Dihexa vs N-Hexanoic-Tyr-Ile-(6) — Same Compound?

Researchers ordering cognitive enhancement peptides frequently encounter two names: Dihexa and N-hexanoic-Tyr-Ile-(6) aminohexanoic amide. The confusion isn't surprising. These designations appear interchangeably in supplier catalogs, research protocols, and published literature without consistent explanation. The nomenclature difference has led to duplicate inventory orders, protocol clarifications mid-experiment, and unnecessary vendor comparisons based on assumed structural differences that don't exist.

We've supplied research-grade peptides to academic and commercial labs since 2015. The single most common question we field about this compound class is whether one designation represents a modified analog of the other. Whether the structural difference justifies ordering both, and which version is 'correct' for replication studies.

What's the difference between Dihexa and N-hexanoic-Tyr-Ile-(6) aminohexanoic amide?

There is no structural difference. Dihexa and N-hexanoic-Tyr-Ile-(6) aminohexanoic amide are identical compounds with the same molecular formula (C27H44N4O5), molecular weight (504.66 g/mol), and CAS registry number (1401708-83-5). 'Dihexa' is the abbreviated research designation coined by its developers at Washington State University, while N-hexanoic-Tyr-Ile-(6) aminohexanoic amide is the systematic IUPAC nomenclature describing its hexanoic acid N-terminal cap, tyrosine-isoleucine core sequence, and aminohexanoic amide C-terminal tail.

The naming convention follows standard peptide chemistry practice: abbreviated trade names for research convenience versus full systematic names for regulatory and synthesis documentation. The compound was first synthesized in 2012 by researchers seeking orally bioavailable analogs of brain-derived neurotrophic factor (BDNF). Dihexa emerged as the lead candidate with 10^6-fold greater potency than BDNF in hippocampal neuron culture assays. The systematic name appears in patents, MSDS documentation, and analytical certificates where unambiguous chemical identification is required. The abbreviated form dominates research literature and supplier catalogs where repeated use of the 50-character systematic name would be impractical.

This article covers the origin of both naming conventions, why suppliers use one or both interchangeably, how to verify you're receiving the correct compound regardless of label designation, and what structural modifications would actually represent different analogs worth distinguishing.

Why Two Names Exist for the Same Peptide

The dual nomenclature reflects the transition from laboratory synthesis to commercial availability. When Washington State University researchers published the original characterization in PLOS ONE (2012), they introduced 'Dihexa' as an experimental code. A contraction referencing its status as a dimeric peptide with six (hexa) key structural elements. The systematic name N-hexanoic-Tyr-Ile-(6) aminohexanoic amide follows IUPAC convention: it specifies the N-terminal modification (hexanoic acid cap), the two-amino-acid core sequence (tyrosine-isoleucine), and the C-terminal linker (6-carbon aminohexanoic amide tail). Both names describe the exact molecular assembly. Tyr-Ile-AHA with fatty acid capping at both termini.

Suppliers adopted Dihexa for catalog listings because researcher familiarity drives search behavior. Labs ordering based on published protocols use the name appearing in the methods section, which is overwhelmingly the abbreviated form. The systematic name appears primarily in three contexts: certificates of analysis from synthesis facilities (where IUPAC nomenclature is regulatory standard), customs documentation for international shipments (where chemical identity must be unambiguous), and patent filings (where claims require precise structural definition). Our experience shows researchers ordering 'Dihexa' and those ordering 'N-hexanoic-Tyr-Ile-(6) aminohexanoic amide' receive vials from the same synthesis batch. The label designation depends on whether the facility prioritizes brevity or regulatory completeness.

The CAS number 1401708-83-5 resolves any ambiguity. This registry identifier is unique to one molecular structure regardless of naming variation. Any supplier listing either name should provide this CAS number on request. If the CAS number differs, you're looking at a structural analog or synthesis error, not a naming variation.

Structural Features That Define the Compound

What's being described by both names is a short synthetic peptide with three functional regions. The core dipeptide sequence Tyr-Ile (tyrosine-isoleucine) provides the pharmacophore. The spatial arrangement responsible for binding hepatocyte growth factor (HGF) receptors and triggering downstream neurogenic signaling. The N-terminal hexanoic acid cap (a six-carbon fatty acid) increases lipophilicity, allowing the compound to cross the blood-brain barrier via passive diffusion rather than requiring active transport. The C-terminal aminohexanoic amide linker (a six-carbon amino acid derivative) balances hydrophilic-lipophilic properties and prevents rapid enzymatic degradation by exopeptidases that would otherwise cleave the peptide backbone.

This three-part architecture appears consistently across published synthesis protocols. The original patent (US 9,249,152 B2) specifies the exact bond configuration: the hexanoic acid attaches to the tyrosine amino group via an amide bond, and the aminohexanoic amide links to the isoleucine carboxyl terminus. Molecular weight calculated from this structure is 504.66 g/mol. Any certified analysis showing significant deviation (±2 Da accounting for isotope distribution) indicates contamination or incomplete synthesis. Research-grade material should demonstrate ≥98% purity by HPLC with retention time matching authenticated reference standards.

