Peptide guides

This index pairs every relevant research peptide with a dosing protocol, a comparator compound and an application category, so that two clicks take you from your research objective to the titration figure in mg per week. In 2026, the benchmark for research-grade material is an HPLC (high-performance liquid chromatography) purity of ≥95% on the CoA (certificate of analysis), with premium batches being advertised at 98% or above [3][4].

Purity on its own confirms neither the identity, nor the sterility, nor the endotoxin status of the material. HPLC only measures the concentration of the target compound; it does not tell you whether impurities or bacterial endotoxins are present [4].

Dosing guides: the essentials

• A "research use only" label is no substitute for proper due diligence: the identity, the sterility and the endotoxin status of the material must all be stated on the CoA
• The 2026 dosing matrix covers all of the relevant compounds across five categories: recovery, growth, weight loss, longevity and skin
• The whole range comes as pre-filled multi-dose pens: the dose dial sets the dose directly in milligrams, so there is no reconstitution, no concentration to calculate and no reading to take off a syringe
• Tirzepatide and retatrutide show the strongest published weight-loss data; BPC-157 and TB-500 are the recovery peptides most often combined, and they are supplied together in a single pen
• Third-party certificates of analysis with batch traceability and confirmation of sterility and endotoxin status are essential when you are assessing a supplier

What you will learn in this guide:

• How to read a peptide dosing protocol and how to convert between units (mcg, mg, IU)
• The 2026 peptide matrix: dose ranges, presentation and cycle length for each of the relevant compounds
• Direct comparisons of weight-loss peptides (the GLP-1 class), recovery peptides, growth hormone secretagogues and longevity compounds
• Practical supply and supplier checks for research peptides
• Answers to the dosing questions that come up most often

What this guide covers at a glance

There are also reference compounds that are not part of the Spanish catalogue and are covered here purely as comparative context: semaglutide, CagriSema and somatropin (HGH). If you are weighing up formats, pen or vial sets the two workflows side by side.

A pen labelled "research use only" is treated in this index purely as a laboratory reference. All of the dose data describe research protocols, not instructions for human use.

The 2026 peptide protocol matrix

Below is the central reference table, which assigns every research peptide covered in this index its category, the usual research dose, the presentation available in Spain, the injection frequency, the cycle length and the primary variable being measured. Dose ranges are tied to the study or protocol source wherever one exists. Newer compounds with no published human dosing are flagged as being at the research stage.

Every figure in the dose column is the amount you set on the pen's dose dial. There is nothing to convert to volume: the pen arrives pre-filled and the dial is graduated in milligrams (in IU only in the case of somatropin).

For the recovery row, How to dose BPC-157 and TB-500 explains the timing of the stack and the logic behind the choice of injection site. For the GLP-1 block, Retatrutide vs. semaglutide vs. tirzepatide is the comparison index that those rows lead on to.

How to read this table

Each dose range is the band used in the research protocol, not a prescribed human dose. Where a row cites a study published between 2021 and 2024, the titration scheme comes from the published trial arm. Where it cites [4], the figures are supplier protocols and should be treated as a starting reference and not as a clinical target. MOTS-c is included for the sake of completeness, but it has no standardised human dose in the literature cited [2].

How to read a peptide dosing protocol

With a pre-filled pen, a dosing protocol boils down to a three-part instruction: what figure you set on the dial, how often you set it, and for how long you keep doing so [4]. There is no fourth step for preparation, because the pen arrives ready to use straight out of the box.

mcg, mg, IU: what the units mean

1 mg = 1000 mcg. The dial on every pen in the range is graduated in milligrams, with a single exception: somatropin is dosed in IU (international units), which is a measure of biological activity. With IU, 1 mg does not correspond to a fixed value, so a schedule written in IU cannot be converted into mg [4]. For everything else in the matrix above, work exclusively in mg and mcg.

The figure on the dial is the dose

Set 0.25 mg on the dial and 0.25 mg is what gets delivered. There is no concentration to work out, no draw-up volume to calculate and nothing at all to translate into syringe markings: the accuracy of the dose is validated at the point of manufacture and holds from the first administration through to the very last.

The number in the name is the total quantity, not the dose

Retatrutide 32, Tesamorelin 32 or NAD+ 1000 state the total milligrams of peptide that the unit contains, not what you administer each time. Between two sizes of the same compound the dose does not change: the larger pen simply lasts longer before it needs to be replaced.

Combination pens have a single dial

In BPC-157 + TB-500 and in CJC-1295 + ipamorelin, the two peptides are co-dissolved 50/50 in the same cartridge and there is only one dial. The figure you set is the dose of each of the two peptides, not a total to be split between the two. The full protocol for the recovery stack is in How to dose BPC-157 and TB-500.

