Glycyl-alanyl-L-valine

Glycyl-Alanyl-L-Valine (Gly-Ala-Val): A Comprehensive Reference

1. Identity and Chemical Characterization

Glycyl-alanyl-L-valine (commonly abbreviated Gly-Ala-Val) is a synthetic tripeptide composed of three amino acid residues linked in sequence by peptide bonds: glycine at the N-terminus, L-alanine in the central position, and L-valine at the C-terminus. Its systematic IUPAC name is Glycyl-L-alanyl-L-valine, with the index name L-Valine, glycyl-L-alanyl- and the sequence notation Gly-Ala-Val. The compound is registered under CAS number 121428-48-6. Its molecular formula is C₁₀H₁₉N₃O₄, with a PubChem CID of 129439.

The full IUPAC systematic descriptor for the molecule reflects its stereospecific construction: (2S)-2-[(2S)-2-(2-aminoacetamido)propanamido]-3-methylbutanoic acid. The L-configuration at both the alanine and valine stereocentres is explicit in the naming convention; glycine, the N-terminal residue, is achiral and has no stereocentre.

Glycyl-alanyl-L-valine is a synthetic tripeptide composed of the amino acids glycine, alanine, and valine. As a tripeptide, it is a member of the oligopeptide class: a short-chain peptide containing exactly three amino acid residues. The innovation of combining these amino acids into a tripeptide form is based on research showing that peptides can have superior absorption compared to free amino acids, potentially allowing more efficient delivery of nutrients.

1.1 Constituent Amino Acids

• Glycine (Gly, G): The proteinogenic amino acid of lowest molecular weight, harboring a hydrogen atom as its side-chain. In addition to being a building block for proteins, glycine is required for multiple metabolic pathways, such as glutathione synthesis and regulation of one-carbon metabolism. Although generally viewed as a non-essential amino acid, because it can be endogenously synthesized to a certain extent, glycine has also been suggested as a conditionally essential amino acid.
• L-Alanine (Ala, A): A non-essential, glucogenic amino acid. Alanine plays a central role in the glucose-alanine cycle by transferring nitrogen to the liver and aiding gluconeogenesis in a state of starvation or insufficient supply of glucose. Of the 20 amino acids measured, alanine is the principal amino acid released by forearm muscle of man, in accord with its being the principal amino acid extracted by liver for gluconeogenesis.
• L-Valine (Val, V): An essential amino acid and one of the branched-chain amino acids (BCAAs; valine, leucine, and isoleucine), which serve as substrates and regulators of protein metabolism, particularly in muscles. Because the body cannot synthesize valine in adequate amounts, it must be obtained from the diet.

1.2 Common Forms and Preparations

Glycyl-alanyl-L-valine is a synthetic tripeptide composed of glycine, alanine, and valine, three amino acids fundamental to human nutrition and metabolism. Tripeptides such as this are increasingly being explored in nutritional and functional food products due to their potential benefits in enhancing nutrient absorption, supporting muscle health, and promoting recovery, particularly in clinical nutrition and sports supplementation settings.

As a synthetic compound, Gly-Ala-Val does not occur as a discrete, purified ingredient in traditional whole foods, although the same amino acid residues appear within peptide fragments of larger dietary proteins. In commercial contexts, it is synthesized by chemical or enzymatic methods and formulated primarily as a powder for incorporation into capsules, tablets, sachets, or functional food matrices. The modern synthesis of glycyl-alanyl-L-valine allows for precise delivery of these beneficial amino acids in a form that is easily absorbed and utilized by the body.

2. Natural Sources and Occurrence

Glycyl-alanyl-L-valine as a discrete, isolated tripeptide does not occur in nature in purified form; rather, it arises as a fragment produced during the enzymatic or acidic hydrolysis of dietary proteins that are rich in glycine, alanine, and valine. While the isolated tripeptide itself is a relatively recent innovation in nutritional science, its constituent amino acids have long histories of use in medicinal and nutritional remedies.

The three constituent residues are ubiquitous in animal and plant proteins. Collagen is a particularly notable dietary source of both glycine and alanine: collagen peptides are overwhelmingly glycine, proline, and hydroxyproline, which together account for more than half of all residues in type I collagen, with the profile also including alanine, arginine, glutamic acid, and most other amino acids in smaller proportions. Alanine and glycine are accordingly listed among the non-essential amino acids supplied by hydrolyzed collagen. Valine, an essential BCAA, is present in significant concentrations in meat, dairy products, legumes, and soy. It is naturally found in protein-rich foods such as meat, dairy, legumes, and soy.

