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Reference

Vendors & Sourcing

Where people commonly buy — with appropriate skepticism
Critical context before reading. The peptide vendor space is largely unregulated. Vendors are required to label their products "for research use only — not for human consumption" because none of them are FDA-approved as drugs sold this way. The names below are commonly mentioned in biohacker communities, NOT independently verified by anyone associated with this site. Vendor quality changes month-to-month. Always cross-reference current community reviews (r/Peptides, r/SARMSStores) before buying, and prefer vendors that publish recent third-party HPLC/mass-spec test results. If you have access to a licensed prescriber, the compounding-pharmacy route is a different (legal) tier entirely.

Mixing & compatibility (don’t ruin your peptides)

pH compatibility only matters when peptides are combined in the same vial or syringe. Once injected separately, your plasma buffers everything to ~7.4 and the issue disappears. The 16 stacks on the home page are protocols (use these compounds together over time), not recipes (mix them in one syringe), so as long as each peptide is reconstituted and injected from its own vial, none of those stacks conflict.

Safe to combine in the same syringe (drawn from separate vials):

NEVER mix these in the same vial or syringe:
  • GHK-Cu + anything acidic (Vitamin C in solution, Glutathione, NAD+ at low pH). Breaks the copper bond and inactivates the peptide. This is the most common pH mistake.
  • NAD+ + any peptide. NAD+ is acidic in reconstituted form and degrades most peptides on contact. Always inject NAD+ separately.
  • IGF-1 LR3 + GH-secretagogues in same vial. Different acetate buffer requirements. Inject separately.
  • Anything that’s gone cloudy after mixing. Visible cloudiness or color change = denaturation. Discard.

Reconstitution rules:

Routes of administration & what actually works

The route you can use depends on the molecule’s size and stability. Most peptide marketing oversells what works orally or nasally.

Subcutaneous injection (subQ) — The standard. Works for nearly everything on this site. ~80–100% bioavailability. Insulin syringe (31g x 1/2”), inject into belly fat, thigh, or upper arm. Painless when done correctly.

Intramuscular (IM) — Used for site-specific compounds (IGF-1 DES, MGF) or where slower release matters (Cerebrolysin). Bigger needle (25–27g), goes into glute or shoulder.

Intranasal spray — Works ONLY for small peptides (under ~10 amino acids / 1 kDa). Bioavailability is ~1–10% — lower than subQ but no needle. The peptides legitimately formulated as nasal sprays:

Peptides where “nasal” doesn’t actually work: BPC-157, TB-500, Tesamorelin, CJC-1295, Sermorelin, Hexarelin, IGF-1 LR3, IGF-1 DES, HGH/Somatropin, GLP-1 family (Semaglutide, Tirzepatide, Retatrutide), and most other peptides above ~10 amino acids. They’re too large to cross the nasal mucosa. If you see a vendor selling these as nasal sprays, you’re paying for saline. Use subQ injection.

Oral capsule — Works only for compounds engineered for stomach survival or naturally resistant to digestion:

Topical — GHK-Cu skin serums (legal cosmetic use), sometimes for localized peptide application. Limited systemic effect.

IM / IV (clinic-only typically) — Cerebrolysin (IM), high-dose NAD+ (IV), some GLP-1 protocols. Usually requires a clinic.

How to evaluate a peptide vendor

Before trusting any vendor, look for these markers. A vendor that fails most of these is a hard pass regardless of price.

Commonly-mentioned vendors (peptides)

Names that recur most frequently in community discussions as of 2025-2026. Inclusion here is descriptive, not endorsement.

Commonly-mentioned vendors (SARMs)

SARMs are a separate category and the FDA has been particularly aggressive here. Quality control varies even more than for peptides. Third-party testing is essential.

The legal alternative: compounding pharmacies via prescribers

For compounds with an actual medical pathway (Tesamorelin, Semaglutide, Tirzepatide, BPC-157 in some regions, Sermorelin, HCG, Enclomiphene, PT-141, Oxytocin), the legal route is a licensed prescriber writing for a 503A or 503B compounding pharmacy. This is fundamentally different from the research-chem space — you get pharmaceutical-grade product, real medical oversight, and legal protection.

Common telehealth clinics (US) that prescribe these compounds when clinically indicated:

Ancillary supplies (legal, available anywhere)

The supplies needed to reconstitute and inject peptides are sold legally as standard medical equipment.

Bloodwork & monitoring

Self-administered peptide use without baseline bloodwork is genuinely risky. The minimum panel before starting any GH-secretagogue, IGF-1 analog, or hormone-active peptide:

Direct-to-consumer bloodwork (no doctor visit needed in most US states):

Where to track current vendor reputation

Because vendor quality shifts month to month, real-time community sources beat any static list. Cross-reference these before any purchase:

Educational reference only. Not medical advice. This site does not endorse, verify, or take responsibility for any vendor listed. The legal status of these compounds varies by jurisdiction and changes over time. Most peptides listed elsewhere on this site are not FDA-approved as drugs sold via online vendors and are sold under "research use only" labeling. Use of these compounds outside of a licensed prescriber's care carries real medical and legal risk.