Merck

Do energy drinks contain active components other than caffeine?

Nutrition reviews (2012-12-05)
Tom M McLellan, Harris R Lieberman
ABSTRACT

Energy drinks (EDs) contain caffeine and are a new, popular category of beverage. It has been suggested that EDs enhance physical and cognitive performance; however, it is unclear whether the claimed benefits are attributable to components other than caffeine. A typical 235 mL ED provides between 40 and 250 mg of caffeine, equating to doses that improve cognitive and, at the higher levels, physical performance. EDs often contain taurine, guaraná, ginseng, glucuronolactone, B-vitamins, and other compounds. A literature search using PubMed, Psych Info, and Google Scholar identified 32 articles that examined the effects of ED ingredients alone and/or in combination with caffeine on physical or cognitive performance. A systematic evaluation of the evidence-based findings in these articles was then conducted. With the exception of some weak evidence for glucose and guaraná extract, there is an overwhelming lack of evidence to substantiate claims that components of EDs, other than caffeine, contribute to the enhancement of physical or cognitive performance. Additional well-designed, randomized, placebo-controlled studies replicated across laboratories are needed in order to assess claims made for these products.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Caffeine, SAJ special grade, ≥98.5%
Supelco
Caffeine, Pharmaceutical Secondary Standard; Certified Reference Material
Supelco
Caffeine Melting Point Standard, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Caffeine, anhydrous, tested according to Ph. Eur.
Supelco
Mettler-Toledo Calibration substance ME 18872, Caffeine, analytical standard, for the calibration of the thermosystem 900, traceable to primary standards (LGC)
Supelco
Caffeine, certified reference material, TraceCERT®
USP
Caffeine melting point standard, United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
Caffeine, BioXtra
Sigma-Aldrich
Caffeine, powder, ReagentPlus®
Sigma-Aldrich
Caffeine, meets USP testing specifications, anhydrous
Sigma-Aldrich
Caffeine, Sigma Reference Standard, vial of 250 mg
Sigma-Aldrich
Caffeine, anhydrous, 99%, FCC, FG
USP
Caffeine, United States Pharmacopeia (USP) Reference Standard
Caffeine, European Pharmacopoeia (EP) Reference Standard
Supelco
Caffeine solution, analytical standard, 1.0 mg/mL in methanol
Supelco
Melting point standard 235-237°C, analytical standard
Supelco
Caffeine solution, 1.0 mg/mL in methanol, ampule of 1 mL, certified reference material, Cerilliant®
Caffeine for system suitability, European Pharmacopoeia (EP) Reference Standard