The digestion of dietary proteins in the intestinal lumen results in the release of free amino acids and small peptides. Dietary proteins are cleaved within the intestinal lumen to oligopeptides, which are further processed to small peptides (di- and tripeptides) and free amino acids. The tripeptide sequence Gly-Ala-Val therefore naturally arises as a transient digestive intermediate whenever proteins containing the appropriate adjacent residues are consumed and hydrolysed.

3. Traditional and Historical Use

While the isolated tripeptide itself is a relatively recent innovation in nutritional science, its constituent amino acids have long histories of use in medicinal and nutritional remedies. No documented use of Gly-Ala-Val as a chemically defined entity exists in traditional or historical medical systems, as the concept of a specific synthetic tripeptide is entirely a product of modern peptide chemistry. Any discussion of traditional use must therefore be understood as referring strictly to the constituent amino acids and the whole-protein or food sources from which they derive.

Historically, these amino acids were valued in various cultures for their role in supporting muscle health, energy metabolism, and overall recovery. For instance, glycine-rich broths and alanine-containing plant extracts were common in traditional remedies for fatigue and convalescence, while valine, an essential branched-chain amino acid, has been recognized for its role in muscle repair and endurance.

Glycine is the most important and simple, non-essential amino acid in humans, animals, and many mammals. Glycine acts as a precursor for several key metabolites of low molecular weight such as creatine, glutathione, haem, purines, and porphyrins. Its role in structural proteins such as collagen has been recognized empirically for centuries through the use of bone broths and gelatin preparations in restorative diets across many cultures.

As a discrete synthetic ingredient, Gly-Ala-Val belongs entirely to the modern era of nutritional science. In recent years, the use of tailored peptides in nutritional products has grown, reflecting modern advances in understanding protein metabolism and the specific benefits of amino acid sequences.

4. Key Constituents and Established Mechanisms of Action

4.1 Intestinal Transport via PepT1

The most well-characterized mechanism relevant to Gly-Ala-Val is its expected transport across the intestinal epithelium by the peptide transporter PepT1 (SLC15A1). Bioactive di/tripeptides are among the most efficient structural units that can cross the intestinal barrier and reach the circulation, owing to their small molecular size and compact conformation. Evidence indicates that more than 70% of protein digestion products in the gastrointestinal tract are absorbed in the form of di/tripeptides, primarily via a specialized proton-coupled transport system. The key mediator of this absorption process is peptide transporter 1 (PepT1), a proton-dependent oligopeptide transporter that is highly expressed at the brush-border membrane of intestinal epithelial cells.

Human peptide transporter 1 (PepT1) is an uptake transporter with a major role in the absorption of dietary di- and tripeptides from the small intestinal lumen. It is a high-capacity, low-affinity (K_M of 0.2–10 mM), proton-coupled cotransporter of diverse di- and tripeptides and peptidomimetic substrates, and is primarily expressed on the apical microvilli of enterocytes in the small intestine, with lower expression in epithelial cells in the kidney proximal tubule.

The proton-coupled uptake of more than 8,000 different di- and tripeptides is performed by the high-capacity/low-affinity peptide transporter isoform PepT1 (SLC15A1). The tripeptide Gly-Ala-Val has the appropriate size and charge characteristics to serve as a PepT1 substrate: the peptide binding cavity of PepT1 is reported to be approximately 13 × 12 × 11 Å, which limits attachment to only di- and tripeptides, while being sterically restrictive for peptides with more than tetrapeptide length. This transporter does not transport free amino acids or peptides containing four or more amino acid residues.

PepT1 plays a crucial role in the absorption of small peptides, including not only more than 400 different dipeptides and 8,000 tripeptides digested from dietary proteins, but also a repertoire of structurally related compounds and drugs. Once inside the enterocyte, the tripeptide is largely hydrolysed to its constituent amino acids by intracellular peptidases, and the free amino acids then enter the portal circulation. These free amino acids and small peptides absorbed are delivered to various tissues through the blood as resources for protein synthesis and energy metabolites.

