Educational reference only · Adults 18+ · Not medical or dosing advice · Confirm decisions with a licensed clinician
Peptide Plug Education
A practical guide to peptide categories
This page is a Peptide Plug reference to major peptide categories, the compounds commonly discussed in each, and questions worth taking to a licensed clinician. It does not reproduce protocols, prescribe doses, or tell you what to take.
Important: many compounds discussed in peptide communities are investigational or unapproved for the uses people discuss online. Peptide Plug is an organization and education tool, not a medical provider.
How to use a peptide guide
Start by learning what each compound has been studied for. Whether to use any compound, and how, is a decision for a licensed clinician. Peptide Plug keeps that education-first boundary.
1. Start with your clinicianBring your health history, current medications and questions.
2. Learn the pathwayUnderstand what biological system a compound is meant to influence before comparing names or combinations.
3. Check the evidenceSeparate approved indications, human clinical evidence, early research, and community claims.
4. Use clinician oversightMedical history, labs, medications, risk factors and response matter more than a generic protocol.
Major compound categories
These summaries are written by Peptide Plug for general education. They are intentionally brief and non-prescriptive.
Growth-hormone-axis compounds
Compounds in this group are discussed around GH/IGF signaling, recovery, lean mass, sleep quality and body-composition research.
CJC-1295
A GHRH analogue; not FDA-approved; human evidence limited.
GH axisIpamorelin
A ghrelin-receptor agonist studied as a relatively selective growth-hormone secretagogue.
GH axisSermorelin
A GHRH fragment used clinically to stimulate endogenous GH release in certain settings.
GH axisTesamorelin
A GHRH analog with an FDA-approved indication in HIV-associated lipodystrophy; other uses require separate evaluation.
GH axisIbutamoren (MK-677)
An oral ghrelin-receptor agonist studied for GH/IGF-1 effects; not an FDA-approved peptide therapy.
SecretagogueIGF-1 LR3
A long-acting IGF analog discussed in performance communities, with limited approved clinical context for this form.
IGF signalingAOD-9604
A growth-hormone fragment researched for fat-metabolism effects rather than appetite suppression.
Metabolic researchSLU-PP-915
An early research compound discussed around exercise-mimetic and metabolic signaling; human evidence remains limited. Not FDA-approved; no approved human use; human data absent or very limited.
Early researchPTD-DBM
An experimental peptide discussed around myostatin-related muscle preservation and regeneration pathways. Not FDA-approved; no approved human use; human data absent or very limited.
Experimental Tissue repair & regenerative research
This category centers on connective tissue, wound-healing pathways, inflammation and recovery. Much of the popular discussion exceeds established human clinical evidence.
BPC-157
A gastric peptide fragment widely discussed for tissue and gut repair, but without FDA approval for human therapeutic use.
Repair researchTB-500 / Thymosin beta-4 related
Discussed around actin regulation, cell migration and connective-tissue repair; product identity and evidence vary.
Repair researchGHK-Cu
A copper-binding peptide studied in skin remodeling, collagen biology and wound-healing contexts.
Skin / repair Cognition, mood & nootropic research
These compounds are discussed around attention, neuroplasticity, calm, mitochondrial energy or memory. Evidence quality ranges widely.
Semax
A synthetic ACTH-fragment analog used in some countries and researched for neurocognitive effects.
NeuroSelank
A tuftsin-derived peptide developed as an anxiolytic in Russia and studied for stress and mood-related signaling.
Mood / calmDihexa
A highly experimental cognitive compound with preclinical synaptogenesis research and no established human safety profile.
PreclinicalP21
An experimental cognitive peptide discussed around neuroplasticity and memory-related pathways. Not FDA-approved; no approved human use; human data absent or very limited.
ExperimentalMethylene Blue
A long-used drug and redox agent with an approved methemoglobinemia indication; cognitive use is a separate off-label/research topic.
Drug / redox Sleep, circadian rhythm & longevity
This group is framed around sleep architecture, circadian timing, immune aging and cellular resilience.
DSIP
A peptide investigated historically in relation to sleep physiology, with mixed and limited clinical evidence.
Sleep researchEpitalon / Epithalon
A synthetic tetrapeptide associated with aging and circadian research, with limited high-quality human evidence.
Longevity researchThymosin Alpha-1
An immune-modulating peptide with clinical use in some countries and ongoing research in immune regulation.
Immune signalingThymalin
A thymic peptide preparation discussed in aging and immune-support contexts, primarily outside US-approved medicine. Not FDA-approved; no approved human use; human data absent or very limited.
Immune / longevityLL-37
An endogenous antimicrobial peptide involved in innate immunity; exogenous use is complex and highly experimental.
