Educational information only. Not medical advice.
Compare compounds, understand the differences, and explore the original studies behind them.
Research reviewed October 15, 2026. Start with the overview, then explore the evidence and sources.
Stages summarize the study designs available for the identified material in this selection. Human stages require studies in which people received that material; measuring the body’s own peptide or testing a different analogue does not qualify. Controlled studies can measure hormone responses or other biological changes, as well as clinical outcomes. A higher stage can include unsuccessful trials; the adjacent summary explains the findings and limitations.
Multiple reports from one trial count as one study for this classification. The selected-report totals below describe library coverage. Outcome-specific certainty would require a separate assessment of study limitations, consistency, applicability, precision and publication bias.
Semax is a seven-amino-acid peptide based on a short segment of ACTH, a pituitary hormone. Clinical papers do not consistently identify whether they used the free base or an acetate salt.
Dihexa, also called PNB-0408, is the defined synthetic peptidomimetic N-hexanoic-Tyr-Ile-(6)-aminohexanoic amide. It was derived from an angiotensin IV analogue. Its exact structure distinguishes it from the intact angiotensin IV peptide.
Semax is studied during acute ischemic stroke and rehabilitation, with measurements of neurological recovery and daily activities. Separate healthy-volunteer studies examine short-term brain-network activity; scans alone do not demonstrate improved memory or attention.
Researchers have tested Dihexa in rodents with impaired maze learning, Alzheimer-related genetic changes, toxin-induced Huntington-like deficits and repeated mild head injury. These are experiments on animal behavior and tissue biology; none establishes treatment of a human neurological condition.
The categories describe the most advanced study designs selected for this library. Each summary explains what was measured and what remains uncertain.
Multiple controlled human studies
An acute-stroke comparison reported faster improvement in movement problems and other neurological deficits, while a separate placebo-controlled volunteer study measured brain-network changes. The acquired stroke abstract does not establish random allocation or blinded assessment, and clinical effect sizes remain poorly quantified. Possible overlap between the two imaging publications prevents counting them as independent cohorts. General cognitive benefit was not demonstrated.
Animal studies
In APP/PS1 mice, Dihexa improved swimming-maze performance compared with mice with the same genetic changes given preparation without Dihexa. In a separate head-injury experiment, rats given Dihexa directly into a brain ventricle made more correct delayed maze choices than injured rats given control fluid, identified as DPBS in the Methods. A 40-rat toxin study found no protection of movement, learning or weight gain over five weeks. The early pharmacology report has a Notice of Concern and the 2014 mechanism paper was retracted. Human benefit and safety remain unestablished.
The parent structures and the acetate forms are distinct pieces of the evidence. Clinical reports do not always specify the chemical form.
Semax is the seven-amino-acid sequence Met-Glu-His-Phe-Pro-Gly-Pro, developed from an ACTH fragment. FDA evaluates the free base and acetate separately and notes unclear form reporting in clinical papers.
Dihexa / PNB-0408 is the defined angiotensin-IV-derived peptidomimetic N-hexanoic-Tyr-Ile-(6)-aminohexanoic amide. FDA’s safety entry specifically names Dihexa acetate.
A protein or signaling measurement explains a biological hypothesis. It does not place the two compounds on a common human-benefit or potency scale.
A rat hippocampus study measured more brain-derived neurotrophic factor (BDNF), a protein supporting nerve-cell function, and greater activation of its TrkB receptor after Semax. These are nerve-support signaling measurements, not a measured human memory improvement.
The prominent 2014 HGF/c-Met mechanism paper was retracted in 2025 for falsified or fabricated data in specified figures and an erratum submission. Later mouse signaling and rat antagonist experiments are separate observations; they do not restore those withdrawn measurements.
No direct Semax-versus-Dihexa trial was identified. The human and animal studies below test different populations and measurements.
An older comparison of 30 Semax-treated stroke patients and 80 conventional-treatment controls reported faster neurological improvement, but random allocation, blinded assessment and a dependable treatment-effect estimate are not established. A separate 24-person study measured resting brain-network changes, without demonstrating a memory benefit.
Dihexa-treated APP/PS1 mice found a hidden swimming-maze platform faster than mice with the same genetic changes given preparation without Dihexa. Head-injured rats given Dihexa directly into a brain ventricle made more correct maze choices than injured rats given buffered salt solution (DPBS). A separate 40-rat toxin study found no protection of measured movement, learning or weight gain. Human cognitive benefit remains unestablished.
