Carnosine: A Comprehensive Research Monograph

Introduction

Carnosine (beta-alanyl-L-histidine) is a naturally occurring dipeptide composed of the amino acids beta-alanine and L-histidine, joined by a peptide bond through the beta-amino group of alanine rather than the conventional alpha-amino group. This small molecule was first isolated from meat extract in 1900 by the Russian biochemist Vladimir Sergeyevich Gulewitsch at Moscow University, making it one of the earliest bioactive peptides identified in mammalian tissues. The name “carnosine” derives from the Latin carnis (flesh), reflecting its abundant presence in skeletal muscle, where concentrations can reach 20 millimoles per liter in certain fast-twitch fiber types.

Beyond muscle tissue, carnosine is distributed throughout the body, with notable concentrations in the brain (particularly the olfactory bulb and prefrontal cortex), cardiac muscle, kidneys, and stomach lining. It belongs to a family of histidine-containing dipeptides (HCDs) that also includes anserine (beta-alanyl-N1-methylhistidine), balenine (beta-alanyl-N3-methylhistidine), and homocarnosine (gamma-aminobutyryl-L-histidine). While most animals express one or more methylated carnosine variants alongside carnosine itself, human tissues contain predominantly carnosine, with homocarnosine found exclusively in the brain.

The biosynthesis of carnosine is catalyzed by carnosine synthase (also known as ATP-grasp domain-containing protein 1, ATPGD1), which ligates beta-alanine and L-histidine in an ATP-dependent reaction. Beta-alanine availability is the rate-limiting factor for carnosine production, as histidine is typically present in sufficient concentrations in most tissues. This biochemical relationship underlies the widespread use of beta-alanine supplementation in sports science, where chronic intake of 3.2 to 6.4 grams per day for several weeks reliably elevates intramuscular carnosine levels by 40 to 80 percent. The connection between dietary beta-alanine and muscle carnosine loading has become one of the most well-characterized supplement-metabolite relationships in exercise physiology.

Over the past century, carnosine has accumulated a remarkable body of scientific literature spanning biochemistry, physiology, pharmacology, neuroscience, and clinical medicine. Research has revealed a diverse array of biological activities, including antioxidant defense, anti-glycation, metal ion chelation, pH buffering, aldehyde scavenging, and cytoprotection. This unusual breadth of action has earned carnosine the description of a “pluripotent” molecule, one that addresses multiple homeostatic challenges through distinct but complementary mechanisms. The dipeptide’s ability to extend cultured cell lifespan, protect against protein damage, and attenuate age-related pathology in animal models has positioned it at the intersection of aging research, metabolic disease, and neuroprotection.

Molecular Structure and Properties

Carnosine possesses the molecular formula C9H14N4O3 and a molecular weight of 226.23 g/mol. Its structure is distinguished from typical dipeptides by the presence of a beta-amino acid (beta-alanine) rather than an alpha-amino acid at its N-terminal position. This beta-alanyl linkage creates a longer, more flexible backbone compared to conventional alpha-peptide bonds, which may contribute to carnosine’s resistance to cleavage by generic peptidases and its ability to adopt conformations favorable for its diverse biochemical interactions.

The most functionally significant structural feature of carnosine is the imidazole ring of its L-histidine residue. The imidazole group has a pKa of approximately 6.83, which is remarkably close to the physiological pH of muscle cytoplasm during intense exercise (approximately 6.5 to 7.1). This property makes carnosine one of the most effective intracellular pH buffers in muscle tissue, capable of accepting or donating protons precisely in the pH range where buffering is most needed. The imidazole ring also provides the chemical basis for many of carnosine’s other activities: its nitrogen atoms serve as coordination sites for transition metal ions, its electron-rich aromatic system participates in free radical scavenging, and its nucleophilic character enables reactions with electrophilic carbonyl compounds.

Carnosine’s physicochemical properties include high water solubility, zwitterionic character at physiological pH (carrying both positive and negative charges), and the absence of significant lipophilicity. These characteristics favor its distribution in aqueous cytoplasmic compartments but limit its ability to cross lipid membranes through passive diffusion. Cellular uptake of carnosine is mediated primarily by the proton-coupled oligopeptide transporters PEPT1 and PEPT2, as well as the high-affinity transporter PHT1. The dependence on active transport mechanisms for cellular entry adds a layer of tissue-specific regulation to carnosine’s distribution and function.

