Can Carnosine Improve Endurance? New Research Suggests It May Help With Repeated, High Intensity Efforts

Carnosine has been sitting quietly in the sports nutrition conversation for a long time.

Most people know it indirectly through beta-alanine, because beta-alanine is used by the body to make carnosine inside skeletal muscle. That is why beta-alanine has become a common ingredient in pre workout and performance supplements.

But carnosine itself has been studied far less.

A new 2026 randomized, placebo controlled clinical trial published in the Journal of the International Society of Sports Nutrition looked directly at whether supplementing with 2 grams of carnosine per day for up to 12 weeks could improve physical performance.

The answer was not a simple yes.

Carnosine did not improve every performance measure. It did not improve grip strength. It did not clearly improve performance across the entire study population.

But it did appear to improve certain forms of muscular and cardiorespiratory endurance, particularly in specific age and sex groups.

That makes this study interesting because it reinforces something that often gets lost in supplement marketing:

A supplement does not have to improve everything to be useful. It may work best for a very specific type of exercise.

TLDR

This was one of the largest randomized trials to directly examine carnosine supplementation and physical performance, using 2 grams per day for 6 to 12 weeks. The benefits were selective rather than universal, which is probably more realistic than the broad performance claims you often see.

• 2 grams of carnosine per day improved calf raise performance in participants 40 and younger after about 6 weeks.
• That improvement averaged about 10.2% relative to placebo.
• After about 12 weeks, men over 40 improved performance on a 2 minute step test by about 7.4% relative to placebo.
• The study found no clear improvement in grip strength.
• The benefits appeared to be strongest in males.
• Carnosine seems more likely to help with repetitive, short duration, fatiguing exercise than with pure maximal strength.
• The mechanism probably involves carnosine's role as an intracellular pH buffer, which may help delay fatigue during repeated high intensity efforts.
• This was a carnosine study, not a beta-alanine trial, but the results are relevant because beta-alanine is a precursor used by the body to synthesize carnosine.

What Is Carnosine?

Carnosine is a dipeptide made from beta-alanine and histidine. It is found in relatively high concentrations in tissues with high metabolic activity, including skeletal muscle, the heart, and the brain.

One of its best known roles is helping buffer hydrogen ions inside muscle cells. During repeated high intensity exercise, hydrogen ions accumulate and contribute to the decline in muscle pH. As muscle acidity increases, force production and muscular performance can begin to fall.

Carnosine can help buffer some of those hydrogen ions, which is one reason it has long been associated with high intensity exercise performance.

The paper also notes that carnosine has several other biochemical roles, including antioxidant activity, metal chelation, and the ability to bind reactive carbonyl compounds. But from a sports performance standpoint, its buffering role is probably the most relevant.

Why Most Athletes Know Beta-Alanine Instead

If carnosine is the compound doing the buffering, you might wonder why athletes usually supplement with beta-alanine instead.

The reason is that beta-alanine is a precursor for carnosine synthesis.

By increasing beta-alanine availability, you can raise muscle carnosine concentrations over time. That is why beta-alanine has much more research behind it as an ergogenic aid.

The authors point out that previous beta-alanine studies have shown benefits for time to exhaustion, anaerobic capacity, repeated contractions, rowing, cycling, and strength endurance, although the results have not always been consistent.

This new trial is interesting because it skips the precursor and gives participants carnosine directly.

What Did the Researchers Do?

The study included 299 randomized participants, with 283 providing usable baseline physical performance data.

Participants received either placebo or 2 grams of carnosine per day, taken as two 0.5 gram capsules twice per day.

They were tested at baseline, again after roughly six weeks, and again after roughly 12 weeks.

The researchers measured several different aspects of physical performance, including grip strength, calf raise endurance, a 2 minute step test, and walking speed.

Importantly, they also monitored compliance and excluded participants in the carnosine group who did not show at least a 10% increase in urinary carnosine, which gave the researchers some evidence that the supplement was actually being absorbed.

Most Performance Measures Did Not Improve

This needs to be said clearly.

When the researchers looked at the entire study population, there were no statistically significant differences between carnosine and placebo across the full set of performance measures.

That means this was not a study where everybody taking carnosine suddenly got stronger, faster, and more fit.

The interesting results appeared only after the researchers divided participants by age and sex.

That makes the findings more specific, but also means we should interpret them more cautiously.

Subgroup findings can be useful, but they are generally less robust than a clear overall effect.

Younger Participants Improved Calf Raise Endurance

After about six weeks of supplementation, participants age 40 and younger in the carnosine group performed significantly better on the bilateral calf raise test than the placebo group.