Storage

The whole range is stored in exactly the same way: between 2 and 8 °C and protected from light, with a shelf life of 24 months while unopened and 12 months from the first puncture [3]. If you have no fridge available, the pen will tolerate up to 30 days at room temperature, up to a maximum of 30 °C. Let it come up to room temperature before injecting and never freeze it.

Weight-loss peptides compared (GLP-1 class)

Tirzepatide currently has the best published mean weight loss of any of the authorised peptides in the GLP-1 class, because it activates two receptors rather than just one. Retatrutide leads the phase 2 data with a triple-receptor mechanism of its own. Semaglutide remains the single-agonist option with the broadest body of evidence behind it. CagriSema (cagrilintide + semaglutide) sits mechanistically in between the two and is still maturing in terms of outcome data. With all four compounds, nausea concentrates in the first two steps, so the speed of titration matters more than the final dose when the focus is on the burden of adverse effects.

The receptor targets differ clearly from one compound to the next, and that difference shapes both the titration ladder and the adverse-effect profile. Semaglutide is a pure agonist of GLP-1 (glucagon-like peptide-1). Tirzepatide is a dual agonist of GIP (glucose-dependent insulinotropic polypeptide) and GLP-1. Retatrutide is a triple agonist (GIP/GLP-1/glucagon). CagriSema combines a long-acting amylin analogue with semaglutide, which is why its appetite-suppression curve looks different from week to week.

Titration is not optional. Nausea and discontinuations for gastrointestinal reasons in both STEP-1 and SURMOUNT-1 concentrate in the first two dose steps [5][6], which is exactly why the 4-week hold phase exists in the first place. Half-lives in the 5-to-7-day range mean that skipping a single week barely shifts the trough levels at all, but two skipped weeks in a row usually justify stepping back down one level before carrying on upwards.

Retatrutide's glucagon arm is the reason why its weight-loss curve had not reached a plateau at 48 weeks, as semaglutide's does at 60. Glucagon drives additional hepatic glucose release and additional lipolysis.

The full comparison, including injection-site rotation, the cost per mg in euros and the interplay between titration and training volume, is in Retatrutide vs. semaglutide vs. tirzepatide.

Recovery and healing peptides compared

BPC-157 and TB-500 are the two recovery peptides most often combined in research models, because they act through different repair pathways. BPC-157 drives angiogenesis and upregulates VEGFR2 (vascular endothelial growth factor receptor 2), which is why it dominates the gut, tendon and ligament protocols. TB-500 (the synthetic fragment of thymosin beta-4) binds G-actin and accelerates cell migration, which makes it the first choice for muscle-belly tears and for systemic soft-tissue damage. Combining the two costs more than using either one alone, but the synergistic effect on repair timelines is well documented in animal models.

When to use them alone and when to combine them

BPC-157 on its own makes sense for localised, poorly vascularised structures: the Achilles tendon, the patellar tendon, the medial epicondyle and the intestinal mucosa, because those particular tissues have a limited blood supply and therefore benefit from the angiogenic signal. Subcutaneous injection close to the site of injury is the dominant research route, although the systemic subcutaneous route also shows an effect in animal models. TB-500 on its own suits research into diffuse or multifocal soft tissue, where a targeted injection site is simply not feasible.

The rationale for the stack is straightforward: TB-500's slower, systemic cell-migration effect complements BPC-157's faster, more local angiogenic response. In the published models, the two of them showed no competition for receptors. Here the two peptides are not dosed separately at all: they share a single cartridge, so they are always administered together and always in the same amount. Most protocols step down from the loading dose to the maintenance dose after a few weeks. Dialled doses and injection-site rotation are dealt with on the protocol page How to dose BPC-157 and TB-500.

Growth hormone peptides compared

All four of these compounds sit on a spectrum that runs from pulsatile stimulation at one end to direct replacement at the other. GHRH (growth hormone-releasing hormone) analogues (CJC-1295, tesamorelin) prompt the pituitary to release endogenous GH. Ghrelin mimetics (ipamorelin) reinforce the pulse through a different receptor. Recombinant HGH (somatropin) bypasses the pituitary altogether. Combining a GHRH with a ghrelin mimetic is the standard research design, because the two pathways multiply rather than simply add together. In the Spanish catalogue that combination exists in a single pen, with CJC-1295 in its DAC form.

