The Library — A Field Guide
An evolving reference on peptides, genetics, and the biology behind both.
Essays in print
103
Dossiers
6
Last dispatch
Aug 4
Editor’s Pick · Stacking
What the pairing is, the protocol people run, how to mix and draw it, where to inject, and what to expect week by week. Plus the finding that makes it far easier to run than most guides suggest.
Start here
Our most complete work: video, diagrams, and every compound linked to its reference page.
Departments
The Field Guide is organised in six standing departments. Begin where you are most curious.
Each peptide gets its own file. What it does, what the research really shows, who responds, who does not.
Why two people on the same dose of the same compound get opposite results, written in your DNA.
Mechanisms, in plain language. Receptors, pathways, half-lives, and what it all means for your protocol.
What works together, what cancels itself out, and the protocols people are actually running.
Doses, cycles, interactions, contraindications. The unflashy work that keeps the rest of it working.
Tests, services, peptides, head to head. Sorted by what actually matters.
The Archive
103 essays. Search, filter, sort, or switch to the index for a compact reference view.
GHK-Cu turns up in almost every scalp serum sold. Here is the actual mechanism, how it compares to minoxidil and finasteride, whether microneedling changes the answer, and what a realistic timeline looks like.
The same 80 mg vial, the same '10 units', three different doses. Here is why peptide dosing charts contradict each other, and the 30-second check that tells you which one to trust.
How do you know when your peptide protocol is hurting you? Seven warning signs tell you when to pause, what to do next, and which ones your genetics make more likely.
Sermorelin vs CJC-1295: which GHRH analog actually has the data? One ran FDA trials for 25 years. The other has one Phase I study and an unresolved cardiac flag.
CJC-1295 with DAC vs without DAC: most protocols treat them as interchangeable. They aren't. One raises your GH floor 750%. The other fires a single pulse. Here's which version your protocol needs.
How much muscle do you lose on semaglutide? Between 25 and 40 percent of weight lost is lean mass. Here is why, and why GH peptides fix the root cause protein alone cannot.
SS-31 just became FDA approved. BPC-157 faces a US compounding ban. Here is how their brain injury mechanisms differ and which one you should reach for first.
Some people gain lean mass on every peptide protocol. Others barely respond. The difference is usually genetic. Here are the 5 variants that control your myostatin response and what each type should stack.
Does selank increase BDNF? It does, but not directly. Selank removes the cortisol block on your brain repair system. BDNF variants relate to how that signal is carried.
Why do two people run the same BPC-157 protocol and one heals in 8 weeks while the other stalls at 20? Five genetic variants explain most of the gap. Here is how to find yours.
How much BPC-157 for brain and neurological protocols? Radiolabeled data shows brain tissue gets the least peptide after injection. Here is how to dose for actual CNS effect.
How much ipamorelin and CJC-1295 should you take together? The answer depends on your IGF-1 labs and one key genetic variant. Here is the protocol that adjusts for both.
Kisspeptin-10 raised testosterone 45 percent in a 2011 human study. Why twice-daily use erases the effect in 2 weeks, and what the correct pulsed protocol actually looks like.
How much TB-500 should you inject? Loading phase, maintenance dose by body weight, weekly vs twice-weekly frequency, and 3 injury-specific protocols. Plus the FDA ruling that just changed US access in 2026.
One in four Semax users get brain fog instead of clarity. Three variants are associated with it: COMT, BDNF Val66Met and MTHFR. Here is how to know which group you are in before you dose.
IGF-1 flat despite a clean GH spike on ipamorelin or MK-677? STAT5B is the liver gene that converts your GH pulse into IGF-1 -- and partial variants silently block the translation.
What blood tests do you need for peptides? Beyond IGF-1, six more numbers tell you if your GH, healing, or fat-loss protocol is working or quietly going wrong.
What does high IGF-1 feel like? Nine signs to check before your next injection: from carpal tunnel to glucose shifts, and what to do when you spot them.
How much sermorelin should you take? Start with this body-weight dosing chart. IGF-1 titration at 6 weeks, cycling protocol, and why sermorelin replaced CJC-1295 in 2026.
Low IGFBP-3 means more free IGF-1 than your blood test implies. What the IGF-1:IGFBP-3 molar ratio tells you on GH peptide protocols, and what a skewed value signals.
When to take ipamorelin? The real variable is fasting state, not bedtime. Post-meal dosing loses 40-70% of GH pulse amplitude to somatostatin. Here is the complete protocol guide.
How long does MK-677 actually work? A 2-year RCT found IGF-1 elevated for 24 months with no fading of the receptor response. A 2011 trial was stopped early for a cardiac signal most guides skip.