4.2 Mechanisms of the Constituent Amino Acids

Glycine: Glycine plays an important role in metabolic regulation, anti-oxidative reactions, and neurological function. It is synthesized from serine, threonine, choline, and hydroxyproline via inter-organ metabolism involving primarily the liver and kidneys. Glycine is also utilized for the biosynthesis of glutathione, heme, creatine, nucleic acids, and uric acid. Of the total amino acid content in the human body, 11.5% is represented by glycine, and 20% of the total amino acid nitrogen in body proteins comes from glycine. In collagen, glycine is located at every third position; glycine residues bring together the triple helix of the collagen.

L-Alanine: Alanine is the central carrier of nitrogen in the glucose-alanine cycle. Data suggest the existence of a glucose-alanine cycle in which alanine is formed peripherally by transamination of glucose-derived pyruvate and transported to the liver, where its carbon skeleton is reconverted to glucose. Of the 20 amino acids measured, alanine is the principal amino acid released by forearm muscle of man, in accord with its being the principal amino acid extracted by liver for gluconeogenesis. This occurs in both the postabsorptive state and after 4 to 6 weeks of starvation, when total amino acid release is markedly diminished.

L-Valine: The branched-chain amino acids leucine, isoleucine, and valine have raised considerable interest because of their different metabolic and physiological functions. BCAAs are used for protein synthesis in mammalian cells, and transaminated in the presence of α-ketoglutarate, allowing the production of glutamate and the corresponding α-ketoacids. Each α-ketoacid can then undergo several steps of conversion resulting in the synthesis of acetyl-CoA and succinyl-CoA. These compounds can then enter the tricarboxylic acid cycle allowing the synthesis of reduced equivalents, which are finally used in the mitochondrial respiratory chain allowing ATP synthesis. BCAAs are precursors not only for the dispensable amino acid glutamate, but also for alanine and glutamine. BCAAs are involved in the regulation of metabolic pathways engaged in glucose and lipid metabolism, and in protein synthesis in skeletal muscles.

5. Scientific Evidence by Area of Use

Important caveat on evidence scope: Scientific investigations on glycyl-alanyl-L-valine specifically remain limited, with most research focusing on similar di- and tripeptides. No randomized controlled clinical trials, systematic reviews, or pharmacokinetic studies examining Gly-Ala-Val as an isolated, purified ingredient in human subjects were identified in the peer-reviewed literature at the time of this writing. All specific human and clinical evidence reviewed below relates to (a) the general class of di/tripeptides, (b) individual constituent amino acids, or (c) branched-chain amino acid (BCAA)-containing supplements. Each subsection identifies explicitly which body of evidence is being drawn upon.

5.1 Protein Absorption and Amino Acid Delivery

Evidence class: Di/tripeptide transport — in vitro and mechanistic; strong for transport mechanism, not specific to Gly-Ala-Val.

Bioactive di/tripeptides are among the most efficient structural units that can cross the intestinal barrier and reach the circulation, owing to their small molecular size and compact conformation. Evidence indicates that more than 70% of protein digestion products in the gastrointestinal tract are absorbed in the form of di/tripeptides, primarily via a specialized proton-coupled transport system.

Some studies have demonstrated that tripeptides are absorbed more rapidly through the intestinal peptide transporters than free amino acids or larger proteins, suggesting a possible advantage for nutritional supplementation. The mechanistic basis for this is well established at the molecular level: PepT1 is predominantly expressed on the apical membrane of intestinal epithelial cells, where its unique substrate recognition and structural adaptability enable it to mediate the uptake of a broad range of small peptides. PepT1, a proton-coupled oligopeptide symporter, facilitates the efficient uptake of various bioactive di/tripeptides, driven by the proton electrochemical gradient.

Caco-2 cell models, the standard in vitro tool for studying human intestinal transport, have been used extensively to characterise PepT1 kinetics. The Caco-2 cell model, derived from human colon carcinoma cells, is a well-documented and widely used model to study the in vitro transport behaviour of target compounds. Differentiated Caco-2 cells express transporter proteins, paracellular junctions and digestive enzymes similar to those of the intestinal epithelial cells. Direct Caco-2 data for Gly-Ala-Val are not reported in the available literature, but the physicochemical properties of the tripeptide are consistent with PepT1 substrate requirements.

5.2 Muscle Protein Synthesis and Skeletal Muscle Metabolism

Evidence class: Evidence relates primarily to constituent BCAAs (valine) and to di/tripeptides in general — human studies are mixed and context-dependent; no specific Gly-Ala-Val clinical studies identified.