Pulse versus steady state: what DAC changes

The DAC (Drug Affinity Complex) modification binds to albumin and stretches the GHRH signal out over a period of days, instead of the bare thirty minutes of the unconjugated variant. The practical consequence is the schedule: with the DAC form there is no need to spread several administrations across the day or to fit them into a fasting window. A single daily dose in the evening coincides with the best-described somatostatin trough and is the reference scheme for the combination pen. The full contrast between the two forms is set out in CJC-1295 vs. ipamorelin.

Tesamorelin's niche

Tesamorelin is the only GHRH analogue with a regulatory dossier behind it: the 2 mg daily subcutaneous dose was approved back in 2010 for HIV-associated lipodystrophy. The research protocol is a different matter altogether and starts lower down, at 0.25 mg daily, titrating upwards to a maximum of 2 mg daily in blocks of 8-12 weeks with 4 weeks off in between each block. Its selectivity for visceral fat sets it apart from CJC-1295 in body-composition research. It is the comparator compound of choice when the subject is truncal adiposity rather than general recovery or sleep quality.

Longevity and metabolic peptides

MOTS-c and NAD+ fall into the metabolic longevity category, because both of them act on mitochondrial performance rather than on the GH or GLP-1 axes that dominate the rest of this index. In 2026, neither of them has an established human dosing standard, so the figures that follow reflect ranges that are frequently cited in research models, not authorised protocols of any kind [2]. Anyone combining these compounds should start conservatively; the human safety data are scarce.

MOTS-c: the mitochondrial peptide

MOTS-c is a 16-amino-acid peptide that is encoded in the mitochondrial 12S rRNA gene. Most of the published research models use 5-10 mg by the subcutaneous route, two or three times a week. The research use case is insulin sensitivity and exercise capacity in metabolic syndrome models, not body recomposition in healthy adults. Human data are so scarce that any titration at all has to be considered experimental [2].

NAD+: two valid schedules

The NAD+ pen contains 1000 mg in total and the dial comes marked at 20, 30, 40 and 50 mg, up to 200 mg a day; doses below or between the printed marks can also be set, 10 mg included. From there, the research protocols split into two schedules. The intermittent one administers 10-50 mg two or three times a week for the first 4 weeks and then 20-80 mg two or three times a week. The daily one administers 10-20 mg a day, 5 days a week, and then moves up to 20-30 mg a day. They are alternatives, not phases of a single plan: pick one and keep to it for the whole cycle.

If you are combining these compounds with tissue-repair work, the recovery page to go to is the guide How to dose BPC-157 and TB-500. If you are pursuing fat loss alongside mitochondrial support, lean on the comparison Retatrutide vs. semaglutide vs. tirzepatide.

Peptides for skin and pigmentation

Research protocols with GHK-Cu usually use somewhere between 0.5 and 2 mg subcutaneously per day, close to the site in question, for localised collagen and wound-healing work. Topical cosmetic formulations sit in the 0.05-0.2% range and are applied twice daily. The subcutaneous route concentrates the delivery of copper, but carries a higher risk of injection-site irritation and transient flushing. Topical application dominates the commercial skincare literature, because systemic absorption is negligible and tolerability is high. In sensitive skin, research models begin with topical GHK-Cu before attempting any subcutaneous dosing.

Melanotan II is dosed on a loading-and-maintenance pattern: 200 mcg subcutaneously per day, rising to a maximum of 500 mcg per day during loading, and then dropping to 200 mcg twice a week once the target pigmentation has been reached. The adverse signals described include nausea in the first 30-60 minutes after injection, spontaneous erections, appetite suppression and the appearance or darkening of naevi, the signal most frequently cited as the reason for discontinuation in the published dermatology case reports.

If you are combining GHK-Cu with injury recovery, lean on the guide How to dose BPC-157 and TB-500 for the tissue-repair protocols that fit most logically alongside the use of the copper peptide.

Research-model stacks for the GH axis and tissue repair

The published research clusters around three stack archetypes for the GH axis and tissue repair: lean-mass models (GH secretagogue + tissue repair), visceral-fat models (GLP-1/GIP agonist + lipolytic GHRH analogue) and recovery (synergistic tissue-repair peptides). In 2026, none of these stacks has an authorised indication in bodybuilding, and no GLP-1 receptor agonist is authorised for aesthetic or performance purposes. Consult the compound-specific protocols linked below before starting any one of these stacks.

The matrix below assigns each research-model stack its usual components, the outcome being modelled and the comparative literature that is worth reading alongside it.

Why the recomposition stack is the most cited combination

CJC-1295 is paired with ipamorelin because the GHRH analogue raises the basal release of GH while the ghrelin mimetic adds a pulse on top of it; the two receptors involved are different, so the two signals do not overlap one another. In the combination pen both go in the same cartridge and are administered at the same time, once daily in the evening. The BPC-157 + TB-500 pen is added in research models where the workload is heavy enough to generate stress on the tendons or the intestinal mucosa.

