# Supplement Use Among Athletes: Insights from Gyms in Sarajevo
## 1 Introduction  
Physical activity and its benefits have been known for centuries [1] and the World Health Organization (WHO) has recently published guidelines on physical activity andsedentary behaviour [2], highlighting important health benefits related to physical activity. For example, in adults, physical activity provides benefits for various health outcomes, including reduced all-cause and cardiovascular disease mortality, lower risk of developing hypertension, certain site-specific cancers, and type-2 diabetes, as well as improvements in mental and cognitive health [2]. Nevertheless, a notable increase in the number of individuals attending fitness centres is not mainly driven by health aspirations, but aesthetic and socialization goals as well [3]. With this increase, surveys show a parallel increase in food supplement (FS) use [4; 5]. Food supplements encompass a wide range of products designed for ingestion to fulfil essential nutritional needs [6]. Additionally, many professional athletes, and more recently, recreational athletes, use FS or other \"magic substances\" to improve or optimize exercise performance. For example, it has been shown that creatine monohydrate is the most widely used supplement among power and strength athletes, while caffeine has been demonstrated to enhance alertness, endurance, and performance in both aerobic and anaerobic activities [7]. The prevalence of FS use was previously reported [8] but only a small number of studies are reporting poor nutritional knowledge among athletes, coaches and trainers [9; 10; 11; 12]. Since it has recently become somewhat of a'must' to use FS among professional athletes, an increasing number of individuals engaged in recreational sports are considering FS as a prerequisite for performance improvement and a shortcut to achieving their goals. Furthermore, the prevalence and usage of FS among recreational gym users is endorsed by athletes advertising supplement products shaping the perception and overstating the benefits, thus omitting the importance of deep understanding of nutrition and physiology [13]. Peer influence, such as recommendations from other gym users and trainers, is having a significant impact on attitudes and usage patterns, respectively. Attitudes and practices regarding FS are also influenced by individual beliefs, personal goals, social norms, economic status, and marketing strategies [8]. Based on previous findings [14; 15; 16], it is evident that gym and fitness users associate FS with several categories, including: (a) the improvement of muscle growth and strength, with a preference for protein and creatine supplements; (b) the enhancement of energy and performance, favouring pre-workout supplements containing caffeine or similar ingredients; (c) the reduction of recovery time, with supplements aimed at minimizing muscle soreness; (d) the reduction of body fat, often using supplements marketed for metabolism enhancement; and (e) health-related benefits, such as the use of multivitamins. Numerous studies have yielded differing findings, though muscle mass gain and fat loss consistently emerge as key motivational factors [14; 15]. Since FS use has greatly increased over the last few decades, studies evaluating FS usage among gym-goers have begun to emerge. For example, there are studies from Egypt [14], Spain [15], Brazil [16], and Switzerland [17], as well as comparisons between urban and rural areas [18], and there are even programs regularly evaluating national health and nutrition, such as those operating in the US since the early 1960s [2]. However, to the best of our knowledge, no studies reporting FS use in Bosnia and Herzegovina are yet available. Therefore, this study aimed to examine the FS habits of a sample of gym-goers in Sarajevo, Bosnia, and Herzegovina.