For research purposes only. Not for human use. This guide covers how laboratories source and compare multi-compound research orders. It does not describe combining, administering or dosing any compound in people or animals.
What a "Stack" Means in a Sourcing Context
In the research-peptide market a stack is a set of compounds a study needs at the same time: BPC-157 with TB-500 for a tendon-repair model, a GHRH analogue with a ghrelin-receptor agonist for a growth-hormone-secretion assay, semaglutide with cagrilintide for an appetite-signalling comparison. Ordering several compounds at once raises three questions that a single-vial order does not. Which suppliers carry the whole set, so one shipment, one cold chain and one certificate-of-analysis request covers it? Is a pre-mixed blend vial a reasonable substitute for separate vials? And does the published literature support treating the compounds as a unit at all?
This guide answers those questions with the peptides.so listings database (119 suppliers, 10,863 priced listings at a list price of $5 or more, price-checked through 28 September 2026) and with the combination studies that exist in PubMed. The combination literature is thinner than storefront copy suggests, and where it exists it does not always favour the combination.
What the Combination Literature Shows
GHRH plus a ghrelin-receptor agonist. This is the best-documented peptide pairing in endocrinology. Bowers and colleagues reported in 1990 that the hexapeptide GHRP-6, given to 18 healthy men, stimulated growth hormone release on its own and that submaximal GHRP-6 combined with GHRH-(1-44) stimulated release synergistically, which the authors took as evidence the two peptides act through independent mechanisms (Bowers et al., 1990). Nearly two decades later Veldhuis and Bowers showed that the size of that synergy is not fixed: in healthy men studied under a sex-steroid clamp, abdominal visceral fat, IGF-I and IGFBP-3 together explained 60% of the between-subject variability in GHRH-GHRP synergy, and synergy fell with age and with visceral fat (Veldhuis & Bowers, 2009). A GHRH-plus-secretagogue combination is a well-characterised experimental system whose response depends heavily on the model's metabolic state. The compounds sold under this pairing are CJC-1295 (no DAC), sermorelin and tesamorelin on the GHRH side, and ipamorelin, GHRP-6, GHRP-2 and hexarelin on the secretagogue side.
BPC-157 plus TB-500. The only controlled comparison of this pairing against each compound alone was published in 2026. Biçer and colleagues transected and repaired the Achilles tendon in 32 rats and assigned them to control, BPC-157, TB-500 or the combination for four weeks. TB-500 alone produced a statistically significant biomechanical advantage in maximum load to failure and lower Bonar and Movin histology scores; BPC-157 alone improved histology without reaching biomechanical significance; and the combination "did not confer additional benefits compared to either agent alone" (Biçer et al., 2026). The authors suggest convergence on shared downstream pathways as one explanation and call the study exploratory. It is a single rat model, but it is the only head-to-head evidence, and it does not support the assumption that the pair is additive. Compound pages: BPC-157 and TB-500.
Semaglutide plus cagrilintide. This pairing has the most rigorous combination data of any in the research market because it became a pharmaceutical programme. Enebo and colleagues ran a phase 1b multiple-ascending-dose trial in which cagrilintide was co-administered with semaglutide in six cohorts of adults with overweight; body weight fell more with the combination than with semaglutide plus placebo, and glycaemic parameters improved independently of the cagrilintide arm (Enebo et al., 2021). The phase 3a REDEFINE 1 trial then randomised 3,417 adults and reported a −20.4% mean weight change at 68 weeks with the combination against −3.0% with placebo (Garvey et al., 2025). The two compounds act on different receptor families (GLP-1 and amylin), which is the mechanistic reason the combination adds rather than overlaps. Compound pages: semaglutide and cagrilintide; background in the GLP-1 sourcing guide.
GHK-Cu with anything. GHK-Cu is often sold in a three-way blend with BPC-157 and TB-500. There is no published study of that triple combination. Pickart's 2015 review summarises GHK's own literature in skin regeneration, wound healing and gene-expression modulation (Pickart et al., 2015); it says nothing about co-formulation. What the chemistry literature does say is that copper(II) catalyses oxidation of methionine and histidine side chains in peptides, a reaction studied in detail by Bodnár and colleagues using HPLC-MS to identify singly, doubly and triply oxidised products (Bodnár et al., 2021). A blend that puts a copper complex in the same vial as other peptides is therefore a stability question before it is a pharmacology question, and a CoA for the blend should report each component's purity after mixing, not before.
