Dictionary of Terms

A GLP1 Forum Escrow reference for buyers. Educational and research context only; nothing here is medical advice.

ADA

Short for antidrug antibodies: immune proteins a body may produce against a therapeutic peptide, which in principle can change its pharmacokinetics, safety and efficacy. In the SURPASS Phase 3 program reviewed by the FDA, ADA responses were reported not to have altered tirzepatide pharmacokinetics or efficacy.

API

Active pharmaceutical ingredient: the compound a vial is actually sold for, as opposed to any filler or salt. On a tirzepatide listing, tirzepatide itself is the API.

Bacteriostatic water (BAC)

Sterile water containing 0.9% benzyl alcohol, a preservative that stops bacteria from multiplying further. It is the diluent most often named in reconstitution literature, and community threads frequently cite its pH as one variable linked to injection site reactions.

COA

Certificate of Analysis: a lab document reporting a sample’s measured purity and quantity. It is usually produced with high-performance liquid chromatography (HPLC), most often by PeptideTest or Janoshik.

Counterion

Many peptides are supplied as a salt. The API is paired with an oppositely charged ion, the counterion, to form a stable compound that tends to dissolve, store and keep better, which simplifies manufacturing and handling.

Deamidation

A degradation pathway in which residues such as asparagine or glutamine shed an amide group and convert into related but different structures, leaving the peptide potentially less stable and less active. Because the degraded forms separate on an HPLC trace, deamidation is already reflected in a reported purity figure.

Endocrine System

The network of glands that release hormones and, through them, regulate a wide range of bodily processes. Hunger signaling is only one of the many functions it governs.

GLP1

Glucagon-like peptide-1, and by extension the drug class built around its receptor, with which tirzepatide is grouped. Approved medicines in the class are prescribed for type 2 diabetes (T2D) and obesity.

Research-Peptide Market

Shorthand for buying lyophilized tirzepatide labeled “for research only” rather than liquid tirzepatide prepared by a compounding pharmacy.

Group Buy

1. Run by the vendor as a sale or promotion: usually backed by a purity and overfill guarantee or a reship offer, and sent from the vendor’s own warehouse. Scam risk is generally lower because the seller stays accountable.
2. Organized by a third-party individual: a private person pools buyers to purchase 1,000 or more vials. High risk, little accountability, many documented losses; these are nearly always scams and should be avoided.

Injection Site Reaction (ISR)

A term from clinical literature for a local reaction where an injectable product was given, described as stinging at the time or redness shortly afterward. Proposed causes include histamine release and the pH of the reconstituted solution.

LTEV

Linked To Each Vial. A supplier practice of tying a lab test to the batch number on every vial, so the report matches the product in hand.

MOQ

Minimum Order Quantity. Many suppliers set a floor on order value or kit count before accepting an order, and some set a separate threshold for free shipping.

Peptides

Short chains of amino acids; a broad family of molecules that includes tirzepatide.

Powder

1. Lyophilized Powder: freeze-dried tirzepatide, normally in a vacuum-sealed vial. It may look loose or like a compact puck, and neither appearance signals a difference in quality.
2. Raw Powder: unprocessed tirzepatide without the mannitol or other excipients lyophilization requires. Usually sold in bulk from grams to kilograms, it is less shelf-stable and hard to measure accurately at milligram scale without specialized equipment, so buyers are generally cautioned against it.

Reconstitution

Dissolving a freeze-dried peptide in a diluent such as bacteriostatic water, converting lyophilized powder back into a solution.

RS

Research Subject. Community shorthand for a person who receives tirzepatide as a subject in a research context.

SPPS

Solid-Phase Peptide Synthesis, the method used to manufacture tirzepatide by building the chain step by step on a solid support. For this compound it first appears in Eli Lilly’s 2016 patents.

Sterility Test

An add-on to the COA that looks for microbial contamination. The lab dissolves the powder in ordinary water rather than BAC, places it on culture media such as broth or agar, and watches for growth over several weeks.

• TAMC: Total Aerobic Microbial Count, offered by Janoshik.
• TYMC: Total Yeast and Mold Count, also from Janoshik.
• USP71: the US Pharmacopeia chapter 71 sterility test, offered by PeptideTest.

Third Party Testing (3P)

Testing an end user arranges independently, with the results shared publicly. Generally regarded as more trustworthy than vendor-supplied tests, though less so than testing your own sample.

USP

United States Pharmacopeia standard: the pharmaceutical-grade benchmarks applied in FDA-regulated settings.

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