What is beta alanine

Beta-alanine is a non-proteogenic amino acid that is produced in your liver by the degradation of dihydrouracil and carnosine. In addition, humans acquire beta-alanine through the consumption of foods such as poultry and meat ¹⁾. By itself, the performance-enhancing (ergogenic) properties of beta-alanine are limited; however, beta-alanine has been identified as the rate-limiting precursor to carnosine synthesis ²⁾ and has been consistently shown to increase levels of carnosine in human skeletal muscle. Carnosine (β-alanyl-l-histidine) is present in high concentrations in human skeletal muscles. The oral ingestion of beta alanine, the rate-limiting precursor in carnosine synthesis, has been shown to elevate the muscle carnosine content both in trained and untrained humans ³⁾. Doses of 4 to 6 g/day of beta-alanine have been shown to increase muscle carnosine concentrations by up to 64 % after 4 weeks ⁴⁾ and up to 80 % after 10 weeks ⁵⁾. Baguet et al. ⁶⁾ demonstrated that individuals vary in the magnitude of response to 5 to 6 weeks of beta-alanine supplementation (4.8 g/day), with high responders increasing muscle carnosine concentrations by an average of 55 %, and low responders increasing by an average of only 15 %. The difference between high and low responders seems, at least in part, to be related to baseline muscle carnosine content and muscle fiber composition ⁷⁾.

Beta-alanine works by enhancing muscle carnosine concentrations. Over the past ten years, beta-alanine has grown to become one of the most popular sports nutrition ingredients. Although relatively new, with the first human study published in 2006, beta-alanine use and formulation has expanded into nearly every pre-workout formula on the market, and a number of daily and recovery formulas.

Figure 1. Beta alanine

The dipeptide carnosine is present in high concentrations in muscle and is a relatively stable characteristic of human skeletal muscle with approximately 10% variation over a 3-month period ⁸⁾. Only long-term vegetarianism ⁹⁾ or high-dose beta-alanine supplementation for several weeks can change the muscle carnosine content ¹⁰⁾. Short-term exercise training would probably have little or no impact on muscle carnosine levels ¹¹⁾. Explosive athletes had ∼30% higher carnosine levels compared to a reference population, whereas it was ∼20% lower than normal in typical endurance athletes. Similar results were found in young talents and ex-athletes. When active elite runners were ranked according to their best running distance, a negative sigmoidal curve was found between logarithm of running distance and muscle carnosine. Moreoever, muscle fiber type is a major determinant of carnosine levels. The fatigue-sensitive fast-twitch (FT) or type-II fibers contain twice as much carnosine as the fatigue-resistant slow-twitch (ST) or type-I fibers ¹²⁾. Athletes excelling in 100 m to 400 m all exhibit a high carnosine level, likely because these distances require a similar high percentage of fast-type muscle fibers ¹³⁾, whereas 1,500–3,000 m and especially 10,000 m to marathon runners have low carnosine content, likely because these distances require a high percentage of slow-type muscle fiber ¹⁴⁾. In fact, the 800 m runners show least resemblance with any other distance as their muscle carnosine content lies in between those of sprint and endurance athletes and is situated on the steepest part of the sigmoidal curve (the midpoint of the curve lies at ∼1,000 m). Consequently, marathon runners seem to have low muscle carnosine content ¹⁵⁾. In untrained subjects, moderately positive correlations have been found between fatigue-sensitive fast-twitch (FT) or type-II fibers proportion and carnosine content, using muscle biopsies ¹⁶⁾. Classical papers from the 70s ¹⁷⁾ established that excellence in sports with short and long exercise duration requires a high proportion of fatigue-sensitive fast-twitch (FT) and fatigue-resistant slow-twitch (ST) muscle fibers, respectively. There is an ongoing nature/nurture debate whether a fiber can modify into another type in humans, but the effect of specific types of exercise training on the transition between fatigue-sensitive fast-twitch (FT) and fatigue-resistant slow-twitch (ST) fiber population is probably limited ¹⁸⁾.

Van Damme et al. ¹⁹⁾ explored the performance constraints in elite decathletes and concluded that performances on different subdisciplines, like 100 m and 1,500 m, correlate negatively, partly because of the conflicting muscle fiber type requirements. Moreover, excellence in a particular discipline (specialist) is detrimental for overall decathlon performance (generalist). The findings from this study involving 80 Belgian track-and-field athletes and 83 not specifically trained controls in muscle seem to agree with both of these points ²⁰⁾. With respect to muscle carnosine, disciplines like 100 m and 1,500 m indeed have antagonistic requirements. Additionally, the 5 elite decathletes measured had intermediate carnosine levels within a relatively narrow range, suggesting that they were all generalists, rather than specialists ²¹⁾.

Figure 3. Carnosine content of gastrocnemius muscle in track-and field and triathletes compared to an untrained male control population

Figure 4. Carnosine content of gastrocnemius muscle in male and female active elite runners, according to their best running distance

Figure 5. Comparison of the gastrocnemius carnosine content in male young talented athletes (n = 15), active elite athletes (n = 19) and ex-athletes (n = 14).

