Peptide Glossary

Complete A-Z index of research peptides with scientific data, categories, and links to detailed profiles.

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ACTH (Cosyntropin)
Hormones & Endocrine (Non-GH)

Cosyntropin is a synthetic version of the first 24 building blocks of the body's natural stress hormone ACTH. It is used as an FDA-approved diagnostic tool (Cortrosyn) to test whether the adrenal glands are working properly, and is also used to treat certain conditions like infantile spasms.

AHK-Cu
Skin, Hair & Aesthetics

AHK-Cu (Copper Tripeptide-3) is a synthetic copper peptide designed specifically to target hair follicle cells. Unlike the naturally occurring GHK-Cu, AHK-Cu was engineered to stimulate hair growth by extending the active growth phase of the hair cycle and increasing follicle cell activity. It is applied topically to the scalp.

AOD-9604
Metabolic & Weight Loss

AOD-9604 is a modified fragment of human growth hormone (amino acids 176-191). Originally developed as an anti-obesity compound, it shows preclinical evidence for promoting fat metabolism without affecting blood sugar or growth.

ARA-290 (Cibinetide)
Immune & Inflammation

ARA-290 (cibinetide) is a synthetic 11-amino-acid peptide based on the tissue-protective part of erythropoietin, without stimulating red blood cell production. Research focuses on nerve pain, small fiber neuropathy, sarcoidosis, and metabolic syndrome.

Argireline (Acetyl Hexapeptide-3)
Skin, Hair & Aesthetics

Argireline is a synthetic six-amino-acid peptide widely used in cosmetic skincare as a topical alternative to botulinum toxin injections. It works by partially blocking the nerve signaling pathway involved in muscle contractions, reducing the intensity of facial movements and softening expression lines around the eyes and forehead.

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MGF (Mechano Growth Factor)
Performance & Body Composition

MGF (Mechano Growth Factor) is a natural variant of the IGF-1 gene that the body produces in response to muscle being stretched or loaded during exercise. Research focuses on muscle repair, activation of muscle stem cells, and recovery from exercise-related damage.

MK-677 (Ibutamoren)
Growth Hormone / IGF-1 Axis

MK-677 (Ibutamoren) is an oral (non-injectable) compound that triggers growth hormone release by mimicking the hunger hormone ghrelin. Research focuses on increasing growth hormone and IGF-1 levels, improving sleep quality, body composition, and bone density.

MOTS-c
Longevity & Cellular Health

MOTS-c is a 16-amino-acid peptide produced by mitochondria (the energy centers of cells), encoded in mitochondrial DNA. It was the first mitochondrial peptide to enter clinical trials. Research focuses on metabolic health, exercise performance, and longevity, with natural levels declining with age.

Matrixyl (Palmitoyl Pentapeptide-4)
Skin, Hair & Aesthetics

Matrixyl is a fat-soluble signal peptide used in cosmetic skincare to boost collagen production. It works by mimicking collagen breakdown signals, prompting skin cells to produce more collagen. It is one of the most clinically validated anti-wrinkle peptides and is found primarily in topical products.

Melanotan 1 (Afamelanotide)
Skin, Hair & Aesthetics

Melanotan 1 (Afamelanotide) is a synthetic version of the natural skin-darkening hormone alpha-MSH. It is FDA-approved as Scenesse, a subcutaneous implant for treating EPP, a rare genetic condition causing extreme sun sensitivity. It is also commonly used via injection or nasal spray for tanning.

Melanotan II
Skin, Hair & Aesthetics

Melanotan II is a synthetic version of alpha-MSH, a natural hormone involved in skin pigmentation. It activates hormone receptors involved in skin color and sexual function, and is being studied for both tanning and sexual health applications.

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SNAP-8 (Acetyl Octapeptide-3)
Skin, Hair & Aesthetics

SNAP-8 is an eight-amino-acid peptide used in cosmetic skincare to reduce wrinkles. It works by partially blocking nerve-to-muscle signaling in a way similar to botulinum toxin but through a different mechanism. It is used primarily in topical formulations.

