Pepdex A-Z: zero to first cycle

If you've never used peptides and you don't know where to start, read this once end-to-end. It links to everything else on Pepdex in the order it actually matters.

1. What a peptide actually is

A peptide is a short chain of amino acids — somewhere between 2 and 50. Your body already uses thousands of them as signals between cells. Insulin is a peptide. Oxytocin is a peptide. The peptides on Pepdex are either synthetic copies of natural ones (like Tesamorelin, Sermorelin), modified versions for longer effect (like CJC-1295, IGF-1 LR3), or fully designed compounds (like BPC-157, Retatrutide).

The point: peptides are signals. They tell specific receptors to do specific things. That's why they're narrower than steroids and broader than vitamins.

For the full breakdown of how peptides differ from steroids, SARMs, and supplements, read Peptides vs steroids, SARMs, supplements.

2. Are they safe? Are they legal?

Two different questions.

Safe: it depends on which peptide and how you use it. The well-studied FDA-approved ones (Tirzepatide, Semaglutide, Tesamorelin, MT-1, PT-141) have well-mapped side effects. Research-grade peptides like BPC-157, Ipamorelin, GHK-Cu have decades of community use and modest formal evidence. Truly experimental compounds (FOXO4-DRI, P-21, dihexa) have almost no human data and shouldn't be your first peptide.

Legal: research peptides are sold as "research use only" — meaning they're not approved for human use, but possessing them isn't illegal in most jurisdictions. The big shift right now is the FDA Peptide Reclassification — 12+ peptides moving back to Category 1, meaning compounding pharmacies will be able to prepare them legally under prescription.

For region-by-region detail: Regulatory differences by region.

3. Pick the goal first, then the peptide

Don't browse Pepdex and pick the most interesting peptide. Pick the outcome you want, then pick the tool.

• Healing a chronic injury → BPC-157, TB-500, GHK-Cu
• Losing significant weight → GLP/GIP class (Tirzepatide, Semaglutide, Retatrutide, Liraglutide)
• Gradual GH-axis support (sleep, recovery, body comp) → Ipamorelin + CJC-1295 stack
• Tanning support → MT-1 (or MT-2 if you want the libido side effect)
• Libido → PT-141, Kisspeptin
• Cognitive / anxiety → Selank, Semax, Cerebrolysin

Browse the full index and filter by category.

4. Read the entry top to bottom

Every peptide page on Pepdex follows the same structure. Read all of it before you order:

1. Plain English — what it actually does 2. Status panel — Natty, FDA, Compounding category, WADA, Prescribed 3. Quick facts — half-life, route, cycle, schedule 4. Who it's for — does this apply to you 5. Timeline — what happens at week 1, 4, 8 6. Mechanism — how it works 7. Dosing protocol — documented dose ranges 8. Stacks well with — what it pairs with 9. Side effects — ranked by frequency 10. When NOT to use — contraindications 11. Bloodwork to monitor — what to test 12. Common mistakes — what new users get wrong 13. Drug & supplement interactions — what to avoid combining 14. FAQ — common questions

Read the contraindications section especially carefully. If anything in there applies to you, stop.

5. Sourcing — vendors and COAs

Research peptides come from research-vendor websites. Quality varies enormously. Two things separate good vendors from bad: published Certificates of Analysis (COAs) and consistent batch testing.

A COA is a lab report. It tells you what's actually in the vial. The 7 tests you should look for:

1. Identification (is it the right molecule) 2. Net content (how much peptide) 3. Net purity (how clean) 4. Endotoxins (bacterial contamination) 5. Sterility 6. Heavy metals 7. Conformity (vial-to-vial consistency)

Full breakdown: COA Education.

How to spot a scam vendor: Spotting scam vendors.

Members get full unlocked access to additional member-only references and the rest of Pepdex's content + tools — AI Coach, Personal Stack tracking, and the full breakdown on every entry. Become a member for $7.99/mo or $80/yr.

6. Reconstitution — turning powder into liquid

Peptides ship as a freeze-dried powder. You mix it with bacteriostatic water (BAC water) before injecting. The math (vial size, BAC water volume, target dose, units to draw) is what the Reconstitution Calculator handles.

Step-by-step technique: How to reconstitute.

For different routes (sub-q, IM, intranasal, oral), the reconstitution and delivery approach changes. Full breakdown: How to take peptides.

7. The first injection

For most peptides, this is sub-q (under the skin into the fat layer). Site: lower abdomen, 2 inches from the navel. Needle: 29-31 gauge insulin syringe. Pinch fat, insert at 45°, push slowly, withdraw straight out.

Full technique: Injection technique.

The first one feels like a big deal. The third one is nothing.

8. Track what you're doing

Log your stack on the Personal Stack page. The AI Coach reads it on every message — so when you ask "is my BPC dose normal," the answer references your actual numbers, not a generic protocol.

What to log: peptide, dose, frequency, start date, vial size, BAC water amount, notes.

9. Cycle off

Most peptides need cycle breaks — receptors downregulate when you signal them too long. Standard pattern:

• Healing peptides (BPC-157, TB-500, GHK-Cu): 4-6 weeks on, 4 weeks off
• GH secretagogues (Ipamorelin, CJC-1295): 8-12 weeks on, 4 weeks off
• GLP/GIP class: open-ended in clinical use; users often pulse 4-8 weeks off every 6 months
• MT-1: loading then weekly maintenance, long break after a year of use

Full reasoning: Cycling basics.

10. Bloodwork

Pull a baseline before your first cycle. Pull again at week 8 if running GH-axis or GLP-class. The panels worth pulling for each category: Bloodwork guide.

In the US, you can order yourself through Quest, LabCorp, or services like Marek Health and OwnYourLabs. No prescription needed for the standard panels.

11. What to do if it's not working

Three failure modes:

1. Bad vial. Symptoms: cloudiness, color shift, particles, no effect when there should be. Solution: stop, check the vendor's COA, contact support. 2. Wrong peptide for the goal. Symptoms: 6 weeks in, nothing has shifted, even though the timeline says you should feel something. Solution: read the timeline section of the entry — if the documented effect window has passed, the peptide either doesn't work for you or you picked the wrong tool. 3. Wrong dose or wrong route. Symptoms: subtle effects but not what was described. Solution: re-check the calculator math, re-check the route (e.g., sub-q vs oral for BPC).

If something feels actively wrong (severe pain, allergic reaction, persistent malaise), stop and see a provider. Educational content here can't replace clinical judgment.

12. The next cycle

Second cycle is the easy one. You know your dose, you know your reconstitution math, you know what to expect. Most users compound benefit cycle-over-cycle as they dial in protocols.

Use the AI Coach for protocol questions. Update your Personal Stack when you change dose or peptide.

That's it. That's the whole arc.