A practical reference on c-Met receptor: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-01-18. Anything still debated is marked as such rather than presented as settled.
Regulatory treatment varies by country. Dihexa does not appear in major pharmacopeias as a licensed therapeutic substance. Suppliers may use labels such as research use only or not for human consumption. Such labels reflect legal and quality-control boundaries rather than evidence of clinical benefit. Importation, possession, and sale can be restricted depending on local laws, and enforcement focuses on claims, distribution channels, and product categories. These rules can change, and they differ from rules for approved medicines.
Dihexa is a synthetic peptide studied in preclinical neuroscience. It is often described as an angiotensin IV analog or derivative. The compound also appears under research codes such as PNB-0408 and N-hexanoic-Tyr-Ile-(6)-aminohexanoic amide. It is not an approved drug, and it is not a conventional vitamin or nutrient. In many jurisdictions, material sold as dihexa is handled as a research chemical rather than a medicine or supplement. This classification affects how the material is labeled and distributed.
Chemically, dihexa is a short peptide-like molecule with nonstandard components. Its structure includes tyrosine and isoleucine residues linked to a hexanoic acid group and an aminohexanoic amide segment. This design distinguishes it from endogenous angiotensin IV, though the two are discussed together because of shared origins. Published summaries classify it as a small synthetic peptide with lipophilic features that may influence how it crosses biological barriers in experimental systems. Exact conformational details depend on the specific salt or free base form.
The compound has been examined in animal models for effects on learning, memory, and synaptic connectivity. Some reports describe increased dendritic spine density and improved performance on certain behavioral tasks after administration in rodents. These findings are often cited in discussions of nootropic research peptides, but replication across independent laboratories remains limited. The absence of published phase 1 or phase 2 clinical trial data makes it difficult to assess safety, effective routes, or long-term outcomes in humans. Consequently, claims about cognitive benefits in people remain speculative.
Dihexa is not approved as a medicine in major regulatory jurisdictions. It is commonly sold as a research chemical for laboratory use, though such products may not be standardized or independently verified. Scientific literature on dihexa includes in vitro assays, rodent studies, and reviews that discuss its proposed mechanism. The distinction between peer-reviewed findings and commercial promotion is important when evaluating available information. Open questions include its precise binding interactions, pharmacokinetics, and whether animal results translate to human biology.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic peptide analog | Modeled on angiotensin IV |
| Common synonyms | PNB-0408; N-hexanoic-Tyr-Ile-(6)-aminohexanoic amide | Research codes vary by supplier |
| Appearance | White to off-white powder | Typical for lyophilized peptides |
| Solubility | Soluble in organic solvents; limited in water | Formulation dependent |
| Typical storage | −20 °C, desiccated, protected from light | Stability depends on purity and container |
Dihexa is a synthetic compound studied in laboratory and animal models for effects on synaptic connectivity and cognitive performance. It is often described as a peptide analog because its structure incorporates amino acid residues linked to a hexanoic acid group. The molecule is not a naturally occurring human hormone or neurotransmitter. Its name appears in research literature and online discussions, but it has not been approved as a medicine by major regulatory agencies. Most information comes from preclinical experiments rather than controlled human trials.
The compound originated from work on angiotensin IV, a peptide fragment of the renin-angiotensin system. Researchers modified angiotensin IV-related structures to produce molecules with altered stability and activity. Dihexa emerged from that effort and was reported to promote dendritic spine growth in cultured neurons. Some studies link its effects to hepatocyte growth factor signaling and the c-Met receptor, while other work points to insulin-regulated aminopeptidase. The precise primary target remains a subject of investigation, and findings may depend on cell type, assay conditions, and species.
The full name often given is N-hexanoic-Tyr-Ile-(6)-aminohexanoic amide. This name indicates a chain containing tyrosine, isoleucine, and a six-carbon amino acid derivative. Databases list a CAS Registry Number and a molecular formula for the compound. The peptide is small compared with proteins, and its structure allows it to be studied in cell cultures and animal models. Exact identity depends on the supplier's synthesis and purification process. Minor impurities can remain after synthesis.
Chemically, dihexa belongs to a broader group of angiotensin IV analogs. Researchers have modified the natural peptide to alter stability, binding, or distribution. Such changes can affect how the molecule behaves in experiments. The parent peptide angiotensin IV is involved in various physiological processes, but the modified analog is not identical to it. Public summaries sometimes blur the distinction between the natural fragment and the synthetic research compound. This distinction matters when interpreting study results.
Dihexa is a synthetic peptide that has been examined in laboratory and animal research. Its design is based on angiotensin IV, a naturally occurring peptide fragment produced in the body. The short name dihexa appears in scientific papers and online discussions, while the full chemical name describes a modified peptide chain. It is not a vitamin, mineral, or plant-derived compound. Suppliers typically present it as a research chemical rather than an approved medicine.
