Beta-alanine is a non-essential amino acid that the liver makes on its own and that people also get from meat and poultry. It is not used to build proteins. Its job in the body is to combine with histidine to form carnosine, a dipeptide stored in skeletal muscle that helps buffer the acid produced during hard exercise.
As a supplement, beta-alanine is taken daily for weeks to raise muscle carnosine. It is one of the most common ingredients in sports supplements and appears in most “pre-workout” powders. The key fact: it works slowly and modestly. Meta-analyses find a small benefit, mainly for all-out efforts lasting about 1–10 minutes, and its only consistent side effect is a harmless-seeming tingling of the skin.
This page summarizes what clinical trials, meta-analyses and sports-nutrition consensus statements report. It is for education only and is not medical advice.
| Property | Detail |
|---|---|
| Class | Non-proteinogenic beta-amino acid; dietary supplement ingredient |
| Chemistry | 3-aminopropanoic acid, C₃H₇NO₂, 89.09 g/mol |
| Route | Oral (powder, capsules, regular or sustained-release tablets) |
| Doses studied | 1.6–6.4 g/day in divided doses for 4–10 weeks; position stands cite 4–6 g/day |
| Plasma kinetics | Peaks about 30–60 min after a dose; back to baseline within ≈2 h (no formal elimination half-life reported) |
| Main effect | Raises muscle carnosine by roughly 40–65% in 4 weeks and up to ≈80% in 10 weeks |
| Main side effect | Paresthesia (tingling), OR 8.9 vs placebo in a meta-analysis |
| US status | Sold as a dietary supplement; FDA does not approve supplements before sale |
| WADA status | Not on the 2026 Prohibited List |
What it is
Beta-alanine (3-aminopropanoic acid) is the beta isomer of the common amino acid alanine, with the amino group on the third carbon instead of the second (PubChem). Because of that position, it is not built into proteins. The liver makes it, and diets containing meat, poultry and fish supply more (Trexler et al., JISSN 2015).
Inside muscle, the enzyme carnosine synthase joins beta-alanine and L-histidine into carnosine (β-alanyl-L-histidine). Beta-alanine is the rate-limiting precursor in this reaction, which is the whole rationale for supplementing it (Derave et al., Sports Med 2010).
Carnosine is relevant to exercise for a few reasons, as summarized by the International Society of Sports Nutrition (ISSN) position stand:
- pH buffer. Its pKa (the pH at which it best absorbs or releases protons) is 6.83, inside the range muscle passes through during intense work. Estimates of its share of total muscle buffering range from about 40% in animal work to as low as 7% in humans.
- Other proposed roles. In laboratory studies it scavenges free radicals and binds metals such as copper and iron. How much this matters during exercise in people is not established.
- Concentrations vary. Human muscle typically holds 10–40 mmol/kg dry weight. Levels are higher in men than in women and in fast-twitch fibers, and they tend to fall with age.
Muscle carnosine is also probably lower in vegetarians, whose diets supply little beta-alanine (Derave et al., Sports Med 2010).
Why not take carnosine itself? The enzyme carnosinase, present in human blood but absent from skeletal muscle, breaks down much of an oral carnosine dose before it reaches muscle. Most non-primate mammals lack this serum enzyme, which is one reason animal carnosine data translate poorly to people (Trexler et al., JISSN 2015).
How it works in the body
Absorption and plasma levels
The first human kinetic study gave single oral doses of beta-alanine, or chicken broth supplying an equivalent amount (Harris et al., Amino Acids 2006):
| Dose | Peak plasma beta-alanine |
|---|---|
| 10 mg/kg | 47 µmol/L |
| 20 mg/kg | 374 µmol/L |
| 40 mg/kg | 833 µmol/L |
| Chicken broth, ≈40 mg/kg equivalent | 428 µmol/L |
Plasma levels returned to baseline within 2 hours, and less than 5% of each dose was lost in urine. The library’s half-life entry of about 2 hours reflects this short plasma presence. The effect that matters, however, is the carnosine built up in muscle, which changes over weeks.
Formulation changes the curve. In a single-blind, randomized three-arm trial in 11 healthy adults, 1.6 g of pure beta-alanine in solution was compared with 1.6 g in slow-release tablets (Décombaz et al., Amino Acids 2012):
| Measure | Pure solution | Slow-release tablets |
|---|---|---|
| Peak plasma level | 248 µmol/L | 82 µmol/L |
| Time to peak | 0.5 h | 1.0 h |
| Total exposure (AUC) | No difference | No difference |
| Urinary loss | 663 µmol | 202 µmol |
| Whole-body retention | 96.3% | 98.9% |
Muscle carnosine loading
Daily supplementation raises muscle carnosine in a dose-dependent way. Measured responses from the early biopsy studies:
| Study | Daily dose | Duration | Muscle carnosine change |
|---|---|---|---|
| Harris et al. 2006 | 3.2 g | 4 weeks | +42.1% |
| Harris et al. 2006 | 6.4 g | 4 weeks | +64.2% |
| Hill et al. 2007 | Daily supplement (CarnoSyn) | 4 weeks | +58.8% |
| Hill et al. 2007 | Daily supplement (CarnoSyn) | 10 weeks | +80.1% |
A placebo-controlled trial in 31 young men measured carnosine repeatedly by magnetic resonance spectroscopy (Stellingwerff et al., Amino Acids 2012). It found the following:
- 1.6 g/day raised carnosine significantly within 2 weeks.