The improvement averaged about 10.2% relative to placebo, with a 95% confidence interval ranging from 1.6% to 18.9%.

The calf raise test is essentially a muscular endurance test. Participants repeatedly performed plantar flexion movements until fatigue.

That makes this finding fit pretty well with what we already know about carnosine biology.

If carnosine helps buffer acidity inside muscle, you would expect its biggest benefit to appear during repeated contractions where fatigue builds progressively.

You would not necessarily expect it to dramatically improve a one repetition maximum or a brief maximal force test.

Older Men Improved on the Step Test

The second notable finding appeared after about 12 weeks.

Men over age 40 in the carnosine group performed significantly better on the 2 minute step test than those receiving placebo.

The improvement averaged about 7.4% relative to placebo. There was also a trend toward improvement when all men were analyzed together, although that result narrowly missed conventional statistical significance.

The 2 minute step test is more of a cardiorespiratory endurance measure than a local muscular endurance test.

That makes this result a little more intriguing.

The authors speculate that carnosine or related histidine containing compounds in cardiac tissue could potentially contribute, but they also acknowledge that the kinetics of carnosine accumulation in the heart are not well understood.

In other words, the result is real within this study, but the mechanism is still somewhat speculative.

Carnosine Did Not Improve Grip Strength

This is a really useful negative finding.

Grip strength did not improve.

That matters because it helps clarify what carnosine probably does and does not do.

Carnosine appears more likely to help you resist fatigue during repeated efforts than to make you stronger in a pure maximal force sense.

That is consistent with the larger body of research around beta-alanine, where the strongest effects tend to show up in activities involving repeated or sustained high intensity work rather than simple maximal strength.

This is the difference between:

Strength

and

strength endurance.

They are not the same thing.

A supplement can help you maintain output longer without increasing your peak force production.

Why Carnosine Might Help With Repeated High Intensity Efforts

The most likely explanation comes back to pH buffering.

During hard exercise, especially repeated high intensity exercise, hydrogen ions accumulate inside muscle. This contributes to a drop in pH and is associated with muscular fatigue.

Carnosine can accept hydrogen ions and help stabilize intracellular pH.

The authors note that this makes carnosine particularly well suited to activities involving repetitive, high intensity, short duration exercise.

That could include things like repeated sprints, high rep resistance training, rowing intervals, hard cycling efforts, repeated hills, combat sports, and other activities where local muscular fatigue becomes a major performance limiter.

This also explains why you should not expect carnosine to suddenly improve a long, steady endurance event where acid buffering is not the primary bottleneck.

This Probably Matters More for Certain Types of Endurance

The word endurance can mean very different things.

Running a marathon is endurance.

Doing repeated 30 second hill sprints is also endurance.

A 2 minute maximal effort and a 5 hour bike ride are both endurance events, but the underlying physiological limitations are very different.

The research discussed in this paper suggests carnosine is more likely to help with shorter, repetitive, higher intensity endurance than prolonged steady state endurance.

The authors specifically note that prior studies have not shown clear relationships between carnosine and performance during prolonged cycling or long duration exercise.

That distinction is important.

If you're an ultramarathoner jogging for eight hours, carnosine probably isn't solving your main performance problem.

If you're doing repeated hard climbs, surges, intervals, or strength endurance work, it becomes much more relevant.

Why Did Men Seem to Benefit More?

This was one of the more unusual findings.

The researchers observed that most of the apparent benefit was concentrated in males.

They did not find the same clear response in females.

The authors speculate that differences in oxidative stress, training status, and carnosine availability could contribute. In their cohort, older women showed markers suggesting higher oxidative stress, which may have meant more carnosine was being used for antioxidant related functions and less was available for exercise buffering.

That is an interesting hypothesis, but it is still a hypothesis.

We should not jump from this study to saying carnosine doesn't work for women. Other beta-alanine research has shown performance benefits in female athletes, including masters cyclists.

The more accurate conclusion is that this particular study saw stronger effects in males.

Age Also Appeared to Matter

The age findings were not uniform either.

Younger participants showed the clearest improvement in calf raise endurance, while older men showed the clearest improvement in the 2 minute step test.

The authors suggest that age related oxidative stress and tissue carnosine availability might explain part of this pattern.

Again, that is mechanistically plausible, but it is not proven.

What the results really tell us is that carnosine's effects may depend heavily on who is taking it and what type of performance you are measuring.

That is probably true of more supplements than we like to admit.

How Does This Compare With Beta-Alanine?

This is where the study becomes especially relevant for sports nutrition.

Beta-alanine supplementation is much better studied than oral carnosine.