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== Biological activity == Protolichesterinic acid exhibits diverse biological activities, including antimicrobial, enzyme inhibitory, and anticancer properties. Studies with the compound isolated from Usnea albopunctata have demonstrated broad-spectrum antimicrobial activity. It shows strong antibacterial effects against Klebsiella pneumoniae (minimum inhibitory concentration 0.25 μg/mL) and Vibrio cholerae (0.5 μg/mL), exceeding the potency of ciprofloxacin. The compound is also active against methicillin-resistant Staphylococcus aureus (MRSA) and shows notable antifungal activity against Trichophyton rubrum, surpassing amphotericin B in potency. As an inhibitor, protolichesterinic acid selectively targets 5-lipoxygenase while showing minimal effect on cyclooxygenase. This selective inhibition suggests potential applications in treating inflammatory conditions, particularly those involving leukotriene bronchoconstrictors. Structure-activity studies indicate that while the stereospecific side chain and exocyclic double bond are not essential for activity, the carboxylic acid group plays a crucial role. The compound also inhibits the DNA polymerase activity of human immunodeficiency virus-1 reverse transcriptase (HIV-1 RT). Research has revealed that protolichesterinic acid affects cancer cell metabolism by disrupting mitochondrial function through inhibition of oxidative phosphorylation and enhancement of glycolysis. The compound undergoes cellular processing via the mercapturic pathway, forming conjugates with glutathione.
== Dissociation and equilibrium == Reactions of acids are often generalized in the form HA ⇌ H+ + A−, where HA represents the acid and A− is the conjugate base. This reaction is referred to as protolysis. The protonated form (HA) of an acid is also sometimes referred to as the free acid. Acid–base conjugate pairs differ by one proton, and can be interconverted by the addition or removal of a proton (protonation and deprotonation, respectively). The acid can be the charged species and the conjugate base can be neutral in which case the generalized reaction scheme could be written as HA+ ⇌ H+ + A. In solution there exists an equilibrium between the acid and its conjugate base. The equilibrium constant K is an expression of the equilibrium concentrations of the molecules or the ions in solution. Brackets indicate concentration, such that [H2O] means the concentration of H2O. The acid dissociation constant Ka is generally used in the context of acid–base reactions. The numerical value of Ka is equal to the product (multiplication) of the concentrations of the products divided by the concentration of the reactants, where the reactant is the acid (HA) and the products are the conjugate base and H+.
=== Debt categories === The total federal debt is divided into "debt held by the public" and "intra-governmental debt." The debt held by the public refers to U.S. government securities or other obligations held by investors (e.g., bonds, bills, and notes), while Social Security and other federal trust funds are part of the intra-governmental debt. As of September 30, 2012, the total debt was $16.1 trillion, with debt held by the public of $11.3 trillion and intragovernmental debt of $4.8 trillion. Debt held by the public as a percentage of gross domestic product (GDP) rose from 34.7% in 2000 to 40.3% in 2008 and 70.0% in 2012. U.S. GDP was approximately $15 trillion during 2011 and an estimated $15.6 trillion for 2012 based on activity during the first two quarters. This means the total debt is roughly the size of GDP. Economists debate the level of debt relative to GDP that signals a "red line" or dangerous level, or if any such level exists. By comparison, China's budget deficit was 1.6% of its $10 trillion GDP in 2010, with a debt to GDP ratio of 16%.
Sources: en.wikipedia.org
When this happens, the flow of the mobile phase occurs around the stationary phase as well as through it, decreasing resolution. Wall effects have been reduced greatly by advances in column construction. Other advantages of monoliths conferred by their individual construction include greater column to column and batch to batch reproducibility. One technique of creating monolith columns is to polymerize the structure in situ. This involves filling the mold or column tubing with a mixture of monomers, a cross-linking agent, a free-radical initiator, and a porogenic solvent, then initiating the polymerization process under carefully controlled thermal or irradiating conditions. Monolithic in situ polymerization avoids the primary source of column to column variability, which is the packing procedure. Additionally, packed particle columns must be maintained in a solvent environment and cannot be exposed to air during or after the packing procedure. If exposed to air, the pores dry out and no longer provide adequate surface area for reactivity; the column must be repacked or discarded. Further, because particle compression and packing uniformity are not relevant to monoliths, they exhibit greater mechanical robustness; if particulate columns are dropped, for example, the integrity of the column may be corrupted. Monolithic columns are more physically stable than their particulate counterparts.
=== 1991 === 11 August After Desert Storm, the technology deployed in the Gulf War, and whether any lessons were learned - featured Major General Sir Peter de la Billière, Commander of the British Forces in the Gulf; a 66-foot-long F117 at King Khalid Air Base at Khamis Mushait on 16 January 1991 - the aircraft had no radar, but had the radar signature of a small bird; F117 pilot Major Greg Feest; Air Vice-Marshal Bill Written, the air commander of British Forces Middle East from November 1990; Colonel John A.
== External links == "Dr. A. Ajayaghosh". Awardee profile. Infosys Science Foundation. 2016. "Dr. A. Ajayaghosh". Infosys Science Foundation. 26 September 2013. p. YouTube video. "Dr. A. Ajayaghosh'' https://scholar.google.com/citations?user=bYdujAwAAAAJ&hl=en
Sources: en.wikipedia.org
It is a synthetic peptide analog of angiotensin IV studied mainly in laboratory and animal research. It is not an approved medicine. Human clinical data are limited.
It is generally not regulated as a dietary supplement. Products are often sold as research chemicals. That status affects purity, labeling, and legal availability.
Dihexa itself is not a standard endogenous peptide. It is synthesized and modeled on angiotensin IV. Angiotensin IV occurs naturally as a fragment of angiotensin II.
Dihexa is a synthetic peptide derived from angiotensin IV and studied for effects on synaptic plasticity. It is often described as a hepatocyte growth factor mimetic. It is not an approved medication.