barrier-related genes (HAS1, FLG, LOR, IVL). CA-NPs also modulated MAPK and Nrf2 pathways, reducing inflammation and boosting antioxidant defences. CONCLUSION:Cannabis sativa-derived CA-NPs offer a promising natural approach to protect the skin from UVB-induced damage, supporting their potential as bioactive candidates for future skincare or cosmeceutical applications for preventing photoaging and inflammation.
BACKGROUND:Many individuals have expressed a high degree of caution regarding specific health products, including drugs, medical devices and cosmetics. This can result in people deciding to create the products themselves. AIM:The objective of this work was to analyse recipes for preparing products intended to treat acne or the scars that can follow this condition. MATERIAL AND METHODS:To accomplish this, a comprehensive collection of DIY product recipes was meticulously sourced from various online platforms, including popular blogs and social networks such as YouTube, Facebook, Pinterest, Instagram and TikTok. These recipes were then translated into French and English to enable a thorough analysis of their composition. RESULTS AND DISCUSSION:A comprehensive study was conducted on 116 recipes, encompassing a wide range of culinary traditions and techniques. The study revealed that ingredient quantities vary significantly, the proposed substances are not suitable for the intended application and the finished products are not adequately preserved. The findings suggest that formulations designed for use in patients with acne are not considered safe, and their use is likely to have serious consequences. CONCLUSION:Clearly, the recipes presented do not comply with the legislation governing the practice of medicine and pharmacy. Therefore, using them to treat acne is illegal. Patients must be informed that these substances are not a reliable treatment.
OBJECTIVE:Instrumental methods for measuring hair volume can detect physical differences that are not perceptible to consumers, creating a disconnect between in-vitro measurements and real-world perception. This study aimed to establish the Just-Noticeable Difference (JND) for hair volume and to develop a predictive model incorporating hair waviness to better align instrumental data with sensory evaluation. METHODS:Bulk volume and waviness were quantified from hair swatches using a custom image-analysis framework. Volume was determined via pixel intensity-based fibre density classification, while waviness was derived from an amplitude-frequency analysis of the detrended medial axis. Sensory evaluation was conducted by an expert panel across controlled four-swatch sets with defined volume differences (ΔV ≈ 5, 3 and 2 cm2). Mean sensory rank was used as the primary perceptual metric. A multivariable Ordinary Least Squares regression model was developed and validated using Leave-One-Group-Out Cross-Validation across 35 independent sets. RESULTS:A perceptual threshold of ΔV ≈ 3 cm2 was identified as the JND for hair volume. At ΔV ≈ 5 cm2, instrumental and sensory rankings were in strong agreement, whereas at ΔV ≈ 2 cm2, perceptual discrimination failed. Regression analysis confirmed bulk volume as the dominant predictor of perceived volume (β = 0.798, p < 0.001), with waviness providing a significant secondary contribution (β = 0.135, p = 0.005; Adjusted R2 = 0.660). A waviness correction factor (k ≈ 0.169) was derived, and cross-validation demonstrated robust predictive performance (66.67% top-rank accuracy; 94.87% top-two accuracy). CONCLUSION:This study establishes the quantitative perceptual threshold for hair volume and introduces a morphology-aware correction model that aligns instrumental measurements with human perception. Together, these tools provide a practical framework for ensuring that volumising product claims are both physically measurable and perceptually meaningful.
OBJECTIVE:Foundation colour shift, defined as the visible darkening or yellowing following application, continues to pose a significant challenge for colour cosmetics and compromises consumer satisfaction. Existing in vitro protocols often rely on unrealistic sebum loads or static premixes, limiting their predictive accuracy. This study aimed to develop a physiologically relevant in vitro model that simulates dynamic sebum secretion and evaluates timing effects across multiple formulations to support predictive assessment of consumer-perceived foundation colour shift. METHODS:Three lab-prepared liquid foundations were applied to opacity charts and monitored for 6 hours using DigiEye imaging. Artificial sebum, in an amount approximating typical physiological secretion over 3 hours, was sprayed via a calibrated airbrush at four time points (0 h, 1 h, 3 h and 5 h). Colour shift was quantified using CIE L*a*b* parameters and ΔEcmc values. The model's predictive utility was evaluated by comparison with consumer panel observations. RESULTS:The proposed in vitro model exhibited excellent reproducibility, with highly consistent ΔEcmc trajectories across replicates, and showed strong alignment with consumer perception. Most of the perceptible colour shift occurred during the early drying phase, whereas sebum application, regardless of timing, introduced only minor variations. CONCLUSION:This novel airbrush-based in vitro sebum secretion model bridges laboratory precision with consumer relevance, enabling predictive assessment of foundation colour shift under controlled conditions. By revealing the dominant contribution of drying-phase dynamics, it provides actionable guidance for formulation design and offers a cost-effective, scalable screening tool to support early-stage product development and reduce dependence on extensive consumer trials.
Concerns about the environmental impact of cosmetic ingredients are growing among consumers worldwide. These substances, that is, the constituents of cosmetics, are entering wastewater as well as household waste after use, and many of these molecules are not removed during sewage treatment or degraded in the environment, leading to environmental persistence. Addressing this challenge requires intervention at the earliest stages of cosmetic ingredient development, designing them to be biodegradable when released into the environment. This review aimed to provide an overview of the benign by design (BbD) strategies available to improve the biodegradability of chemicals, demonstrating their applicability to cosmetic ingredients. The BbD strategies encompass de novo design, creating novel compounds from scratch, or the re-design by modifying existing molecules highlighting how biodegradability can be enhanced while maintaining, or potentially improving, functional performance. The strategies can be non-targeted or targeted, following a series of rules of thumb, and applying experimental and in silico tools. Overall, the presence of alkyl linear chains and functional groups such as hydroxyl, carbonyl, ester, amide or carboxylic acid groups favours biodegradation, whereas the presence of alicyclic rings and highly branched alkyl chains, halogens, nitro, nitroso or azo groups hinders biodegradability. The review shows that BbD strategies, already applied in pharmaceutical and chemical design, are equally relevant for the design of cosmetic ingredients to avoid environmentally persistent ingredients, such as per- and polyfluoroalkyl substances (PFAS) and silicones. Beyond reducing environmental persistence, the integration of BbD strategies into cosmetic ingredient development supports the transition towards a greener and more sustainable cosmetic industry, contributing to the preservation of natural resources. This also opens new opportunities for innovation within an expanded and environmentally conscious chemical design space.
