Acute effects of a commercially-available pre-workout supplement on markers of training: a double-blind study

Scientific research on ergogenic supplements has led manufacturers to introduce pre-workout drinks to the market. Supplements taken before a workout are often used to improve energy, alertness, strength, power, and body composition. To date, little product-specific research exists on pre-workout supplements containing multiple ingredients. Consumption of various individual ingredients often included in proprietary pre-workout blends are known to effectively increase time to fatigue [1],[2], allowing for an increased training volume [3]-[5] although it is uncertain which combinations of ingredients are most effective. The following scientific support serves as the basis for formulation of proprietary blends and the inclusion of specific ingredients.

Beta-alanine, a precursor to carnosine [6], has been used to improve performance of high-intensity exercise [7],[8] by increasing the muscle carnosine pool [9]. Carnosine serves as a muscle buffer during intense exercise and increasing carnosine stores through beta-alanine supplementation can enhance this buffering ability [6]. Research on beta-alanine has shown that supplementation improves the rate of fatigue in sprinters [10] and improves YoYo Intermittent Recovery performance (the ability to repeatedly perform and recover from exercise) for amateur athletes [7]. Additionally, beta-alanine supplementation has increased the number of repetitions to fatigue and overall work capacity [6].

Creatine, the most extensively researched ergogenic aid [11], has been shown to increase strength and improve body composition in most individuals when combined with exercise [12]. Creatine’s ergogenic abilities are derivative of its ability to rapidly replenish ATP stores, allowing for quicker recovery and potential increased training volume [13]. To properly load creatine stores in the muscle, it is recommended that an individual consume roughly 0.3g/kg/day for three days followed by a maintenance dose of 3-5g/day after the first three days [11]. Alternately, a lower dose of 2-3g/day may also be utilized to increase stores slowly [11]. Supplementation of creatine is also beneficial for improving lean body mass when combined with exercise [14]. According to the International Society of Sport Nutrition Position Stand on Creatine, creatine monohydrate is currently the most effective supplement for increasing anaerobic capacity and lean body mass [11].

Research on branched chain amino acids (BCAA) has concluded that supplementation can result in increased protein synthesis and additional lean body mass in multiple populations [6]. BCAA have also been shown to improve muscular strength as well as an increase thigh mass [15]. Muscle damage has been markedly reduced after exercise and BCAA supplementation [16]. Intake of BCAA, and leucine in particular, can create an anabolic environment [17] by reducing protein oxidation and promoting sarcomerogenesis in skeletal muscle [18]. The inclusion of BCAA before or after an exercise session will help the body maintain a positive nitrogen balance and support muscle growth.

Another well researched ergogenic aid, caffeine, is often a key component to pre-workout supplements due to its stimulatory benefits, and subsequent improvements in time to fatigue [6]. Caffeine has also been shown to have a potential glycogen-sparring effect during exercise, likely improving endurance [19], and chronic beneficial changes in body composition [20]-[22]. A dose of 3-6mg/kg of body weight can improve sport performance in trained individuals [19]. Multiple studies have resulted in increased upper body strength [23],[24] while still others have not seen the same results [25],[26]. Based on varying results, it appears that more research is needed to determine caffeine’s effectiveness in the area of strength and power performance.

Caffeine is also a thermogenic, which explains its inclusion in weight loss supplements [19].

Although beta-alanine, creatine, BCAAs, and caffeine are frequently the active ingredients in pre-workout supplements, different amounts can be used depending on the specific goals of the target population. Additionally, the actual degree of success and time frame for effects of multi-ingredient combinations differ for every individual and some consumers are considered non-responders [27]-[29]. The variances among formulation, composition, and timing of response can cause varying results. The purpose of this study was to determine the acute (one week) effects of a commercially available pre-workout supplement containing a proprietary blend of caffeine, creatine, BCAAs, and beta-alanine on strength, power, body composition, mood states, and tolerance measures when combined with a selected resistance four day training protocol.

Acute ingestion of a pre-workout supplement blend demonstrated positive effects on post-supplementation/training LPM, more than a carbohydrate PLC, when combined with four resistance training sessions. The improvements in LPM (+14.09 ± 6.94 kg) from T1 to T2 for SUP (PLC: LPM: +5.48 ± 7.93 kg) were likely due to a delayed onset of fatigue, attributable to the beta-alanine and creatine content of the supplement. Hoffman and associates [33] discussed the combined effects of creatine and beta-alanine supplementation on delayed fatigue and ultimately increased training stimulus. Although four training sessions may be seen as an insufficient amount of time to significantly increase strength, the supplementation of these two ingredients, combined with a hypertrophy-focused resistance training protocol, may have allowed for increases in lower body strength in the present study. This is supported by Derave et al. [10] in which dynamic knee extension torque was significantly improved after four weeks of 4.8 g/day of beta-alanine supplementation. The improvements in strength in the study by Derave et al. as well as the present findings could be linked to a potential increase in training volume often allowed by increased beta-alanine and carnosine in the body [34]. Hoffman and colleagues also saw a trend toward significance for Wingate anaerobic power tests (p = 0.07) with three weeks of supplementation.

