Carnosine
The dipeptide concentrated in muscle and brain: a century of biochemistry, and small supplement trials with mixed results
Carnosine is β-alanyl-L-histidine, a dipeptide found in high amounts in skeletal muscle and other excitable tissues, where it buffers acid, binds metals and resists glycation. Serum carnosinase breaks it down quickly in the blood. As a supplement it has been tested in small trials: in type 2 diabetes one found lower fasting glucose and HbA1c while another, in well-controlled patients, found no vascular or metabolic benefit, and a 299-person trial found no general effect on physical performance.
What is it?
Carnosine was discovered in 1900 as an abundant nitrogen compound of meat. It is concentrated in skeletal muscle and other excitable tissues, and its chemistry explains the interest in it: it buffers acid, chelates metal ions, acts as an antioxidant and protects proteins from advanced glycation end products. Humans lack the methylated relatives, such as anserine, that most animals carry, and an enzyme in the blood, serum carnosinase, splits carnosine into histidine and β-alanine.
The supplement trials are small and point in different directions. In 54 people with type 2 diabetes, 1 g a day for 12 weeks lowered fasting glucose, HbA1c, triglycerides, an advanced glycation marker and TNF-α against placebo; in 49 people with prediabetes or well-controlled type 2 diabetes, 2 g a day for 14 weeks changed no vascular, metabolic, liver or kidney measure. In 50 patients with heart failure it improved exercise capacity and quality of life over six months against standard treatment alone, and added to citalopram in 58 patients with major depression it improved depression scores more than placebo over six weeks.
A 2025 dose-finding study in healthy volunteers drew the practical line: oral carnosine was tolerated up to 10 g, but at 15 g 77% had side effects, and 5 g twice daily caused none over longer use. Plasma levels peaked within an hour and little was left after four, which is the central problem for any oral carnosine claim.
The largest trial, 299 adults given 2 g a day for 12 weeks, found no difference from placebo in most measures of physical performance, with isolated gains in some age and sex subgroups. Carnosine is sold as a supplement, not approved as a drug.
The clearest signals are metabolic and local. Pooled trials in prediabetes and type 2 diabetes show small falls in fasting glucose and HbA1c, and a 14-week trial found a modest improvement in depressive symptoms in the same population. Zinc carnosine, a different salt used in the mouth and gut, reduced severe oral mucositis across 8 studies and cut regurgitation in infants. On cognition the record stays inconsistent, and the two sports trials, one oral and one a topical gel, each moved only some of their measures.
Mechanism of Action
Carnosine is a dipeptide of beta-alanine and histidine, concentrated in muscle and brain; it buffers acid, binds metals and scavenges reactive aldehydes.
Buffering and antioxidant
It buffers acid in muscle and scavenges reactive carbonyls, the basis of its use in exercise and metabolic studies.
Glucose
Pooled trials show small reductions in fasting glucose and HbA1c in prediabetes and type 2 diabetes.
Mucosal protection
Zinc L-carnosine is used topically in the mouth and gut, where it reduced severe oral mucositis.
Published Research
These are the trials and the review behind carnosine, read from their PubMed abstracts.
Physical endurance: 299 adults
Over 12 weeks, 2 g a day of carnosine did not differ from placebo on grip strength, gait speed or most other measures; calf-raise performance rose in participants under 40 at six weeks and step counts in men over 40 at 12 weeks.
Prediabetes and type 2 diabetes: no benefit
In 49 patients with good glycaemic control, 2 g a day for 14 weeks had no effect on blood pressure, endothelial function, arterial stiffness, lipids, liver or kidney measures compared with placebo.
Type 2 diabetes: 54 patients
After 12 weeks of 1 g a day, fasting glucose fell by 13.1 mg/dL and HbA1c by 0.6% against placebo, with lower triglycerides, carboxymethyl lysine and TNF-α and small shifts from fat to fat-free mass.
Chronic heart failure: 50 patients
Added to optimal therapy, 500 mg a day of orodispersible carnosine for six months improved peak oxygen uptake, six-minute walk distance and quality of life compared with standard treatment alone.
