Caffeine
Caffeine works by antagonizing adenosine receptors in the brain. Adenosine is a neuromodulator that promotes sleep and suppresses wakefulness.
Caffeine is effective in reducing fatigue and increasing alertness by blocking adenosine receptors. These effects of caffeine supplementation have been shown to be beneficial across a variety of exercise performance-related parameters, particularly in sports.
Meta-analyses have highlighted the capacity of acute caffeine ingestion to increase aerobic endurance, anaerobic performance, maximal strength and muscular endurance, resistance exercise movement speed, as well as sprint and agility performance.
Sleepiness impairs performance and attention and is associated with an increased risk of injury. Jet lag and shift work are circadian rhythm sleep disorders that cause sleepiness and may increase the risk of injury. Caffeine has a potential role in promoting wakefulness during jet lag and during times when wakefulness is desired in shift workers.

References
Bodur M, et al. Clin Nutr ESPEN. 2025 Feb;65:76-85. https://pubmed.ncbi.nlm.nih.gov/39551351/
Ker K, et al. Cochrane Database Syst Rev. 2010 May 12;2010(5):CD008508. https://pubmed.ncbi.nlm.nih.gov/20464765/
McLellan TM, et al. Neurosci Biobehav Rev. 2016 Dec;71:294-312. https://pubmed.ncbi.nlm.nih.gov/27612937/

Taurine
Taurine is a beta amino acid that can be obtained through the diet or produced in the body from the amino acid cysteine. Taurine is abundant in the brain, retina, muscle tissue, and other organs in the body.
Although taurine is known as a non-essential or conditionally essential amino acid, it is quite essential in terms of the functions it performs in the body.
Taurine, which can exhibit cell protective effects through different mechanisms, exhibits anti-inflammatory and antioxidant properties by preventing damage to cells from oxidative stress and preserving their functions.
Taurine is assumed to play an important role in a number of physiological functions in the body, including the cardiovascular system, central nervous system, muscular system and endocrine system, and other body systems.

References
Rais N, et al. Arab Gulf Journal of Scientific Research, 2022:41(1); 48-66. ResearchGate
Ripps H, et al. Mol Vis. 2012;18:2673-86. https://pubmed.ncbi.nlm.nih.gov/23170060/

Vitamin C
Vitamin C increases the number of defensive cells in response to infection and stimulates and protects the immune system, helping to fight infections.
Colds weaken the immune system. Taking vitamin C during rhinitis strengthens the immune response.
Vitamin C has been found to have a beneficial effect on the respiratory system's defense system; it is found in high amounts in the cells of the defense system and is quickly used during infection.
Vitamin C supplementation increases the activation of defense cells and stimulates the immune system.
Due to its effects on the immune system, vitamin C is particularly effective in improving symptoms of upper respiratory tract infections such as the common cold.

References
Chambial S, et al. Indian J Clin Biochem. 2013;28(4):314-328. https://pubmed.ncbi.nlm.nih.gov/24426232/
Maggini S, et al. Br J Nutr. 2007;98 Suppl 1:S29-35. https://pubmed.ncbi.nlm.nih.gov/17922955/