The absence of a supplement loading period may have negatively impacted the study. Beta-alanine does require a loading period and while creatine does not, it is often recommended that users follow a specific protocol for the first few days of supplementing with creatine to decrease the time to results [11],[35]. Because the supplementation period was only eight days in duration, a loading period would likely have been beneficial for the SUP group. Buford and colleagues [11], in a review, suggest that creatine benefits will likely occur without a loading period, but may take four or more weeks to happen. In a study investigating different levels of dosing for beta-alanine in untrained males, a higher dose (3.2 g beta-alanine/day for four weeks, followed by 1.6 g beta-alanine/day for four weeks) more quickly increased muscle carnosine levels compared to the low dose (1.6 g beta-alanine/day for eight weeks), providing supporting evidence that beta-alanine may be more beneficial in a more timely manner when received in higher doses initially (loading) [35].

Caffeine contained in the supplement may have contributed to the increase in lower body strength, although this would be a contradictory finding as much of the caffeine research resulted in no significant lower body strength increase [19],[23],[36]. Supplementing with caffeine before a workout has been shown to increase the amount of weight lifted during the chest press exercise although not the leg press [24]. Lower body testing was again not affected by caffeine consumption in a 2006 study by Beck and colleagues [37]. Bench press 1RM was significantly increased after caffeine ingestion, but lower body strength and power (Wingate) were not changed. Although caffeine may have ergogenic effects on upper body strength and during activities more aerobic in nature, it is unlikely that the caffeine content of the active supplement in the current study had any effect on the LPM variable. Despite this finding, caffeine likely played a role in the improvement of %BF. Supplemental caffeine is often used to increase lipolysis during exercise [38] and spare glycogen [39], a benefit that could potentially be seen if the supplement used in the present study was taken for a longer period of time. In one study, overweight participants consumed a dietary supplement containing 240 mg/day of caffeine for eight weeks and achieved a significant (p < 0.006) amount of weight loss and fat mass loss in addition to a decrease in hip girth measurements [40].

It is also plausible that the increased LPM was due to the actual combination of ingredients rather than one single ingredient in particular. A similar pre-workout supplement, when ingested for a period of three weeks, significantly increased leg press strength in recreationally-trained males [41]. The particular multi-ingredient supplement used in Spradley and associates’ research contained 300mg of caffeine as well as beta-alanine, creatine, and BCAAs included in the supplement [41]. Multi-ingredient pre-workout drinks containing a combination of caffeine, creatine, amino acids, and beta-alanine, commonly demonstrating a delay in fatigue and improved peak and mean power measures after acute supplementation [42]-[44]. One such supplemental drink was consumed by 15 trained males before each workout for eight weeks and results revealed significant improvements in strength for the experimental group [44]. This study conducted by Kudrna and colleagues demonstrates the possibility for improvements through pre-exercise supplement drinks with an adequate training and supplementation period [44]. Increased training volume (attributable to delayed onset of fatigue) was seen after trained individuals consumed 18g of a multi-ingredient ergogenic supplement drink before high intensity interval training (HIIT) sessions for three weeks [4] Ingredients in the active supplement were similar to those in the current study (BCAAs, caffeine, creatine) and although group by time interactions were not significant in Smith’s study, 95% confidence intervals suggested that the supplement was beneficial on measures of aerobic performance [4]. Considering the short duration of supplementation, comparable conclusions can be drawn, suggesting potential training benefits related to the supplement if doses of ingredients and supplementation duration are adequate.

Based on the current body of knowledge and the results of this study, the ingredients in the experimental supplement and hypertrophy-focus training regimen may have the potential to increase lower body strength in resistance-trained young males. It is likely that the participants in the SUP group would have seen a significant ergogenic benefit (improved LPM) related to the supplement and training protocol after an extended supplementation period. Data from another study investigated performance variables as well as body composition effects of the same commercially available product used in the current study but with an eight week supplementation period [14]. Results support the conclusions and findings of the present study (improved strength and anaerobic power), suggesting long-term use may have greater benefits. The time delay in measurable results between these two studies reiterates the need for analyses of longer duration on pre-workout supplements as well as acute studies to determine how quickly supplement benefits can be realized.

The lack of a crossover design is one limitation to this study. Future acute research may investigate the effects of the proprietary supplement in a crossover manner to gain further knowledge of the potential for improved performance and/or body composition. A crossover study using the supplement used in the present study would also provide higher quality side-effect information.

It may be beneficial for resistance trained males to consume a proprietary pre-workout supplement containing beta-alanine, creatine, BCAAs, and caffeine when wanting to improve lower body strength. It seems likely, based on the available research, that taking the pre-workout supplement for an extended period of time in combination with exercise is safe and can lead to beneficial changes in strength and body composition.