Theory Of Planned Behavior Variables Research Articles

Enhancing the Theory of Planned Behavior with Perceived Consumer Effectiveness and Environmental Concern towards Pro-Environmental Purchase Intentions for Eco-Friendly Apparel: A Review Article

The textile sector has become a significant source of pollution due to increasing carbon emissions, heightened greenhouse gas emissions, and growing landfill contributions. In response, the industry is turning towards sustainable fashion, which is gaining popularity as an eco-friendly practice. This study utilized the theory of planned behavior (TPB) alongside variables such as environmental concern, personal moral norms, and perceived consumer effectiveness to predict eco-friendly apparel purchasing intentions among educated Indian youth. The research applied variance-based partial least squares structural equation modeling (PLS-SEM) to assess the proposed model. Results revealed that perceived behavioral control significantly and positively impacts purchasing intentions, followed by personal moral norms, general attitude, and perceived consumer effectiveness. Environmental concern was shown to indirectly influence purchasing intentions via the primary TPB variables and personal moral norms. Additionally, multi-group analysis (MGA) was used to investigate the moderating effects of perceived consumer effectiveness on the attitude-intention relationship, finding that individuals with higher perceived effectiveness displayed a more consistent attitude-intention correlation compared to those with lower perceived effectiveness. This study offers valuable insights for professionals and policymakers, suggesting the development of tailored sustainable marketing strategies and policies to address local market conditions.

Bus Drivers’ Behavioral Intention to Comply with Real-Time Control Instructions: An Empirical Study from China

Developing intelligent bus control systems is crucial for fostering the sustainability of urban transportation. Control instructions are produced in real time by the bus control system; these are important technical commands to stabilize the order in which buses operate and improve service reliability. Understanding the behavioral intention of bus drivers to comply with these instructions will help improve the effectiveness of intelligent bus control system implementation. We have developed a psychological model that incorporates decomposed variables of the theory of planned behavior (TPB) and other influencing variables to explain the micromechanisms that determine bus drivers’ behavioral intention to comply with real-time control instructions during both peak and off-peak-hour scenarios. A total of 258 responses were obtained and verified for analysis. The results showed that the influential factors in the peak- and off-peak-hour scenarios were not identical. Female drivers had greater off-peak-hour behavior intention to comply than male drivers, and there were significant differences in peak-hour behavior intention among drivers of different ages. In both peak and off-peak-hour scenarios, perceived benefit positively and perceived risk negatively affected behavioral intention. Perceived controllability positively affected behavioral intention only during peak hours. Self-efficacy only negatively affected behavioral intention during off-peak hours. Three antecedent variables (i.e., trust, mental workload, and line infrastructure support) influenced drivers’ behavioral intentions indirectly via the decomposed variables of TPB. These results provide profound insights for the improvement and implementation of real-time control technology for bus services, thereby facilitating the development of smart and sustainable urban public transport systems.

Online cash waqf behavioral intention: the role of knowledge of cash waqf and trust

Purpose This study aims to explore the determinants that impact state Islamic University/Perguruan Tinggi Keagamaan Islam Negeri students’ intention to adopt online cash waqfs. In doing so, this study integrates knowledge of cash waqf and trust variables within the theory of planned behavior (TPB), allowing an examination of the mediating role of TPB variables and trust within the relationship between knowledge of cash waqf and intention for online cash waqf behavior. Design/methodology/approach To carry out an empirical analysis, the authors developed a well-structured questionnaire and distributed it to a group of students currently enrolled in PTKIN, obtaining 443 usable responses. The partial least squares-structural equation modeling (PLS-SEM) technique was used for the dual purposes of data analysis and hypothesis testing. Findings This study demonstrates that factors such as attitude, subjective norms, perceived behavioral control, trust and knowledge of cash waqf have a significant and favorable influence on the intention to donate through e-cash waqf. Knowledge of cash waqf impacts attitudes, subjective norms, perceived behavioral control and trust. The final analysis shows that attitude, subjective norms, perceived behavioral control and trust partially mediate the relationship between knowledge and intention in the online cash waqf context. Practical implications The aforementioned elucidates the paramount importance of trust in shaping individuals’ tendencies to engage in cash waqfs. The insights mentioned have the potential to be used by cash waqf establishments to promote transparency and accountability, ultimately bolstering the confidence of potential donors. Originality/value The concepts of waqf and the use of online cash waqf as a means of donation in developing countries are relatively new. In this study, the intention of students to adopt online cash waqf was predicted for the first time by considering their knowledge of cash waqf and their trust in online cash waqf transactions.