Immune research Hormonal, reproductive & sexual-health signaling
These compounds act on reproductive-hormone pathways, melanocortin signaling or neuroendocrine bonding systems.
Kisspeptin / Gonadorelin
Upstream hypothalamic-pituitary signaling approaches that influence LH/FSH and reproductive hormone pathways.
Reproductive axisPT-141 (Bremelanotide)
A melanocortin agonist with an FDA-approved indication for acquired generalized HSDD in premenopausal women.
Approved indication existsOxytocin
A naturally occurring neuropeptide and approved medication in obstetric contexts; wellness and intimacy uses are separate topics.
Neuroendocrine Gut, inflammation & mitochondrial metabolism
These research themes focus on inflammatory signaling, intestinal biology, cellular energy and metabolic flexibility.
KPV
A short alpha-MSH fragment researched for anti-inflammatory activity, especially in gut and skin models.
Inflammation researchMOTS-C
A mitochondrial-derived peptide studied for cellular energy, metabolic signaling and exercise-related effects.
Mitochondrial Multi-pathway combination concepts
Peptide Plug does not publish or recommend named combinations or protocols. These are the broader educational concepts behind combining different pathways.
Repair + inflammation control
One pathway may focus on tissue repair while another focuses on inflammatory signaling or circulation. The concept is to address more than one bottleneck, not simply add more compounds.
Sleep timing + sleep depth + recovery
Circadian timing, sleep architecture and hormonal recovery signals are different systems. A clinician may evaluate them separately rather than treating “poor sleep” as one problem.
Cognition + calm + cellular energy
Focus can be affected by neuroplasticity, anxiety/stress signaling and cellular energy. These are distinct contributors that may need different evaluation.
Metabolism + muscle preservation
Body-composition goals can involve fuel use, appetite, visceral fat, training recovery and lean mass. A single scale number does not capture all of those systems.
Questions worth taking to a clinician
Evaluation should be individualized. These questions keep the conversation focused without turning a general guide into a protocol.
What is the actual goal?What symptom, measurement, diagnosis or outcome are we trying to change?
What is the evidence level?Approved indication, human trials, early clinical research, preclinical research, or anecdotal use?
What changes the risk?Cancer history, pregnancy, autoimmune disease, cardiovascular disease, endocrine disorders, allergies and current medications all matter.
What will be monitored?Ask what symptoms, labs, vitals or adverse effects would change the plan or stop treatment.
Common questions
Do all peptides need to be cycled?
No single rule applies. Some therapies are used for defined periods, some are intentionally cycled, and some advanced or experimental compounds are discussed only in short provider-directed contexts. The appropriate schedule depends on the specific compound and medical situation.
Can peptides be combined?
Some clinicians combine therapies when there is a clear rationale and compatible safety profile. Using more compounds is not automatically better: each one adds variables, interactions and monitoring needs.
Are peptides safe long term?
That depends on the specific compound, indication, dose, duration, evidence base and individual health history. Some compounds have established medical uses; many popular peptide products do not have comparable long-term human safety data.
Do I need labs?
Not every therapy uses the same monitoring. A clinician may use baseline or follow-up labs depending on the compound, medical history, goals, symptoms and known risks.
What happens when a peptide is stopped?
Effects may fade after discontinuation depending on the pathway and treatment goal. Stopping considerations are compound-specific, and a clinician can explain whether tapering, follow-up or repeat evaluation is appropriate.
Are all peptide therapies FDA approved?
No. Some peptide-based medications have FDA-approved indications, while many compounds discussed online are investigational, compounded, or unapproved. Approval for one indication also does not automatically validate other uses.
Source transparencyThis guide is written by Peptide Plug for general education. Peptide Plug does not publish any third party’s protocols, combinations, testimonials or dosing tables. For regulatory status and research, see FDA labeling, ClinicalTrials.gov records and our Research Library.
Use education for context. Use Peptide Plug for organization.
Track the schedule your clinician gives you, keep inventory and logs together, and compare your own measurements over time.
Open Peptide PlugTracking tool, not medical advice. Peptide Plug is an organization and calculation tool for adults 18 and older. It does not provide medical advice, diagnosis or treatment, and it does not recommend, suggest or verify any substance, amount, schedule or route. Calculators only perform arithmetic on the numbers you enter; double-check every result. Many compounds referenced on this site are not FDA-approved for human use, and products sold outside an approved supply chain are not verified for identity, purity or concentration. Peptide Plug does not sell, supply, source or link to sellers of any compound. Confirm every decision with a licensed clinician or pharmacist. In an emergency, call 911.