The metal-chelating properties of carnosine deserve particular emphasis. The combination of the imidazole nitrogen, the amino group of beta-alanine, and the carboxyl group of histidine creates a tridentate chelation motif capable of binding divalent cations including zinc (Zn2+), copper (Cu2+), and iron (Fe2+). This chelation capacity has dual significance: it prevents these metal ions from catalyzing Fenton-type reactions that generate highly destructive hydroxyl radicals, and it may modulate the biological activities of zinc in synaptic signaling and copper in neuronal metabolism.

Mechanism of Action

Carnosine exerts its biological effects through a convergence of distinct but interconnected biochemical mechanisms. Unlike many pharmacological agents that act through a single receptor-ligand interaction, carnosine functions as a multimodal protective molecule whose activities arise directly from its chemical properties. This section examines each major mechanistic pathway.

Reactive Oxygen and Nitrogen Species Scavenging

Carnosine directly scavenges a range of reactive oxygen species (ROS) and reactive nitrogen species (RNS), including superoxide anion (O2-), hydroxyl radical (OH), singlet oxygen, hydrogen peroxide, and peroxynitrite. The imidazole ring of histidine is the primary scavenging moiety, with its aromatic pi-electron system capable of donating electrons to radical species and stabilizing the resulting products. In vitro studies have demonstrated that carnosine reduces intracellular ROS generation, protects lipid membranes from peroxidation, and attenuates oxidative DNA damage.

Importantly, while carnosine is a genuine antioxidant, it is not the most potent ROS scavenger available. Compounds such as glutathione, alpha-tocopherol, and ascorbic acid exceed carnosine in raw antioxidant capacity. What distinguishes carnosine from these conventional antioxidants is its combination of moderate ROS scavenging with anti-glycation, metal chelation, and carbonyl trapping activities, providing a multi-layered defense that no single antioxidant can replicate. As Hipkiss noted in his seminal 1998 paper, superior antioxidants do not replicate carnosine’s anti-senescent effects on cultured cells, pointing to mechanisms beyond simple free radical neutralization.

Anti-Glycation and AGE Inhibition

Glycation is the non-enzymatic reaction of reducing sugars (glucose, fructose, ribose) with amino groups on proteins, ultimately producing irreversible cross-linked structures known as advanced glycation end products (AGEs). AGE accumulation is a hallmark of aging and a major driver of diabetic complications, contributing to vascular stiffness, renal fibrosis, cataract formation, and neurodegenerative protein aggregation.

Carnosine inhibits AGE formation at multiple stages. It competes with protein amino groups for reaction with reducing sugars, thereby preventing the initial Amadori rearrangement that initiates the glycation cascade. It also scavenges the reactive dicarbonyl intermediates methylglyoxal and glyoxal, which are potent AGE precursors generated during both sugar and lipid oxidation. Through these combined actions, carnosine prevents protein cross-linking, preserves enzyme activity under glycating conditions, and reduces the accumulation of AGE-modified proteins that trigger inflammatory signaling via the RAGE receptor.

Reactive Carbonyl Species Quenching

Beyond glycation-derived carbonyls, carnosine is a potent quencher of reactive carbonyl species (RCS) generated during lipid peroxidation, including 4-hydroxynonenal (4-HNE), acrolein, and malondialdehyde (MDA). These lipid-derived aldehydes are highly electrophilic and readily form adducts with proteins, DNA, and phospholipids, propagating oxidative damage and generating advanced lipoxidation end products (ALEs).

Carnosine reacts with these aldehydes through its amino and imidazole groups to form stable carnosine-aldehyde conjugates, effectively detoxifying them before they can damage cellular macromolecules. This carbonyl-quenching activity has been demonstrated to be particularly relevant in the central nervous system, where Spaas and colleagues showed that carnosine quenches acrolein in the spinal cord and attenuates neuroinflammation in a mouse model of autoimmune encephalomyelitis (EAE), a model of multiple sclerosis.

pH Buffering

The intracellular pH buffering capacity of carnosine is one of its best-established physiological functions, particularly in skeletal muscle. During high-intensity exercise, anaerobic glycolysis generates large quantities of hydrogen ions (H+), causing intracellular pH to drop from approximately 7.1 to as low as 6.5. This acidification impairs glycolytic enzyme activity, reduces calcium sensitivity of the contractile apparatus, and accelerates fatigue. The imidazole ring of carnosine’s histidine moiety, with its pKa near 6.83, acts as an efficient proton sink in precisely this physiological pH range, accepting H+ ions and mitigating the acidosis that would otherwise limit performance.