SS-31 (Elamipretide)
Longevity & Cellular Health

SS-31 (Elamipretide) is a four-amino-acid peptide that targets and concentrates in the inner membrane of mitochondria (the energy centers of cells). It is being developed for mitochondrial diseases, heart failure, and age-related conditions.

Selank
Cognition, Mood & Neuroprotection

Selank is a synthetic seven-amino-acid peptide derived from the immune protein tuftsin, developed in Russia. Research shows it has both immune-supporting and anti-anxiety properties without causing sedation or dependence.

Semaglutide
Metabolic & Weight Loss

Semaglutide is a medication that mimics a natural fullness hormone (GLP-1) in the body. It is FDA-approved as Wegovy for weight management and Ozempic for type 2 diabetes, with significant effects on appetite control and blood sugar regulation.

Semax
Cognition, Mood & Neuroprotection

Semax is a synthetic peptide derived from a brain hormone fragment (ACTH 4-10), developed in Russia for brain-protective and cognitive-enhancing purposes. Research focuses on stroke recovery, cognitive function, and brain growth factor support.

Sermorelin
Growth Hormone / IGF-1 Axis

Sermorelin is a synthetic 29-amino-acid growth hormone-releasing compound. It was FDA-approved for pediatric growth hormone deficiency and is widely used off-label for anti-aging and body composition improvement.

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Peptide Terminology

General Terms

Reconstitution
The process of dissolving lyophilized (freeze-dried) peptide powder in bacteriostatic water to create an injectable solution.
Subcutaneous injection
An injection administered into the fatty tissue layer just beneath the skin, the most common route for peptide administration.
Lyophilized
Freeze-dried. Most research peptides are sold in lyophilized powder form for stability during storage and shipping.
Bacteriostatic water
Sterile water containing 0.9% benzyl alcohol as a preservative, used to reconstitute peptides. Allows multi-use from the same vial.
Half-life
The time required for half of a peptide to be eliminated from the body. Determines dosing frequency.
Secretagogue
A substance that promotes secretion of another substance. Growth hormone secretagogues stimulate the pituitary to release GH.
GLP-1 agonist
A compound that activates glucagon-like peptide-1 receptors, used in metabolic and weight loss research (e.g., Semaglutide, Tirzepatide).
Loading phase
An initial period of higher or more frequent dosing used with some peptides to reach effective tissue concentrations faster.
Reconstitution calculator
A tool that calculates how much bacteriostatic water to add to a peptide vial and what syringe volume equals your target dose.

Development Stages

Each peptide profile shows a development stage indicating how far the compound has progressed through the drug development pipeline.

Discovery
Earliest research stage. The peptide has been identified and is being studied in laboratory or computational settings only.
Preclinical
Being tested in cell cultures and animal models. Has not yet been tested in humans.
Phase 1
First human trials. Small groups (20–80 people) to evaluate safety, dosage, and side effects.
Phase 2
Expanded trials (100–300 people) to assess efficacy and further evaluate safety.
Phase 3
Large-scale trials (1,000–3,000+ people) to confirm effectiveness, monitor side effects, and compare to existing treatments.
FDA Review
A New Drug Application has been submitted and is under review by the FDA for approval.
Phase 4
Post-marketing surveillance conducted after regulatory approval. Monitors long-term safety and effectiveness in the general population.
Discontinued
Development has been stopped, typically due to safety concerns, lack of efficacy, or commercial reasons.

Regulatory Approvals

Regulatory approval status indicates whether a peptide has been approved for medical use by a government health authority.

FDA Approved
Approved by the U.S. Food and Drug Administration for at least one medical indication.
EMA Approved
Approved by the European Medicines Agency for use in the European Union.
Russia Approved
Approved by Russia’s Ministry of Health. Several peptides (e.g., Selank, Semax) are approved in Russia but not in Western markets.
Investigational
Actively being studied in clinical trials but not yet approved by any major regulatory body.
Not Approved
No regulatory approval in any major jurisdiction. Most research peptides fall into this category.