Clinician reference

Peptide & compounding glossary

Definitions of the peptide, compounding, and clinical terms clinicians use when running white-label peptide, GLP-1, and longevity programs.

503A pharmacy

State-licensed compounding pharmacy that dispenses patient-specific prescriptions. Where most peptide programs source individual patient vials.

See also: 503A vs 503B compounding

503B outsourcing facility

FDA-registered compounder that produces office-use batches without patient-specific prescriptions. Used for clinics that want in-office inventory.

See also: 503A vs 503B compounding

Adjunct therapy

Treatment used alongside a primary therapy to enhance results — e.g., B12 or lipotropics alongside GLP-1s.

Angiogenesis

Formation of new blood vessels; mechanism through which BPC-157 and TB-500 accelerate soft-tissue healing.

Bacteriostatic water

Sterile water containing 0.9% benzyl alcohol used to reconstitute lyophilized peptide vials for subcutaneous injection.

Beyond-use date (BUD)

Date after which a compounded preparation must not be used. Set by the compounding pharmacy per USP guidelines.

Cash-pay medicine

Care paid out of pocket by the patient, common in weight-loss, longevity, aesthetics, and hormone practices.

Certificate of Analysis (COA)

Independent third-party lab report tied to a specific lot documenting identity, purity, sterility, and endotoxin results.

See also: COA sample library, Third-party lab tested peptides

Compounded GLP-1

GLP-1 (semaglutide or tirzepatide) prepared by a licensed compounding pharmacy, often with B12 or other approved excipients.

See also: Compounded vs branded GLP-1

Cycling protocol

Alternating periods of use and rest (e.g., 5-days-on / 2-days-off) to preserve pituitary responsiveness on GH-releasing peptides.

Endotoxin testing

Assay (LAL / kinetic chromogenic) for bacterial endotoxins in injectable preparations. Reported on every reputable COA.

Ghrelin receptor

GPCR whose activation by GHRPs (ipamorelin, hexarelin) triggers growth hormone release.

GHRH analog

Peptides such as sermorelin, CJC-1295, and tesamorelin that mimic endogenous GHRH to stimulate pulsatile GH secretion.

See also: CJC-1295 wholesale

GHRP (Growth Hormone Releasing Peptide)

Peptides such as ipamorelin, hexarelin, GHRP-2/6 that stimulate pituitary GH release via the ghrelin receptor.

See also: Ipamorelin wholesale

GLP-1 receptor agonist

Class of peptide drugs (semaglutide, tirzepatide, retatrutide) that mimic glucagon-like peptide-1 to promote satiety, delay gastric emptying, and improve glycemic control.

See also: GLP-1 titration guide

HbA1c

Glycated hemoglobin, a 90-day glycemic marker followed in GLP-1 and metabolic programs.

HPLC purity

High-performance liquid chromatography assay reporting peptide purity as a percentage. Clinical-grade peptides typically test >98%.

IGF-1

Insulin-like growth factor 1, a downstream marker used to monitor GH-releasing peptide protocols.

Insulin sensitivity

Efficiency with which cells respond to insulin. Improved by GLP-1 agonists; transiently affected by GH-releasing peptides.

Lipotropic (MIC) injection

Injection blend of methionine, inositol, choline, and B-complex used adjunctively in weight-loss programs.

See also: B12 and lipo injections wholesale

Lyophilized peptide

Peptide freeze-dried to a stable powder for shipping and storage; reconstituted with bacteriostatic water before use.

Mass spectrometry (MS)

Analytical method confirming peptide molecular weight and identity. Standard alongside HPLC on a clinical COA.

MC4 receptor

Melanocortin-4 receptor targeted by PT-141 (bremelanotide) to drive central sexual arousal.

See also: PT-141 for libido

Mesotherapy

Technique delivering micro-injections of pharmaceutical, homeopathic, or nutritional compounds into the mesoderm for aesthetic and wellness purposes.

See also: Mesotherapy wholesale

NAD+

Nicotinamide adenine dinucleotide, a coenzyme central to mitochondrial energy and sirtuin activation. Used IV and SC in longevity programs.

See also: NAD+ dosing guide

Patient portal

Branded web app where patients complete intake, receive prescriptions, and manage subscriptions. Central to white-label peptide programs.

Peptide stack

Two or more peptides prescribed together for synergistic effect (e.g., BPC-157 + TB-500 for tendon repair).

See also: Peptide stacks

PRN dosing

'Pro re nata' — as-needed dosing rather than a fixed schedule. Standard for PT-141.

Reconstitution

Adding bacteriostatic water to a lyophilized peptide vial to prepare it for injection.

Refill cadence

The subscription rhythm on which a peptide ships to the patient — typically every 4, 8, or 12 weeks depending on protocol.

Sirtuins

Family of NAD+-dependent enzymes involved in cellular longevity and stress response.

Sterility testing

USP <71> assay confirming a compounded preparation is free of viable microorganisms.

Subcutaneous injection (SC)

Injection into the fat layer beneath the skin. The standard delivery route for most compounded peptides.

Telomere

Repetitive DNA sequence at chromosome ends whose length correlates with cellular aging; targeted by longevity peptides such as epitalon.

Titration

Systematic dose escalation over weeks to reach a target maintenance dose while minimizing side effects. Standard in GLP-1 programs.

See also: GLP-1 titration guide

White-label peptide program

Turnkey program where a clinic sells peptides under its own brand while a partner handles sourcing, compliance, fulfillment, and billing.

See also: How white-label works