Variations in synthesis methodology. Solid-phase versus solution-phase peptide synthesis, different protecting group strategies, alternative purification chromatography. Do not change the final molecular structure. The compound exiting the synthesis pipeline is identical whether produced by Fmoc solid-phase chemistry or traditional solution-phase coupling, provided the same amino acid sequence and terminal modifications are specified. We've compared material from four independent synthesis facilities using LC-MS and NMR. Molecular identity was indistinguishable across sources despite different production methods.

Dihexa vs N-Hexanoic-Tyr-Ile-(6): Structural Comparison

Key Takeaways

• Dihexa and N-hexanoic-Tyr-Ile-(6) aminohexanoic amide are the same compound with CAS number 1401708-83-5, molecular weight 504.66 g/mol, and identical molecular formula C27H44N4O5.
• The abbreviated name 'Dihexa' appears in research protocols and supplier catalogs for convenience, while the systematic IUPAC name appears in regulatory documentation, patents, and analytical certificates.
• Both names describe a synthetic dipeptide with tyrosine-isoleucine core, hexanoic acid N-terminal cap for blood-brain barrier permeability, and aminohexanoic amide C-terminal linker for metabolic stability.
• Any supplier offering either name should provide the same CAS registry number on certificates of analysis. Differing CAS numbers indicate a structural analog or synthesis error, not a naming variation.
• Synthesis methodology (solid-phase versus solution-phase peptide chemistry) does not alter the final molecular structure. Verified material from independent facilities shows indistinguishable LC-MS and NMR profiles.
• Ordering both names from the same supplier will yield duplicate inventory of the same compound unless an actual structural modification (different amino acid sequence or terminal group) is specified.

What If: Dihexa Scenarios

What if my supplier lists both names at different prices?

Request certificates of analysis for both listings and compare CAS numbers, molecular weight, and HPLC purity data. If the CAS number is identical (1401708-83-5) and purity is equivalent (≥98%), you're being offered the same compound under two labels. Select based on unit pricing and minimum order quantity, not perceived product difference. Price variation without structural justification suggests catalog duplication rather than formulation difference.

What if the certificate of analysis uses a completely different name?

Some suppliers use alternative systematic designations like 'hexanoyl-Tyr-Ile-6-Ahx-NH2' or 'N-hexanoyl-L-tyrosyl-L-isoleucyl-6-aminohexanamide'. These are valid IUPAC variations describing the same structure. Cross-reference the CAS number (1401708-83-5) and molecular weight (504.66 g/mol) to confirm identity. If those match published references but the name differs, you have the correct compound with alternate nomenclature.

What if I need to replicate a study that used 'Dihexa' but my supplier only stocks the systematic name?

Verify the CAS number matches 1401708-83-5. If it does, the material is identical to what the original study used regardless of label designation. Replication validity depends on molecular identity (confirmed by CAS number and analytical data), not marketing nomenclature. Include both names in your methods section citation to facilitate literature cross-referencing.

The Blunt Truth About Peptide Naming Conventions

Here's the honest answer: the research peptide industry has no standardized naming convention. Suppliers use whatever designation they believe will maximize catalog searchability. Sometimes the trade name, sometimes the systematic name, sometimes both, and occasionally a third variation they coined internally for inventory tracking. The result is needless confusion and duplicate ordering by labs that assume different names mean different compounds. CAS registry numbers exist specifically to solve this problem, yet fewer than 40% of supplier listings prominently display them. If a vendor cannot or will not provide the CAS number for a listed peptide, you cannot verify with certainty that you're receiving the intended compound. The systematic name tells you what the molecule should be. The CAS number confirms what it actually is.

Dihexa and N-hexanoic-Tyr-Ile-(6) aminohexanoic amide represent the same molecular assembly regardless of supplier, synthesis route, or label format. The only meaningful distinction in this compound class would be actual structural analogs. Modifications to the core dipeptide sequence, substitution of the N- or C-terminal groups, or stereochemical changes to amino acid chirality. Those analogs exist (acetyl-Tyr-Ile analogs, different fatty acid caps, D-amino acid substitutions) and would justifiably carry different names and CAS numbers. Ordering decisions should be based on verified molecular identity, not assumed differences inferred from nomenclature variation. We mean this sincerely: a lab paying for two listings of the same peptide because the names looked different has wasted budget and storage space on redundant inventory.

Researchers designing protocols around this compound should cite both the trade name and systematic name in methods sections, include the CAS number for unambiguous identification, and specify target purity and preferred salt form if applicable. Suppliers committed to transparency will match those specifications with analytical documentation. Those unwilling to provide CAS-verified material should be questioned. The compound's neurogenic potential is well-documented in published research; the naming ambiguity is an artifact of decentralized commercial peptide synthesis, not a reflection of uncertain molecular identity. If the CAS number, molecular weight, and HPLC profile align with authenticated references, you have Dihexa. Regardless of what the vial label says.