Synergistic Formulation of Tomato-Carrot Juice Gel and Nanogel as a Brightening Agent: An In Vivo Study and Skin Analyzer Evaluation

Background: Carrots and tomatoes contain secondary metabolites and carotenoids that have the potential to support skin care. However, the topical delivery of active ingredients can be influenced by particle size and formulation characteristics. Objective: This study aimed to formulate and evaluate a nanogel containing a combination of tomato (Solanum lycopersicum L.) and carrot (Daucus carota L.) extracts, which are rich in lycopene, beta-carotene, and vitamin C, to synergistically inhibit the tyrosinase enzyme. Methods: This laboratory experimental study included phytochemical screening, preparation of a nanodispersion using Tween 80:PEG 400 (8:1), and characterization using a particle size analyzer (PSA) and scanning electron microscopy (SEM). The formulations were evaluated for homogeneity, spreadability, adhesion, and stability through a 28-day cycling test. An irritation test and exploratory efficacy evaluation were conducted on 30 female volunteers aged 20–30 years over a period of 4 weeks. A hedonic test was conducted with 30 panelists. Skin analyzer data were presented descriptively. Results: The particle sizes of the gel and nanogel were 5,485 nm and 175.74 nm, respectively. SEM analysis of the nanogel showed particle sizes ranging from 240–890 nm, with an irregular/amorphous morphology. Spreadability ranged from 5.26–5.83 cm, while adhesion ranged from 4.85–5.13 seconds. Following the cycling test, the pH remained within 6.12–6.48, and the viscosity was recorded at 9,990 mPa·s. However, the color of both the gel and nanogel changed from bright yellow to pale yellow. No redness, itching, or changes in skin texture were observed. At week 4, the mean moisture values for the blank, gel, and nanogel formulations were 12.00, 22.00, and 51.00, respectively. The corresponding elasticity values were 10.33, 17.67, and 50.33. Melanin values were 37.67, 27.33, and 27.67, respectively, compared with initial mean melanin values of 62.00, 70.00, and 73.33. Conclusion: The 5% nanogel met the evaluated physical characteristics and demonstrated the greatest descriptive trend in improving skin moisture and elasticity, as well as a marked reduction in melanin levels. However, superiority among the formulations could not be established inferentially because of the limited number of volunteers and differences in baseline values between groups.