Platform Data: Which Suppliers Cover Common Sets
The table counts suppliers that list every compound in a set under its own name, at a list price of $5 or more.
| Compound set | Suppliers carrying all compounds (of 119) | Notes |
|---|---|---|
| Selank + Semax | 85 | Both compounds have around 90 suppliers each; nearly every store that carries one carries the other |
| Tesamorelin + ipamorelin | 65 | The most widely co-stocked GHRH/secretagogue pair |
| BPC-157 + TB-500 | 48 | TB-500 (36 suppliers) is the limiting compound; BPC-157 has 97 |
| CJC-1295 (no DAC) + ipamorelin | 43 | |
| BPC-157 + TB-500 + GHK-Cu | 35 | |
| Semaglutide + cagrilintide | 14 | Semaglutide (23 suppliers) limits the pair |
Selank and Semax are the easiest pair to source from a single storefront. Semaglutide plus cagrilintide is the hardest, because semaglutide under its own name is carried by only 23 suppliers (many more carry it under coded names such as "GLP-1 (S)", which the platform cannot verify as semaglutide). The stack builder runs this coverage query for any compound set and lists the storefronts that clear it.
Single-vial reference prices
For a same-supplier versus split-order comparison, these are the size-pinned platform medians (vial size parsed from each store's product URL; only sizes with six or more suppliers shown):
| Compound | Size | Suppliers | Median list price |
|---|---|---|---|
| BPC-157 | 5 mg | 27 | $49.99 |
| BPC-157 | 10 mg | 32 | $64.98 |
| TB-500 | 5 mg | 6 | $50.50 |
| TB-500 | 10 mg | 9 | $75.00 |
| GHK-Cu | 50 mg | 26 | $65.00 |
| GHK-Cu | 100 mg | 18 | $61.25 |
| CJC-1295 (no DAC) | 5 mg | 25 | $57.45 |
| Ipamorelin | 5 mg | 18 | $42.50 |
| Ipamorelin | 10 mg | 25 | $60.00 |
| Sermorelin | 5 mg | 20 | $49.50 |
| Tesamorelin | 10 mg | 34 | $80.38 |
| Selank | 10 mg | 39 | $50.00 |
| Semax | 10 mg | 33 | $44.00 |
GHK-Cu's 100 mg median ($61.25) sits below its 50 mg median ($65.00), which is an artefact of different supplier sets at each size rather than a volume discount; the 50 mg and 100 mg groups share only eight suppliers. The cost calculator converts any of these to a per-milligram figure once the vial's net peptide content is known.
Blend Vials Versus Separate Vials
Pre-mixed blends are a large part of the market. The "GHK-Cu, BPC-157 + TB-500" row has 51 listings across 42 suppliers at a median of $99; the "CJC-1295 NO-DAC / Ipamorelin Blend" row has 30 listings across 29 suppliers at $69; "KLOW 80mg" (a four-compound blend) has 61 listings across 44 suppliers at $120; the "Ipamorelin / Tesamorelin Blend" has 35 across 29 at $90; and the "Selank / Semax Blend" has 19 across 16 at $88.
Where a supplier carries both the blend and every single, the blend is almost always the cheaper line item. Eleven suppliers carry the GHK-Cu/BPC-157/TB-500 blend and all three singles; at ten of them the blend is priced below the sum of the three singles (median $94 against $167). Fourteen suppliers carry the CJC-1295/ipamorelin blend and both singles; at eleven the blend is cheaper than the pair (median $67.50 against $97.49).
That comparison is on vial count, not on milligrams. A blend vial holds a fixed ratio set by the supplier, usually with less of each component than a dedicated vial, and it cannot be re-proportioned. Three consequences follow for a laboratory:
1. A blend fixes the ratio before the experiment does. If the study design includes a dose-response on one component while holding the other constant, separate vials are the only option.
2. A blend CoA has to resolve every component. Two or three peptides in one HPLC run produce overlapping peaks unless the method was developed for the mixture. A CoA showing a single purity figure for a multi-peptide vial has not measured what it claims; ask for a chromatogram with each component's peak identified and a mass-spectrometry result for each. The purity-testing guide explains what a resolved multi-component trace looks like.
3. Stability is the blend's, not the components'. The copper-catalysed oxidation chemistry above applies to any GHK-Cu blend. For other blends, the peptide with the shortest solution half-life sets the shelf life of the vial once reconstituted. The degradation pathways guide lists the susceptible residues.
Twenty-seven suppliers carry the three-way blend without carrying all three singles, so for some storefronts the blend is the only way to get the set at all.
Same-Supplier Order or Split Order
Ordering the whole set from one supplier means one shipping charge, one cold-chain exposure and one CoA request. Splitting across suppliers can lower the line-item total but adds shipping and doubles the documentation work. Two platform facts bear on the decision.