Major depression, added to citalopram
In 58 patients, 400 mg twice daily with citalopram improved depression scores more than placebo at weeks 2, 4 and 6, with higher response and remission rates; side effects did not differ.
How much is tolerable
In healthy volunteers, oral carnosine was safe and well tolerated up to 10 g; at 15 g, 77% had side effects, commonly headache, nausea and tingling. Plasma peaked within an hour and little remained after four; brain concentration rose at one hour. Long-term 5 g twice daily caused no adverse events.
Depressive symptoms in prediabetes and diabetes
In 38 people with prediabetes or well-controlled type 2 diabetes randomised for 14 weeks, carnosine modestly improved overall depressive symptoms but not the individual subscores or quality of life.
Mucositis mouthwash trial
In a randomised single-blind trial, moderate and severe mucositis, its symptoms and painkiller use all fell in the zinc L-carnosine group while rising in controls.
Infant regurgitation
In 60 infants randomised to a zinc L-carnosine liquid or thickened formula for 8 weeks, both improved; the carnosine group had a greater reduction in regurgitation frequency and lower average treatment cost, without a significant difference in overall remission.
Carnosine-enriched chicken in coronary disease
In patients with chronic coronary syndrome, eating carnosine-enriched chicken improved microvascular dilation and lowered blood pressure, TNF-α, IL-6 and endoglin from baseline.
Topical gel in elite rugby
In world-class rugby sevens players, a topical carnosine gel raised peak power in three of seven sprints against placebo, without changing mean power, heart rate or perceived exertion.
A century of carnosine research
The review traces carnosine's pH-buffering, metal-chelating and antioxidant chemistry and its protection against glycation and lipoxidation products, and discusses serum carnosinase, which degrades it into histidine and β-alanine.
Prediabetes and type 2 diabetes meta-analysis
Across 8 trials with 377 participants, carnosine or beta-alanine lowered fasting glucose and HbA1c against placebo, without changing BMI, fasting insulin or LDL and HDL cholesterol.
Cognition and mental health review
Across 13 studies, mostly randomised, carnosine's effects on cognition, mood, quality of life and brain imaging were inconsistent, with heterogeneous doses and durations and over half the trials rated as having some risk-of-bias concerns.
Zinc carnosine for the mouth lining
Pooling 8 studies with 544 patients, zinc L-carnosine in mouthwashes, lozenges and suspensions reduced severe oral mucositis (odds ratio 0.48), though most non-randomised studies carried moderate to serious risk of bias.
Dosing Data
Carnosine is sold as a supplement. Trials have used 1 g a day in capsules up to 5 g twice daily, with 10 g the highest tolerated single dose tested.
Educational information, not medical advice. Each dose above is tagged with its source: an approved label, a published human study, animal data, or amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.
Side Effects & Contraindications
Reported Side Effects
From the trials above.
Contraindications & Cautions
Carnosine is a supplement, not a medicine. These cautions follow from the evidence.
Legal Status
Carnosine is sold as a supplement and is not an approved drug.
Frequently Asked Questions
?What is carnosine?
A dipeptide of β-alanine and histidine found in muscle and brain, where it buffers acid, binds metals and resists glycation.
?Does carnosine help type 2 diabetes?
Results conflict. One 12-week trial found lower glucose and HbA1c; a 14-week trial in well-controlled patients found no vascular or metabolic benefit.
?Does it improve exercise performance?
In the largest trial, 299 adults on 2 g a day for 12 weeks performed no better than placebo on most measures.
?How much carnosine is too much?
In a volunteer study, up to 10 g was well tolerated, but at 15 g 77% had side effects, most often headache, nausea and tingling. Five grams twice daily caused no adverse events over longer use.
?Does carnosine help blood sugar?
Modestly. Pooled across 8 trials with 377 participants, carnosine or beta-alanine lowered fasting glucose and HbA1c against placebo, without changing weight, insulin or cholesterol.