Drivers of generative AI adoption in higher education through the lens of the Theory of Planned Behaviour

Drawing on the Theory of Planned Behaviour (TPB), this study investigates the relationship between the perceived benefits, strengths, weaknesses, and risks of generative AI (GenAI) tools and the fundamental factors of the TPB model (i.e., attitude, subjective norms, and perceived behavioural control). The study also investigates the structural association between the TPB variables and intention to use GenAI tools, and how the latter might affect the actual usage of GenAI tools in higher education. The paper adopts a quantitative approach, relying on an anonymous self-administered online questionnaire to gather primary data from 130 lecturers and 168 students in higher education institutions (HEIs) in several countries, and PLS-SEM for data analysis. The results indicate that although lecturers' and students' perceptions of the risks and weaknesses of GenAI tools differ, the perceived strengths and advantages of GenAI technologies have a significant and positive impact on their attitudes, subjective norms, and perceived behavioural control. The TPB core variables positively and significantly impact lecturers' and students’ intentions to use GenAI tools, which in turn significantly and positively impact their adoption of such tools. This paper advances theory by outlining the factors shaping the adoption of GenAI technologies in HEIs. It provides stakeholders with a variety of managerial and policy implications for how to formulate suitable rules and regulations to utilise the advantages of these tools while mitigating the impacts of their disadvantages. Limitations and future research opportunities are also outlined.

Behavioural factors for farmers' adoption of agroforestry practices in Sweden

Agroforestry has recently been recognized as a sustainable land-use system that can both address farmers' productive needs and provide ecosystem services to society such as biodiversity and carbon sequestration. Further investigation into the role played by social and psychological factors for adoption of agroforestry within a European context, is needed. This paper provides an analysis of farmers' behavioural drivers with respect to their adoption of agroforestry practices, using a survey of 387 farmers from Sweden. We extended the Theory of Planned Behaviour (TPB) model to incorporate the following behavioural factors: businessperson identity, network memberships, conservation objectives, as well as perceived economic benefits and labour constraints on actual adoption. Latent constructs in the model were first extracted with factor analysis before estimating their impact on adoption using logit models. The results indicate that network memberships improve the explanation of adoption and positively impact farmers' adoption of agroforestry, while the remaining behavioural variables were found to be statistically insignificant. We therefore recommend to encourage farmers' connection to formal networks in order to disseminate ideas, technical experience and guidance on agroforestry, thereby facilitating adoption. The lack of a significant influence of the TPB-factors in our study suggests that we are not able to confirm that TPB variables have an effect on actual adoption and may support the common criticism given to the model in relation to the well-known intention-behaviour “gap”.

Factors affecting the consumption intention of game meats: Integrating theory of planned behavior and norm activation model

Consuming game meats directly influences human health and environmental conservation, yet research integrating theoretical perspectives remains scarce. The study aims to uncover and assess the factors shaping intentions towards game meat consumption, introducing an integrated theoretical framework that combines the Theory of Planned Behavior (TPB) and the Norm Activation Model (NAM). The study collected 913 genuine responses via a self-administered questionnaire in China. Analysis was conducted using SPSS 22.0 and AMOS 26, leveraging Structural Equation Modeling (SEM) to investigate both direct and indirect relationships among variables of TPB and NAM. The findings highlight that perceived behavioral control plays the most critical role in explaining the intention to consume game meats, followed by attitude and subjective norm. Notably, perceived risk serves as a mediating factor between attitude and the intention to consume game meats. Simultaneously, the ascription of responsibility plays a mediating role within the NAM, intervening in the connection between awareness of consequences and personal norms. The results underscore the effectiveness of TPB and NAM in predicting individuals' intentions to consume game meats, particularly highlighting the critical role of perceived risk in this context.

Psychosocial Factors Influencing Parents' Acceptance of COVID-19 Vaccination for Their Children: An Italian Cross-Sectional Study.