Branched-chain amino acids (BCAA: leucine, isoleucine and valine) are three of the nine indispensable amino acids, and are frequently consumed as a dietary supplement by athletes and recreationally active individuals alike. The popularity of BCAA supplements is largely predicated on the notion that they can stimulate rates of muscle protein synthesis (MPS) and suppress rates of muscle protein breakdown (MPB), the combination of which promotes a net anabolic response in skeletal muscle.

However, human evidence for BCAAs alone stimulating muscle protein synthesis is contested: a multi-million dollar industry of nutritional supplements has grown around the concept that dietary supplements of BCAAs alone produce an anabolic response in humans driven by a stimulation of muscle protein synthesis. In this brief review, the theoretical and empirical bases for that claim are discussed. The catabolic state in which the rate of muscle protein breakdown exceeded the rate of muscle protein synthesis persisted during BCAA infusion. The conclusion reached is that the claim that consumption of dietary BCAAs stimulates muscle protein synthesis or produces an anabolic response in human subjects is unwarranted.

To date, several studies have shown that BCAAs (particularly leucine) increase the phosphorylation status of key proteins within the mechanistic target of rapamycin (mTOR) signalling pathway involved in the regulation of translation initiation in human muscle. However, when the individual BCAAs were examined, the stimulatory effect on MPS was attributed primarily to leucine (not isoleucine or valine). Since Gly-Ala-Val does not contain leucine, its contribution to MPS via the mTOR pathway is expected to be modest relative to leucine-containing peptides.

For synthesis of new muscle protein, all the essential amino acids, along with the eleven non-essential amino acids that can be produced in the body, must be present in adequate amounts. Gly-Ala-Val provides only three of the required twenty amino acids, limiting its standalone anabolic utility.

Regarding glycine specifically, glycine is a building block of proteins and is considered a proteinogenic amino acid that plays a multifaceted role in muscle function, significantly affecting skeletal muscle metabolism, neuromuscular action, and exercise performance. Animal studies suggest that glycine administration may preserve muscle mass, reduce inflammation, and increase growth hormone levels. More randomized controlled clinical trials in humans are needed to confirm glycine's potential as a dietary supplement to support muscle function, recovery, and overall athletic performance as an ergogenic aid.

5.3 Energy Metabolism and Gluconeogenesis

Evidence class: Well-established biochemical and clinical evidence for alanine; mechanisms are firmly established in human metabolic studies. Valine-related BCAA energetics are established. No specific Gly-Ala-Val clinical data identified.

Alanine, released upon post-absorptive hydrolysis of Gly-Ala-Val, participates directly in the glucose-alanine cycle. Data suggest the existence of a glucose-alanine cycle in which alanine is formed peripherally by transamination of glucose-derived pyruvate and transported to the liver where its carbon skeleton is reconverted to glucose. The rate of recycling of glucose carbon skeletons in this pathway appears to occur at approximately 50% of that observed for the Cori (lactate) cycle.

Valine's contribution to energy metabolism is similarly well characterised: BCAAs are used for protein synthesis in mammalian cells, and transaminated in the presence of α-ketoglutarate, allowing the production of glutamate and the corresponding α-ketoacids. Each α-ketoacid can then undergo several steps of conversion resulting in the synthesis of acetyl-CoA and succinyl-CoA. These compounds can then enter the tricarboxylic acid cycle allowing the synthesis of reduced equivalents, which are finally used in the mitochondrial respiratory chain allowing ATP synthesis.

5.4 Antioxidant and Cytoprotective Properties

Evidence class: Primarily related to glycine's role in glutathione synthesis — mechanistically established; for the tripeptide as a whole, evidence is preliminary, based on class effects of small peptides.

Tripeptides have been examined for their bioactive properties, including antioxidant and anti-inflammatory effects, though further studies are necessary to establish these benefits in humans.

For glycine specifically, cytoprotective effects are better characterised: there are clinical and experimental studies demonstrating several potential indications of glycine in subjects without glycine deficiency, many of which are apparently related to its role in glutathione synthesis and cytoprotective and immunomodulatory effects. The protective effect of glycine on ischemia-reperfusion injury, cell damage occurring during transplantation, stroke, cardiac arrest and sepsis is particularly promising.

5.5 Metabolic Health (Obesity, Type 2 Diabetes, NAFLD)

Evidence class: Relates to glycine as a free amino acid — clinical observational and some interventional evidence; context is glycine deficiency or supplementation, not Gly-Ala-Val specifically.

