The aim of the current study was to provide contemporary data on the use of dietary supplements, AAS and SARM, and test the idea that social media, and in particular its images, are associated with the use of these compounds in young male gym users as a result of a negative body image. Findings revealed that the larger part (83%) of young male gym users in the Netherlands uses dietary supplements (e.g., protein, creatine, etc.), and an estimated 9 versus 2.7% of this population have ever used AAS or SARM, respectively. In addition, image-centric social media use was positively associated with the use of dietary supplements and AAS, but not SARM. Furthermore, image-centric social media use was associated with body image, such that more of this type of social media use was related to a more negative body image. Body image, however, did not have a mediating impact on any of the relations between image-centric social media use and substance use.
Prevalence of Dietary Supplement and Pre-workout Use
In a recent Dutch study among the general population, it was shown that 10% of the people aged 21–35 years use protein shakes, and only 1% use creatine . This is in sharp contrast with our data revealing that 83% use dietary supplements, mainly protein (81%) and creatine (46%). This confirms our hypothesis that the use of ‘muscle-building’ supplements is highly prevalent among young male gym users. Our findings expand on previous data showing that 44% of Portuguese gym users use supplements, mostly protein (80%) and creatine (28%) , whereas 36.8% of Brazilian gym users use supplements, also mainly protein (38%) and creatine (8%) . Of the participants in the present study that reported using supplements, 44% reported the use of pre-workout formulas, mainly to stimulate the motivation to work out and increase energy levels. This prevalence rate is considerably higher when compared to German regular gym users (12%) . The reported prevalence reported in the present study can be considered worrying, as pre-workout formulas are associated with side-effects (dizziness and nausea) and adverse events, such as heart rhythm abnormalities . In addition, a recent study, targeting the Dutch market, reported that pre-workout supplements, readily available in web shops, are ‘at risk’ of containing undeclared doping compounds, mostly anabolic steroids and stimulants . In this regard, it is alarming that 25% of the pre-workout users in the present study use a pre-workout supplement before every workout.
Prevalence of AAS Use
Our results show a current AAS prevalence rate of 3.6% and a life-time prevalence rate of 9% among young male gym users in the Netherlands. This is significantly higher than the 1% prevalence rate reported by an earlier study in the Netherlands, dating from 2013 . However, the latter study included both male and female gym users from all ages, whereas the present work centered on young male gym users. In line with our results, a survey in the UK among 377 male and female gym users resulted in a current prevalence rate of 7%, albeit not assessed with randomized responses . Simon and coworkers were the first to assess the use of doping compounds with randomized responses among German regular gym users and reported a life-time prevalence of 12.5% . These results, however, may not be directly comparable to our results, as in the current study we assessed specifically the use of AAS and SARM, while Simon et al. assessed the use of doping substances in general. Further, a meta-analysis by Sagoe and coworkers indicated that the lifetime prevalence of AAS use in recreational sportspeople is 18.4% . However, as the authors of the meta-analysis note, the validity of prevalence rates of the included studies is considerably limited, as most of them are not assessed by the RRT. Indeed, research with regular self-reports, so without RRT, on the use of doping substances has the potential to overestimate or underestimate prevalence rates [4, 21]. Hence, the prevalence data of the current study assessed with the RRT are a noteworthy addition to the literature.
Having a reliable idea of prevalence data of AAS use can be considered important, as the use of AAS is associated with health risks . Although the acute risks of AAS use are relatively low , long-term effects of AAS include cardiac disease [13, 14], mood and anxiety disorders  and higher mortality risks . Finally, it is worrisome that addiction to the use of AAS is highly prevalent [49, 52, 53], increasing the risk of health consequences in the long term.
Prevalence of SARM Use
To the best of our knowledge, this is the first study to present prevalence rates (2.7%) of SARM use. It has been suggested that SARM use has been increased recently, although factual evidence has been lacking . Users of SARM mainly claim that SARM are safe; however, hardly any clinical studies support the efficacy and safety of such experimental drugs . In fact, in 2017 the US Food and Drug Administration (FDA) issued a public statement that SARM were being included in supplements and that these compounds posed an increased risk for heart attack, stroke, and liver damage . The prevalence rates revealed by the current study give a call to medical doctors and other health care providers. That is, they should be aware of the increased popularity of SARM use and other appearance-related drugs among regular gym users. Medical complaints due to substance use may easily be overlooked in this group of non-professional athletes, particularly as individuals using these drugs emerge as sportive based on appearance, while factually substance use contributed to their muscular physiques.
Body Dissatisfaction Among Young Male Gym Users
Based on the used body image scale, ~ 5% of the participants were not satisfied with their body. However, specified to muscularity dissatisfaction, ~ 20% of the participants were not satisfied with this body component. Previous work has revealed that body image concerns are associated with the use of dietary supplements in boys  and AAS in adult males [32, 34]. In line with these findings, the current study revealed a relationship between body image and the use of SARM, with a more negative body image being related to increased SARM use. However, in contrast to the prevailing literature [32, 34], the current study did not reveal a significant relationship between body image and the use of dietary supplements and AAS. In spite of the difficulty of explaining this unexpected finding, some speculations could be placed to provoke further thought on the association between body image and AAS use in men. Pope and coworkers have proposed that concerns about body image among young men, and subsequent AAS use, may be related to the emphasis on a muscular and lean physique in our current society . In this regard, most research used muscle dysmorphia as a tool to assess body image, as opposed to body image in the current study. While muscle dysmorphia is a psychiatric disorder , body image only indicates the extent to which people were satisfied with their physical appearance. Although ~ 20% of the investigated population indicated that they were (partly) unsatisfied with their muscularity, this was not associated with the use of AAS. This may be partly explained by the population of recreational gym users included in the current study, as many studies on the relation between muscle dysmorphia and AAS use have been conducted among bodybuilders [56, 57]. In addition, the use of AAS for appearance-enhancing motives has become increasingly normalized in the Netherlands  and may just be a part of the gym culture, rather than the result of a negative body image. Such speculations obviously need to be corroborated by further research.
