Natural Colorants for Lip Products: Sources, Formulation Strategies, Stability Constraints, Safety, and Translational Opportunities-A Narrative Review

Natural colorants have gained increasing attention in the development of lip products, including lipsticks, lip balms, lip glosses, and lip tints, driven by growing consumer demand for naturally derived, renewable, and multifunctional ingredients. However, replacing synthetic colorants and conventional lake pigments remains challenging from a formulation perspective. Lip products are generally formulated as anhydrous matrices with low water content and a high lipid fraction, whereas red-to-purple natural pigments, particularly anthocyanins and betalains, are polar and sensitive to heat, light, oxygen, metal ions, and pH. This narrative review aims to analyze the scientific evidence regarding major classes of natural colorants with potential applications in lip products, including anthocyanins, betalains, carotenoids, curcuminoids, chlorophyll derivatives, annatto pigments, carmine/cochineal, and microbial pigments. The literature was identified through database searches and citation tracking of articles published in Scopus-indexed international journals and Sinta-indexed national journals, with emphasis on pigment characteristics, extraction methods, formulation compatibility, stability, safety, regulatory considerations, and evaluation methods. The review indicates that carotenoids, bixin/norbixin, naturally derived iron oxides, and carmine generally exhibit good compatibility with lipophilic systems, whereas anthocyanins and betalains provide intense coloration and potential antioxidant activity but typically require specialized delivery and stabilization strategies. Promising approaches include the selection of standardized pigment sources, optimized extraction methods, dry pigment powders, oil-based dispersions, lake-like systems, microencapsulation, liposomal delivery, copigmentation, antioxidant systems, and controlled exposure to oxygen and light. Product development should integrate colorimetric assessment, stability testing, contamination control, local tolerance evaluation, and compliance with applicable color additive regulations in target markets. Future research should prioritize standardized extract specifications, assessment of pigment migration and potential oral exposure, life-cycle evaluation, and stronger safety evidence through clinical studies and real-world consumer use.