Caveats for the cutting stack

The weekly tirzepatide titration used in research models mirrors the scheme from the obesity trials. Read the SURMOUNT-1 [6] and retatrutide phase 2 [7] weight-loss percentages in the primary NEJM publications and not in secondary summaries. Tesamorelin's visceral-fat signal comes from the HIV-associated lipodystrophy literature and does not transfer cleanly to lean bodybuilding cohorts.

Buying research peptides in 2026

A "not for human consumption" label is no substitute for due diligence on the supplier itself. If a supplier cannot explain what the classification of its product actually rests on, that in itself is a warning sign.

The minimum checklist to run through before ordering, for use in assessing a supplier:

A minimum threshold of 95% by HPLC is the usual commercial benchmark, but 98% or above is what we would accept for anything that is going to be injected into a research model [3][4]. Purity on its own validates neither identity, nor sterility, nor endotoxin status, which is why the CoA has to cover all four of those points.

Practical supply pointers

The Body Pharm catalogue is organised by use case, which means the recovery row of the matrix above points straight to How to dose BPC-157 and TB-500. The GLP-1 cutting row, in turn, points to Retatrutide vs. semaglutide vs. tirzepatide. If a supplier cannot produce a batch-linked CoA when asked for one, that is an absolute exclusion criterion and not something to negotiate over.

Frequently Asked Questions: peptide dosing

Common questions, answered in the order in which they tend to come up. Each of the answers is written so that it stands on its own if it gets lifted out into an AI-generated summary or a featured snippet.

Does the pen need preparing before use?

No. The whole range arrives pre-filled, in a sealed 3 ml cartridge. You set the figure on the dial and inject: there is no water to add, nothing to mix, no volume to calculate and no syringe to draw up. The only thing worth doing before you inject is taking the pen out of the fridge and letting it come up to room temperature first.

How long does a pen last?

Unopened, it lasts 24 months when stored between 2 and 8 °C and protected from light. Once it has been punctured for the first time, it lasts 12 months. If you have no fridge, the pen stays stable for up to 30 days at room temperature provided it does not go above 30 °C. Never freeze it under any circumstances.

What does the number in the product name mean?

The total milligrams of peptide that the unit contains: Retatrutide 32 holds 32 mg in total, NAD+ 1000 holds 1000 mg. It is not the dose per administration, which is what you set on the dial. Between two sizes of the same compound the dose does not change; the larger pen just lasts longer.

Are research peptides authorised for human use?

No. All of the compounds covered here are supplied exclusively for research and analytical purposes. The dose data in this index describe published research protocols and are not instructions for either human or animal use [1].

Where do I find compound-specific protocols?

Recovery stacks are covered in detail in How to dose BPC-157 and TB-500. The GLP-1 titration schemes are set out in Retatrutide vs. semaglutide vs. tirzepatide.

Next steps

Start with the compound-specific protocol guide that best matches your use case: How to dose BPC-157 and TB-500 for recovery work, or Retatrutide vs. semaglutide vs. tirzepatide for weight-loss protocols. Before placing any order at all, ask the supplier for a batch-linked CoA that confirms the HPLC purity, the identity by mass spectrometry, the sterility and the endotoxin status. Change supplier if they are unable to produce one.

Sources

1. Directive 2001/83/EC, Article 1: definition of a medicinal product by presentation and by function; consolidated text on EUR-Lex. eur-lex.europa.eu — legal basis for a reagent labelled "research use only" remaining subject to pharmaceutical regulation if it is presented for human use.
2. Lee C, et al. The Mitochondrial-Derived Peptide MOTS-c Promotes Metabolic Homeostasis and Reduces Obesity and Insulin Resistance. Cell Metab. 2015. pubmed.ncbi.nlm.nih.gov/25738459
3. Body Pharm product specification: pre-filled multi-dose pen, 3 ml cartridge, dial in milligrams, storage at 2–8 °C, 24 months unopened and 12 months from the first puncture, up to 30 days below 30 °C without a fridge. Supplier specification, not a study.
4. Body Pharm dosing protocol for the pen range (supplier specification, revised October 2026). Supplier research protocol, not a peer-reviewed study.
5. Wilding JPH, et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). N Engl J Med. 2021. pubmed.ncbi.nlm.nih.gov/33567185
6. Jastreboff AM, et al. Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1). N Engl J Med. 2022. pubmed.ncbi.nlm.nih.gov/35658024
7. Jastreboff AM, et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. N Engl J Med. 2023. pubmed.ncbi.nlm.nih.gov/37366315