Relationship Between Muscle Dysmorphia and Other Factors with Supplement Consumption among Selected Gym Members in Jakarta

Ergogenic supplements can enhance exercise performance. However, many gym members use them without consulting professionals such as nutritionists/dietitians, increasing the risk of adverse effects. This study investigates the consumption of ergogenic supplements and factors associated with them among members of selected fitness centers in Jakarta. This cross-sectional study was conducted on 116 participants from 3 fitness centers in Jakarta. The independent variables studied were Muscle Dysmorphia, Exercise Addiction, self-esteem, body image, age, gender, exercise duration, exercise experience, exercise intensity, and social media exposure. Data was collected via interviews based on a prepared questionnaire. Results showed that 67.2% of the respondents had used ergogenic supplements, with the majority using whey protein for muscle enhancement reasons. The main sources of information were friends (39.7%) and the internet (37.2%). The chi-square test showed a significant relationship between male gender (OR = 3.055; 95%CI: 1.298—7.188), exercise experience of 7—12 months (OR = 5.4; 95%CI: 1.621—17.991), and >1 year (OR = 5.091; 95%CI: 1.910—13.571) with supplement consumption. In conclusion, this study unveils a high prevalence of ergogenic supplement consumption, particularly whey protein for muscle enhancement, among fitness center members.


Introduction
Proper nutrition plays a vital role in supporting physical activity, impacting sports performance, energy levels, and more [1].Achieving nutritional needs typically involves a balanced diet and, if necessary, supplements under professional guidance, like dietitians [2].However, many fitness center members may not consult professionals when using supplements, potentially leading to misuse and adverse effects [3].It's important to note that while supplements promise health and performance benefits, their scientific backing often falls short for fitness center members [4].Caution and awareness are essential when evaluating supplement claims and potential risks in the context of fitness centers [5,6].
While there is no global prevalence data for supplement consumption, the magnitude of consumption can be inferred from the size of the industry market.According to Persistence Market Research (2022), the global sports supplement market is valued at $21 billion and is projected to reach $52.2 billion by 2032.Sports supplement consumption also constitutes 20% of the total market share of food products or derivatives with health benefits.Research on supplement usage among fitness center members across the world reveals varying prevalence rates, ranging from 34% to 85.4%.In Europe, several studies have investigated supplement consumption among physically active individuals.A study in Portugal found that 43.8% of fitness center members consumed at least one supplement in the past year [8].Another study in Italy reported a higher supplement consumption rate of 85.4% among both visitors and instructors at fitness centers [9].In the Netherlands, a study revealed an ergogenic supplement usage prevalence of 83% among fitness center members [10].Some research conducted in Latin America indicates lower supplement usage rates compared to Europe.Two studies in different Brazilian cities reported supplement usage prevalence rates of 36.8% and 64.7% among fitness center members [11,12].Another study in Chile recorded a prevalence rate of 43.2% [1].In Indonesia, there have also been several studies documenting supplement consumption prevalence among fitness center visitors.A study in Sleman, Yogyakarta, by Gusmaya et al. (2019) indicated a prevalence rate of 34.1%.Research in Sidoarjo found that 61.7% of fitness center members consumed supplements [14].Another study in Semarang by Fitranti et al. (2022) showed that 55% of male fitness center visitors in Semarang consumed supplements.
Various studies have demonstrated factors associated with supplement consumption.According to [15], one of these factors is muscle dysmorphia, where individuals with muscle dysmorphia are 2.56 times more likely to consume supplements.Another study by García-Rodríguez et al. (2017) also revealed that the presence of muscle dysmorphia symptoms predicts the use of ergogenic compounds.Individuals with muscle dysmorphia constantly desire a more muscular body, leading them to undertake various efforts, including supplement consumption, to increase muscle mass [17,18].Based on several studies in Indonesia, the prevalence of muscle dysmorphia among fitness center visitors ranges from 43.6% to 61% [15,19,20].Apart from muscle dysmorphia, body image is also a factor that can influence supplement consumption.Individuals with belowideal body image or appearance-related anxiety tend to lean towards supplement consumption [12,21].Another influencing factor on supplement consumption among fitness center members is exercise addiction and selfesteem [21][22][23].
