Since the onset of the COVID-19 pandemic, there has been a significant surge in sales of ABHSGs [70]. To meet the challenge of increased demand and raw material shortages, many countries have permitted manufacturers and medical institutions to develop and produce hand sanitizers independently. Unfortunately, this has led to a situation where some manufacturers fail to adhere to proper quality control measures or use denatured alcohol, resulting in a notable increase in substandard hand sanitizer products in the market [47,71,72,73]. Furthermore, the fermentation and distillation processes employed by manufacturers, along with the impact of production equipment and the environment, may introduce impurities such as benzene and acetaldehyde into hand sanitizers, exacerbating public health concerns [74,75]. Consequently, it is recommended that users critically evaluate the antimicrobial functional ingredients in hand sanitizer formulas and carefully review product labels to avoid potential allergens based on their personal sensitivities before use [76], as shown in Figure 2.

Common antimicrobial components found in regular hand sanitizer products (such as ABHSGs) can cause corneal epithelial cell destruction at high concentrations, leading to eye diseases. Prolonged contact with hands may also increase the risk of local adverse reactions, such as contact dermatitis and atopic dermatitis [77]. In recent years, clinical cases involving adverse effects from ABHSGs have been on the rise, particularly among children [78,79]. Children tend to use hand sanitizers more frequently than adults [80], and face an increased risk of ingestion and exposure problems after using informal ABHSGs, underscoring the importance of adult supervision during use [78,81]. Additionally, healthcare workers who apply ABHSGs before handling newborns may heighten the risk of neonatal exposure to ethanol vapor, potentially causing neuronal damage and leading to neurodevelopmental delay and behavioral issues. However, the impact of such low-dose ethanol exposure on neonatal brain development is currently unclear [82,83]. Furthermore, isopropanol ingestion can result in common health problems. Accidental inhalation or dermal exposure may cause poisoning, although it usually does not lead to serious health hazards [84]. Repeated exposure of microbes to disinfectants, antibiotics, and other genotoxic chemicals leads to the development of resistance, becoming a significant global concern, particularly burdening healthcare professionals [85]. Triclosan serves as a prime example, having been used as an antimicrobial component in NABHSGs over the past decades, but evidence indicates its potential for environmental impact and antibiotic resistance [86]. Therefore, excessive and prolonged use of HSGs also entails potential risks. Furthermore, the impact of ethanol, isopropanol, and other ingredients on the environment has long been a topic of concern [87]. These compounds can volatilize or seep into soil and groundwater, significantly affecting aquatic organisms [88]. Thus, while addressing potential issues associated with the long-term use of HSGs, it is crucial to emphasize effective management of good hygiene practices.

To maintain hand hygiene, particularly among children and healthcare workers, frequent hand washing is crucial. Therefore, it is important to select an emollient that effectively strengthens the skin barrier. Research indicates that BAK, an antiseptic ingredient, provides immediate and long-term antimicrobial effects, and the addition of emollients typically does not diminish its effectiveness [89]. Furthermore, BAK tends to be less irritating to the skin and rarely causes allergic reactions [63]. In cases where adverse reactions, such as hand rashes, arise from using ABHSGs, it is recommended to either switch to hand sanitizers containing BAK or seek medical treatment [90]. It is important to note that ethanol and isopropanol, commonly found in ABHSGs, are volatile and combustible substances that could cause fires when used near flames or exposed to high temperatures [16,18,91]. As such, the inclusion of novel safe antimicrobial ingredients can offer a safer alternative with an improved safety profile.

The stability of the gel is related to the pH of the compound, with a lower pH resulting in decreased mobility. Considering that ethanol and isopropanol have different polarities, and isopropanol exhibits a significantly lower polarity compared to ethanol, a greater amount of triethanolamine must be incorporated into isopropanol to produce a stable polymer with carbomer [92]. Studies have demonstrated that anionic thickeners (such as carbomer or acrylate) notably impair the antimicrobial persistence of ABHSGs on the skin. As an alternative, non-ionic polymer thickeners like hydroxypropyl cellulose may be considered to replace carbomer and improve antimicrobial persistence [93]. In addition, by optimizing the manufacturing process of the gel, it is possible to explore materials with good biocompatibility, fast volatilization, and even completely natural edible ingredients in HSGs, which not only contribute to the stability of the gel, but also provide enhanced biocompatibility, leading to faster volatilization. This exploration opens up the possibility of reducing reliance on synthetic ingredients and instead adopting entirely natural and edible ingredients. The trend towards using natural and edible ingredients in hand hygiene products is in line with consumers’ growing preference for environmentally friendly and safe options.