This pH buffering function accounts for an estimated 10 to 20 percent of the total intracellular buffering capacity in human skeletal muscle and is the mechanistic basis for the ergogenic effects of beta-alanine supplementation, which raises muscle carnosine stores and thereby enhances acid-base homeostasis during intense exertion.

Metal Ion Chelation

Carnosine’s tridentate chelation of transition metal ions contributes to its cytoprotective effects through two primary mechanisms. First, by sequestering free Fe2+ and Cu+ ions, carnosine prevents their participation in Fenton chemistry, the catalytic cycle that converts relatively innocuous hydrogen peroxide into extremely reactive hydroxyl radicals. Second, carnosine modulates the biological availability of Zn2+ in the central nervous system, where zinc is released as a co-transmitter at glutamatergic synapses. Excessive zinc accumulation following ischemia or seizure activity is neurotoxic, and carnosine’s ability to chelate synaptic zinc may provide neuroprotection under these conditions.

Research Applications

Anti-Aging and Cellular Senescence

Carnosine’s anti-aging effects have been documented at both cellular and whole-organism levels. In a series of landmark experiments, Hipkiss and colleagues demonstrated that carnosine extends the replicative lifespan of cultured human fibroblasts, delays the onset of the senescent phenotype, and can partially reverse the morphological characteristics of senescent cells, restoring a more juvenile appearance. These effects could not be replicated by more potent antioxidants alone, suggesting that carnosine’s anti-glycation and carbonyl-scavenging activities are essential to its geroprotective function.

At the whole-organism level, carnosine supplementation has been shown to delay aging phenotypes in senescence-accelerated mouse (SAM) strains and Drosophila models. The proposed mechanisms include suppression of protein carbonyl accumulation, enhanced proteasomal degradation of damaged proteins, reduced AGE formation, and modulation of the translational machinery through effects on the initiation factor eIF4E. More recently, Hipkiss proposed that carnosine’s ability to suppress eIF4E phosphorylation may decrease the rate of error-prone protein synthesis, reducing the burden of misfolded proteins that characterizes the aged cellular phenotype.

The age-related decline in endogenous carnosine levels adds another dimension to its anti-aging significance. Studies have shown that both muscle and brain carnosine concentrations decrease with advancing age, correlating with the progressive loss of buffering capacity, antioxidant defense, and protein quality control that accompanies aging. Whether this decline is a cause or consequence of aging remains an active area of investigation.

Neuroprotection

Carnosine’s neuroprotective potential has attracted substantial research interest, driven by its combination of antioxidant, anti-glycation, metal-chelating, and anti-inflammatory activities, all of which address central pathological mechanisms in neurodegenerative diseases.

Alzheimer’s Disease (AD): AGEs and oxidative stress are recognized contributors to AD pathology. Carnosine inhibits the glycation of amyloid-beta peptide and tau protein, processes that promote the aggregation and neurotoxicity of these hallmark AD proteins. In aged rat models, exogenous carnosine treatment reduced beta-sheet content in the secondary structure of amyloid-beta, improved cognitive performance on radial arm maze tasks, and restored endogenous carnosine levels and dendritic spine density across multiple brain regions.

Parkinson’s Disease (PD): Boldyrev and colleagues reported clinical improvement in Parkinson’s disease patients receiving carnosine supplementation alongside standard levodopa therapy, with enhanced treatment efficacy and reduced oxidative stress markers compared to levodopa alone. These findings were supported by preclinical data showing carnosine’s protective effects against dopaminergic neurotoxins and its ability to modulate the dopamine system.

Neuroinflammation: The role of carnosine as an acrolein quencher in the central nervous system has opened a new dimension of neuroprotection research. Spaas et al. demonstrated that acrolein, a neurotoxic reactive carbonyl, is substantially increased in inflammatory lesions of multiple sclerosis patients and EAE mice. Oral carnosine treatment augmented spinal cord carnosine levels more than tenfold, increased acrolein detoxification, and significantly alleviated clinical disease severity.