Additionally, demographic factors such as age and gender can influence reasons, types, and patterns of supplement consumption.Several studies have also found correlations between exercise patterns, such as duration, frequency, and intensity, and supplement consumption among fitness center members [1,8,11,12].Lacerda et al. (2015) also identified a relationship between exercise experience and supplement consumption.Smoking habits and knowledge, attitudes, and behaviors are also associated with supplement consumption [12,24,25].Social factors like media exposure, particularly imagebased social media, can also influence supplement consumption [10,11] The high prevalence of supplement consumption among fitness center members worldwide, combined with the limited research conducted in Indonesia, especially in DKI Jakarta, has piqued the interest of researchers to explore this phenomenon.Hence, this study was designed to analyze supplement usage among fitness center members in DKI Jakarta and to determine its relationship with various factors such as muscle dysmorphia, exercise addiction, selfesteem, age, gender, exposure to social media, and the duration, experience, and intensity of workouts.

Methods
This study employs a quantitative research method with a cross-sectional study design.The study is conducted in May to June at three fitness centers in Jakarta .The study population consists of fitness center members in selected fitness centers in Jakarta in the year 2023.The inclusion criteria include active members of fitness centers, individuals who exercised at the fitness center at least once a week for a month prior to fasting month, aged at least 18 years, and willing to participate as respondents in this study.The required sample size was calculated using the hypothesis test formula for two proportions.Based on this calculation, the minimum sample size is determined to be 52 individuals.Since a twoproportion test is conducted, this number is doubled and then increased by 10%, resulting in a minimum sample size of 115 respondents.The sampling method utilized is purposive sampling, and data collection is performed through direct interviews based on a prepared questionnaire.The researcher waited at the gym and asked about the willingness of potential respondents.
This study utilizes primary data with the dependent variable being supplement consumption.The independent variables under investigation include Muscle Dysmorphia, Exercise Addiction, selfesteem, body image, age, gender, workout duration, workout experience, workout intensity, and exposure to social media.Muscle Dysmorphia is measured using the Muscle Dysmorphic Disorder Inventory (MDDI) [26].Respondents who scored above 39 is considered to have MD tendencies.Exercise Addiction is assessed using the Exercise Addiction Inventory (EAI) [27], with 24 as the cutoff score.Self-esteem is gauged using the Rosenberg Self-Esteem Scale [28], those who scored under 15 are considered to have low self-esteem, 15-25 as medium self-esteem, and above 25 as high self-esteem.Body image is measured using Stunkard's figure rating scale [29].Respondents are asked which body they think represented their body at the time and which one represented what they think is the ideal body.The score difference is then classified, those with scores more or less than 0 are considered not satisfied with their body and those who scored 0 are classified as satisfied.Exposure to social media is assessed using a questionnaire related to imagecentric social media use [10] with those who scored above mean/median are classified as yes, and those below mean/median as no.These questionnaires are translated into Indonesian and pre-tested on 30 fitness center members outside of the study respondents.
Validity testing is conducted using the critical value of r at 0.361.Reliability testing is conducted using Cronbach's Alpha, with a test result of ≥ 0.6 considered reliable.
Data is analyzed univariately and presented in the form of frequency distribution tables.The generated data is categorized as categorical data, and bivariate analysis is performed using the chi-square test.Data is analyzed using IBM SPSS Statistics 22.0.Statistical results are deemed significant if the pvalue is < 0.05.

Results
Based on Table 1, out of 116 respondents, 78 individuals (67.2%) consumed supplements in the three months leading up to the fasting month of 2023.Based on Table 3, most supplement users (50%) consume supplements between one to six times per week.Around 30.8% of respondents consume supplements at least once daily.Meanwhile, 19.2% of respondents rarely consume supplements, which is one to three times per month.The most common sources of information about supplements were obtained from friends (39.7%), followed by the internet (37.2%) in the second position.Only one respondent (1.3%) stated they obtained information about supplements from a nutritionist/dietitian.Based on the data presented in Table 4, the study respondents spent an amount ranging from Rp100,000 to Rp3,000,000 per month on purchasing supplements.The median cost incurred was Rp500,000, with a standard deviation of Rp448,477.
