<p>Ultrasonic homogenization technology is a popular method for creating nano-emulsion systems due to its cavitation mechanism, which separates oil droplets into nano-sized particles in a short time. It is applied in many cosmetic and hair care products. Hair care products containing pomelo essential oil nano-emulsion systems are an advanced formulation in which pomelo essential oil is coated or dispersed as nanoparticles in an emulsion system. Nano-sized nanoparticles help pomelo essential oil easily penetrate deep into the scalp and hair roots, increasing hair care efficiency and stimulating hair growth. Experiments were conducted to determine the parameters affecting the process of creating nano-emulsification systems using ultrasonic homogenization technology, including time, homogenization speed, pomelo essential oil content, and emulsifier, based on the criteria of turbidity and stability of the product. The optimized parameters for creating pomelo essential oil nano-emulsion systems were determined to be a homogenization time of 9&#xa0;min and 50% device power (500&#xa0;W). The average particle size measured using the Dynamic Light Scattering (DLS) method was 30.3&#xa0;nm. The transparency of the product directly depends on the turbidity of the nano-emulsion system; there is a strong correlation between particle size and turbidity, with smaller particle sizes resulting in a more transparent emulsion. Hair care products containing grapefruit essential oil nano-emulsion systems exhibit high stability, with no phase separation occurring at 45&#xa0;°C after 4 weeks. Therefore, the product is expected to have the potential for efficient distribution of active ingredients in hair care products, while also ensuring long-term product stability.</p>