References
- [pubmed] O'Toole TE, et al. "Effects of carnosine supplementation on physical endurance: a placebo-controlled randomized clinical trial." J Int Soc Sports Nutr, 2026;23(1):2679716. PMID: 42308284.
- [pubmed] Saadati S, et al. "Carnosine Did Not Affect Vascular and Metabolic Outcomes in Patients with Prediabetes and Type 2 Diabetes: A 14-Week Randomized Controlled Trial." Nutrients, 2023;15(22). PMID: 38004228.
- [pubmed] Houjeghani S, et al. "l-Carnosine supplementation attenuated fasting glucose, triglycerides, advanced glycation end products, and tumor necrosis factor-α levels in patients with type 2 diabetes: a double-blind placebo-controlled randomized clinical trial." Nutr Res, 2018;49:96-106. PMID: 29420997.
- [pubmed] Lombardi C, et al. "Effects of oral administration of orodispersible levo-carnosine on quality of life and exercise performance in patients with chronic heart failure." Nutrition, 2015;31(1):72-8. PMID: 25287762.
- [pubmed] Araminia B, et al. "L-Carnosine combination therapy for major depressive disorder: A randomized, double-blind, placebo-controlled trial." J Affect Disord, 2020;267:131-136. PMID: 32063564.
- [pubmed] Boldyrev AA, et al. "Physiology and pathophysiology of carnosine." Physiol Rev, 2013;93(4):1803-45. PMID: 24137022.
- [fda] FDA. Drugs@FDA (openFDA): no application for carnosine. Read September 30, 2026.
- [other] European Medicines Agency. Medicines register: no entry for carnosine. Read September 30, 2026.
- [pubmed] Ali AN, et al. "Dietary Carnosine Supplementation in Healthy Human Volunteers: A Safety, Tolerability, Plasma and Brain Concentration Study." Nutrients, 2025;17(13). PMID: 40647235.
- [pubmed] Li N, et al. "Effect of carnosine or beta-alanine supplementation therapy for prediabetes or type 2 diabetes mellitus: a systematic review and meta-analysis of randomized controlled trials." BMC Endocr Disord, 2025;25(1):210. PMID: 40999397.
- [pubmed] Hsiao YF, et al. "The Effects of Carnosine on Cognitive Function and Mental Health-A Systematic Review and Meta-Analysis." Nutrients, 2026;18(9). PMID: 42123986.
- [pubmed] Kabthymer RH, et al. "The Effect of Carnosine Supplementation on Depressive Symptoms and Health-Related Quality of Life in Individuals With Prediabetes and Well-Controlled Type 2 Diabetes: A Randomized Controlled Trial." Food Sci Nutr, 2026;14(3):e71514. PMID: 41767833.
- [pubmed] De Francesco P, et al. "Protective and Healing Effects of Zinc L-Carnosine on the Oral Mucosa: A Systematic Review and Meta-Analysis." Dent J (Basel), 2026;14(7). PMID: 42505716.
- [pubmed] Togni L, et al. "Zinc-L-carnosine mouthwash in oral mucositis patients: a single-blind, randomized, controlled trial." Minerva Dent Oral Sci, 2026;75(4):263-272. PMID: 41855025.
- [pubmed] Piccirillo M, et al. "Zinc-L-Carnosine (Polaprezinc) in managing infant regurgitation: a two-center randomized controlled trial." Front Pediatr, 2026;14:1754324. PMID: 42093671.
- [pubmed] Uršić D, et al. "Carnosine-Enriched Chicken Meat Improves Microvascular Function and Anti-Inflammatory Phenotype in Patients with Chronic Coronary Syndrome." Nutrients, 2026;18(6). PMID: 41901102.
- [pubmed] Beaven CM, et al. "Topical carnosine gel improves intermittent high-intensity exercise performance in world-class rugby sevens players." J Int Soc Sports Nutr, 2025;22(1):2550311. PMID: 40859880.
Sources & Citations
Studies were read from their PubMed abstracts. Read October 7, 2026.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Talk to a licensed clinician about your own situation.