The Library — A Field Guide
An evolving reference on peptides, genetics, and the biology behind both.
Essays in print
98
Dossiers
6
Last dispatch
Jul 18
Editor’s Pick · Mechanisms
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.
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
98 essays. Search, filter, sort, or switch to the index for a compact reference view.
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.
Can BPC-157 help with TBI recovery? Animal models show full functional recovery after stroke. What 30 years of CNS research actually shows, what genetics change, and the human trial gap.
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.
Can BPC-157 heal leaky gut? It restores tight junctions, protects your liver, and feeds enteric nerves. 7 gut effects tendon articles skip. Your genetics change the math.
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 zero desensitization. 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 more human trial data than any other GHRP. Japan uses it to diagnose pituitary disorders. But it spikes cortisol like CRH, and that 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.
BPC-157 clears your blood in 4 minutes. But the cascade it triggers runs for 72 hours. Here is the step-by-step timeline of what fires, and when, after a single injection.
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%. Your GLP1R gene predicts which agonist works best for your biology.
AOD-9604 and semaglutide target completely different fat pathways. Here is the combination protocol, the receptor science, and the genetics that predict 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. The AEDP bioregulator targets the cerebral cortex -- 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, lipohypertrophy, 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? Your GLP1R and GIPR genes predict the gap. 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 you take BPC-157 orally and get results? Oral has 3% bioavailability vs 14-51% for injection. But oral wins in one scenario, and most dosing guides miss it.
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.
Which supplements actually interfere with peptides? Most CYP enzyme fears are misplaced for injectable research peptides. Here are the 5 combos that genuinely matter and why your genes change the severity.
Akkermansia triggers GLP-2, your gut's own repair hormone. Your FUT2 and MUC2 genes determine whether the bacterium can colonize at all. Here is what the research 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. Your TLR4 genes decide how hard it hits.
Dihexa is 10 million times more potent than BDNF in synaptogenesis tests. 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 oral BPC-157 loses 99% before reaching 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. Three genes in your circadian clock predict who gets the full sleep benefit.
Do peptides work after 50? Yes, but the rules change. Your FOXO3, KLOTHO, and APOE variants decide which peptides hit hardest and which ones you waste money on.
GLP-2 heals your gut lining directly, something GLP-1 cannot do. Here is what 30 years of clinical trials show and which gut inflammation genes predict your response.
Why do healing peptides work dramatically for some people and almost nothing for others? Your TNF-alpha, IL-6, and IL-10 genotype may be the actual answer.
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.
GHK-Cu before and after results are real. The best published RCT found 55.8% wrinkle reduction in 8 weeks. Here is the honest week-by-week timeline, plus what your collagen genes predict.
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 determine your results: serum concentration, age-related collagen deficit, and your skin genetics.
Best anti-aging peptides in 2026, ranked by human evidence. GHK-Cu has RCTs. Thymosin alpha-1 has 30 trials. BPC-157 has almost none. Your genetics predict which works.
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 peptides heal gut inflammation? KPV calms it at the cellular level. GLP-2 has FDA-approved human data. BPC-157 has zero human trials. Here is what the research shows.
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 boosts BDNF for the right genotype. 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. Your COMT gene determines which one helps and which backfires.
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 different sleep problems. Your PER3 gene predicts which one you actually need.
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 ran more human trials than most research peptides and still failed its pivotal test. Here is what the data shows and whether your genes predict your response.
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 K14Q genetic variant changes your entire response profile.
If you carry the CYP3A4*22 variant, standard drug doses can build to 150-170% of intended levels. Here is what that means for your peptide stack.
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 receptor desensitization, and why your genetics determines your reset window.
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. Your BDNF and GABRA2 genes predict if you are a fast responder.
BPC-157 cut soft-tissue recovery time by up to 50% across 35+ preclinical studies. But around 1 in 5 users report no benefit. Your collagen and NOS3 genes explain why.
Ipamorelin fires a clean GH pulse that peaks at 40 minutes. CJC-1295 keeps GH elevated for six days per injection. Your GHSR and GHR genes determine which one fits your biology.
BPC-157 clears your blood in 15 minutes. TB-500 persists in tissue for days. Your CYP enzyme status and protease genetics decide how these half-lives translate to your protocol.
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 searches have surged over 500% in the past year. Here's what this copper peptide actually does, what it doesn't, and why your genetics determine whether it's worth trying.
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 should you take? Find your dose by body weight. Daily vs weekly protocols, mcg per kg, oral vs injection, and why your liver enzymes change the math.
Peptide stacking searches are up 800% this year. Everyone wants to stack — but most guides ignore the genetic factors that determine whether a combination will work for you or waste your money.
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.
Semaglutide dominates the headlines, but it's not the only peptide that moves the scale. Here are the top 5 peptides for weight loss — ranked by evidence — and why your GLP1R and PPARG gene variants determine which one actually works for you.
GHK-Cu, BPC-157, collagen peptides, Epithalon, Matrixyl — the skincare peptide market is exploding. Here's what actually works, what's marketing, and why your COL1A1 and SOD2 genes determine which peptide delivers results for your skin.
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 the most-researched healing peptide in the biohacking world. Here's exactly how it works — from nitric oxide signaling to tendon repair — and why your genetics determine how well it works for you.
The most popular peptide combination in biohacking. Here's how the Wolverine Stack works, who it's best for, and what your MMP3 and FN1 gene variants mean for your response.
Everything you need to know before trying peptides — what they are, how they work, which ones are most popular, and the 5 genetic factors that affect which peptide to choose first.
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 why your TGFB1 and COL1A1 variants determine your response.
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.
Your liver's CYP450 enzymes process ~75% of all drugs — but most peptides aren't among them. Here's what CYP enzymes actually do, why your metabolizer status matters for drug interactions, and how the 7 key CYP enzymes affect your peptide protocol.
Showing 98 of 98 articles.
The Colophon
Upload an existing 23andMe, AncestryDNA, or MyHeritage file for $99. The report ranks up to 26 peptides against your unique genetics. One purchase. No subscription.