Routes, species and analytes matter. A tissue radioactivity signal, plasma concentration and behavioral result cannot be substituted for one another.
FDA found no human pharmacokinetic study of free base or acetate by any route. Its rat review describes labeled-peptide distribution and rapid breakdown in blood and brain; label measurements need separation of parent peptide from metabolites.
A 2013 rat report with a Notice of Concern calculated terminal plasma half-lives of 12.68 days intravenously and 8.83 ± 2.41 days intraperitoneally (mean ± standard error), with four rats in the latter analysis. These do not establish human exposure or effect duration. FDA found no human exposure data for Dihexa acetate.
The sources do not provide a shared clinical safety comparison. An absence of sufficiently studied harms cannot establish safety.
FDA found insufficient clinical safety information and no safety data for the proposed subcutaneous route. It raised possible bleeding and immune-reaction concerns without establishing reliable event rates. Russian nasal-drop registration does not establish safety for every form or route.
FDA’s acetate entry states that important human safety information is missing, including whether administration would cause harm. The reviewed rodent studies cannot quantify uncommon events, medicine interactions or long-term human risks.
Semax is a registered nasal-drop medicine in Russia, according to FDA's 2026 review; it has no FDA-approved therapeutic indication. The review found insufficient clinical information to characterize safety and no safety data for the proposed subcutaneous route. Its discussion also raises a possible bleeding concern from reported antithrombotic activity. The available material does not provide a reliable rate for that harm. FDA clinical-safety assessment.
The reviewed evidence establishes no human Dihexa safety profile. FDA found no human exposure data for Dihexa acetate and states that important safety information is missing. Animal maze findings do not quantify human cancer risk, interactions or long-term harms.
These are selected reports; several reports can come from one trial or cohort. Counts describe this library’s coverage.
No sections match this focus. Choose All sections to read the full comparison.
Read how the compounds differ, what direct studies found, and which questions remain open.
BPC-157 has been studied in several animal injury models and a few small human reports. Research on the defined acetylated TB-500 fragment is largely analytical or laboratory work. A small 2026 rat study tested BPC-157 alongside a TB-500-labeled preparation, but the paper did not fully identify that preparation or establish a clear difference between the two compounds.
CJC-1295 with DAC was designed to bind albumin and prolong growth-hormone signaling, and early studies measured its persistence and hormone effects in healthy volunteers. Modified GRF(1–29) shares the modified GHRH core but lacks that extension; most selected reports concern chemical identification, leaving much less human pharmacology to compare.
Direct trials found greater average weight and blood-glucose reductions with tirzepatide at the formulations tested. Receptor biology, available products, approved uses, cardiovascular outcomes and tolerability add context when comparing the two medicines.
Liraglutide and semaglutide activate the same GLP-1 receptor. Direct trials found larger average weight and blood-glucose reductions with semaglutide under the protocols tested. The comparison explains those trials, formulation differences, tolerability and separate cardiovascular evidence.
ACHIEVE-3 directly compared oral orforglipron capsules with oral semaglutide tablets in adults with type 2 diabetes taking metformin. Orforglipron lowered average blood glucose more. More participants reported stomach or intestinal adverse events or stopped treatment because of adverse events, and the average pulse increase was larger with orforglipron. The results concern the trial formulations and strengths; weight-management products need separate context.
Dihexa is a defined synthetic peptidomimetic with rodent research and important publication warnings. Cerebrolysin is a porcine-brain-derived mixture with randomized human trials, including favorable rehabilitation findings and unsuccessful acute-stroke comparisons. There is no direct trial establishing which is more effective or safer, and neither a shared brain-research theme nor separate study results makes the preparations interchangeable.
Semax is a seven-amino-acid peptide with small human neurological and brain-imaging reports. Dihexa is an angiotensin-IV-derived peptidomimetic with rodent research, a formal concern on its early pharmacology report and a retracted mechanism paper. Their separate studies do not establish which improves human memory more, and neither record provides a dependable human half-life comparison.
Epitalon studies focus on telomere maintenance, while FOXO4-DRI studies test removal of senescent cells. Separate mouse results, failed cartilage improvement and a pulmonary-vessel harm signal do not establish which would improve human aging. Neither has a validated human blood half-life in the sources reviewed here.