Cognitive Function: Clinical trials have explored carnosine’s cognitive effects across different populations. Masuoka et al. found that anserine/carnosine supplementation (1000 mg/day for 12 weeks) improved clinical dementia ratings in individuals with mild cognitive impairment, with particularly notable benefits in APOE4 carriers, a genetic subgroup at elevated Alzheimer’s risk. Separately, the NEAT clinical trial reported significant improvements in cognitive speed and efficiency in younger adults (23-35 years) supplemented with 2 g/day carnosine.

Diabetic Complications and Glucose Metabolism

The connection between carnosine and diabetes operates on two levels: its anti-glycation properties directly antagonize the molecular damage caused by hyperglycemia, and its metabolic effects may independently improve glucose homeostasis.

In a landmark pilot RCT, de Courten et al. randomized 30 overweight or obese non-diabetic individuals to 2 g/day carnosine or placebo for 12 weeks. The carnosine group showed a significantly blunted increase in fasting insulin and insulin resistance (HOMA-IR) compared to placebo, with notable improvements in 2-hour glucose and insulin among those with impaired glucose tolerance.

This was followed by a larger RCT by Hariharan et al., in which 43 adults with prediabetes or type 2 diabetes received 2 g/day carnosine or placebo for 14 weeks. Carnosine supplementation produced significant reductions in blood glucose at 90 and 120 minutes post-oral glucose tolerance test and decreased the total glucose area under the curve. The investigators proposed that changes in hepatic glucose output may underlie these effects, as insulin secretion itself was unchanged.

In diabetic nephropathy, Siriwattanasit et al. demonstrated that 12 weeks of carnosine supplementation (2 g/day) significantly reduced urinary TGF-beta levels, a key fibrogenic mediator, by 17.8 percent compared to a 16.9 percent increase in the placebo group, suggesting a renoprotective effect.

Exercise Performance and pH Buffering

Carnosine’s role in exercise physiology is primarily mediated through its pH buffering capacity in skeletal muscle. Since beta-alanine supplementation is the most effective strategy for raising muscle carnosine levels, the exercise performance literature is dominated by beta-alanine rather than direct carnosine supplementation studies.

A comprehensive systematic review and meta-analysis by Saunders et al. analyzed 40 double-blind, placebo-controlled beta-alanine supplementation studies encompassing 1,461 participants and 70 exercise outcome measures. The analysis found a significant overall effect size of 0.18, with exercise duration serving as a significant moderator. The greatest ergogenic benefit was observed for exercise capacity tests lasting 0.5 to 10 minutes, with an effect size of 0.50 for capacity measures in that time domain. These findings are consistent with the pH buffering hypothesis, as exercises in this duration range are heavily dependent on glycolytic metabolism and therefore most susceptible to intracellular acidosis.

Ophthalmology and Cataract Research

The lens of the eye contains significant carnosine concentrations that decline with age, coinciding with the progressive oxidative and glycation damage that underlies cataract formation. This observation has motivated research into carnosine-based approaches for cataract prevention or treatment. Because direct topical application of carnosine is hindered by poor corneal penetration, the prodrug N-acetylcarnosine (NAC) was developed to traverse the cornea and release L-carnosine in the aqueous humor.

While early studies from Russian research groups reported improvements in lens clarity and visual acuity with NAC eye drops, a 2017 Cochrane systematic review identified only two potentially eligible studies and was unable to obtain sufficient methodological information to reliably assess their quality. The review concluded that there is currently no convincing evidence that NAC reverses or prevents cataract progression and called for properly designed randomized, double-masked, placebo-controlled trials.

Wound Healing

Carnosine’s role in wound healing has been explored primarily in the context of zinc-carnosine complexes (marketed as polaprezinc or Z-103 in Japan). Zinc-carnosine combines the tissue-repair properties of zinc with carnosine’s antioxidant and anti-inflammatory activities. This compound has been used clinically for gastric ulcer treatment and has demonstrated mucosal protective effects in models of gastrointestinal injury, NSAID-induced gastropathy, and oral mucositis associated with cancer chemotherapy. The chelation of zinc within the carnosine structure slows zinc dissociation, enabling sustained local delivery to damaged mucosal surfaces.

