Dikmen Küçük, Sibel2026-08-252026-08-252026https://hdl.handle.net/20.500.12684/23767In this study, a multi-component cosmetic hair care oil formulation composed of natural botanical oils was developed, and its safety characterization was comprehensively evaluated. The formulation consists of apricot kernel oil (15%), argan oil (15%), jojoba oil (15%), sweet almond oil (15%), castor oil (10%), squalane (10%), coco-caprylate (10%), sacha inchi oil (6%), horse chestnut oil (0.5%), vitamin E (1%), rosemary essential oil (1%), and a natural preservative system (Lexgard Natural, 1.5%). Safety assessment was carried out through three complementary analytical approaches: stability analysis, microbiological analysis, and antimicrobial efficacy (challenge) testing. In the stability study, the formulation was monitored over a 3-month period at both 25°C and 40°C; parameters including color, odor, appearance, density, packaging integrity, and phase separation were evaluated. All parameters remained stable throughout the study period, no phase separation was detected, and density variations were negligible. Microbiological analysis results demonstrated that total aerobic mesophilic microorganism and yeast-mold counts were below 10 cfu/g, with Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans not detected, confirming full compliance with cosmetic microbiological guidelines. In the antimicrobial efficacy test conducted in accordance with TS EN ISO 11930:2019, the formulation met Criterion A for all test microorganisms, including Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, and Aspergillus brasiliensis. These results demonstrate that the developed plant-based hair care oil formulation is both microbiologically safe and physicochemically stable, confirming its suitability for cosmetic commercial application.eninfo:eu-repo/semantics/openAccessHair care oilFormulation developmentStabilityAntimicrobial efficacyMicrobiological safetyConference Object8372