Journal Title (Medline/Pubmed accepted abbreviation): J. Int. Soc. Sports Nutr
Summary of background and research design:
Background: Creatine is one of the only supplements to date that exhibits irrefutable enhancements in muscle growth and strength. Creatine monohydrate is the most common form of creatine available, though different forms of creatine are on the market. A buffered creatine (Kre-Alkalyn®, All American Pharmaceuticals, Billings, MT) offers a combination of creatine and an alkaline powder (including bicarbonate) with claims of a more effective creatine product with fewer side effects.
Hypothesis: Consumption of buffered creatine at lower doses (1.5 g/day) will have similar effects on muscle growth as creatine monohydrate taken at 5 g/day and cause fewer gastrointestinal side effects.
Subjects: Healthy males (n = 36), age 20.2 ± 2 y
Experimental design: randomized, double-blind, parallel design
- Kre-Alkalyn (KA) at the manufacturer’s recommended dose- 1.5 g/day for 28 days
- KA at generally accepted effective doses of creatine (which were determined using creatine monohydrate)- loading at 4 ×5 g/day for 7 days and then maintenance at 5 g/day for 21 days
- Creatine monohydrate (CrM)- loading at 4 ×5 g/day for 7 days and then maintenance at 5 g/day for 21 days
Protocol: The participants reported to the laboratory on four occasions. The first occasion was for familiarization and entry. The participants completed health, diet, and exercise questionnaires and practiced the Wingate Anaerobic capacity test. This test includes cycling as hard as possible against a constant force for a set amount of time. At their second visit to the lab the participants were evaluated for baseline measurements. They provided a muscle biopsy and fasting blood sample. They also were evaluated for body composition, including body water. Their one repetition maxima were determined for leg press and bench press. They then completed the Wingate Anaerobic Capacity test. After this baseline session, they began to take their assigned supplement according to the regimen. Seven days later, at the completion of the loading phase, the participants returned to be evaluated for body composition and anaerobic capacity. They provided muscle and blood samples as well. The fourth and final visit was after the 21 days of maintenance. Body composition, anaerobic capacity, and one repetition maxima for leg press and bench press were determined. Final muscle samples were provided.
Summary of research findings:
- Upper and low body training volume did not differ between groups over the course of the experiment (28 days, p > 0.5).
- Calories and protein consumed tended to decrease over the course of the study, but diet composition was not different between groups.
- Creatine content in muscle increased significantly in all groups during the course of the study (p = 0.03 from baseline to 28 days). The CrM group increased from 51.5 ± 12.7 mmol/kg DW (dry weight*) to 62.8 ± 25.0 mmol/kg DW after the loading phase to 73.8 ± 15.6 mmol/kg DW after the maintenance phase. In contrast, KA-L only increased from 65.8 ± 15.4 mmol/kg DW to 70.5 ± 20.4 mmol/kg DW over the whole study. In KA-H, creatine concentrations increased from 57.3 ± 17.7 to 66.3 ± 12.6 during the study (similar trend as creatine monohydrate). With that said, the differences in groups did not reach statistical significance (p = 0.078).
- Body weight (+1.42 ± 2.5 kg) and fat free mass (0.89 ± 0.1 kg) increased for all groups with no statistically significant difference between groups.
- One repetition maxima for bench press increased over time for participants in all groups with no changes between groups. However, there were no significant changes in one repetition maxima for leg press.
- Average anaerobic capacity increased for all groups with no significant differences between groups. In fact, average power, peak power, and total work all increased significantly (p < 0.01).
- Blood lipids, total cholesterol, the ratio of total cholesterol to high density lipoprotein (HDL), and triglycerides were similar at 7 and 28 days as they were at baseline for participants in all groups. Low density lipoprotein (LDL) was slightly decreased in the creatine monohydrate group after the loading phase.
- There were no differences between groups in regard to changes in enzymes related to catabolism (break down; e.g., blood urea nitrogen and aspartate aminotransferase).
- Creatinine concentrations in serum increased over time in all groups with more elevated levels in the creatine monohydrate and KA-H groups compared to those in KA-L. Concentrations remained within a healthy range.
- No differences between groups were noted in markers related to bone health.
- No clinically significant differences were observed in concentrations of electrolytes in serum.
- Markers of whole blood (e.g. red blood cells, white blood cells) were similar between groups.
*dry weight = weight-water weight
Key practice applications: Supplementation with the buffered form of creatine (KA) did not provide the athletes a greater benefit than the traditional creatine monohydrate at the manufacturer’s recommended doses. Performance enhancement was equivalent among all groups and there were no differences in clinical measures or reported side effects. Manufacturers of KA promote their product by stating that KA is “up to ten times more powerful than ordinary Creatine”. Also, they declare that KA is metabolized into creatinine at a much lower rate than creatine in creatine monohydrate. However, neither of these claims was substantiated in this experiment. Therefore, either buffered creatine or creatine monohydrate can be recommended for similar enhancement of anaerobic performance.
Limitations: This study did not include a control group (a group that did not consume creatine). Therefore, changes that were observed here cannot be compared to changes in anaerobic capacity or clinical markers that may have changed for reasons other than creatine supplementation.
Key search terms for this article (5-7 terms): creatine, buffered creatine, types of creatine, Kre-Alkalyn