In metabolic disorders associated with obesity, type 2 diabetes (T2DM), and non-alcoholic fatty liver disease (NAFLDs), lower circulating glycine levels have been consistently observed, and clinical studies suggest the existence of beneficial effects induced by glycine supplementation. Dietary supplementation of proper dose of glycine is effectual in treating metabolic disorders in patients with cardiovascular diseases, several inflammatory diseases, obesity, cancers, and diabetes. These findings are derived from studies of free glycine supplementation, not from studies of Gly-Ala-Val itself, and cannot be directly extrapolated to the tripeptide without specific clinical investigation.

6. Body Systems and Health Areas of Association

Based on the established biochemistry of its constituent amino acids and the general properties of small tripeptides, Gly-Ala-Val is associated with the following body systems and functional health areas:

• Gastrointestinal and absorptive system: Di- and tripeptides can be absorbed as such in the intestine. Their transport across the human luminal border of the intestinal cell is mediated by the proton-dependent dipeptide transporter (PepT1). PepT1 is located in the apical membrane of intestinal enterocytes operating as an electrogenic proton–peptide transporter.
• Skeletal muscle and musculoskeletal system: Through provision of valine (an essential BCAA), alanine (nitrogen carrier for muscle-derived gluconeogenic substrate), and glycine (structural component of muscle connective tissue proteins). BCAAs are involved in the regulation of metabolic pathways engaged in glucose and lipid metabolism, and in protein synthesis in skeletal muscles.
• Hepatic and glucoregulatory system: Alanine is extracted by the liver as the primary gluconeogenic amino acid: of the 20 amino acids measured, alanine is the principal amino acid released by forearm muscle of man, in accord with its being the principal amino acid extracted by liver for gluconeogenesis.
• Antioxidant and immune defence: Via glycine's role in glutathione biosynthesis. In addition to being a building-block for proteins, glycine is required for multiple metabolic pathways, such as glutathione synthesis and regulation of one-carbon metabolism.
• Connective tissue (skin, joints, tendons): Glycine is essential for collagen structure. In collagen, glycine is located at every third position; glycine residues bring together the triple helix of the collagen.
• Renal system: In the kidney, PepT1 reabsorbs peptides from the primary filtrate in the proximal tubule, in conjunction with a similar transporter, PepT2.

7. Dosage Forms and Reported Dosages

Tripeptides such as Gly-Ala-Val are increasingly being explored in nutritional and functional food products due to their potential benefits in enhancing nutrient absorption, supporting muscle health, and promoting recovery, particularly in clinical nutrition and sports supplementation settings.

No peer-reviewed clinical studies defining specific dose ranges for Gly-Ala-Val as an isolated ingredient were identified in the literature search. Accordingly, no evidence-based dosage range for the tripeptide itself can be stated. The dosage information available in the scientific literature relates entirely to the constituent free amino acids:

• Valine (as part of BCAA supplementation): In typical study doses, BCAAs are often administered at 5 to 20 grams per day and are generally tolerated.
• Hydrolyzed collagen (as a glycine and alanine source): Hydrolyzed collagen has been used as a source of essential amino acids (including valine) and non-essential amino acids (including alanine and glycine) at doses of 2.6 to 10 grams per day.

Because Gly-Ala-Val is formulated as a synthetic ingredient, commercially available products may list it at milligram-range quantities within broader amino acid or peptide matrices, but no dosage from a peer-reviewed human study specific to this tripeptide can be confirmed at this time.

8. Safety Considerations and Interactions

8.1 General Safety Profile of the Tripeptide

No dedicated toxicological studies, safety evaluations, or adverse event reports for Gly-Ala-Val as an isolated ingredient were identified in the peer-reviewed literature or in regulatory databases at the time of this writing. Safety inferences must therefore be drawn from the properties of its constituent amino acids, which individually have well-characterised safety profiles at nutritional intakes.

For glycine specifically: No adverse effects of glycine administered orally to rats for 4 weeks at doses of 500, 1000, and 2000 mg/kg/day were observed. No apparent metabolic disadvantages to using amino acid solutions that contain up to 25% nitrogen as glycine in total parenteral nutrition have been reported in humans.

8.2 Potential Concerns with BCAA-Containing Preparations

Enhanced intake of most amino acid supplements may not be risk-free and can cause a number of detrimental side effects. In the context of valine as a BCAA component: observational human data show that higher circulating BCAA levels correlate with insulin resistance and type 2 diabetes risk. This association does not prove causation; it might reflect underlying diet and metabolism.