Vaccine hesitancy poses a significant threat to the health of individuals across all age groups, which has been exacerbated by the COVID-19 pandemic. In this cross-sectional study, an extension of the Theory of Planned Behavior (TPB) was applied to investigate psychosocial variables predicting intention to vaccinate children under 12 against COVID-19 in a sample of 420 Italian parents (Mean age = 40.4, SD = 5.9; Women = 78.1%). Hierarchical regression analysis revealed that, among the TPB variables, cognitive attitude, descriptive norms, and perceived behavioral control significantly predicted parents' vaccination intention. Furthermore, including trust in the institutions' ability to manage the vaccination campaign in the model significantly increased the explained variance in intention. These findings suggest that campaigns promoting childhood COVID-19 vaccination should not only emphasize the safety and effectiveness of vaccines for children but also focus on reducing barriers to vaccination. Additionally, attention should be given to enhancing the perception that this behavior is widespread among other parents, thus leveraging the power of social influence. Finally, and not less important, significant efforts should be directed toward building and reinforcing trust in the system of actors promoting and managing the COVID-19 vaccination campaign.

Utility of the Theory of Planned Behaviour for predicting parents' intentions to vaccinate their children against COVID-19.

Vaccination is a crucial form of primary prevention, and it is important to understand the factors that influence parents' decisions to vaccinate their children. The current study examines the utility of the Theory of Planned Behaviour (TPB) and anticipated affect for explaining parents' intentions to vaccinate their children against COVID-19. Parents (N = 843) living in the United States completed an online survey. The TPB variables explained 65% of the variability in parents' intentions. In addition to all three of the TPB antecedents predicting vaccine intentions, both anticipated regret of not vaccinating and anticipated positive emotions of vaccinating were associated with parent intentions. Contrary to predictions, subjective norms were a stronger predictor of intentions when perceived behavioural control was lower compared to higher. These findings help further our understanding of parent-for-child vaccine decisions in the context of novel health threats and inform intervention efforts aimed at encouraging this behaviour.

Determinants of HPV vaccine uptake intentions in Chinese clinical interns: an extended theory of planned behavior approach.

This study aims to utilize the extended Theory of Planned Behavior (TPB) model to examine the intentions of clinical interns in China towards Human papillomaviruses (HPV) vaccination. It also fills a significant gap in the literature concerning vaccine acceptance in this specific population. This cross-sectional study was carried out with clinical interns in Shandong Province, China, with a total of 1,619 participants. Data were collected through self-reported questionnaires, including demographic characteristics, TPB variables, and HPV-related health knowledge. Hierarchical regression analysis was employed to identify key factors influencing vaccination intentions, and Structural Equation Modeling (SEM) was used to analyze the interrelationships between these factors. This study initially identified key predictors affecting clinical interns' intentions to receive the HPV vaccine through hierarchical regression analysis. The preliminary model, which accounted for demographic factors, revealed foundational impacts of household income and HPV-related clinical experience on intentions. After integrating TPB variables-attitude, subjective norm, perceived behavioral control, and HPV-related health knowledge-the model's explanatory power was enhanced to 37.30%. SEM analysis focused on the interplay among TPB constructs and extended variables, confirming their significance in forming vaccination intentions, with subjective norm having the most substantial impact (β = 0.375, p < 0.001). The extended TPB model explained over half of the variance in vaccination intentions, substantiating the hypotheses and revealing the psychological determinants behind clinical interns' decision-making for HPV vaccination. The extended TPB model from this study effectively explains the vaccination intentions among clinical interns for HPV, offering theoretical support for public health strategies and educational interventions targeting this group. These findings are of significant importance for public health practice and future health promotion strategies.

Expanding financial inclusion participation in Muslim-dominated communities through Islamic finance products (IFP) adoption

Purpose This study aims to expand the theory of planned behaviour (TPB) to understand determinants of financial inclusion participation behaviour through the mediating effect of Islamic finance product (IFP) adoption. Design/methodology/approach A quantitative research design was deployed using primary data from a survey conducted within the Muslim-dominated regions in Nigeria, which was analysed using partial least squares structural equation modelling. Findings It was found that the original TPB variables, attitude, subjective norms, perceived behavioural control (PBC) and behavioural intention have strong positive influences on financial inclusion participation behaviour, however, among the new variables, government support and IFPs adoption directly influence, while awareness and access to banking and digital channels were not. Furthermore, IFPs adoption significantly mediates the relationship between attitude, behavioural intention, government support and access to banking and digital channels and financial inclusion participation, but it failed to mediate that of subjective norms, PBC and awareness. Research limitations/implications These findings imply the need to establish more Islamic financial institutions or conventional banks to introduce IFPs in Muslim-dominated regions in Nigeria, as such products are desirable in expanding financial inclusion. While such is being pursued, policymaking bodies responsible for financial inclusion should design appropriate programmes to create awareness of IFPs for expanding financial inclusion. Originality/value To the best of the authors’ knowledge, this study could be the first to expand the TPB by integrating IFP adoption as a mediator within the context of financial inclusion participation as well as the incorporation of awareness, government support and access to banking and digital channels as additional variables.

