Peptide Glossary
Definitions of peptide terminology, compound shorthand, and common abbreviations. Plain language, no jargon.
A
AI (Aromatase Inhibitor)
A compound that blocks the enzyme aromatase, which converts testosterone to estrogen. Used to manage estrogen levels when running hormonal protocols. Not a peptide, but relevant in the context of TRT + peptide stacks.
B
Bac Water (Bacteriostatic Water)
Sterile water containing 0.9% benzyl alcohol as a preservative. Used to reconstitute lyophilized peptides for injection. Allows multiple draws from the same vial over weeks without bacterial growth.
BDNF (Brain-Derived Neurotrophic Factor)
A protein that supports neuron growth and survival. Some peptides (like Semax) are thought to increase BDNF, supporting cognitive function and mood.
BPC (BPC-157)
Body Protection Compound-157. A healing peptide used for tendon, ligament, muscle, and gut repair. One of the most popular peptides in the community.
C
COA (Certificate of Analysis)
A lab report showing the purity, identity, and sometimes endotoxin levels of a peptide. A batch-matched COA from a third-party lab (like Janoshik) is the gold standard for verifying peptide quality.
Cycle / Cycling
Running a peptide for a specific duration (e.g., 8 weeks), then taking time off. Some peptides benefit from cycling, others (like GLP-1s) can be run continuously. Context-dependent.
CJC (CJC-1295)
A growth hormone releasing hormone (GHRH) analog. Comes in two forms: with DAC (long-acting) and without DAC (short-acting). Often stacked with ipamorelin for GH release.
E
E2 (Estradiol)
The primary form of estrogen. Relevant for people running testosterone or growth hormone protocols, as these can affect estrogen balance. Monitored via bloodwork.
G
GHRP / GHRH
Growth Hormone Releasing Peptide (GHRP) and Growth Hormone Releasing Hormone (GHRH). Two classes of peptides that signal the pituitary to release growth hormone. Examples: ipamorelin (GHRP), CJC-1295 (GHRH).
GLP-1 (Glucagon-Like Peptide-1)
A hormone that regulates blood sugar and appetite. GLP-1 agonists (semaglutide, tirzepatide, retatrutide) mimic this hormone, suppressing appetite and improving insulin sensitivity. Used primarily for weight loss.
H
Half-Life
The time it takes for half of a substance to be eliminated from the body. Short half-life peptides (like BPC-157) are injected daily. Long half-life peptides (like semaglutide) are injected weekly.
I
IGF-1 (Insulin-Like Growth Factor 1)
A hormone produced by the liver in response to growth hormone. IGF-1 levels are used to monitor the effectiveness of growth hormone secretagogues. Higher IGF-1 indicates increased GH activity.
IM (Intramuscular)
Injection into muscle tissue (e.g., glute, thigh, deltoid). Less common for peptides than sub-q. Used for some compounds where IM absorption is preferred.
Ipa (Ipamorelin)
A growth hormone releasing peptide (GHRP). Stimulates GH release with minimal side effects. Commonly paired with CJC-1295 for a synergistic GH boost.
L
Lyophilized
Freeze-dried. Most research peptides are sold as lyophilized powder, which is more stable than liquid. Must be reconstituted with bacteriostatic water before injection.
M
mcg vs mg
Micrograms (mcg) vs milligrams (mg). 1 mg = 1000 mcg. Common mistake: dosing in mg when protocol calls for mcg, resulting in 1000x overdose. Always double-check units.
P
Peptide
A short chain of amino acids (2-50 amino acids). Peptides act as signaling molecules in the body. Longer chains (50+) are proteins. In this context, bioactive peptides used for weight loss, healing, growth, etc.
Pin / Pinning
Slang for injection. "Pinning BPC daily" means injecting BPC-157 every day. From the needle (pin) used to inject.
R
Reconstitution
The process of mixing lyophilized (powder) peptide with bacteriostatic water to create an injectable solution. Requires math to calculate correct dose per syringe unit. Use the reconstitution calculator on this site.
Reta (Retatrutide)
Shorthand for retatrutide, a triple-agonist GLP-1 peptide (GLP-1 + GIP + glucagon). Currently the most powerful weight loss peptide. More expensive than tirz or sema.
S
Sub-Q (Subcutaneous)
Injection into the fat layer just under the skin. Most peptides are administered sub-q (lower abdomen, thigh, upper buttock). Easier and less painful than IM.
Sema (Semaglutide)
Shorthand for semaglutide, a single-agonist GLP-1 peptide. The original GLP-1 for weight loss (Ozempic/Wegovy). Still effective, but tirz usually outperforms it.
T
Titration
Gradually increasing dose over time to find the effective dose with minimal side effects. Common with GLP-1s (start low, increase every 1-2 weeks until appetite is suppressed).
TRT (Testosterone Replacement Therapy)
Medical treatment for low testosterone. Not a peptide, but often stacked with peptides (e.g., TRT + growth hormone secretagogues). Requires medical supervision and bloodwork.
Tirz (Tirzepatide)
Shorthand for tirzepatide, a dual-agonist GLP-1 peptide (GLP-1 + GIP). Popular for weight loss, more effective than semaglutide for most people, less expensive than reta.
TB (TB-500)
Thymosin Beta-4 fragment. A healing peptide often stacked with BPC-157 for soft tissue recovery. Works systemically (affects the whole body, not just local injection site).
U
U100 Syringe
Insulin syringe calibrated for 100 units per ml. Standard for peptide injection. Each unit = 0.01ml. Used because most peptide doses are small (measured in units, not ml).
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