Is beta alanine safe?

Current, although limited information, suggests that beta-alanine is safe in healthy individuals at recommended doses.

Tingling is the most widely known side effect of beta-alanine and is commonly experienced in individuals consuming more than 800 mg of beta-alanine in a non-sustained release form ²²⁾. To circumvent this, slow-release beta alanine have been developed which result in slower absorption kinetics and which reduce the incidence of parasthesia to the level of placebo ²³⁾. The mechanism of the itching/tingling sensation upon oral beta alanine has recently been ascribed to Mas-related G protein-coupled receptor member D (MrgprD), a G protein-coupled receptor, expressed in dorsal root ganglion neurons involved in cutaneous mechanosensation ²⁴⁾.

Beta alanine benefits

The International Society of Sports Nutrition ²⁵⁾ provides an objective and critical review of the mechanisms and use of beta-alanine supplementation. Based on the current available literature, the conclusions of the International Society of Sports Nutrition ²⁶⁾ are as follows:

1. Four weeks of beta-alanine supplementation (4–6 g daily) significantly augments muscle carnosine concentrations, thereby acting as an intracellular pH buffer;
2. Beta-alanine supplementation currently appears to be safe in healthy populations at recommended doses;
3. The only reported side effect is paraesthesia (tingling), but studies indicate this can be minimized by using divided lower doses (1.6 g) or using a sustained-release formula;
4. Daily supplementation with 4 to 6 g of beta-alanine for at least 2 to 4 weeks has been shown to improve exercise performance, with more pronounced effects in open end-point tasks/time trials lasting 1 to 4 min in duration;
5. Beta-alanine attenuates neuromuscular fatigue, particularly in older subjects, and preliminary evidence indicates that beta-alanine may improve tactical performance;
6. Combining beta-alanine with other single or multi-ingredient supplements may be advantageous when supplementation of beta-alanine is high enough (4–6 g daily) and long enough (minimum 4 weeks);
7. More research is needed to determine the effects of beta-alanine on strength, endurance performance beyond 25 minutes in duration, and other health-related benefits associated with carnosine.

While evidence suggests that athletes engaged in resistance training and high-intensity exercise have higher concentrations of muscle carnosine ²⁷⁾, longitudinal training studies have demonstrated equivocal changes in intramuscular carnosine ²⁸⁾. The variability of increases in carnosine appears to be reflective of baseline levels, with vegetarians having greater increases in carnosine concentrations compared to carnivores. In humans, muscle carnosine contents generally range from 10 – 40 mmol/kg dry weight ²⁹⁾ with average values around 20–30 mmol/kg dry weight ³⁰⁾, although these contents can be influenced by a number of factors. Carnosine concentrations tend to be higher in males compared to females ³¹⁾, and in fast-twitch compared to slow-twitch muscle fibers ³²⁾. Carnosine concentrations may also decline with age and is most likely influenced by habitual dietary intake of carnosine-containing foods (e.g. beef, pork, poultry, fish, etc.) ³³⁾.

Despite this, beta-alanine supplementation will still increase carnosine concentrations, regardless of low or high baseline levels ³⁴⁾, with no upper limit for muscle carnosine concentrations having yet been identified. While cross-sectional studies have shown higher baseline carnosine contents in the gastrocnemius muscle of sprinters ³⁵⁾ and resistance-trained athletes ³⁶⁾ versus their untrained counterparts, beta-alanine supplementation has also been shown to increase muscle carnosine in both trained ³⁷⁾ and untrained ³⁸⁾ populations. A recent study by Bex et al. ³⁹⁾ suggests that increases in whole muscle carnosine concentrations may be slightly higher in trained athletes compared to non-athletes supplementing with beta-alanine, but more research is needed to replicate this finding and account for potential differences in single muscle fiber concentrations. Much of the research evaluating increases in muscle carnosine has been performed in young males, but evidence also suggests that beta-alanine supplementation is effective in females ⁴⁰⁾ and the elderly ⁴¹⁾.

Effects of beta-alanine on exercise performance

It has been suggested that chronic beta-alanine supplementation improves high-intensity exercise performance by increasing muscle carnosine content, thereby enhancing intracellular proton buffering ⁴²⁾. Excess protons are also buffered independently of carnosine by a number of physicochemical buffering constituents; extracellular bicarbonate is the most relevant for increasing muscle buffering capacity ⁴³⁾, thereby acting to maintain intramuscular pH. As a result of augmented muscle buffering and mitigating H+ accumulation, beta-alanine has been suggested to be most beneficial in activities limited by acidosis, generally ranging from 2 to 4 min ⁴⁴⁾. A collective view of the literature on anaerobic (0–4 min) and aerobic performance, neuromuscular fatigue, strength, and tactical challenges has been included.

Beta alanine bodybuilding

Strength outcomes: Beta-alanine appears to increase training volume, however, current research does not indicate an additive benefit on strength gains during resistance training ⁴⁵⁾.

