Frequently Asked Questions
Answers to the most common questions about peptide research, reconstitution, sourcing, and this platform.
On this page
What Peptides Are Used For
What are peptides used for?The research areas peptides cluster into, and why “used for” on this site means what a study examined rather than what a vendor advertises.
What specific peptides are used for (9)
BPC-157
What BPC-157 has been studied for, the three small uncontrolled human reports, the rat and cell work behind the healing claims, and its FDA status.
Full answercjc-1295-dac
What CJC-1295 has been studied for: hormone-level trials in healthy adults, a terminated HIV trial and mouse growth data, and why only the DAC form has human data.
Full answerGHK-Cu
Two small topical skin trials in people, and a wound, ligament, lung and brain literature that is animal-only, with the figures each study reported.
Full answerGlutathione
What the human trials of glutathione measured — body stores, skin, cystic fibrosis and Parkinson’s — and where the results came up short.
Full answerIpamorelin
One human efficacy trial (postoperative ileus) that missed its endpoint, one that never posted results, and animal data on bone, muscle and weight.
Full answerRetatrutide
Obesity, type 2 diabetes and liver fat: what each retatrutide trial measured and found, with the trial behind every figure.
Full answerSemaglutide
What the randomized trials found in obesity, heart, kidney, liver and joint disease, including the Alzheimer’s trials that failed.
Full answerSermorelin
Child growth trials, small adult studies, and what the intranasal data actually tested.
Full answerTirzepatide
The trials behind each use with their figures, how the dual-hormone action works, and the adverse events the studies reported.
Full answerReconstitution & Preparation
How are peptides reconstituted?Why any volume works, what the water actually changes, and the handling steps that protect the material — the general version of the per-compound maths.
The needle gauge and length commonly used for subcutaneous peptide injection, and the insulin-syringe barrel sizes that pair with them.
Full answerWhether insulin syringes are the right tool for subcutaneous peptide injection (yes), the U-100 unit system, and how the markings map to peptide doses.
Full answerHow the amount of bacteriostatic water sets the concentration (mg ÷ mL), the commonly used range, and a worked 10 mg / 2 mL example — with the math on the calculator.
Full answerReconstituting specific peptides (3)
Retatrutide
There is no single correct volume — the water sets the concentration, and the concentration sets the syringe units. The reference table converts vial size and volume into units for the trial dose points.
Full answerSemaglutide
The volume-to-concentration-to-units arithmetic for the 5 mg and 10 mg vials, tabulated against the labelled dose ladder.
Full answerTirzepatide
The volume-to-concentration-to-units arithmetic for the 10, 30 and 60 mg vials, tabulated against the labelled ladder — including where a vial cannot hold a dose at all.
Full answerDosing
How are peptides dosed?Why two kinds of dosing figure circulate, how to tell them apart, and what half-life has to do with injection frequency.
Dosing for specific peptides (4)
BPC-157
Why no trial-established dose exists, where the 250 and 500 mcg figures actually came from, and what the species extrapolation behind them assumes.
Full answerRetatrutide
The doses the retatrutide trials actually administered — Phase 2's 0.5-12 mg range and the Phase 3 TRIUMPH escalation — and why no approved dosing standard exists.
Full answerSemaglutide
Why there is no such thing as “the semaglutide dose” — four labels, four ceilings and four different missed-dose rules, each attributed to the label it comes from.
Full answerTirzepatide
The labelled escalation ladder and its ceiling, why the steps are four weeks apart, and the missed-dose rule as the labels actually write it.
Full answerDosing Frequency
How often are peptides dosed?Why one compound appears weekly and another several times a day, what titration is actually for, and how to read a schedule nobody ran a trial on.
Frequency for specific peptides (6)
BPC-157
Why there is no established BPC-157 dosing frequency — the circulating numbers are convention, and the human evidence is three small uncontrolled reports, none testing a schedule.
Full answerCJC-1295 (No DAC) + Ipamorelin
Why the pair's frequency splits by half-life — CJC-1295 DAC weekly vs no-DAC CJC and Ipamorelin multiple times daily — with the combination's no-trial caveat.
Full answerRetatrutide
The once-weekly subcutaneous schedule and every-4-week titration the retatrutide trials used, reported from the profile's cited Phase 2/3 protocols.
Full answerSemaglutide
The once-weekly injectable schedule (0.25→2.4 mg), the Ozempic/Rybelsus variants, and the every-4-week titration the semaglutide trials and label used.
Full answerTB-500
Why there is no established TB-500 dosing frequency — the loading/maintenance numbers are convention, and the cited studies are mechanism/wound-healing with an animal-estimated half-life.
Full answerTirzepatide
The once-weekly subcutaneous schedule and every-4-week titration (2.5→15 mg) the tirzepatide trials and FDA label used.
Full answerSide Effects
What are the side effects of peptides?Why a general answer is mostly an absence, what the documented effects look like where they exist, and why injection-site reactions are the one common thread.