- The rise depended only on the total amount consumed, about 2.01 mmol/kg wet muscle per 100 g of beta-alanine. It did not depend on baseline carnosine, muscle type or the daily dose within 1.6–3.2 g.
- After stopping, carnosine fell slowly, by about 2% per week.
Link between carnosine and performance
In the Hill study, 13 men took beta-alanine and 12 matched men took placebo. Total work done in a cycling test to exhaustion at 110% of maximum power rose by 13.0% after 4 weeks, with a further 3.2% gain by 10 weeks. Work done did not change in the placebo group, and the gain followed the rise in muscle carnosine (Hill et al., Amino Acids 2007). Larger analyses, below, show that effects across studies are smaller and depend on the type of exercise.
The ISSN notes that response varies widely between people. In one study cited there, “high responders” raised carnosine by an average of 55% and “low responders” by 15% on 4.8 g/day for 5–6 weeks. Return to baseline after stopping took 6–15 weeks (Trexler et al., JISSN 2015).
Regulatory status
In the US, beta-alanine is sold as a dietary supplement. Under the Dietary Supplement Health and Education Act (DSHEA), FDA does not have the authority to approve dietary supplements before they are marketed; manufacturers are responsible for ensuring their products are not adulterated or misbranded (FDA).
Beta-alanine does not appear on the WADA 2026 Prohibited List. The 2018 International Olympic Committee (IOC) consensus statement lists it among the few performance supplements with evidence of a possible benefit, alongside caffeine, creatine, nitrate and sodium bicarbonate (Maughan et al., BJSM 2018).
What the research shows
Typical studied doses
The two main consensus documents describe these regimens from the research literature:
| Source | Dose described | Duration |
|---|---|---|
| ISSN position stand 2015 | 4–6 g/day, split into doses of 2 g or less | At least 2–4 weeks; ≈20–30% carnosine rise at 2 weeks, ≈40–60% at 4 weeks |
| IOC consensus 2018 | ≈65 mg/kg body mass per day, split as 0.8–1.6 g every 3–4 h | 10–12 weeks |
Both treat beta-alanine as a loading supplement taken daily over weeks. The ISSN notes that single large doses have not improved performance and cause stronger tingling.
Exercise capacity and performance
The largest meta-analysis included 40 double-blind, placebo-controlled studies with 1,461 participants (Saunders et al., BJSM 2017):
| Analysis | Effect size (95% CI) |
|---|---|
| Overall effect vs placebo | 0.18 (0.08–0.28) |
| Exercise capacity tests, 0.5–10 min (e.g. time to exhaustion) | 0.50 (0.25–0.75) |
| Performance tests, 0.5–10 min (e.g. time trials) | 0.11 (−0.20 to 0.42) |
| Beta-alanine plus sodium bicarbonate vs placebo | 0.43 (0.22–0.64) |
An effect size of 0.18 is small by conventional standards. The benefit depended on exercise duration and was clearest in open-ended “go until you can’t” tests rather than in races against the clock. Training status and total amount of beta-alanine consumed did not change the effect.
An earlier meta-analysis of 15 studies with 360 participants reached a similar picture (Hobson et al., Amino Acids 2012):
- Efforts lasting 60–240 s improved, as did efforts over 240 s.
- Efforts under 60 s did not improve.
- The median improvement was 2.85% with a median total intake of 179 g.
The IOC consensus describes the likely gain as small but potentially meaningful, about 0.2–3%, in continuous and intermittent tasks of 30 s to 10 min. It also notes large differences between individuals and that benefits appear harder to achieve in well-trained athletes (Maughan et al., BJSM 2018).
More recent analyses refine this:
| Meta-analysis | Population | Main finding |
|---|---|---|
| Georgiou et al., IJSNEM 2024 | 18 trials, 331 trained men aged 18–40, maximal efforts of 0.5–10 min | ES 0.39 (95% CI 0.09–0.69); efforts of 4–10 min ES 0.55 (0.07–1.04); 5.6–6.4 g/day ES 0.35 (0.09–0.62) |
| Liang et al., Front Nutr 2026 | 17 randomized trials of repeated sprints | No effect on mean sprint performance (SMD −0.02, 95% CI −0.21 to 0.17), peak performance or fatigue |
| Gu et al., Front Nutr 2026 | 11 randomized trials, 312 women | Time to exhaustion improved (SMD 0.49, 95% CI 0.20–0.79); no clear effect on peak power, VO₂max or body fat; certainty very low |
Strength and muscle mass
This is where evidence is weakest. The ISSN reviewed the resistance-training trials and found mixed results (Trexler et al., JISSN 2015):
- Some 4-week studies reported more training volume or less fatigue without a significant strength gain.
- In a 10-week training study, strength and body composition improved equally with beta-alanine and placebo.