A total of 38 respondents (32.8%) stated that they did not consume supplements in the three months prior to the fasting month of 2023.The reasons for their non-use of supplements are outlined in Table 5 where it's evident that the most frequently mentioned reason among respondents is feeling that they don't need supplements.Among these 38 respondents, 61% expressed an interest in using supplements.
Table 1 indicates that 36.2% of respondents have a tendency towards Muscle Dysmorphia (MD), while Exercise Addiction (EA) has a prevalence of 24.1%.Most respondents have moderate self-esteem (60.3%) and does not feel satisfied with their body image (81.9%).The characteristics of most respondents in this study are aged ≤25 years (66.4%) and predominantly male (73.3%).Around 83.6% of respondents reported engaging in 1-2 hours of exercise per session, with 53.6% exercising at a light intensity.Approximately 44.8% of respondents stated that they have been working out at the fitness center for ≤6 months.In this study, 40% of respondents have social media exposure scores above the median value.
Based on the chi-square test results, the factors significantly associated with supplement consumption are gender and workout experience.Compared to October 2023, Vol. 4 Issue 1 page 44 -58 Regarding workout experience, it's found that fitness center members who have been members for more than one year are 5.091 times more likely to consume supplements compared to those who have been members for less than 6 months.Similarly, fitness center members who have been exercising for 7-12 months are 5.4 times more likely to consume supplements compared to those who have been working out for less than 6 months.

Discussion
Based on this study, the prevalence of supplement consumption among selected fitness center members in East Jakarta is 67.2%.When compared to other studies conducted in various regions of Indonesia, this research found a higher prevalence compared to Sleman (34.1%) [13], Semarang (55%) among male fitness center visitors [15], and Sidoarjo (61.7%) [14].In comparison to studies in other countries, the prevalence of supplement use in this study is also relatively high.Although not as high as Italy and the Netherlands, which reached 85.4% and 83% respectively [9,10].Nevertheless, these figures are still higher than research in Brazil, Portugal, and Chile, which found prevalence of 64.7%, 43.8%, and 43.2% [1,8,12].
In this study, whey protein was found to be the most consumed type of supplement, followed by creatine and then vitamin/mineral supplements.This is in line with several other studies that also identified whey protein as the most popular supplement [1,8,9,11,12].This trend can be attributed to the importance of protein intake for muscle growth [30].The findings regarding supplement types align with the reasons for usage, where majority of respondents in this study cited muscle gain as the main reason for using supplements.Similarly, increasing muscle mass was also a popular reason in the studies by Goston  Similar to previous research, this study also found that most supplement users obtain information from sources other than nutritionists/dietitians.In this study, only one respondent (1.3%) received supplement-related information from a nutritionist/dietitian, which is significantly lower compared to other studies such as 23.1% reported in Portugal [8], 28.1% in Belo Horizonte [11], and 10.3% in Sao Luiz [12].This study, in line with Lacerda et al. (2015), found that friends were the primary source of supplement information among fitness center members.These findings indicate the limited role of nutrition experts in this community and the strong influence of peers in supplement decisions within this population.The median age in this study is 23 years.According to Venticinque et al. (2021), the decision-making process of young adults can be significantly affected by peer influence.Besides friends, the internet is also mentioned as a significant source of supplement information, highlighting the need for credible and curated supplement information available online.
This study revealed that respondents spend between Rp100,000 to Rp3,000,000 on supplements per month, with a median expenditure of Rp500,000.In 2023, the Provincial Government of DKI Jakarta set the Regional Minimum Wage (UMR) at Rp4,901,798.This suggests that majority of supplement consumers spend approximately 10.2% of their UMR on supplements.This percentage is about 10% lower than the findings of a study in Belo Horizonte, Brazil [11].However, both this study and previous research did not inquire about respondents' income, making it difficult to compare expenditure against specific income levels.
Out of 116 respondents, 38 individuals (32.8%) stated that they did not consume supplements in the three months before the fasting month of 2023.The most common reason given by respondents who did not use supplements was that they felt they did not need them.Among these 38 respondents, 61% expressed an interest in using supplements, indicating a high level of appeal for supplement consumption among fitness center members in Jakarta.