Studies investigating the effects of beta-alanine on strength outcomes have reported mixed findings. While short-term (30 days) studies by Hoffman et al. ⁴⁶⁾ did not show statistically significant improvements in performance, supplementation was shown to increase training volume and reduced subjective ratings of fatigue. In a similar length study (4 weeks), Derave et al. ⁴⁷⁾ showed beta-alanine supplementation increased muscle carnosine content and attenuated fatigue in five sets of 30 maximal dynamic knee extensions, while isometric endurance was unaffected. In contrast, Sale et al. ⁴⁸⁾ demonstrated a significant improvement in isometric endurance following 4 weeks of supplementation.

It has been hypothesized that the documented improvements in training volume and fatigue may translate to meaningful changes over prolonged interventions. Despite improvements from baseline testing, Kern and Robinson ⁴⁹⁾ did not show eight weeks of beta-alanine supplementation to significantly improve flexed arm hang performance in wrestlers or football players compared to placebo. In a 10-week intervention, Kendrick et al. ⁵⁰⁾ showed significant improvements in isokinetic force production, whole body strength, arm curl repetitions to fatigue, and body composition, but with no difference between the beta-alanine and placebo groups. Finally, Hoffman et al. ⁵¹⁾ investigated the effects of creatine monohydrate, creatine + beta-alanine, or placebo in conjunction with ten weeks of training. Compared to placebo, both creatine and creatine + beta-alanine significantly improved squat 1RM, bench press 1RM, and weekly squat intensity. Only creatine + beta-alanine improved body composition and weekly training volume for squat and bench press, but differences were not significantly greater than creatine alone. Collectively, the evidence suggests that beta-alanine may improve indices of training volume and fatigue for resistance exercise, but more long-term studies are needed to clarify potential effects on strength and body composition compared to placebo.

Aerobic exercise performance

Beta-alanine may improve exercise duration during tasks requiring a greater contribution from aerobic energy pathways.

For exercise bouts lasting greater than four minutes, ATP demand is increasingly met via aerobic metabolic pathways. As such, it has been suggested that beta-alanine is not beneficial for exercise bouts lasting over 4 min. To the contrary, however, Hobson et al. ⁵²⁾ concluded that beta-alanine supplementation resulted in improvements of exercise tests of >4 min duration, when compared to the effect of a placebo, although the effect size calculated was smaller in comparison to exercise bouts lasting 1 to 4 min.

Research has demonstrated a modest benefit of beta-alanine supplementation on time to exhaustion in exercise tests over 4 min in duration. In conjunction with 6 weeks of interval training, Smith et al. ⁵³⁾ demonstrated larger improvements in time to exhaustion in a graded exercise test with beta-alanine supplementation compared to placebo. Participants consuming a placebo improved time to exhaustion from 1128.7 s to 1299.6 seconds, whereas the beta-alanine group improved from 1168.2 s to 1386.7 seconds. Similarly, Stout et al. ⁵⁴⁾ showed that participants supplementing with beta-alanine for 28 days improved time to exhaustion in a graded exercise test from 1117.6 s to 1146.7 seconds, while no improvement was shown in the placebo group. In aerobic, open end-point exercise, beta-alanine appears to result in modest improvements that, nonetheless, could be meaningful in competitive athletics, such as running, cycling, etc.

Benefits have also been reported using fixed end-point exercise bouts lasting over 4 minutes. Baguet et al. ⁵⁵⁾ showed that participants supplementing with beta-alanine performed a 2,000-m rowing time trial 4.3 seconds faster than the placebo group, despite being 0.3 second slower at baseline. While such results suggest modest benefits, changes of this magnitude may be meaningful to competitive athletes. Similarly, Ducker et al. ⁵⁶⁾ showed beta-alanine to improve 2,000-m rowing performance by 2.9 seconds, resulting in a relative effect of 99.0.

Currently, limited research is available for exercise over 25 min in duration. In a graded exercise test, Van Thienen et al. ⁵⁷⁾ reported that eight weeks of beta-alanine supplementation (2–4 g/day) was unable to improve time to exhaustion more than placebo. Although the beta-alanine group did improve time to exhaustion from 49.7 to 54.2 min, slightly larger improvements were observed in the placebo group, suggesting beta-alanine had limited effects. Chung et al. ⁵⁸⁾ investigated the effects of beta-alanine supplementation on one-hour time trial performance in trained cyclists. Although beta-alanine supplementation substantially increased muscle carnosine concentrations, both the beta-alanine and placebo groups saw performance decrements following six weeks of supplementation ⁵⁹⁾. Overall, available research indicates that beta-alanine provides a modest benefit for exercise lasting up to approximately 25 min in duration. To date, research beyond this time frame is limited and does not demonstrate a consistent positive effect.

Anaerobic exercise performance

Beta-alanine generally enhances high intensity exercise lasting over 60 seconds, with greater effects on open end point exercise bouts, such as time to exhaustion tasks.

