Basics
17 GUIDESHow Many Peptides Are There? Six Counting Rules, Six Answers
Every count on this page is computed from this site's own registries, with its counting rule stated beside the number: nature's thousands, the library total, approvals, trials, and the compounds with nothing behind them.
Are Collagen Peptides the Same as Injectable Peptides? What the Trials Measured
Collagen peptides are real peptides, but a drinkable food-protein mixture, not a defined sequence. What the skin and joint trials measured, and who paid for them.
What Is a Peptide Half-Life? Why It Differs From How Long It Works
Half-life tells you how fast a drug leaves your blood. Tesamorelin's is 11 minutes and it is dosed daily. Seven questions, seven different answers.
Is Everything a Peptide Vendor Sells Actually a Peptide?
35 of 247 compounds in our library are not peptides. NAD+, 5-Amino-1MQ and SLU-PP-332 alone carry 387 listings, and the distinction changes five things.
Calculating and injecting
20 GUIDESMissed a Semaglutide or Tirzepatide Dose? What the Labels Say
What approved product labels say about missed doses, why their rules differ, and why none transfers to research peptides.
Foundayo (Orforglipron) Dose: Why 36 mg Is Not an Approved Dose
The approved maximum is 17.2 mg daily, not the 36 mg in trial coverage. The six strengths, the 30-day steps, and the label's own capsule-to-tablet mapping.
Why Does GHK-Cu Burn When You Inject It?
Nobody has measured the cause. The pH figures quoted disagree, the most-cited paper found the opposite, and the copper-free GHK fix has never been tested.
Why Two Peptide Calculators Give Different Answers
Reconstitution calculators are arithmetic and should agree. Blood level calculators are models built on a half-life that, for most compounds, nobody has measured.
Storage and handling
13 GUIDESCan You Freeze Peptides? What the Labels Say About Powder and Solution
No approved peptide label says to freeze anything. What the labels say about sealed powder and mixed vials, and what freeze-thaw has been measured to do.
My Peptide Vial Has No Expiration Date. Is That Normal?
Why research-labeled peptide vials lack expiration dates, what stability testing establishes, and how shelf life differs from the in-use clock.
My Fridge Lost Power. Are My Peptides Still Good?
The temperature it reached matters more than how long the power was off. What each GLP-1 label allows out of the fridge, and the one condition with no tolerance.
My Peptide Vial Looks Empty. Is That Normal?
Why a freeze-dried peptide vial can look empty, what 10 mg of powder looks like, and what the vial can and cannot tell you about its contents.
Buying and safety
15 GUIDES"Pharmaceutical Grade" vs USP: What the Labels Mean
The phrase appears zero times in the federal drug regulations. USP and GMP do, and almost nothing sold on a peptide site has either one.
What Does 99% Peptide Purity Actually Mean?
Purity compares peptide to peptide, not the whole vial. What HPLC leaves out, how net peptide content works, and why purity is not a safety test.
Wegovy Pill vs Foundayo: The Two GLP-1 Pills Compared
One is a peptide and needs an empty stomach, one is not and needs nothing. What each does, and which trade suits whom.
Is It Safe to Buy Retatrutide Online?
What independent tests of online retatrutide found, how careful buyers check a vial, what it costs and where the law stands.
Understanding compounds
36 GUIDESDo Amylin Drugs Work as Well as GLP-1s? What the Trials Measured
One amylin drug has been approved since 2005 and moves weight by about a kilogram and a half. Newer analogs report 9.2% to 22.0%, all from company releases but one.
Glutathione by Mouth, IV, IM or Nebulized: The Evidence
The two routes people inject have no published human trial. The best-designed glutathione trial used a nebulizer and missed its primary endpoint.
Does GHK-Cu Reverse Gray Hair?
Why no study in any species has measured hair color after GHK-Cu, what happened when someone tested the copper-and-tyrosinase mechanism directly, and the twenty other things that do make gray hair repigment.
Can BPC-157 Cause Anxiety, Depression or Anhedonia? What the Reports and the Research Show
People report anxiety, low mood and anhedonia on BPC-157. What those reports, the FDA record and animal research can and cannot establish.
Life stages
17 GUIDESDoes Tirzepatide Make Birth Control Less Effective? What the Label Says
What the tirzepatide label says about oral contraceptives, the four-week window after starting and after each dose increase, and why semaglutide's label differs.
Does Lifting Protect Muscle on a GLP-1? What Was Tested
What the exercise, protein and muscle-preservation studies on GLP-1 drugs actually tested, and what remains unanswered.
Does Kisspeptin Work for IVF? What the Trials Measured
What the egg-maturation trials measured, why kisspeptin-54 is not kisspeptin-10, and what remains untested.
Do GLP-1 Drugs Affect Sperm, Testosterone or Male Fertility? What Has Actually Been Measured
Two 2026 reviews counted 10 studies and 639 men. One randomized trial measured semen in 25 men. No study has recorded a pregnancy. What the evidence shows.
News
19 ARTICLESThis Pancreatic Cancer Vaccine Did Everything but Work. Then the Explanation Changed
The KRAS vaccine missed its primary endpoint at a hazard ratio of 0.85. Elicio has now explained that miss two different ways, four months apart.
When Will CagriSema Be Approved? What Novo Has Filed
Novo filed in December 2025 and expects a decision in Q4 2026. No PDUFA date is public. The application rests on REDEFINE 1 and 2, not the trial it lost.
Oral VK2735 Just Entered Phase 3. The Injectable Is a Year Ahead
SUNRISE-1 and SUNRISE-2 test 27.5 mg, 35 mg and 55 mg once daily. The 12.2% figure everyone quotes came from 120 mg, a dose the Phase 3 program does not use.
Has Anyone Died From Retatrutide? What the Two FDA Reports Actually Say
Two unverified FDA reports describe deaths after people used products sold as retatrutide. Nobody has established what was in the vials, and the controlled trials show no cardiac excess.
Commonly confused peptides
Compare toolPetrelintide vs Semaglutide
Semaglutide produced 16.9 percent in STEP 1 against petrelintide's 10.7 in ZUPREME-1. Petrelintide's case is tolerability: no vomiting at its best dose, and no added dropouts over placebo.
Semaglutide vs Tirzepatide vs Retatrutide
One head-to-head trial, three pivotal trials, and why their headline weight-loss figures are not directly comparable.
GHK vs GHK-Cu
The same sequence, with or without copper: topical trial evidence, formulation caveats and the research-vial market.
Tesamorelin vs HGH
Both are FDA approved. Tesamorelin asks your pituitary for growth hormone and HGH is the hormone itself, and only one is a felony to distribute off-label.