# Four compounds, eight questions, and the designs that answer them

> The planning matrix: four Research Peptide Fundamentals research peptides against the designs that could settle them — A question-to-design matrix for BPC-157, MOTS-c, tirzepatide and CJC-1295: which study design answers which question, which of the four has each design, and the specification of the study each one is still missing.

**THE PLANNING MATRIX**

Not a ranking. A map from the question a reader actually asks to the study design capable of answering it, and then to whichever of these four happens to have that design.

## In plain terms

Comparing peptides by asking which one is best does not work, because the four on this site have not been tested in the same ways. One has been through large trials in thousands of people. Another has never been given to a person in a published study at all.

So this page compares something else: the kinds of study that exist for each. The first table lists eight questions people actually ask, the kind of study that can answer each one, and which of the four compounds has that kind of study behind it.

Read it row by row rather than column by column. A row shows what a question needs. A column shows how far one compound has got. The empty cells are the useful part, and the second table turns them into a short specification of the study each compound is still missing.

## The question-to-design matrix

Two rows appear here that the home page folds together: how the body handles a compound, and how common its rare harms are. Both are separate design problems and both matter for planning.

| Question | Design that can answer it | Which of the four has it |
| --- | --- | --- |
| Does the molecule act on a target at all? | Cell-free binding or receptor assay | MOTS-c, casein kinase 2 [6] |
| Does it change a process in a living animal? | Animal model, in that species | BPC-157 [4][5], MOTS-c [9][11][12] |
| How does the body handle it? | Pharmacokinetic characterisation | BPC-157 in animals [3], CJC-1295 in humans [21] |
| Does it track with anything in people? | Prospective observational cohort | MOTS-c, 94 patients [7] |
| What does it do to human physiology, and is it tolerated? | Open-label study in volunteers | CJC-1295 [20][21][22], BPC-157 in two adults [1] |
| Does giving it change an outcome? | Randomised placebo-controlled trial | Tirzepatide, 2539 participants [16] |
| Is it better than the existing option? | Active-comparator randomised trial | Tirzepatide [17][13] |
| How common are the rare harms? | Pooled analysis across many trials | Tirzepatide, nine trials [15] |

Three of the four compounds occupy the upper half of that table and none of the lower. One occupies the lower half completely. That is the whole finding, and it survives every attempt to soften it.

## Four shapes, not four grades

Reading down the columns rather than across the rows produces four distinct patterns, and the differences between them matter more than any ordering.

**BPC-157 is bottom-heavy.** Two decades of animal work, a mapped angiogenic mechanism [4], a foundational ulcer result [5], and human exposure limited to three small pilot reports, one of them in two people [1]. Depth in the lower rows, nothing above.

**MOTS-c is discontinuous.** An unusually precise molecular result [6], solid animal intervention data [9][11][12], and a respectable human cohort [7] — with the entire human interventional half of the table empty. It skipped a rung rather than climbing partway.

**Tirzepatide is complete and top-loaded.** Its lower rows are of no particular interest because its upper rows are occupied several times over [16][17][13][15].

**CJC-1295 is narrow and high.** Almost nothing worth citing in the animal rows, three genuine human pharmacology studies [20][21][22], then nothing.

Grading these four against a single scale would put tirzepatide first and then argue about the order of the rest. The shapes say something more useful: each of the other three needs a different next study, and the reason is legible in which cells are empty.

## Surrogates, and where each record stops

A surrogate endpoint is a measurement that stands in for the result actually cared about. It is used because it is faster, cheaper or easier to assay, and it is defensible exactly as far as the link between it and the real outcome has been established.

CJC-1295 is the clearest case on the site. Growth hormone and IGF-1 both move, substantially and for days [21][22]. Whether that movement produces a difference in body composition, function or sleep has not been tested. The surrogate is not wrong; it is simply not the question.

MOTS-c has a subtler version of the same problem. Circulating MOTS-c predicts outcomes in a dialysis cohort [7], which makes the peptide a promising marker. A marker of risk and a treatment for risk are different objects, and the design that establishes the first says nothing about the second.

BPC-157 has an intermediate of a third kind: mechanism. Angiogenesis via VEGFR2 is a real, measured pathway [4], and mechanistic plausibility functions as a surrogate whenever it is offered in place of an outcome.

Tirzepatide illustrates the ceiling of the practice. Weight change and glycated haemoglobin are excellent intermediates, measured rigorously in trials of good size [16][17], and they remain intermediates. Even the best-evidenced compound here has a row above the one it occupies.

## The commissioning table

The same four compounds, written as specifications rather than summaries. Each row states the design that is missing, the endpoint it would have to measure, and the reason that design cannot be substituted with something cheaper.

| Compound | The missing design | The endpoint it must measure | Why nothing cheaper will do |
| --- | --- | --- | --- |
| BPC-157 | Randomised placebo-controlled trial in one defined, imaged injury | Structural change on imaging, or measured function | Spontaneous recovery imitates an effect, and uncontrolled reports cannot separate the two [2] |
| MOTS-c | Human pharmacokinetics first, then a randomised metabolic trial | Insulin sensitivity or glycaemic control, measured directly | No human exposure data of any kind exists, so no later design has an exposure to use |
| Tirzepatide | Randomised withdrawal, plus follow-up powered for rare events | Regain after stopping, and gallbladder or biliary events | The biliary signal appeared only when nine trials were pooled [15] |
| CJC-1295 | Randomised placebo-controlled trial with a clinical endpoint | Body composition, physical function or recorded sleep | Human work stops at growth hormone and IGF-1, one measurement short [21][22] |

None of these four designs is unusual. Every one is an ordinary trial of a kind run routinely in other fields, which makes their absence a fact about attention and funding rather than about feasibility.

## Reading the matrix forwards

The habit this page is built against is reading backwards from a result. A number appears, it sounds impressive, and the design behind it gets inspected afterwards if at all. Read that way, a hundred rodent experiments look like progress and a well-run cohort study looks like proof.

Read forwards, the same material sorts itself. Start with the question. Identify the design class capable of settling it. Then check whether that design exists for the compound in hand. Most of the time it does not, and the useful output of the exercise is not a verdict but a specification.

That is why this site publishes design briefs instead of scores. A score compresses a record into one number and discards the information about which rung is empty. A brief keeps it, and it can be checked: if the study it describes is ever run, the brief either anticipated the design or it did not.

One caution about the matrix itself. Occupying a row means a design of that class exists, not that its result was positive, large or replicated. The matrix is a map of what has been asked. It is not a map of what has been found, and the compound pages carry that second layer.

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Peptide Precision Planner is an independent literature digest that specifies the studies four research peptides still lack; the only thing planned on these pages is a trial, and a trial is not a treatment.