The primary physiological mechanism associated with beta-alanine supplementation is most likely related to enhancing intracellular buffering capacity, consequently it has been hypothesized that beta-alanine supplementation would have ergogenic potential for activities that are primarily reliant on anaerobic metabolism. A meta-analysis on beta-alanine supplementation ⁶⁰⁾ indicated that supplementation improved exercise capacity in tasks lasting 60 to 240 s, but not in tasks lasting under 60 s in which acidosis is not likely the primary limiting factor. Additionally, literature evaluating repeated short-duration sprint tasks do not seem to demonstrate an effect: Sweeney et al. ⁶¹⁾ reported no significant improvements in power output in repeated five-second bouts, and Derave et al. ⁶²⁾ did not report significant improvements in 400 m sprint time in response to beta-alanine supplementation (average sprint time = 51.3 seconds).

The effects of beta-alanine supplementation on time to exhaustion, with effects on fixed end-point exercise, such as races and time trials. Similar to the results of Hobson et al. ⁶³⁾, the most pronounced effects of beta-alanine supplementation on time to exhaustion are seen in tasks under 270 seconds. For example, Hill et al. ⁶⁴⁾ reported marked improvements in cycling time to exhaustion at 110 % of maximal power output (average time = 104.1 seconds), resulting in a relative effect of 115.2, suggesting an improvement in performance. A similar percentage increase (13-14 %) in cycling time to exhaustion for the beta-alanine groups was reported by Sale et al. ⁶⁵⁾ and Danaher et al. ⁶⁶⁾.

In a critical velocity test, Smith-Ryan et al. ⁶⁷⁾ showed large improvements in time to exhaustion for female participants running at 90 % and 100 % of the velocity at which VO2max was achieved (average time = 267.6 and 132.3 seconds), resulting in relative effects of 129.3 and 117.0, respectively. It should be noted that results are not entirely consistent, as relative effects below 100 are seen for anaerobic exercise tests between 1 to 4 min. According to data from Jagim et al. ⁶⁸⁾, beta-alanine resulted in a relative effect of 95.1 for sprinting at 140 % of VO2max. Further, data from Smith-Ryan et al. ⁶⁹⁾ indicated relative effects of 81.1 and 87.1 for male participants running at 100 % and 90 % of the velocity at which VO2max was achieved, respectively. In all three instances, relative effect calculations were influenced by substantial performance improvements in placebo groups ranging from 8 to 15 %.

In a recent meta-analysis, Hobson et al. ⁷⁰⁾ concluded that beta-alanine improved exercise capacity, or open end-point tests to volitional exhaustion, to a greater extent than fixed end-point exercise performance, such as race times or time trial performance. In agreement with Hobson et al. ⁷¹⁾, relative effect values near 100 indicate modest effects of beta-alanine supplementation. Nonetheless, the three largest relative effects were observed in exercise bouts lasting 63.2-141.0 seconds ⁷²⁾. Taken together, research currently suggests that beta-alanine has the greatest potential to improve performance in high-intensity exercise lasting over 60 seconds, with more pronounced effects observed in open end-point exercise tasks taken to volitional exhaustion.

Tactical athletes

Initial results in tactical athletes demonstrate a positive effect on military-specific tasks.

The training and duties of military personnel and other tactical athletes often consist of prolonged and rigorous exercise, resulting in reductions in physical and cognitive performance ⁷³⁾. Beta-alanine supplementation may be advantageous in this population, potentially attenuating fatigue, enhancing neuromuscular performance, and reducing oxidative stress. In 2014, an expert panel published a review regarding the use of beta-alanine in military personnel ⁷⁴⁾. The panel concluded that there was insufficient evidence to recommend the use of beta-alanine by military personnel ⁷⁵⁾. More recently, the use of beta-alanine in tactical personnel was directly investigated by Hoffman et al. ⁷⁶⁾. Soldiers involved in military training supplemented with either beta-alanine or placebo for 28 days, with researchers testing a number of outcomes pertaining to physical and cognitive performance. While cognitive performance was not affected, beta-alanine resulted in moderate improvements in peak power, marksmanship, and target engagement speed, compared to placebo ⁷⁷⁾. A subsequent study by Hoffman et al. ⁷⁸⁾ showed beta-alanine to significantly increase muscle carnosine, cognitive function, and performance on a test simulating a 50-m casualty carry; however, beta-alanine did not improve performance in a 2.5 km run, one minute sprint, repeated sprints, or marksmanship. Recently, it was reported that beta-alanine had no significant effect on brain carnosine or cognitive function in non-tactical athletes ⁷⁹⁾. While evidence in this population is scarce, it would appear that beta-alanine supplementation yields promising results for tasks relevant to tactical personnel. More research is needed to determine which tasks are consistently improved with supplementation.

Health benefits

Beta-alanine may act as an antioxidant.

