The peptide frontier, mapped from the source.
Short chains of amino acids, outsized reach — from the signals that run the body to the compounds redrawing the edge of research and discovery. PeptideHormone is the independent, research-grade catalog of peptide science: every signaling family, the molecules that matter, and the evidence behind them — sourced, graded, and cross-linked, with pharmacokinetic tools.
New to the subject? Start with what a peptide hormone is.
The catalog, by signaling family
The whole landscape, mapped into the families that share receptors, anatomy, and logic — each a hub of the molecules that matter and the evidence behind them. Open any one for the full reference.
Browse the full catalogIncretins & metabolic
Glucose-dependent signaling that reshaped obesity and diabetes care.
GLP-1 · GIP · glucagon · amylin · insulin
Growth & repair
The somatotropic axis and the secretagogues that pulse it.
GH · IGF-1 · GHRH · ghrelin · GHRPs
Melanocortins
Pigmentation, appetite, inflammation, and sexual function from one receptor family.
α-MSH · MC1R–MC5R · setmelanotide
Neuropeptides
Hypothalamic and posterior-pituitary signals that tune behavior and fluid balance.
oxytocin · vasopressin · CRH · TRH
Gut & appetite
The enteroendocrine peptides that report on the meal you just ate.
PYY · CCK · secretin · motilin
Reproductive & gonadal
Pulsatile control of the reproductive axis, from hypothalamus to gonad.
GnRH · LH · FSH · kisspeptin · hCG
Adipokines & energy balance
The hormones fat tissue uses to report energy reserves to the brain.
leptin · adiponectin
Calcium & bone
The peptide hormones that hold blood calcium in a tight range.
PTH · calcitonin · PTHrP
Cardiovascular & natriuretic
Peptides the heart and vessels use to manage pressure and fluid.
ANP · BNP · CNP
Muscle & TGF-β signaling
The signals that cap muscle growth — and the targets for releasing the brake.
myostatin · activin A · follistatin
Repair & regenerative
Endogenous repair signals — and the community 'research peptides' that target them.
thymosin β4 · GHK-Cu · BPC-157 · TB-500
Mitochondrial-derived peptides
Short peptides encoded inside the mitochondrial genome that signal to the cell.
MOTS-c · humanin
The mechanisms, in long form
Long-form deep-dives that trace one molecule — or one question — back to the source: receptors, second messengers, and the evidence behind them. Biology over benefits.
All insightsWhat does GLP-1 do? How the hormone actually works
From an intestinal cell to a closed potassium channel: the receptor, the second messenger, and why the whole system only fires when glucose is high.
Read the deep-diveThe note without the incretin
In December 2025 The Lancet published a 48-week trial in which a once-weekly injection took off a mean 20% of body weight, and the GLP-1 receptor was nowhere in the molecule. Eloralintide is Lilly’s amylin analog: 37 residues on the hormone insulin is co-secreted with, the native disulfide swapped for a methylene-thioacetal ring that cannot be opened, backbone methyls the ribosome cannot make, and a C20 fatty diacid on an engineered lysine that binds albumin for a fortnight. It was tuned to prefer the amylin-1 receptor twelve-fold over the bare calcitonin receptor it is built from, which is the whole argument for calling it gentler, and the only evidence for that is a rat taste-aversion assay. We read the structure off the public registry record, walk the three monotherapy trials and the EloraTZP combination that reached 23.3% in type 2 diabetes in September 2026, and separate what selectivity has proved from what a press release with a 27% discontinuation rate has not. Bullish on the science, sceptical on the page. No dosing.
Read the deep-diveOral GLP-1: can you take semaglutide as a pill?
A peptide is food — swallow it and your gut digests it before it works, which is why this class has lived on the needle. Yet the pill is arriving, by two philosophically opposite routes: smuggle the fragile peptide across the gut wall, or stop using a peptide at all and rebuild the signal from a rugged small molecule. The second one is the real revolution, and it comes down to a quiet truth about receptors — they read the message, not the messenger.
Read the deep-diveWhat is retatrutide? The triple agonist explained
The newest metabolic peptides don't mimic one hormone — they play three at once. Why the field moved from a single signal to a chord, and why glucagon, of all things, earns a seat.
Read the deep-diveMuscle loss on GLP-1: how to keep muscle while losing weight
The next leap in weight loss isn't losing more — it's losing better. Pair a GLP-1 drug with myostatin inhibition and you can strip fat while sparing, even building, muscle. Inside the TGF-β biology and the combination therapies engineering it.
Read the deep-diveRun the numbers yourself
Free, in-browser, no sign-up — the pharmacokinetics the vendor pages skip. Educational, not dosing advice.
All tools & calculatorsHalf-life & dosing
Model how long a compound stays bioactive and how dose frequency vs half-life builds to steady state.
Analog comparison
Put a native hormone beside the analogs engineered from it — receptor, weight, half-life, and evidence tier on one axis.
Cycle planner
Sketch a research cycle from a goal stack: week-by-week timeline, reference dosing, and a supply estimate. Shareable by URL.
Bullish on the science. Sceptical on the page.
A signaling system this old, this economical, and this suddenly writable has earned real enthusiasm — pretending otherwise would be its own kind of dishonesty. But enthusiasm that outruns its citations is just marketing with better vocabulary. So every claim here carries its evidence, graded by how far it actually goes — settled where the science is settled, the frontier where it isn’t.
Sourced, not asserted
Every mechanism traces to primary literature, structural data, and registered trials — cited, not paraphrased into authority.
Research-grade, not medical
Reference material for understanding the biology. Nothing here is medical advice, a recommendation, or a substitute for a clinician.
Editorially independent
No storefront, no sponsored conclusions. Disclosed affiliate links fund the work — but the incentive that shapes the catalog is to be correct, never to sell.
Sourcing your own research material? Our American Peptide network vetted two research-use-only sources you can actually reason about — AminoClub and ElyriaBio. Code at AminoClub. See what’s reachable.