Pharmacokinetics and Stability

Oral Absorption and Carnosinase Degradation

The pharmacokinetics of carnosine in humans are dominated by the activity of serum carnosinase (CN1, also known as CNDP1), a dipeptidase with remarkably high activity in human blood. Following oral ingestion, intact carnosine is absorbed through the intestinal epithelium via the PEPT1 transporter, enters the portal circulation, and is rapidly hydrolyzed by CN1 into beta-alanine and L-histidine. The plasma half-life of intact carnosine in humans is extremely short, estimated at minutes rather than hours.

This rapid enzymatic degradation represents the central pharmacokinetic challenge for carnosine supplementation in humans. It is important to note that CN1 activity is essentially absent in rodents, which means that the dramatic beneficial effects observed in mouse and rat studies may overestimate the therapeutic potential achievable in humans through simple oral carnosine administration. The discrepancy between rodent and human carnosinase activity is a critical consideration in translating preclinical carnosine research to clinical applications.

Tissue-Specific Carnosinase Activity

Two carnosinase isoforms exist in humans. CN1 (serum carnosinase, encoded by CNDP1) is secreted primarily from the brain into the blood and exhibits high specificity for carnosine and homocarnosine. CN2 (tissue carnosinase, encoded by CNDP2) is a cytoplasmic enzyme with broader substrate specificity that is found in most tissues. The relative expression of these isoforms varies between tissues and between individuals.

Importantly, genetic polymorphisms in the CNDP1 gene that result in lower CN1 activity have been associated with reduced risk of diabetic nephropathy in some populations, providing genetic evidence that carnosine’s bioavailability influences disease susceptibility. Individuals with longer trinucleotide (CTG) repeat lengths in the CNDP1 signal peptide produce less CN1, maintain higher serum carnosine levels, and show a lower prevalence of diabetic kidney disease, particularly in type 2 diabetes.

Bioavailability Enhancement Strategies

Despite the challenge of rapid CN1-mediated degradation, clinical trials using 2 g/day oral carnosine have consistently produced measurable biological effects, including increased urinary carnosine levels and improved metabolic parameters. This suggests that even transient exposure to intact circulating carnosine, combined with the constituent amino acids’ potential to resynthesize carnosine locally in target tissues, may be sufficient to exert therapeutic effects.

Several strategies are being explored to overcome the carnosinase barrier. Carnosinase-resistant derivatives such as FL-926-16 (a modified carnosine analog) have shown remarkable efficacy in preventing diabetic nephropathy in mouse models, attenuating creatinine levels by 80 percent and albuminuria by 77 percent compared to untreated diabetic controls. D-carnosine prodrugs, where the L-histidine is replaced with D-histidine to resist CN1 cleavage, represent another approach. Co-supplementation strategies, such as combining carnosine with its methylated analog anserine (which is more resistant to CN1), have been shown to competitively inhibit carnosinase and increase plasma bioavailability of both dipeptides.

Carnosine Variants

Carnosine belongs to a family of histidine-containing dipeptides (HCDs) that share structural similarities and overlapping biological activities but differ in key pharmacological properties.

Anserine (beta-alanyl-N1-methylhistidine) is the most abundant HCD in avian and fish muscle and is present at low levels in human tissues. Its methylation at the N1 position of the imidazole ring confers increased resistance to hydrolysis by CN1 while preserving most of carnosine’s antioxidant and pH-buffering properties. Combined anserine/carnosine supplementation has been used in cognitive impairment trials and has shown synergistic bioavailability effects when co-administered, as the two dipeptides competitively bind CN1.

Homocarnosine (gamma-aminobutyryl-L-histidine) is found exclusively in the brain, where it is synthesized from GABA and L-histidine by carnosine synthase. It is resistant to CN1 degradation and is present at concentrations of 0.5 to 1.0 millimoles per liter in human cerebrospinal fluid. Homocarnosine has been proposed to function as a GABA reservoir, a neuromodulator, and an intracellular antioxidant. Its brain-specific distribution suggests specialized neuroprotective functions distinct from those of carnosine in muscle.

N-acetylcarnosine is a synthetic derivative in which the alpha-amino group of beta-alanine is acetylated. This modification protects the molecule from peptidase degradation during topical application and enables corneal penetration. Once in the aqueous humor, esterases cleave the acetyl group to release L-carnosine in proximity to the lens.