FOXO4-DRI experiments test senescent-cell clearance; MOTS-c experiments examine metabolic adaptation and physical capacity. Separate mouse results and human endogenous-MOTS-c measurements do not establish a clinical aging or fitness ranking. A pulmonary-vessel harm signal for FOXO4-DRI and major native-MOTS-c safety gaps remain consequential.
Retatrutide activates GIP, GLP-1 and glucagon receptors; semaglutide activates GLP-1 receptors. Separate placebo-controlled obesity trials found substantial weight loss with each, but their percentages cannot establish which works better in a shared population. Semaglutide has approved products and cardiovascular-outcome evidence. Retatrutide remains investigational, with a direct semaglutide diabetes comparison registered but no result report located for this review.
Three direct trials have preliminary sponsor results. REDEFINE 4 in obesity failed to establish CagriSema noninferiority to tirzepatide for weight loss. In type 2 diabetes, higher-dose REIMAGINE 4 met weight noninferiority but failed the glucose criterion; lower-dose REIMAGINE 5 reported greater weight loss with CagriSema and met glucose noninferiority. Exact doses, populations and analysis assumptions determine what each result means.
GHK-Cu combines a three-amino-acid peptide with copper; BPC-157 is a separate fifteen-amino-acid peptide. GHK-Cu has been tested in specific topical skin and wound products, with mixed human results. BPC-157 has repair-related cell and animal findings and small human reports. No direct GHK-Cu–BPC-157 trial was identified, so these sources cannot establish which improves skin or injury recovery more.
Analytical studies identify TB-500 as the acetylated seven-amino-acid thymosin β4 fragment Ac-LKKTETQ. GHK-Cu is a copper-bound tripeptide studied in specific skin and wound preparations. TB-500 fragment findings involve analytical and cell studies; GHK-Cu has mixed human topical findings. Full-length thymosin β4 trials and ambiguously named products cannot establish a fragment-versus-GHK-Cu clinical ranking.
Semax and Selank are different seven-residue peptides with a shared Pro-Gly-Pro ending. Their patient studies addressed different conditions: stroke-related deficits for Semax and anxiety-related symptoms for Selank. A small study included both compounds and placebo in healthy participants, but measured brain-scan connectivity rather than clinical benefit. These sources cannot rank them as treatments for anxiety, cognition or stroke.
Oxytocin is an endogenous hormone with established obstetric uses; its sexual-function studies used particular nasal or vaginal preparations in distinct populations. Bremelanotide, also called PT-141, is a melanocortin-receptor agonist approved as Vyleesi for premenopausal women with acquired, generalized hypoactive sexual desire disorder. Separate trials cannot establish which is a better treatment for a shared patient group.
GHRP-6 and GHRP-2 are different six-residue peptides that stimulate growth hormone through the ghrelin-receptor system. Controlled GHRP-2 meal studies found greater food intake, while GHRP-6 has direct human peptide measurements and detailed endocrine experiments. These sources do not establish which produces more muscle, better recovery or a stronger appetite effect in a direct comparison.
Ipamorelin stimulates the ghrelin receptor; tesamorelin stimulates the growth hormone-releasing factor receptor. Ipamorelin’s bowel-surgery trial observed earlier meal tolerance but did not establish a benefit over placebo. Tesamorelin reduced visceral abdominal fat in adults with HIV lipodystrophy and has an approved product for that setting. Their trials do not establish relative muscle growth, recovery or general weight-loss effects.
BPC-157 and KPV have both been investigated in intestinal injury models, but they are different peptides with different experimental explanations. BPC-157, called BPC-15 in the rat report, reduced chemical colon injury when injected into the abdomen before the injury; KPV studies connected cellular peptide transport with reduced inflammation in mouse colitis. Neither literature establishes which is more effective or safer for human inflammatory bowel disease.
BPC-157 and LL-37 have been studied in wound-related research, but their results come from different settings. BPC-157 accelerated closure of chemical burns in rats. LL-37 has randomized topical ulcer trials in people: an early study found faster wound shrinkage, while the larger trial did not establish better complete closure overall. These sources do not compare the peptides directly or support a general healing ranking.