Planned behavior theory: Exploring health risk, insurance literacy, and infrastructure effects

ABSTRACT This study aimed to create a comprehensive health insurance coverage model, integrating key factors like health insurance literacy, health illness, and healthcare infrastructure availability, using the Theory of Planned Behavior (TPB) as its theoretical foundation. In Gujarat, India, a cross-sectional survey involving 1005 respondents was conducted. The survey measured the effects of health insurance literacy, health illness, and healthcare infrastructure availability on health insurance coverage. Data analysis was performed using Hayes's process macros model, considering socio-demographic factors to understand their influence on health insurance coverage. Unexpectedly, healthcare infrastructure and health insurance literacy didn't significantly affect health insurance coverage. However, attitude emerged as a key factor, influencing the intention to purchase health insurance alongside all independent variables. The study's model, incorporating health insurance literacy, health illness, healthcare infrastructure, and the TPB, provided detailed insights into the factors affecting health insurance coverage. The study highlights the critical role of attitude as a mediating factor in health insurance coverage, while demonstrating the minimal impact of healthcare infrastructure and health insurance literacy. It offers a novel model integrating TPB variables, providing valuable perspectives for policymakers, insurers, and healthcare providers.

Psychological Factors Affecting Drive-by-Lane Behavior at Lane Offset Intersections: Analysis Based on Extended Theory of Planned Behavior in a Chinese Sample

Traffic conflict commonly occurs in intersections with offset lane lines because of mismatched choices of entrance and exit lanes. This conflict drives down overall traffic efficiency and can cause crashes. At such intersections, the driver’s lane choice behavior seriously affects the traffic system. The theory of planned behavior (TPB) was used in this study to excavate the impact mechanism of drive-by-lane behavior at offset intersections. A scale incorporating TPB constructs and additional variables (risk perception [RP], traffic environment [TE], optimization measures [OM], and driving style [DS]) was developed to collect empirical data with 557 valid samples in China. A structural equation model of drivers’ drive-by-lane behavior was established to explore the causal relationship between behavior and influencing factors, as well as the interrelationships between TPB variables. TE, behavior intention (BI), subjective norms (SN), and RP show the most significant effects on drive-by-lane behavior. DS, perceived behavior control, attitude (ATT), and OM have little impact on drive-by-lane behavior. BI, TE, RP, and DS have significant, direct effects on drive-by-lane behavior. The TE, OM, and DS variables significantly affect drive-by-lane behavior through mediators. RP, BI, and ATT mediate the influence of other variables as well as affecting drive-by-lane behavior. We put forward suggestions to improve driving behavior at offset intersections including changing external factors, education, and training. The direct and indirect relationships between the influencing factors and drive-by-lane behavior are discussed in this paper to provide technical and reference support for future research on managing irregular urban traffic intersections.

The Impact of Social Norms, Personality, and Time Perspective Factors On Indonesian Highways Safety Driving Behavior

The number of traffic accidents per year increases in proportion to the number of drivers. The higher traffic accident in particular on highways is due to speeding behavior. Traffic accidents are caused by the environment, the vehicle, and the driver factors. The purpose of this study is to incorporate driver personality, time perspective, and applicable norms, on the speeding behavior model and design proposals for intervention policies, and improve current policies on driving behavior to maintain and increase safety driving the highways speed limit. Personality (BFI-10) was incorporated into the model to investigate which personality types that often speed, time perspective (ZTPI-18) was use to understand the current driver behavior from past experience and the driver will likely take in future, while the theory of normative social behavior (TNSB) was incorporated to enhance the theory of planned behavior (TPB) model used in previous studies. The method used in this paper is the PRISMA framework. Result of this study is a conceptual model that incorporates variables of TPB, TNSB, BFI-10 personality inventory, and ZTPI-18 and consists of 23 variables. Further study will be conducted to prove the conceptual model by using the method of self-report questionnaires, field observations, and driving simulations.