When should you draw IGF-1 on ipamorelin, CJC-1295, or MK-677? The fasting rule is half right. Here is the compound-specific timing guide no clinic publishes.
GHRP-2 has the deepest human trial record of its class, and Japan uses it to diagnose pituitary disorders. It also provokes cortisol as hard as a clinical stress test, which changes the dosing math completely.
Ipamorelin is hitting your receptor and your GH spike is real. But the GHSR variant nobody tests for is silencing the 50% of your GH signal that runs between injections.
Which GH peptide actually burns fat in RCTs? Tesamorelin has Phase III trial data. MK-677 added lean mass but not fat loss. CJC-1295 has never completed a body composition trial.
Most Thymosin Alpha-1 users run one layer of a three-layer immune stack. Here are 7 protocol mistakes to fix, why zinc must come first, and what Cortagen actually does.
Why does your IGF-1 barely move on ipamorelin while someone else's jumps 80 points on the same dose? The GHR Exon 3 deletion explains more of that gap than protocol ever does.
The 28-day storage rule everyone follows came from a bacteriostatic water label, not peptide science. Here are the real temperature, light, and pH rules that protect your protocol.
How potent is hexarelin compared to ipamorelin? The strongest GHRP ever tested peaks in 7 days, works through a second heart receptor, and has no FDA compounding pathway in 2026.
In the only head-to-head RCT, tirzepatide beat semaglutide 20.2% vs 13.7% body weight loss. Retatrutide hits 28%. GLP1R variants relate to the receptor these agonists act on.
AOD-9604 and semaglutide target completely different fat pathways. Here is the combination protocol, the receptor science, and the genetics that shape your results.
If your IGF-1 barely moved on ipamorelin, it is probably not the dose. Two genetic variables explain 43% of why growth peptide IGF-1 response varies up to 3-fold between users.
What is Cortagen? Most articles call it a thymus peptide. That is wrong. It is aimed at the outer layer of the brain, and the real data is about nerve repair, not immune aging.
Intranasal peptide absorption via the olfactory nerve bypasses the BBB. Studies show up to 20x more brain delivery than injection, depending on where the spray actually lands.
How much bacteriostatic water goes in a 5mg peptide vial? Full reconstitution guide: dilution ratios by dose, the solvent-decision table, and storage rules by peptide.
Can a peptide injection give you an abscess? Yes. Here are 9 injection hygiene mistakes causing site infections, lumpy scarred fat, and failed protocols, with fixes for each.
What does Pinealon actually do? The Russian tripeptide has 30 years of neuroprotection data. Dosage guide, melatonin connection, and circadian genes explained.
Methylfolate works for some MTHFR carriers. For the rest, elevated homocysteine keeps suppressing BDNF no matter how much B9 you take. Semax changes the equation entirely.
Thymulin drops to zero in most people after 60. It drives T-cell production from birth. Here is what losing it means for immune aging and what zinc has to do with it.
BPC-157 just entered its first human RCT for muscle injury. TB-500 has never had one. The evidence on recovery speed, tissue specificity, and which to use first.
Three Russian peptides, three separate brain pathways. Here are 7 rules for stacking Semax, Selank, and Dihexa correctly, and how your BDNF and COMT genes change every one.
How much Semax should you take? The 0.1% vs 1% difference is a 10x error that breaks most protocols. Dosage chart, mcg per spray, cycling guide, and what Russian trials dosed.
Why does tirzepatide produce 20% weight loss while semaglutide delivers 5% for the same patient? GLP1R and GIPR variants relate to both receptor pathways. 2026 data inside.
Retatrutide weight loss results hit 28% of body weight in Phase 3 trials. How the triple agonist mechanism works, how it compares to semaglutide and tirzepatide, and why your GLP-1 gene changes the math.
How do you know if peptides are working? Sleep changes by day 14, IGF-1 at week 6. Seven confirmed signals, 3 red flags, and why your genetics change the timeline.
Peptide stopped working and cycling is not fixing it? Anti-drug antibodies may be neutralizing your protocol. Clinical data, ADA timeline, and which genetics make you higher risk.
Can PT-141 fix low libido that testosterone therapy could not? Yes, but only because they target completely different problems. Here is how to know which one you actually need.
How long off GH peptides before restarting? Research shows 21-28 days minimum, but which peptide you ran and your receptor genetics changes the exact number.
How do you run the GHK-Cu, Epithalon, and SS-31 anti-aging stack? The 12-week protocol, current research, SS-31's FDA approval, and why timing beats simultaneous dosing.