Side effects of specific peptides (7)
BPC-157
Why there is no characterised human side-effect profile, what “no toxic dose identified” does and does not mean, and the angiogenesis question the literature leaves open.
Full answerIGF-1 LR3
The one cited IGF-1 LR3 side effect (hypoglycemia) versus what is not established — the analog has no controlled human trials, and the cited sources leave the IGF-1/cancer question open.
Full answerKLOW
Why there is no blend-level side-effect data for KLOW — no trial has studied the four-peptide combination, so side effects are per-component, and each component's human safety data is limited or absent.
Full answerRetatrutide
The reported rates with the trial behind each, the dysesthesia finding that is specific to retatrutide, and what trial safety data does not tell you about a research-market vial.
Full answerSemaglutide
The reported rates with the trial behind each, why escalation is when they cluster, and what a label warns about that a trial did not measure.
Full answerTB-500
Why there is no characterized human side-effect profile for thymosin beta-4 / TB-500 — human exposure is two terminated Phase 2 trials, the cited studies are animal wound-healing mechanism, and the tumor question stays theoretical.
Full answerTirzepatide
The reported rates with the trial behind each, the head-to-head discontinuation figure, and what a boxed warning drawn from rodent data does and does not establish.
Full answerForms: Oral, Nasal & Injectable
What is the difference between peptide pills, nasal sprays and injections?What the FDA labels measure for swallowed, sprayed and injected peptides, why the gap is so large, and how the few approved pills and sprays work around it.
Which peptides regulators have approved as pills, the three ways those products get around digestion, and what the record shows for research peptides taken by mouth.
Full answerEvery oral form of a peptide on this site with its status — approved product, human trials, animal only, or research market only — and how many vendors list each.
Full answerEvery nasal form of a peptide on this site with its status, what the approved peptide sprays show about nasal absorption, and which sprays sold for research have any nasal study at all.
Full answerForms of specific peptides (8)
BPC-157
What the human record actually holds for oral BPC-157 (one registered trial, no results), what the rat studies showed, and why nasal and sublingual forms have no studies at all.
Full answerGHK-Cu
What the one controlled human trial of topical GHK-Cu found, why it applies to one serum rather than to copper-peptide creams in general, and what is missing for injected, oral and nasal forms.
Full answerGlutathione
Why the oral glutathione trials disagree, what the sublingual, inhaled and nasal trials found, and what is and is not known about injected glutathione.
Full answerNAD+
What the one oral NAD+ trial measured, how the precursor pills (NR, NMN) compare, what the injected-NAD+ trial used, and why nasal NAD+ has no study.
Full answerOxytocin
What the trials of intranasal oxytocin found, whether a nasal dose reaches the brain, and where the nasal product stands with US and Swiss regulators.
Full answerPT-141
Why the approved PT-141 is an injection only, what the small intranasal trials found, and which nasal papers carry a retraction or an expression of concern.
Full answerSemaglutide
The three approved tablets against the injection, label by label: how much is absorbed, why the milligram doses differ, what the trials found, and which other GLP-1 drugs come as pills.
Full answerSemax
What the one human intranasal Semax trial found, what rat studies show about nasal Semax reaching the brain, and where the nasal drops stand with regulators.
Full answerTestosterone & TRT
What is TRT?Prescribed testosterone for diagnosed hypogonadism — what the guideline requires before treatment, which formulations are FDA-labeled, and what the reference ranges and the cardiovascular-safety trial actually reported.
Two FDA labels, the 2018 Endocrine Society and AUA guidelines, and the published literature on peak-to-trough management and sub-weekly dosing in practice — what each named source states.
Full answerWhat the classic intramuscular testosterone enanthate label, the weekly-subcutaneous Xyosted label, and the 2018 Endocrine Society guideline each state about injection frequency.
Full answerWhether testosterone can be injected subcutaneously — the FDA-approved weekly SC product, the intramuscular-only classic labels, and a published SC-vs-IM pharmacokinetic comparison.
Full answerWhat the published onset-of-effects review (Saad et al. 2011) reports about when testosterone therapy's effects appear and peak, domain by domain.
Full answerThe harmonized normal testosterone reference range (264–916 ng/dL) from Travison 2017 and the Endocrine Society's 264 ng/dL diagnostic threshold — with the caveat that ranges vary by lab and assay.
Full answerThe 2018 Endocrine Society monitoring schedule for testosterone therapy — testosterone and hematocrit at baseline, 3–6 months, and annually; PSA and a prostate exam for men 40+.
Full answerThe DHT mechanism behind androgenetic alopecia and why TRT-specific hair-loss outcomes are not quantified in the cited literature — mechanism known, outcome not established.
Full answerAbout This Site
Still have questions?
Browse the Peptide Library for detailed compound-specific information, check the Supplement Library for evidence-based supplement profiles and supplement FAQs, or explore the Research Hub for in-depth guides.
Need help with technical terms? Browse the Research Glossary for plain-English definitions. Ready to calculate a dose? Try the Dosage Calculator.