Decades of literature support a potential for carnosine to influence some mechanisms related to health including antioxidant properties, anti-aging, immune enhancing, and neurotransmitter actions. However, the majority of these health benefits have been explored in vitro and in animal models. Carnosine is widely considered an important anti-glycating agent that serves to prevent reactions that threaten to impact the structure and function of proteins in the body. Advanced glycation end products are associated with the aging process and diabetic complications, but carnosine is thought to reduce the formation of these end products ⁸⁰⁾. Previous research has also indicated that carnosine acts as a “sacrificial peptide,” reacting with carbonyl groups of aldehydes, ketones, and proteins to prevent damage to proteins ⁸¹⁾.

Carnosine is also known to be an antioxidant that is capable of preventing the accumulation of oxidized products derived from lipid components of biological membranes ⁸²⁾. The antioxidant mechanism of carnosine has been postulated to be due to metal chelation or free radical scavenging ⁸³⁾. The combination of histidine-containing compounds, such as carnosine, at near physiological concentrations, have resulted in synergistic antioxidant activity ⁸⁴⁾. Minimal data in humans exists regarding the potential antioxidant effect of increasing muscle carnosine vis-a-vis beta-alanine. Initial research suggests that beta-alanine may effectively reduce lipid peroxidation and mitigate accumulation of free radicals when combined with aerobic exercise in men and women ⁸⁵⁾. Future research evaluating potential anti-aging effects and the impact of potential antioxidant properties in humans would be important to explore, especially due to the positive effects beta-alanine has shown in older populations ⁸⁶⁾.

What does beta alanine do?

Beta-alanine works by enhancing muscle carnosine concentrations. Carnosine (β-Alanyl-L-histidine) is a naturally occurring dipeptide with numerous potential physiological functions and is formed by combining its constituent amino acids, L-histidine and beta-alanine, with the assistance of the enzyme carnosine synthetase. Carnosine is predominantly stored within skeletal muscle, and can vary widely between species ⁸⁷⁾. Carnosinase, the enzyme that catalyzes the breakdown of carnosine, is present in serum and various tissues in humans, but is absent in skeletal muscle ⁸⁸⁾ and many animals. It is important to note that carnosinase is not present in most non-primate mammals ⁸⁹⁾, which must be considered when evaluating carnosine supplementation and data obtained from animal models. Therefore, oral carnosine supplementation is an inefficient method of augmenting muscle carnosine levels in humans, as ingested carnosine is ultimately metabolized before reaching skeletal muscle ⁹⁰⁾.

Figure 6. Carnosine physiological roles in skeletal muscle

Footnotes: Potential roles of carnosine in skeletal muscles cells: 1) proton buffering capacity; 2) regulator of calcium release and calcium sensitivity; 3) protection against reactive oxygen species (ROS); 4) chelation of transition metal ions; and 5) extracellular provider of histidine/histamine.

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Carnosine’s role as an intracellular proton buffer was first identified by Severin et al. in 1953 ⁹²⁾, who demonstrated that the absence of carnosine resulted in more rapid fatigue and acidosis. By virtue of a pKa of 6.83 and high concentrations in muscle ⁹³⁾, carnosine has been shown to be more effective at sequestering protons than either bicarbonate (pKa 6.3) or inorganic phosphate (pKa 7.2), the other two major physio-chemical buffers, over the physiological pH range. With respect to carnosine’s structure, nitrogen atoms on the imidazole ring can readily accept a proton at physiological pH, and therefore it has been suggested that carnosine buffering precedes involvement of the bicarbonate buffering system during exercise ⁹⁴⁾. Preliminary estimates of what contribution carnosine may play in buffering suggested as much as 40 % of the buffering capacity of muscle ⁹⁵⁾ when evaluated in animals; more recent research in humans has indicated the contribution may be as low as 7 %  ⁹⁶⁾. More evidence documenting the contribution of carnosine in muscle buffering is needed to further identify its role in exercise performance. Nonetheless, beta-alanine supplementation has been shown to increase muscle carnosine concentrations ⁹⁷⁾ and attenuate exercise-induced reductions in pH ⁹⁸⁾, supporting the concept that carnosine plays a significant role in buffering exercise-induced acidosis.

The potential physiological roles of carnosine extend beyond its function as a proton buffer. Previous research has suggested that reactive oxygen species (ROS), which are produced at an elevated rate during exercise ⁹⁹⁾, may contribute to muscle fatigue and exercise-induced muscle damage under certain circumstances ¹⁰⁰⁾. Carnosine has been shown to act as an antioxidant by scavenging free radicals and singlet oxygen ¹⁰¹⁾, thereby reducing oxidative stress. Carnosine can further reduce oxidative stress by chelating transition metals, such as copper and iron ¹⁰²⁾. In doing so, these transition metals are prevented from reacting with peroxides in the Fenton reaction, which results in the production of free radicals. Carnosine is abundant in human skeletal muscle, and may influence these contributors to fatigue and oxidative stress by buffering excess protons ¹⁰³⁾, scavenging free radicals ¹⁰⁴⁾, and chelating transition metals ¹⁰⁵⁾. As the rate-limiting precursor to carnosine synthesis, beta-alanine supplementation has been shown to consistently elevate carnosine in a variety of populations, and may therefore improve performance during high-intensity exercise and/or enhance the quality of training in athletes participating in strength and power sports ¹⁰⁶⁾.