Akkermansia is sold as a gut-repair supplement, but it does not patch your gut wall itself. Whether it can colonise you at all comes down partly to the genes that build the mucus it eats. Here is what the research actually shows.
Leaky gut sends bacterial toxins straight to your liver via the portal vein. BPC-157 and GLP-2 stop the damage at the source, and how sensitive your toxin alarm is decides how hard each hit lands.
Dihexa is 10 million times more potent than BDNF at building new synapses in a dish. No human trial has been completed. Here is what the animal research shows and what your genetics change.
Can you take peptides orally? Yes. But almost none of an oral dose reaches your blood. The bioavailability data by route, and what it changes in your protocol.
PT-141 (bremelanotide) targets desire in the brain, not blood flow. Dosage, side effects, the 2026 compounding update, and why your DNA changes the response.
Peptide stacking hits different after 40. GHK-Cu plasma drops 60% by age 60, collagen loss accelerates, and estrogen changes which peptides hit hardest. Here is the protocol.
Which skin repair compound wins on RCT evidence: GHK-Cu, retinol, or vitamin C? Retinol has 8 pooled RCTs. GHK-Cu has zero. Your skin genetics predict which gap to close first.
Why isn't your BPC-157 working? Usually it is not the peptide. These 7 protocol mistakes, from concentration math to skipped cycling, are quietly wasting your results.
Does ipamorelin actually improve sleep, or just growth hormone? A 2022 study inverted the answer. How deep and how late your own body clock runs decides who feels anything.
Do peptides work after 50? Yes, but the rules change. Three inherited differences decide which deficit is biggest for you, and therefore which peptide is worth buying first.
GLP-2 heals your gut lining directly, something GLP-1 cannot do. Here is what the trials on the approved version show, and which gut inflammation variants relate to it.
Thymosin Alpha-1: tested in 11,000 humans, approved in 35 countries, used in COVID-19 hospitals. A 2025 Phase 3 trial clarified what it actually does and who it helps.
Your peptide DNA report has 9 sections that most people skim past. Here is what each one is actually telling you, the mistakes readers make, and how to turn a score into a protocol.
SS-31 failed a 218-patient randomized trial in 2023, then got FDA approval in 2025. What the research actually shows, who responds, and what your mtDNA haplogroup predicts.
APOE4 triples your Alzheimer's risk and suppresses BDNF by 30 percent. But it makes you a better responder to Cerebrolysin. Seven peptides ranked by APOE4 failure mode.
The most-quoted GHK-Cu result, 55.8% wrinkle reduction in 8 weeks, comes from a small trial using a nano-carrier formulation. Here is the honest week-by-week timeline, plus where collagen variants fit.
Where can you legally access peptides in Europe? Most guides cite a compounding exemption that does not apply to BPC-157 or TB-500. Here is what EU law actually allows in 2026.
Which peptides actually speed muscle recovery? The one with the most human RCT data costs $15 a month. Here are 7 ranked by evidence, not marketing hype.
Why doesn't GHK-Cu work for everyone? Three factors shape the outcome: serum concentration, age-related collagen deficit, and your skin genetics.
Peptide stack for endurance athletes: MOTS-c, BPC-157, and TB-500 are the core. Every one is WADA-banned. A triathlete took a 4-year suspension in 2025 for this exact protocol.
Which peptide suits which gut problem, in plain language. What each one actually does, whether to swallow it or inject it, how long before anything changes, and when to see a doctor instead.
Semax for focus, Selank for anxiety. Both clear from your blood in 5 minutes. Here is the symptom-first guide to choosing, plus how your BDNF and COMT genes change the math.
Which peptides clear brain fog? Semax raises the growth factor your neurons use to build connections. BPC-157 targets gut inflammation. The most-hyped option had its founding science retracted in 2025.
How accurate is your DNA test for peptide response? 23andMe directly genotypes just 0.02% of your genome. Here is what your kit misses, and where it actually gets it right.
Which peptides work best for anxiety? Selank and Semax target the same problem with opposite tools. How fast your brain clears dopamine is one input into which one helps and which one leaves you more wired.
Is the Wolverine Stack still the best peptide combination in 2026? Nine things changed since your last guide: FDA status, TB-500 prodrug finding, and new dose data.
Which peptides work best for sleep in 2026? DSIP, Epithalon, and ipamorelin each target a different sleep problem, and picking the wrong one for your problem is why most people feel nothing.
First peptide therapy appointment? Most clinics skip labs, legal checks, and the genetic step that changes everything. Here is the 7-point checklist to run before you book.