First, discounting is concentrated. Of 10,863 priced listings, 1,829 (17%) carry a sale price below list, but 73 of 119 suppliers discount at least one line and 11 suppliers with ten or more listings discount their entire catalogue. A storefront with a sitewide sale can undercut a split order on every line at once; compare at sale price for those stores and at list for the rest.
Second, nothing on the platform distinguishes suppliers by documentation. None of the supplier rows has a non-zero testing score or a certificate-of-analysis URL on file, so the coverage and price tables above are the extent of what the data can rank. The supplier checklist covers the documents to request before committing to a multi-vial order from a storefront that has not been used before, and it is sensible to request them for one compound before ordering five.
Handling a Multi-Compound Shipment
Lyophilised peptides arriving in one box have different storage tolerances. Fatty-acid-conjugated compounds (semaglutide, cagrilintide) and copper complexes (GHK-Cu) should be checked for colour and cake integrity on arrival and moved to frozen storage first; short unmodified peptides tolerate a longer bench interval. Reconstitute compounds separately unless the study specifically requires a mixture, and if it does, prepare the mixture immediately before use rather than storing it. Adsorption to container walls is measurable at low concentrations: Grohganz and colleagues found the decapeptide cetrorelix lost analyte to vial surfaces in dilute aqueous solution, with adsorption falling in the order glass > polypropylene = polyethylene > PTFE and varying considerably between glass vials from different suppliers (Grohganz et al., 2004). Dilute working solutions of any peptide in a stack are exposed to the same loss. The storage guide and reconstitution guide cover the details.
Frequently Asked Questions
Is a blend vial cheaper than separate vials? Per vial, usually yes: at ten of the eleven suppliers carrying the GHK-Cu/BPC-157/TB-500 blend and all three singles, the blend costs less than the three singles together. Per milligram of each component, the platform cannot say, because blend composition is not standardised across suppliers.
Which common pairing has the strongest published evidence? Semaglutide plus cagrilintide, which has phase 1b and phase 3a trials. GHRH plus a ghrelin-receptor agonist has decades of physiology literature. BPC-157 plus TB-500 has one rat study, and it found no additive benefit.
Which pair is hardest to source from one supplier? Semaglutide plus cagrilintide under their own compound names (14 suppliers). Selank plus Semax is the easiest (85).
Should GHK-Cu be reconstituted in the same vial as other peptides? Copper(II) catalyses oxidation of methionine and histidine residues, which is documented chemistry. Unless the study requires a mixture, keep the copper complex separate and mix immediately before use.
How many suppliers discount their whole catalogue? Eleven of the 119 with ten or more listings, at the time of the query. Sitewide-sale stores should be compared at sale price.
References
1. Bowers CY, et al. Growth hormone (GH)-releasing peptide stimulates GH release in normal men and acts synergistically with GH-releasing hormone. J Clin Endocrinol Metab. 1990. PMID 2108187
2. Veldhuis JD, Bowers CY. Determinants of GH-releasing hormone and GH-releasing peptide synergy in men. Am J Physiol Endocrinol Metab. 2009. PMID 19240251
3. Biçer O, et al. Effects of BPC-157 and TB-500 on Achilles tendon healing in rats: A histopathological and biomechanical study. Jt Dis Relat Surg. 2026. PMID 42542926
4. Enebo LB, et al. Safety, tolerability, pharmacokinetics, and pharmacodynamics of concomitant administration of multiple doses of cagrilintide with semaglutide 2·4 mg for weight management: a randomised, controlled, phase 1b trial. Lancet. 2021. PMID 33894838
5. Garvey WT, et al. Coadministered Cagrilintide and Semaglutide in Adults with Overweight or Obesity. N Engl J Med. 2025. PMID 40544433
6. Pickart L, Vasquez-Soltero JM, Margolina A. GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration. Biomed Res Int. 2015. PMID 26236730
7. Bodnár N, et al. Ambivalent role of ascorbic acid in the metal-catalyzed oxidation of oligopeptides. J Inorg Biochem. 2021. PMID 34126320
8. Grohganz H, Rischer M, Brandl M. Adsorption of the decapeptide Cetrorelix depends both on the composition of dissolution medium and the type of solid surface. Eur J Pharm Sci. 2004. PMID 14757490
Research Disclaimer
The compounds named here are supplied to laboratories for research use only and are not approved for human or veterinary use. Combination studies are cited to describe the published evidence, not to recommend any pairing, and no part of this guide describes administration to people or animals. Anyone seeking treatment should consult a licensed clinician about approved medicines.