<p>This study focuses on the influence of environmental and brand factors on customers’ purchase intentions. The study was conducted among health-conscious individuals in Ho Chi Minh City interested in buying green products. In total, 403 valid survey responses were collected and analysed. The respondents were selected based on a convenient sampling procedure. The results show that environmental factors—environmental concern, environmental knowledge and environmental belief—positively influence two intermediate factors: brand image and brand trust. These intermediate factors, in turn, positively impact purchase intention. Our results suggest that companies that produce personal care or environmentally friendly products, particularly those emphasising health, should opt for environmentally friendly materials with transparent origins. These products should adhere to high health standards to benefit consumers. Companies should also use a green processing method in manufacturing and include this information in marketing campaigns. Producing safe and environmentally friendly products enhances brand image and trust, resulting in increased customer purchase intention for natural and environmentally friendly personal care products. This study provides valuable insights into how environmental and brand factors influence customers’ purchase intentions and lays the groundwork for future scholars to delve deeper into the exploration and analysis of customer behaviour. It also provides guidance for companies to create products that align with consumer health and environmental concerns, thereby connecting this research to the achievement of the United Nations’ Sustainable Development Goals, specifically Goal 12—ensuring sustainable consumption and production patterns.</p>