The authors point out that previous beta-alanine research has shown improvements in time to exhaustion and anaerobic capacity in trained cyclists, rowers, and strength trained individuals. It has also improved fatigue resistance during repeated contractions in some studies.

But the research is mixed.

Some studies have found no benefit, particularly when the exercise does not rely heavily on repeated high intensity efforts.

That is exactly what we would expect if the primary benefit comes from increasing muscle carnosine and buffering acidity.

The more your activity is limited by acid accumulation and local muscular fatigue, the more likely beta-alanine or carnosine is to matter.

Is Direct Carnosine Supplementation Better Than Beta-Alanine?

This study does not answer that question.

The researchers gave participants 2 grams of carnosine per day.

They did not directly compare carnosine with beta-alanine.

So we cannot conclude that carnosine is better, worse, or equivalent.

What we can say is that direct carnosine supplementation appeared capable of increasing body carnosine levels. The researchers previously reported approximately a twofold increase in erythrocyte carnosine and a sevenfold increase in urinary carnosine in this cohort.

That is useful because there has historically been some uncertainty around how much orally consumed carnosine survives digestion and meaningfully contributes to tissue levels.

This trial suggests direct supplementation can have a measurable physiological effect.

Whether that is more practical or effective than beta-alanine remains an open question.

The Dose Was Relatively Modest

Another interesting feature of this study is that the dose was not particularly aggressive.

Participants took:

2 grams per day

for up to:

12 weeks.

The authors contrast this with much of the beta-alanine literature, where doses of 4 to 6.4 grams per day are commonly used, often for around four weeks.

That makes the current trial useful because it shows that a relatively modest daily dose of carnosine may still produce measurable benefits over a longer period.

It also reinforces that these types of supplements are not acute stimulants.

You do not take one dose and suddenly perform better.

The effect builds over time.

This Study Had Some Important Limitations

The biggest limitation was attrition.

By the final visit, there was 38% attrition in the carnosine group compared with 26% in the placebo group.

Some participants withdrew, some were noncompliant, and some were classified as nonresponders because their carnosine levels did not increase as expected.

The researchers also did not directly measure skeletal muscle carnosine concentrations.

Instead, they relied on urinary and red blood cell measurements as indirect indicators of carnosine status.

That is understandable in a trial this large, because muscle biopsies or magnetic resonance spectroscopy would have been far more difficult and expensive, but it does add some uncertainty.

Another limitation is that the meaningful results emerged mainly from subgroup analyses rather than from clear improvements across the entire study population.

That means replication matters.

What I Think This Study Actually Tells Us

I would not read this study and conclude that everyone should start taking carnosine.

I also would not read it and say carnosine doesn't work because the overall group did not improve.

The more reasonable interpretation is that carnosine may be useful for specific types of repetitive endurance work, particularly where local muscular fatigue and acidosis are limiting performance.

The fact that grip strength did not improve actually makes the findings more believable to me.

The result fits the mechanism.

Carnosine is not acting like a stimulant or muscle building agent.

It is acting more like a fatigue buffer.

Who Might Benefit Most?

Based on this study and the research the authors discuss, carnosine or beta-alanine is probably most relevant for athletes doing repeated high intensity efforts.

That could include:

• Cyclists doing repeated climbs or attacks
• Runners doing hard intervals or hill repeats
• CrossFit athletes
• Rowers
• Combat sport athletes
• Team sport athletes
• Strength athletes doing high rep sets
• Hyrox or functional fitness athletes
• Anyone performing repeated efforts where muscular burn becomes the limiting factor

It is probably much less important for someone doing easy, steady aerobic exercise where muscular acidity is not a major performance constraint.

The Bottom Line

This new randomized trial gives us more evidence that carnosine can improve certain forms of endurance, but it is not a universal performance enhancer.

At 2 grams per day, carnosine improved calf raise endurance in younger participants after about six weeks and improved 2 minute step test performance in men over 40 after about 12 weeks. The study found no meaningful improvement in grip strength or across the full study population.

That pattern actually makes physiological sense.

Carnosine appears most useful when the limiting factor is repeated muscular fatigue, not maximal strength.

And because beta-alanine is used to increase muscle carnosine, this study also helps reinforce why beta-alanine has stayed relevant in sports nutrition for so long.

The bigger takeaway is pretty simple:

Carnosine probably won't make you stronger.

It may help you keep going when your muscles start burning.

Reference

O'Toole TE, Wingard CJ, Bariess SK, et al. Effects of carnosine supplementation on physical endurance: a placebo controlled randomized clinical trial. Journal of the International Society of Sports Nutrition. 2026;23(1):2679716.