- In a 10-week trial of creatine, creatine plus beta-alanine, or placebo, adding beta-alanine did not improve strength significantly more than creatine alone.
The ISSN concluded that beta-alanine may increase training volume but that current research does not show an additive benefit on strength gains. Beta-alanine is not an anabolic agent: it acts through muscle carnosine, and the trials reviewed did not show added muscle or strength gain over placebo. For creatine, see Creatine Monohydrate.
Other proposed uses
Carnosine and beta-alanine have also been studied for metabolic conditions such as diabetes. A 2021 meta-analysis pooled carnosine and beta-alanine together and found only 4 human studies. It estimated reductions in fasting glucose and HbA1c with moderate certainty, but the two supplements were not analyzed separately (Matthews et al., Adv Nutr 2021). These findings are preliminary and do not establish beta-alanine as a treatment.
Side effects and risks
Paresthesia (tingling)
Tingling, usually felt as “pins and needles” on the face, neck, arms, trunk or backs of the hands, is the only side effect consistently linked to beta-alanine. A systematic risk assessment of 101 human and 50 animal studies estimated an odds ratio of 8.9 (95% credible interval 2.2–32.6) for paresthesia with beta-alanine compared with placebo (Dolan et al., Adv Nutr 2019).
What the research reports about it:
- It is common with single doses over 800 mg of regular (non-sustained-release) beta-alanine and is dose-dependent (Trexler et al., JISSN 2015).
- After 1.6 g in solution, symptoms appeared quickly, peaking at about 15 minutes, and tracked plasma levels. With the same dose as slow-release tablets, symptoms could not be distinguished from placebo (Décombaz et al., Amino Acids 2012).
- With regular forms, symptoms generally fade within 60–90 minutes. The proposed mechanism is activation of a sensory-neuron receptor (MrgD) in the skin; the ISSN found no evidence that the tingling is harmful.
The IOC consensus also lists skin rashes as a possible side effect (Maughan et al., BJSM 2018).
Lab values and taurine
Beta-alanine shares a transporter with taurine, which raised concern that it might deplete muscle taurine. The 2019 risk assessment found the following (Dolan et al., Adv Nutr 2019):
| Outcome | Finding |
|---|---|
| Dropout rates | Similar to placebo |
| Alanine aminotransferase (ALT, a liver enzyme) | Small increase (effect size 0.27), with mean values well within the normal range |
| Muscle taurine in humans | No significant effect |
| Muscle histidine in humans | No significant effect |
| Taurine in rodents | Reduced, but only at 3% or more beta-alanine in drinking water |
The authors concluded that beta-alanine at the doses used in research did not adversely affect participants. See Taurine for that compound.
At much higher intakes, a small randomized trial gave 15 g/day of a sustained-release form for 30 days to 10 recreationally trained men, with 9 on placebo. Triglycerides, LDL cholesterol and urea nitrogen rose from baseline in the beta-alanine group, but the changes did not differ significantly from placebo. Most participants reported tingling, nearly all rated under 3 on a 10-point scale (Maestre-Hernández et al., Front Nutr 2023). The authors called for longer studies of blood markers at high intakes.
Gaps in the safety data
- Long-term use. As of the ISSN position stand, there were no safety data on use beyond 1 year (Trexler et al., JISSN 2015).
- Populations studied. The safety conclusions come from research in mostly healthy participants. They do not establish safety in pregnancy, breastfeeding, children or people with kidney or liver disease, where data are lacking.
Quality and product issues
Beta-alanine is usually taken inside multi-ingredient products rather than alone. A review of the 100 top-selling pre-workout supplements found beta-alanine in 87% of them, at an average of 2.0 g per serving, below the doses used in the loading studies (Jagim et al., Nutrients 2019). Points from that analysis:
- Products contained a mean of 18.4 ingredients.
- 44.3% of ingredients were in “proprietary blends” with undisclosed amounts.
- These products also usually contained caffeine, averaging 254 mg per serving.
Because FDA does not approve supplements before sale, the manufacturer is responsible for ensuring a product is not misbranded. The IOC consensus warns that athletes face a known risk of inadvertently consuming prohibited substances through contaminated supplements (Maughan et al., BJSM 2018).
Key takeaways
- A carnosine precursor, not an anabolic. Beta-alanine acts by raising muscle carnosine, an intracellular acid buffer, rather than through hormones.
- Slow to load, slow to wash out. Carnosine rises by roughly 40–65% over 4 weeks of daily intake and up to ≈80% by 10 weeks, then falls by about 2% per week after stopping.
- Small, duration-specific benefit. Meta-analyses find a small overall effect (ES 0.18), mainly in efforts of about 1–10 minutes, and no benefit for repeated sprints or efforts under 60 s.
- No clear strength or muscle gain. Trials show possible increases in training volume but no added strength gain over placebo or creatine alone.
- Tingling is the main side effect. The odds of paresthesia are about nine times those on placebo; split doses or slow-release forms reduce it. Long-term (over 1 year) safety data are lacking.
Sources
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- World Anti-Doping Agency. The 2026 Prohibited List. WADA 2026 Prohibited List.