Beta alanine supplement combined with other sports supplements

The combined effects of beta-alanine with other performance enhancing aids, such as sodium bicarbonate, creatine, and multi-ingredient pre-workout formulas, have gained popularity. Due to the potential positive effects of beta-alanine during high-intensity exercise, it has been hypothesized that combining it with other ergogenic aids may further augment performance and proton buffering.

Sodium bicarbonate supplementation has been shown to acutely increase bicarbonate levels, blood pH, and high-intensity exercise performance ¹⁰⁷⁾, prompting interest in combined supplementation with beta-alanine. Sale et al. ¹⁰⁸⁾ first examined the effects of this combination on exercise performance and showed that beta-alanine supplementation alone improved performance on a cycling test at 110 % of maximal power output, and that there was a 70 % probability of an additive effect of beta-alanine + sodium bicarbonate compared to beta-alanine alone. Tobias et al. ¹⁰⁹⁾ investigated the effects of beta-alanine, sodium bicarbonate, or the combination on repeated upper-body Wingate performance, separated by 3 min of rest. Both beta-alanine and sodium bicarbonate improved mean power output, but the results for the beta-alanine + sodium bicarbonate group were superior, but not significant, compared to either supplement alone. Despite non-significant differences between groups, authors of other studies have calculated the probability of an additive effect with combined beta-alanine and sodium bicarbonate supplementation. In a 2,000-m rowing time trial, Hobson et al. ¹¹⁰⁾ used magnitude-based inferences to determine that beta-alanine was very likely to improve time trial performance (96 % chance of positive effect), sodium bicarbonate was likely to improve performance (87 % chance), and that adding acute sodium bicarbonate supplementation to chronic beta-alanine consumption had a small, possibly beneficial affect compared to beta-alanine alone (64 % probability). In swimmers, de Salles Painelli et al. ¹¹¹⁾ showed a 71.8 % and 78.5 % probability of an additive effect on 100-m and 200-m sprints, when adding sodium bicarbonate to beta-alanine supplementation. In contrast to these studies, other findings do not suggest a synergistic effect between beta-alanine and sodium bicarbonate.

In a series of two repeated 100-m sprints in swimmers, Mero et al. ¹¹²⁾ showed that sodium bicarbonate supplementation alone attenuated increases in sprint time for the second sprint, but neither beta-alanine nor beta-alanine + sodium bicarbonate resulted in significant improvements compared to placebo. Ducker et al. ¹¹³⁾ investigated the efficacy of beta-alanine and sodium bicarbonate in the context of a repeated sprint test consisting of three sets of 6 (18 total), 20-m sprints. Results demonstrated that sodium bicarbonate supplementation improved performance more than placebo, beta-alanine, or a combination of beta-alanine and sodium bicarbonate. Saunders et al. ¹¹⁴⁾ had participants complete a repeated sprint protocol (five bouts of 6-s sprints) before, in the middle, and after a simulated football game in hypoxic conditions. Results indicated that neither beta-alanine, sodium bicarbonate, nor beta-alanine plus sodium bicarbonate improved performance on the sprint test. Bellinger et al. ¹¹⁵⁾ showed that sodium bicarbonate improved mean power output on a 4-min cycling test, but beta-alanine did not. While not statistically significant, subjects consuming beta-alanine + sodium bicarbonate did improve power slightly more than those consuming sodium bicarbonate alone, and 6 of 7 participants consuming beta-alanine saw an increase in average power output after additional supplementation with sodium bicarbonate. It is also important to note that the protocols employed by Ducker et al. ¹¹⁶⁾ and Saunders et al. ¹¹⁷⁾ consisted of very short bouts (<7 s), in which proton buffering would not be the primary factor limiting performance.

Collectively, the body of literature suggests a modest additive effect when adding sodium bicarbonate to beta-alanine supplementation in exercise bouts in which metabolic acidosis may be performance-limiting. While this additive benefit is not typically revealed with traditional statistical analyses, studies using magnitude-based inferences have suggested that a modest additive effect is likely to exist. The studies reviewed have used supplement dosages ranging from 4.8-6.8 g/kg/day of beta-alanine for at least 28 days, and 0.3-0.5 g/kg of sodium bicarbonate taken acutely. However, the only study to indicate a statistically significant synergistic effect of beta-alanine and sodium bicarbonate ¹¹⁸⁾ employed a unique dosing protocol for sodium bicarbonate, providing daily doses of 0.5 g/kg/day for seven days, whereas other studies typically provide a dose of 0.3 g/kg acutely in the hours preceding the exercise bout. Individual responses to sodium bicarbonate supplementation may vary, likely due to side effects including headache and gastrointestinal discomfort ¹¹⁹⁾. In terms of practical application, those wishing to combine beta-alanine and sodium bicarbonate supplementation must carefully evaluate the dosage and timing with which sodium bicarbonate is consumed and weigh the modest additive benefit against the risk of potentially ergolytic side effects.

