Laser treatment of acne scars: a bibliometric analysis and descriptive summary of clinical evidence directions over the past 20 years.

Caffeine is among the most commonly consumed psychoactive substances and is a key component in commercial energy drinks. Its ergogenic effects on exercise performance have been extensively researched vis-à-vis endurance, strength, and mental performance. While some research has shown improvements in reaction time, attention, and vigilance, other studies have reported no significant effects. Similarly, findings on the influence of energy drinks on muscular strength and endurance have been inconsistent. Although some studies suggest energy drinks may offer benefits beyond those of caffeine alone, others indicate no notable differences compared to placebo or caffeine-only drinks. Results from various studies likely differ due to caffeine doses, experimental protocols, and measures. Energy drinks may contain additional ingredients beyond caffeine (200 mg), including vitamin B, beta-alanine (BA), and betaine. BA is a non-proteogenic amino acid that serves as a precursor to carnosine that buffers hydrogen ions in skeletal muscle. It improves anaerobic performance by delaying fatigue and enhancing the ability to sustain high-intensity exercise, particularly in efforts lasting longer than 60 s. Betaine is a trimethylglycine naturally occurring in foods such as spinach and beets. Literature suggests it improves performance by increasing intracellular creatine levels. Cobalamin, commonly known as vitamin B, has many functions in the body. It is thought to confer an ergogenic aid due to its role in the production of red blood cells and serving as a cofactor for energy production and red blood cell production. However, the efficacy of these added ingredients combined with caffeine is unclear and warrants additional studies. Thus, the purpose of this study was to evaluate the effects of a commercially available energy drink on tasks related to mental and physical performance – such as sustained attention (i.e. psychomotor vigilance test (PVT)), memory (i.e. MemTrax), lower body muscular endurance (i.e. wall-sit), and handgrip strength – relative to a positive control drink containing an equivalent amount of caffeine. This study used a two-arm, randomised, double-blind design. Inclusion criteria were as follows: adults aged 18 years or older who engaged in physical activity at least three times per week for a minimum of 30 min per session. Individuals with diabetes or pre-existing heart or kidney disease, as determined by self-report, were excluded from participation. Participants were randomly assigned to consume either a commercially available energy drink (C4 – Nutrabolt®) containing 200 mg of caffeine (Figures  and ) or a caffeine-matched control beverage (200 mg caffeine mixed with Crystal Light). All procedures involving human subjects were conducted in accordance with the Declaration of Helsinki and were approved by the university’s Institutional Review Board (IRB# 2025-32).