AOD-9604 went through more human testing than most research peptides, failed its pivotal trial, and never published any of it. Here is what the record actually supports and where the genetics fit.
Are peptides legal in the US? BPC-157 was banned in 2023, partially reversed in 2026, and is still not legal to compound. Here is exactly where every major peptide stands right now.
Your mitochondria produce MOTS-c as a metabolic hormone. Levels fall with age and collapse in diabetes. One inherited variant breaks the peptide outright, and exercise routes around it.
KPV and LL-37 both fight skin inflammation without thinning your skin. But they target opposite biology, and a 2024 JCI study found the wrong choice can accelerate heart disease.
Peptide cycling rules differ completely by class. Here is what the research shows about receptors wearing down, and why your reset window may not match the population default.
Epithalon broke the Hayflick limit in cultured human cells and cut cardiovascular mortality by 50% across a 12-year trial. Here is what 30 years of Russian data actually shows.
A 27,885-person study found the gene that predicts who loses weight fast on semaglutide and who barely moves. Your DNA already has the answer.
Selank matched medazepam in trials: 40% of patients hit sub-clinical anxiety in 3 days, with no withdrawal. BDNF and GABRA2 variants relate to the pathways involved.
Ipamorelin fires a clean GH pulse that peaks at 40 minutes. CJC-1295 keeps GH elevated for six days per injection. GHSR and GHR variants relate to the pathway each one acts on.
BPC-157 clears your blood in 15 minutes. TB-500 persists in tissue for days. Why the gap between how fast they clear and how long they act is what actually sets your dosing schedule.
Picking a peptide based on your goal is the wrong starting point. Your COMT, BDNF, SOD2, and GLP1R variants determine whether a protocol works before you pick the peptide.
Your 23andMe raw file is a survey of 650,000 known variants. Here is which peptide-response SNPs it reliably genotypes, what gaps exist across chip versions, and why the data is more useful than most realize.
GHK-Cu is in every second skincare serum right now. Here's what this copper peptide actually does, what it doesn't, and where the evidence in humans stops.
SelfDecode offers a peptide response report as part of their subscription platform. We break down what you get, what you don't, and how it compares to a dedicated genetic peptide test.
How much BPC-157 people take by condition, how long they run it, and the bit everyone gets stuck on: turning a microgram dose into units on the syringe. With reconstitution tables for 5mg and 10mg vials.
Everyone wants to stack peptides. Most guides skip the factors that decide whether a combination is worth the money, starting with whether the two compounds do different jobs at all.
Two companies now offer DNA-to-peptide matching. Here's an honest comparison of PlexusDx and PeptidesDNA: what each test covers, how they differ, and which one fits your needs.
GHK-Cu, BPC-157, collagen peptides, Epithalon, Matrixyl — the skincare peptide market is exploding. Here's what actually works, what's marketing, and how COL1A1 and SOD2 variants relate to skin structure.
BPC-157, TB-500, GHK-Cu, KPV, Thymosin Alpha-1 — healing peptides cover everything from torn tendons to gut lining repair. Here's what the evidence actually supports, and how your NOS3, MMP3, and COL1A1 gene variants predict which one works best for your biology.
BPC-157 is one of the most-researched healing peptides in the biohacking world. Here is exactly how it works, from nitric oxide signaling to tendon repair, and why your genetics are associated with how well it works for you.
What the pairing is, the protocol people run, how to mix and draw it, where to inject, and what to expect week by week. Plus the finding that makes it far easier to run than most guides suggest.
What peptides are, why they are injected, the twelve people actually start with, what a vial costs, how to tell a real vendor from a bad one, how to mix and inject it, and what to expect across your first 90 days.
GHK-Cu is the most scientifically validated anti-aging peptide in existence — 50 years of research, 4,048 genes modulated, and a direct SIRT1 binding mechanism discovered in 2025. Here's how it works and how TGFB1 and COL1A1 variants relate to the collagen pathway.
10-17% of semaglutide users are non-responders. New genetic research — including a 27,885-person GWAS from 23andMe — reveals why. Your GLP1R, TCF7L2, and ARRB1 variants determine whether you'll lose 15% of your body weight or barely notice a difference.
Combining peptides can produce synergistic effects, or expensive futility. Here's the receptor rule, the CYP competition reality, the most popular stacks, and the 8 mistakes that waste your money.
Showing 103 of 103 articles.
The Colophon
Upload an existing 23andMe, AncestryDNA, or MyHeritage file for $99. The report ranks 39 peptides against your unique genetics. One purchase. No subscription.