Given the proton-buffering capacity of muscle carnosine ¹²⁰⁾, beta-alanine is most commonly purported to improve performance in exercise of high enough intensity to induce intramuscular acidosis. Creatine supplementation has been consistently shown to improve high-intensity exercise performance, primarily by increasing phosphorylcreatine and adenosine triphosphate (ATP) availability ¹²¹⁾. The first study investigating co-ingestion of these ingredients was reported in a published abstract by Harris et al. ¹²²⁾, finding that power output in a 4-min cycling test was improved more by creatine + beta-alanine than creatine alone. Similarly, Hoffman et al. ¹²³⁾ showed greater improvements in lean mass, fat mass, and strength in creatine + beta-alanine compared to creatine alone. Notably, these studies did not include a treatment arm ingesting beta-alanine alone. Zoeller et al. ¹²⁴⁾ investigated the effects of beta-alanine and creatine on performance on a graded, maximal exercise test on a cycle ergometer. No significant group effects were shown (creatine, beta-alanine, creatine + beta-alanine, or PL), but authors noted that the creatine + beta-alanine did have significant within-group improvements for 5 of the 8 outcomes measured, compared to only one in the beta-alanine group and two in the creatine group. Stout et al. ¹²⁵⁾ showed that beta-alanine and creatine + beta-alanine improved PWC_FT compared to creatine and PLA. There was no evidence of a synergistic effect on this outcome, as CRE + beta-alanine was not significantly different than beta-alanine alone. Kresta et al. ¹²⁶⁾ investigated both aerobic and anaerobic exercise outcomes. The creatine group trended toward an increase in VO2max, while the beta-alanine group trended toward an improvement in rate of fatigue on a series of two Wingate tests. However, no significant effects on performance were noted for any treatment arm, and results did not suggest a synergistic effect between creatine and beta-alanine.

Two studies have shown additive ergogenic effects when beta-alanine is combined with creatine supplementation ¹²⁷⁾, ¹²⁸⁾, but did not include a treatment group ingesting beta-alanine only. Other studies including a beta-alanine treatment arm have not demonstrated a synergistic effect between beta-alanine and creatine ¹²⁹⁾, ¹³⁰⁾. Despite promising findings from initial studies, more research is needed to evaluate potential synergy between creatine and beta-alanine supplementation. Based on the ergogenic mechanisms of each ingredient, performance improvements are more likely to occur in high-intensity bouts of exercise, and studies investigating exercise bouts over 15 min in duration have not shown beta-alanine + creatine to be significantly more effective than placebo ¹³¹⁾.

Multi-ingredient pre- and post-workout supplements have become increasingly popular, with formulations that include a number of purportedly ergogenic ingredients including creatine, caffeine, branched-chain amino acids, whey protein, nitric oxide precursors, and other isolated amino acids ¹³²⁾. Such supplements are typically consumed once per day prior to training, with beta-alanine doses generally ranging from 2 to 4 g single boluses. When ingested acutely before exercise, previous studies have shown these multi-ingredient supplements to improve muscular endurance ¹³³⁾, running time to exhaustion ¹³⁴⁾, and power output ¹³⁵⁾. Some studies have documented improvements in subjective feelings of energy and focus ¹³⁶⁾, while Gonzalez et al. ¹³⁷⁾ did not. When taken chronically for a period of 4 to 8 weeks, multi-ingredient pre-workout supplements have been shown to increase measures of strength ¹³⁸⁾, power output ¹³⁹⁾, and lean mass ¹⁴⁰⁾. In contrast, Outlaw et al. ¹⁴¹⁾ found no significant benefit for body composition, strength, or power output with ingestion of a multi-ingredient supplement versus placebo. While the supplement group tended to improve leg press strength to a greater degree than the placebo group, this difference was not statistically significant. These discrepant findings may be attributed to the short duration of supplementation (8 days), or the substantial improvements in lean mass, strength, and peak power output displayed by the placebo group.

When to take beta alanine

The body of literature suggests that acute and chronic ingestion of multi-ingredient pre-workout supplements can contribute to improvements in performance and body composition. It is difficult to attribute these ergogenic effects directly to beta-alanine, as multi-ingredient supplements include a wide range of ergogenic ingredients that may improve performance independently (e.g., caffeine, creatine, etc.). It typically takes a number of weeks (at least 2 weeks) for beta-alanine supplementation to yield meaningful increases in muscle carnosine content ¹⁴²⁾. As such, it is unlikely that beta-alanine is the primary ingredient improving performance outcomes in studies utilizing acute, one-time supplementation. In studies extending over 4 to 8 weeks, the likelihood of beta-alanine contributing to improvements in performance and indirect effects on body composition is greater. While it is difficult to determine the relative contributions of individual ingredients, research has demonstrated that multi-ingredient pre-workout supplements containing 2 to 4 g of beta-alanine are safe and efficacious when taken acutely, or chronically for up to 8 weeks.