High doses of valine in isolation have also been associated with neurological concerns in some reports. High doses of valine potentially causing hallucinations and a skin-crawling sensation have been noted; this could be because taking too much of this supplement can cause an imbalance in the body's nitrogen levels. These concerns are reported for pharmacological doses of isolated valine; they have not been studied in the context of Gly-Ala-Val administration.

8.3 Amino Acid Competition and Imbalance

In addition to toxicity, mutagenicity and carcinogenicity, safety considerations for amino acid supplements also focus on renal and gastrointestinal tract functions, ammonia production, and consequences of competition with other amino acids for a carrier at the cell membranes and enzymes responsible for their degradation.

Valine and the other BCAAs share intestinal and blood-brain barrier transport systems with aromatic amino acids. High-dose supplementation of isolated BCAAs can in principle reduce the cerebral uptake of precursors such as tryptophan (for serotonin) or phenylalanine/tyrosine (for catecholamines), although this is primarily a concern with pharmacological-level BCAA doses rather than nutritional tripeptide amounts.

8.4 Renal Considerations

Like all nitrogen-containing compounds, amino acids from Gly-Ala-Val hydrolysis produce urea as a byproduct of catabolism. In individuals with impaired renal function, increased amino acid load may place additional stress on nitrogen excretory capacity. Renal and gastrointestinal tract function is among the considerations when evaluating the safety of elevated amino acid intake. However, at the small quantities typically found in supplement formulations, this risk is generally considered low in people with normal renal function.

8.5 Inflammatory Bowel Disease and PepT1 Upregulation

The role and pathophysiological relevance of membrane transporter PepT1 in intestinal inflammation and inflammatory bowel disease has been described. In healthy individuals, PepT1 is primarily expressed in the small intestine and transports di/tripeptides for metabolic purposes. However, during chronic inflammation such as inflammatory bowel disease, PepT1 expression is upregulated in the colon, wherein the protein is normally expressed either minimally or not at all. The implications of this upregulation for the absorption of supplemental tripeptides like Gly-Ala-Val in inflammatory bowel conditions are not known from current clinical evidence.

8.6 Interactions

No specific pharmacokinetic drug-interaction studies for Gly-Ala-Val have been identified. Glycine is metabolically co-regulated with serine: because of the close links in glycine and L-serine metabolism mediated by serine hydroxymethyltransferase (SHMT), decreased concentrations of both amino acids coincide in most glycine-deficient states. Alanine infusion has been shown experimentally to stimulate glucagon secretion and may interact with glucoregulatory medications, though this is a pharmacological-level effect. Observational human data show higher circulating BCAA levels correlate with insulin resistance and type 2 diabetes risk, a consideration potentially relevant to individuals using insulin-sensitising medications who substantially increase their valine intake.

9. Evidence Quality and Research Gaps

Scientific investigations on glycyl-alanyl-L-valine specifically remain limited, with most research focusing on similar di- and tripeptides. Some studies have demonstrated that tripeptides are absorbed more rapidly through the intestinal peptide transporters than free amino acids or larger proteins, suggesting a possible advantage for nutritional supplementation. Additionally, tripeptides have been examined for their bioactive properties, including antioxidant and anti-inflammatory effects, though further studies are necessary to establish these benefits in humans.

The following research gaps are material to any comprehensive evaluation of this ingredient:

• No human pharmacokinetic study has characterised the absorption, distribution, and metabolic fate of Gly-Ala-Val as a discrete molecule.
• No randomised controlled clinical trial has examined any health outcome in a human population receiving Gly-Ala-Val specifically.
• No regulatory body (EMA, EFSA, FDA, NIH Office of Dietary Supplements) has issued a formal safety opinion or ingredient monograph for Gly-Ala-Val as an isolated ingredient.
• No established tolerable upper intake level (UL) or recommended dietary allowance (RDA) exists for this tripeptide.
• Dose-response relationships, long-term safety, and population-specific considerations (paediatric, geriatric, pregnant, renally impaired) have not been studied.

In summary, glycyl-alanyl-L-valine is a chemically well-defined synthetic tripeptide whose physiological relevance is grounded in the well-established biochemistry of its three constituent amino acids and in the class-level evidence for small-peptide intestinal transport via PepT1. Its specific activity as a defined dietary supplement ingredient remains uncharacterised at the clinical level, and no health claim for it specifically can be considered evidence-based at this time.

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