Table 3 Classification of supplements examined in this study

Group A

Evidence level:

Strong scientific evidence for use in specific situations in sports using evidence-based protocols

Sports foods

Whey protein, gainer, egg powder, carbohydrate powder, soybean powder, protein-rich, and energy drink

Medical supplements

Vitamin D, Vitamin B12, vitamin B complex, multivitamin, calcium, iron, calcium + vitamin D, vitamin B9, and zinc

Performance supplements

Caffeine, creatine, beta-alanine, aspartic acid, and theophylline

Group B

Evidence level:

Emerging scientific support,

deserving of further research

Food polyphenols

Antioxidants

Vitamin C

Tastants

Other

Omega-3 fatty acids, carnitine, green tea, green coffee, fish oil, and flaxseed

Group C

Evidence level:

Scientific evidence not supportive of benefit amongst athletes or no research undertaken to guide an informed opinion

Category A and B products used outside approved protocols

Named products

Vitamin E, glutamine, magnesium, amino acids, arginine, and branched-chain amino acids

The rest

Group D

Evidence level:

Banned or at high risk of contamination with substances that could lead to a positive doping test

Stimulants

Ginseng, ephedrine, amphetamine, and methylphenidate

Prohormones and hormone boosters

Testosterone, oxymetholone, nandrolone, metandienone, insulin, and erythropoietin

GH releasers and peptides

Growth hormone

Beta-2 agonists

Selective androgen receptor modulators

Metabolic modulators

Other