Assessment of Organ Donation Intention Among Employees Based on the Theory of Planned Behavior: Application of Structural Equation Modeling

Background: Organ transplantation is one of the options to increase the life expectancy and quality of life (QOL) of patients waiting on the organ transplant list. The lack of body parts for transplants remains a worldwide concern. This study was designed and implemented to assess organ donation intention among the staff of government and non-government offices in Qom based on the theory of planned behavior (TPB). Methods: Using stratified random sampling, this cross-sectional and analytical study was conducted on 440 employees in Qom, Iran, in 2022. The data collection instrument was a researcher-designed questionnaire, including demographic characteristics, possession of an organ donation card or blood donation history, and constructs of the TPB. The data were analyzed using descriptive statistics, the Pearson correlation coefficient, multiple regression analysis, and structural equation modeling. Results: The mean±standard deviation age of participants was 38.21±3.6. The results showed that 29.2% of participants (n=116) had a signed blood donation card, and 107 participants (27%) had a blood donation history. The structural model fits the data well [χ2 /df=2.84, P&lt;0.001), CFI=0.916, GFI=0.902, RMSEA=0.053]. The TPB constructs could predict 75% of the variance of the behavioral intention (P&lt;0.001). Finally, no statistically significant relationship was found between knowledge and intention to donate organs (β=0.003, P=0.93). Conclusion: The result of the regression analysis of the relationship between TPB variables and organ donation intention indicated that perceived behavioral control (PBC) had a great influence on the organ donation intention of government and non-government employees.

Determinants of consumers’ intention to visit green hotels: Combining psychological and contextual factors

Despite growing interest, the associations between contextual and psychological factors concerning consumers’ intentions to visit green hotels have been scarce in the literature. The main purpose of this investigation is to evaluate the intentions of consumers to visit green hotels and establish determinants of this intention. We developed and tested a research model grounded on the theory of planned behavior (TPB) and inclusion of the contextual factors, biospheric value and green trust. A quantitative study was carried out among consumers in Portugal. Findings revealed that consumers have high intentions to visit green hotels. The TPB variables (attitude, subjective norms, and perceived behavioral control) and the biospheric value positively affect behavioral intentions. Green trust has a positive influence on TPB variables. Similarly, the biospheric value impacts on attitude and subjective norms. The study withdraws implications for hotel managers to design effective marketing strategies in the context of green hotels.

Exploring the role of consumer ethnocentrism in predicting the purchase intention for locally produced organic food in an emerging market

PurposeThe current study investigates the role of consumer ethnocentrism (CE) in the context of locally produced organic food. This research work further extends the extended theory of planned behavior (TPB) model by examining the mediating effect of extended TPB variables (ATT, SN, PBC, PV) between CE and PI for locally produced organic food.Design/methodology/approachData were obtained from the visitors of two shopping malls situated in a large, heavily populated city of India using survey method. Further, two-step approach was applied to analyze the hypothesized model.FindingsFindings indicate that CE is a substantial determinant of PI for locally produced organic food. Moreover, extended TPB mediates the relation between CE and PI for locally produced organic food.Practical implicationsPost Covid-19, market size of organic food is rapidly growing in India. In this regard, this study presents useful implications for the marketers of organic food for gaining better consumer insights to further develop appropriate marketing strategies.Originality/valueCE has been found to be a useful predictor of their food attitudes. However, studies, investigating the role of CE in the context of sustainable food consumption, are scant. Moreover, studies exploring the mediating effect of extended TPB variables are also very limited.

Investigating the dietary intentions of Iranian tourists regarding the consumption of local food.

Attention to local food among tourists is increasing day by day. However, studies on the behavior and intention of tourists towards consuming these foods are few. Limited studies in this field prompted us to help fill the research gap by doing this research. This study aims to use the extended theory of planned behavior (TPB) by adding risk perception (RP) to investigate the tourists' intentions towards local food (TILF) in Iran. The extended model tested 313 tourists visiting local food supplies. Results show that the extended TPB explains 87.8% of tourist intention variance. Three variables of the original TPB had positive impacts on tourists' intentions. A notable result of this study was the realization of a negative relationship between RP and TILF. This research has provided recommendations to strengthen tourists' intentions toward local foods by influencing their attitudes, mental beliefs, perceived behavioral control, and risk perception.

