Skip to main content
  • Poster presentation
  • Open access
  • Published:

Examination of the health and safety aspects of 28-days ingestion of a supplement containing slow-release caffeine

Background

Moderate amounts of caffeine can lead to an increase in both physical and mental task performance. However, a single dose of caffeine typically induces only 90-120 minutes of increased alertness and is often associated with an acute “crash” state following its metabolism. Recently, slow/sustained release caffeine (SRC) alternatives have been developed to prolong the effects of caffeine. While prior investigations have demonstrated the efficacy of SRC, there is currently limited information regarding the safety of SRC during prolonged usage. Therefore, the purpose of this study was to investigate the effects of 28-days of daily SRC ingestion on blood lipid profiles, comprehensive blood chemistry, and complete blood counts in young, healthy men and women.

Methods

Forty healthy individuals (20 males, 20 females; age: 22.73 ± 3.06 years; height: 171.68 ± 10.45 cm; mass: 74.49 ± 15.51 kg; BMI: 25.08 ± 3.66 (kg/m2) who were regular consumers of caffeine volunteered to participate in this randomized, double-blind, placebo controlled study. While enrolled in the study, participants were permitted to maintain their normal caffeine intake. Following a 12-hour fast, participants reported to the Human Performance Laboratory (HPL) for pre-testing. Testing consisted of resting heart rate (RHR) and blood pressure (BP) measures, followed by a resting blood draw obtained from an antecubital vein in the superficial forearm using a 21-gauge disposable needle stick. Upon completion of pre-testing, participants supplemented with either Energize™ (SUPP) or placebo (PL) for 28 days. Daily supplementation was witnessed by lab personnel. On weekends, participants were provided 2 dosages of SUPP or PL to consume on each weekend day. Weekend supplementation was provided in zip lock bags, which were returned to demonstrate adherence. Post-testing occurred 24-hours after ingestion of the final dose and consisted of the same protocol at the same time of day as pre-testing. Within 24-hours of pre- and post-testing, blood samples were packaged along with a requisition form for analysis at a commercial laboratory. Statistical analysis of the data was accomplished using a 2 by 2 repeated measures analysis of variance (ANOVA) to determine between groups differences (SUPP vs. PL). Consent to publish the results was obtained from all participants.

Results

Compliance was 98.3%. No significant differences between the groups were observed for resting cardiovascular measures, blood lipids, or complete blood counts. A significant difference between groups was observed for plasma glucose concentrations (p = 0.028); however, follow-up testing revealed that pre- to post-supplementation changes were not significant for either SUPP (p = 0.077) or PL (p = 0.116). No other between group differences were observed for metabolic blood chemistry. All variables remained within normal adult reference ranges. Study participants reported no adverse events during supplementation with either SUPP or PL.

Conclusion

These findings indicate that 28 consecutive days of moderate SRC ingestion in caffeine users is both safe and tolerable. This may have important relevance in professions, where continuous operations demand peak cognitive and physical performance for sustained periods of time.

Acknowledgement

Funding for this study was provided by iSatori, INC, Golden, CO.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Jeffrey R Stout.

Rights and permissions

Open Access  This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.

The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.

The Creative Commons Public Domain Dedication waiver (https://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Wells, A.J., Hoffman, J.R., Gonzalez, A.M. et al. Examination of the health and safety aspects of 28-days ingestion of a supplement containing slow-release caffeine. J Int Soc Sports Nutr 11 (Suppl 1), P17 (2014). https://doi.org/10.1186/1550-2783-11-S1-P17

Download citation

  • Published:

  • DOI: https://doi.org/10.1186/1550-2783-11-S1-P17

Keywords