The Role of Social Media in Body Image Concerns and Substance Use
Social media exposure has been associated with body image concerns in men , sexual minority men  and adolescents boys (11–18 years) . In line, our results show a negative relationship between image-centric social media use and body image in young male gym users. The current study expands on previous findings by specifically showing that image-centric social media such as Instagram and exposure to fitness-related content, is associated with body dissatisfaction, and with the use of dietary supplements and AAS. Noteworthy is that the frequency of social media use did not show this association, indicating that particularly the content of social media is related to body dissatisfaction and the use of supplements and AAS. Image-centric social media use was not associated with the use of SARM. This non-significant relationship between image-centric social media use and SARM may be explained by the low prevalence rate of SARM.
So-called influencers on social media can have an enormous amount of followers, and are already part of companies’ marketing strategies [61, 62], because of their ability to affect the behavior of their followers . These findings together show the potential influence of social media in young male’s decision making in the context of fitness, nutrition and doping.
Considering the high use of dietary supplements and pre-workout formulas, the considerable use of AAS and SARM, and the concerns regarding muscularity among young male gym users, it seems urgent to devote more attention to this population, particularly from the sports medicine community. This is particularly crucial in light of fitness currently being one of the most popular sports activities. Young male gym users are often highly motivated to reach their fitness goals, mostly an increase in muscle mass and strength in combination with a decrease in fat mass. Such goals are comparable to those of elite athletes. However, where elite athletes, a relative small population, are likely to receive high-quality advice from professionals such as strength and conditioning coaches, sports nutritionist and sports physicians, the relative large population of regular gym users has limited (free) access to such expert advice. Consequently, regular gym users mainly retrieve information on nutrition, supplements and training from the internet and social media . Indeed, the present study shows that 65% use the internet and 32% use social media as their primary source of information on dietary supplements. In this regard, it is worrying that 38% of high-risk dietary supplements (e.g., pre-workout) sold online in the Netherlands contain undeclared doping compounds . On top of that, it is alarming to note that regular gym users have a higher lifetime prevalence rate of AAS use than elite athletes . Therefore, we call to action from national fitness associations, national anti-doping agencies and national sports medicine communities to work together to support gym users to reach their fitness goals in a healthy and sustainable manner. Furthermore, more attention should be given to the education of fitness professionals and healthcare providers about the use of compounds like dietary supplements, AAS and SARM, and associated body image concerns among gym users.
Limitations and Recommendations
This study is innovative due to its large sample size, applying the RRT to estimate image and performance-enhancing drug use, including SARM use which can be considered as novel, and relating substance use to the impact of social media, particularly image-centric social media use. Despite these strengths, it is also important to acknowledge some limitations of the current study. First, data collection took place during the Covid-19 pandemic, which may have resulted in an underestimation of the AAS and SARM prevalence rates as a result of the closure of all gyms in the Netherlands preceding this study. Future studies should thus reproduce these prevalence rates. Also in relation to the link between image and performance-enhancing drugs use and social media, replications are desirable, as social media develops constantly and fast in rather unpredictable ways. Therefore, it seems important to keep track of social media trends, including its potential undesirable side effects.
Next, the present study may suggest that image-centric social media use is associated with body image and increased use of image and performance-enhancing drugs. It is important to note, though, that the correlational design impedes drawing inferences about any causal relationships among the variables. Future studies could omit this limitation by incorporating experimental, longitudinal or ecological momentary assessment designs to establish whether there exist any causal relationships, for example to assess if image-centric social media use impacts body image, or vice versa, if body image influences image-centric social media use. The potential future detection of such causal relations could subsequently aid in understanding the relation of these phenomena with the use of performance-enhancing drugs.
Furthermore, the present research relied on self-report measures to investigate social media use. Consequently, our findings pertain to self-perceptions of social media use, which inevitably adds bias, such as contingency of awareness of one’s social media habits and social desirability. Although the social media measures were based on previous research and scales revealed acceptable to good reliability, future research should further develop and validate scales to capture social media use. Particularly, the questionnaire measuring image-centric social media use should be developed in more detail as it relates to the comparison of physical appearance with others on social media in combination with the exposure to fitness-related content on social media. This deserves more validity research. Moreover, future researchers could explore the additional value of adding standardization of the time frame of reference as a valuable asset, such as how often people use image-centric social media on a typical day in terms of minutes or hours, to decrease potential variability in the current relative scores that capture the relative extent to which people use this type of social media. This is particularly important as the present findings seem to suggest that not so much the frequency of social media use may have undesirable effects, but rather the content of social media’s images relating to creating a perfect ‘me.’