A comprehensive model to explain consumers’ purchasing intention of energy-efficient household appliances: A case study in China

ABSTRACT Given the significant increase in residential electricity consumption in China, promoting the use of energy-efficient household appliances in residential buildings is imperative. Considering this, we construct a new comprehensive model, including the theory of planned behavior (TPB) and Theory of value belief norms (VBN), to identify consumers’ intentions to purchase energy-efficient household appliances. The model is empirically tested using a structural equation modeling approach based on 891 effective questionnaires from Chinese respondents. The results show that TPB variables are important factors in predicting consumers’ intentions to purchase energy-efficient household appliances. Product cognition is the best predictor of purchasing intention, followed by perceived behavioral control, environmental awareness, and subjective norms. For VBN variables, the egoistic value and altruistic value placed on the awareness of consequence is insignificant; the other VBN variables all affect purchasing intention. Compared with the original TPB model or VBN model, this comprehensive model exhibits superior predictive ability in the purchase intention of energy-efficient household appliances. In this comprehensive model, environmental awareness creates a significant effect between the awareness of consequence and ascription of responsibility and the interactive influence of subjective norms on the personal norm. Finally, several important policy implications are documented.

Only the best for my kids: An extended TPB model to understand mothers’ use of food labels

Despite the evidence that mothers’ food purchasing behavior impacts the quality of children’s diet, few studies have explored psycho-social factors influencing how mothers choose the food to buy for their children. To fill this gap, this study tested an extended Theory of Planned Behavior (TPB) model to predict mothers’ tendency to seek information on food labels before purchasing food for children. Participants included 311 Italian mothers who completed a self-report questionnaire measuring their information-seeking behavior, TPB variables, anticipated regret and healthy-eater identity. Results from a Multiple Correspondence Analysis showed that mothers’ information-seeking behavior involved a continuum of choices ranging from selecting conventional or prepackaged foods to choosing to read the food label before making a purchase. Besides, a Partial Least Squares–Structural Equation Modeling analysis showed that information-seeking behavior was positively predicted by intention (β = 0.309, p < 0.001) and healthy-eater identity (β = 0.195, p < 0.001). In turn, intention was positively affected by attitude (β = 0.208, p < 0.001), subjective norms (β = 0.155, p < 0.01), perceived behavioral control (β = 0.124, p < 0.05), anticipated regret (β = 0.193, p < 0.001), and healthy-eater identity (β = 0.191, p < 0.001). These findings emphasize that future initiatives could usefully target attitude, anticipated regret and self-identity to encourage mothers’ informed food choices for their children.

The theory of planned behavior and dietary behaviors in competitive women bodybuilders

BackgroundWomen bodybuilders build their ideal physique by manipulating their diet, supplement, and exercise regimens to extreme levels. Excess protein intake and dietary supplement use is ubiquitous in women bodybuilders preparing for a competition, i.e., in-season competitors, however the impetus for these two dietary behaviors are relatively unknown. The Theory of Planned Behavior (TPB) has been used to explain dietary behaviors. The purpose of the study was to examine how the TPB can explain protein intake and dietary supplement use in in-season competitors.MethodsUsing a cross-sectional design, an online questionnaire was developed, validated, and administered to collect dietary supplement use, TPB variables, and other measures from 112 in-season competitors. Protein intake was assessed using multiple 24-h dietary recalls. Associations between TPB and protein intake and dietary supplement use were determined with multiple regression analysis while adjusting for confounders.ResultsFor protein intake: attitude, subjective norm, and perceived behavioral control explained 8% of the variance in intention; subjective norm independently predicted intention. Behavioral beliefs predicted attitude; subjective norm was predicted by trainer/coach, workout partners, and social media influencers. For dietary supplement use: intention explained 5% of the variance in dietary supplement use; attitude, subjective norm, and perceived behavioral control together explained 38% of the variance in intention. Attitudes towards dietary supplements use were predicted by five factors (not a waste of money, help improve physique, sustain energy levels, provide enough calories, help with recovery). Primary determinants of subjective norm were fellow competitors, social media influencers, and trainer/coach. Perceived behavioral control was predicted by three factors (ease of purchase, affordability to purchase, availability to purchase).ConclusionsTPB predicted dietary supplement use in women bodybuilders during in-season but there was little evidence for the prediction of protein intake using the TPB. Health professionals should develop effective interventions using strategies that align health education messages with in-season competitors’ outcome beliefs and collaborate with their referent others to influence safer and effective dietary supplement use.