Beta alanine dosage

1. Four weeks of beta-alanine supplementation (4–6 g daily) significantly augments muscle carnosine concentrations, thereby acting as an intracellular pH buffer;
2. Beta-alanine supplementation currently appears to be safe in healthy populations at recommended doses;
3. The only reported side effect is paraesthesia (tingling), but studies indicate this can be minimized by using divided lower doses (1.6 g) or using a sustained-release formula;
4. Daily supplementation with 4 to 6 g of beta-alanine for at least 2 to 4 weeks has been shown to improve exercise performance, with more pronounced effects in open end-point tasks/time trials lasting 1 to 4 min in duration;
5. Beta-alanine attenuates neuromuscular fatigue, particularly in older subjects, and preliminary evidence indicates that beta-alanine may improve tactical performance;
6. Combining beta-alanine with other single or multi-ingredient supplements may be advantageous when supplementation of beta-alanine is high enough (4–6 g daily) and long enough (minimum 4 weeks);
7. More research is needed to determine the effects of beta-alanine on strength, endurance performance beyond 25 minutes in duration, and other health-related benefits associated with carnosine.

So far, the highest reported increases in human muscle carnosine content are 80–85% upon 10–12 wk of supplementation ¹⁴³⁾. Stellingwerff et al. ¹⁴⁴⁾ indicated that the major determinant of supplementation-induced carnosine loading is the total ingested dose over a supplementation period, rather than the daily amount. Coingestion of beta alanine supplements with meals seems to promote carnosine synthesis, which points to a possible role of insulin in this process ¹⁴⁵⁾. Once accumulated in the muscle, the elevated carnosine content remains present for an extended period upon cessation of supplementation. The effective washout period (return to presupplementation baseline) apparently amounts to 10–20 wk ¹⁴⁶⁾. Little side-effects have been reported for β-alanine ingestion in the concerned doses, except from transient and unpleasant itching/flushing sensations on the skin, called parasthesia¹⁴⁷⁾.

Several questions with regard to dietary manipulation of muscle carnosine content remain to be answered. It still has to be determined whether or not a normal (omnivore) variation in the type and amount of meat ingestion will influence the muscle carnosine concentration between individuals. An initial comparison of high versus low meat eaters did not show a difference in muscle carnosine content ¹⁴⁸⁾. Furthermore, the upper safe limit of muscle carnosine loading is still unknown. Finally, it is unclear whether dietary intake of beta alanine has also consequences for histidine containing dipeptide content of nonmuscle tissues. In this respect, Tomonaga et al. ¹⁴⁹⁾ recently showed that acute chicken breast extract administration in rats can elevate the histidine containing dipeptide concentrations in certain brain regions.

Beta alanine side effects

Current, although limited information, suggests that beta-alanine is safe in healthy individuals at recommended doses.

Paraesthesia (i.e., tingling) is the most widely known side effect of beta-alanine and is commonly experienced in individuals consuming more than 800 mg of beta-alanine in a non-sustained release form ¹⁵⁰⁾. It appears that the symptoms of paraesthesia are substantially reduced with the use of sustained-release formulations. In studies using the non-sustained release supplement, paraesthesia has generally been reported to disappear within 60 to 90 min following supplementation ¹⁵¹⁾. It is hypothesized that beta-alanine activates Mas-related genes (Mrg) ¹⁵²⁾, or sensory neuron specific G-protein coupled receptors. Specifically, MrgD, which is expressed in the dorsal root ganglion, terminates in the skin ¹⁵³⁾. It is likely that activation of MrgD from beta-alanine results in paraesthesia on the skin. To date, there is no evidence to support that this tingling is harmful in any way. The paraesthesia side effect is typically experienced in the face, neck, and back of hands. Although not all individuals will experience paraesthesia, it is typically dose-dependent, with higher doses resulting in greater side effects. Recent data also suggests that males of Asian descent may experience a reduced effect, with Asian females experiencing greater paraesthesia ¹⁵⁴⁾. Moreover, there is no known mechanism to explain why certain individuals may be predisposed to experiencing paraesthesia. Currently, there is no safety data on the long-term use of beta-alanine (i.e., > 1 year). However, due to the non-essential nature of this constituent (i.e., beta-alanine is produced endogenously), the likelihood of safety concerns are low.

A secondary effect of beta-alanine supplementation is a potential decrease in taurine concentrations. Beta-alanine and taurine share the same transporter (Tau-T) into skeletal muscle, with beta-alanine thereby inhibiting taurine uptake within the muscle ¹⁵⁵⁾. In animal models, beta-alanine has been shown to decrease circulating taurine levels by about 50 % ¹⁵⁶⁾. Interestingly, Harris et al. ¹⁵⁷⁾ reported that 4 weeks of beta-alanine supplementation (10–40 mg∙kg−1bw) resulted in an increase in plasma taurine concentration; however, there was no significant decrease in muscle taurine content. While taurine has a number of essential physiological functions, to date there is no human data to support decreases with beta-alanine supplementation. Additionally, when extrapolated to humans, the decrease in taurine would not be of physiological significance.