Regarding significant relationships, this study found that gender is significantly associated with supplement consumption, with males being 3.055 times more likely to consume supplements.This finding aligns with studies by Goston and Toulson Davisson Correia (2010); Lacerda et al. (2015); Ruano and Teixeira (2020).This study also found that the most popular type of supplement is whey protein, and the primary reason for supplement consumption is to increase muscle mass.The results of statistical tests this study also indicate that males are more likely to consume whey protein and creatine, while females are more likely to consume vitamins/minerals.In terms of reasons, this study also discovered that males tend to consume supplements for muscle mass enhancement, whereas females often cite reasons related to boosting energy or reducing fatigue.According to Alhakbany et al. (2022), males are more focused on muscle growth and are more aware of the potential of protein supplements in aiding muscle development.The male attention to body aesthetics can be traced back to ancient Greek times when athletes trained to win the Olympics and showcased athletic physiques [11].Since that era, athletes have adopted varying dietary patterns and rituals.As time progressed and scientific knowledge advanced, protein became increasingly associated with strength and muscle mass enhancement [11,32,33].A study on athletes also found that women consume more multivitamin supplements [34].According to Aguillar-Navarro et al, this may indicate that women prioritize health benefits over performance.
This study demonstrates a significant relationship between training experience and supplement consumption.In this research, respondents who had been members of the fitness center for more than one year were 5.091 times more likely to consume supplements compared to those who had been members for ≤6 months.These findings align with Goston and Toulson Davisson Correia (2010) and Lacerda et al. (2015) who also found that the longer someone trains, the more likely they are to use supplements.According to Lacerda et al. (2015), this could be attributed to increased interactions with other gym members as one spends more time in the fitness center, facilitating the exchange of supplement-related information.These reasons are also supported by the findings of this study and Lacerda et al. (2015), both of which reported that respondents most commonly cited "friends/acquaintances" as their primary source of supplement information.Another possible explanation for the relationship between these two variables is the emergence of feelings of stagnation after a prolonged period of following a training program, prompting a perceived need for supplements.Muscles adapt to resistance training.According to Hughes et al. (2018), this results in rapid muscle growth or strength development during the initial stages of training.However, over time, the rate of growth tends to slow down.This can lead to a perception that muscle development has plateaued, hence creating a greater allure for supplement consumption [12].

Conclusion
67.2% of respondents consume supplements, indicating a relatively high prevalence in fitness center members.
The most consumed supplement type is whey protein (79.5%).The primary reason for supplement usage is to increase muscle mass (80.8%).Only 1.3% of respondents received supplement information from nutritionists/dietitians, while the majority obtained information from friends (39.7%) and the internet (37.2%).
This study finds that 36.2% of respondents exhibit tendencies toward Muscle Dysmorphia, while 24.1% show signs of Exercise Addiction, a relatively high figure compared to other studies.Most respondents have moderate selfesteem (60.3%) and are dissatisfied with their bodies (81.9%).A significant majority of respondents are male (73.3%) and younger than 25 years old (66.4%).The majority of respondents engage in 1-2 hours of exercise per session (83.6%), have light exercise intensity (53.4%), and have trained for less than six months (44.8%).About 40.5% of respondents are exposed to social media.
The study finds significant associations between supplement consumption and gender, as well as exercise experience among the selected fitness center members in Jakarta.No significant associations were found between supplement consumption and other variables, such as Muscle Dysmorphia, Exercise Addiction, selfesteem, body image, age, exercise duration, exercise intensity, and social media exposure among the selected fitness center members in Jakarta.
Fitness center members should seek consultation with nutritionists for supplement information.Fitness centers can collaborate with nutritionists to create informative materials like posters about supplements.They can also offer personalized nutrition education.Governments can establish accessible information channels, such as the ABCD system from the Australian Sports Commission's website, providing categorized supplement information.Targeting long-term male fitness center members for interventions is recommended.Further research could explore supplement knowledge, the influence of friends on supplement consumption, assessing income-related expenses, and how promotion/sales of supplements in the gym affects its consumption.