Current Research Landscape

Clinical Trials

The clinical investigation of carnosine has accelerated in recent years, with multiple randomized controlled trials completed or underway across diverse therapeutic areas. The most robust clinical data exist for metabolic endpoints. The glucose metabolism trials by de Courten (2016) and Hariharan (2024) have established that 2 g/day oral carnosine for 12 to 14 weeks can improve glycemic parameters in overweight/obese and prediabetic/diabetic populations. The NEAT trial (Nucleophilic Defense Against PM Toxicity) has expanded the scope of carnosine research to include cognitive function and environmental health, examining whether carnosine’s carbonyl-scavenging properties can mitigate the health effects of particulate matter exposure.

Delivery and Bioavailability Strategies

The development of carnosinase-resistant derivatives represents one of the most active frontiers in carnosine research. Aldini and colleagues at the University of Milan have pioneered the rational design of modified carnosine analogs optimized for carbonyl-scavenging reactivity, selectivity (avoiding reaction with physiological aldehydes), and resistance to CN1 hydrolysis. Their compound FL-926-16 demonstrated that carnosinase-resistant derivatives can achieve the therapeutic effects predicted by rodent carnosine studies but not fully realizable in humans due to CN1 degradation.

Other delivery approaches under investigation include nanoparticle encapsulation, transdermal formulations, and sustained-release oral preparations designed to maintain therapeutic plasma levels despite ongoing CN1 activity.

Biomarker Research

Carnosine and its metabolites are emerging as potential biomarkers in several clinical contexts. Urinary carnosine-propanal (the carnosine-acrolein conjugate) has been proposed as a marker of in vivo carbonyl quenching activity, while serum CN1 activity and CNDP1 genotype are being investigated as predictive biomarkers for diabetic nephropathy risk. The relationship between muscle carnosine concentrations (measurable by proton magnetic resonance spectroscopy) and age-related sarcopenia is also under active study.

Safety and Tolerability

Carnosine has an excellent safety profile supported by its status as a naturally occurring endogenous compound, its presence in the human diet at significant levels (estimated at 50 to 300 mg/day from meat consumption), and clinical trial data from multiple randomized controlled studies.

No serious adverse effects have been reported in any published clinical trial using doses of 2 g/day for periods up to 14 weeks. The most commonly reported side effects in clinical studies, which were rare and mild, include transient gastrointestinal discomfort. Both the de Courten (2016) and Siriwattanasit (2021) trials explicitly noted that carnosine was well tolerated with no serious side effects.

The 2025 review by Barbati et al. specifically highlighted carnosine’s safety profile, lack of toxicity, and absence of significant side effects as properties supporting its application for long-term therapeutic use. As an endogenous molecule present at millimolar concentrations in healthy human tissues, carnosine does not raise the xenobiotic safety concerns associated with synthetic pharmacological agents.

There are no established contraindications for carnosine supplementation, though individuals with histidinemia (a rare metabolic disorder) or severe renal impairment should exercise caution due to altered histidine metabolism. Pregnant or nursing women should consult a healthcare provider before supplementation, as there are insufficient safety data in these populations.

Conclusion

Carnosine occupies a unique position in the landscape of bioactive peptides. Discovered more than 125 years ago and present at remarkably high concentrations in human tissues, it has emerged as a molecule of considerable scientific and therapeutic interest, particularly in the interconnected fields of aging, metabolic disease, and neurodegeneration. Its combination of antioxidant, anti-glycation, metal-chelating, pH-buffering, and carbonyl-scavenging activities provides a multi-mechanistic defense against the molecular damage that accumulates with age and drives chronic disease.

The clinical evidence base for carnosine is growing, with randomized controlled trials demonstrating meaningful improvements in glucose metabolism, renoprotective effects in diabetic nephropathy, and cognitive benefits in select populations. However, the rapid degradation of carnosine by human serum carnosinase remains a central pharmacological challenge that may limit the full therapeutic potential of oral supplementation. The development of carnosinase-resistant derivatives, improved delivery systems, and co-supplementation strategies with related dipeptides such as anserine represent promising avenues for overcoming this barrier.

As Boldyrev, Aldini, and Derave concluded in their comprehensive 2013 review, “far more experiments in the fields of physiology and related disciplines are required to gain a full understanding of the function and applications of this intriguing molecule.” More than a decade later, that assessment remains apt. Carnosine’s pluripotent biochemistry continues to yield new insights, and its transition from a “forgotten dipeptide” to a serious candidate for translational medicine is well underway.