MOTS-c is a mitochondrial-encoded peptide studied in cells, mouse interventions and human measurements of the body’s own peptide. SS-31 is a development name for elamipretide, which acts at mitochondrial membranes and has controlled patient trials. Its large mitochondrial-myopathy trial did not establish better walking or fatigue, while its defined product has accelerated approval for muscle strength in Barth syndrome. These findings cannot rank the compounds for general energy, exercise or aging.
AOD9604 is a modified growth-hormone fragment whose oral obesity program failed to establish useful weight loss. Semaglutide activates the GLP-1 receptor and produced substantially greater weight reduction than placebo in STEP 1. No direct randomized comparison establishes their relative effect or safety; the informative contrast is between their different controlled human results.
Retatrutide activates GIP, GLP-1 and glucagon receptors; tirzepatide activates GIP and GLP-1 receptors. Both have substantial placebo-controlled weight-loss results, but the trials differ in duration, population and analysis. Retatrutide remains investigational in October 2026, and the registered direct TRIUMPH-5 comparison has no outcome result in the accessed official listing.
Retatrutide is one peptide activating GIP, GLP-1 and glucagon receptors. CagriSema combines the amylin analogue cagrilintide with semaglutide, a GLP-1 receptor agonist. Both have substantial placebo-controlled human weight-loss findings, including separate trials with type 2 diabetes, but no direct randomized comparison in the selected sources establishes which is more effective or safer. Both remain investigational as of October 2026.
CJC-1295 with a drug affinity complex (DAC) binds albumin, a blood protein, and stimulates the receptor for growth hormone-releasing hormone (GHRH). Small healthy-adult studies found prolonged growth hormone (GH) and insulin-like growth factor 1 (IGF-1) increases with this form. Ipamorelin acts through the ghrelin-receptor system; a human infusion study measured a shorter peptide half-life, and its bowel-surgery trial left clinical benefit uncertain. No cited trial establishes which improves muscle growth, recovery or longevity.
Hexarelin and ipamorelin stimulate growth hormone through the ghrelin-receptor system, but their research differs. Small human hexarelin experiments measured brief cardiac changes and a smaller growth hormone (GH) response during repeated exposure. Ipamorelin has animal selectivity data, a human infusion study and a postoperative trial with uncertain clinical benefit. These findings do not establish which provides better muscle growth or long-term safety.
Ipamorelin acts through the ghrelin-receptor system. Sermorelin is the amidated fragment containing the first twenty-nine residues of growth hormone-releasing hormone (GHRH) and stimulates its receptor. Ipamorelin’s postoperative trial left meal-tolerance benefit uncertain. Historical sermorelin research measured growth in children deficient in growth hormone (GH) and body composition in a small HIV study. Neither literature establishes superior healthy-adult muscle growth, recovery or anti-aging effects.
AOD-9604 is a modified fragment of growth hormone investigated for metabolic effects; its major oral obesity study did not establish greater weight loss than placebo. Tesamorelin stimulates growth hormone release and reduced fat around abdominal organs in adults with HIV and lipodystrophy. Its approved use concerns that specific fat distribution, with little overall weight change. The two compounds have not been compared directly in the selected trials.
Ipamorelin and GHRP-2 stimulate the ghrelin-receptor system. Their research differs: ipamorelin’s often-cited selectivity result comes from animals, and its human bowel-surgery trial left clinical benefit uncertain. GHRP-2 increased how much people ate in small controlled meal experiments. These findings do not establish a ranking for muscle growth, injury recovery or long-term safety.
Sermorelin is the amidated first twenty-nine residues of growth hormone-releasing hormone. Its studies include growth in children with diagnosed growth hormone deficiency. CJC-1295 with a drug affinity complex (DAC) is a modified albumin-binding analogue whose healthy-adult trials measured prolonged hormone increases. Their different molecular forms, populations and outcomes do not establish which improves adult strength, recovery or aging.
BPC-157 and ipamorelin intersect with growth-hormone biology at different points. BPC-157 increased growth-hormone receptors in rat tendon cells; ipamorelin stimulated growth-hormone release in human exposure research. BPC-157 also improved rat tendon-repair measurements, while ipamorelin’s postoperative meal-tolerance trial left benefit uncertain. These studies do not establish which improves human injury recovery or whether combining them helps.
GHK-Cu is a copper-bound tripeptide studied in connective-tissue biology and specific topical skin and ulcer preparations. Epithalon, also called Epitalon, is AEDG, a four-residue peptide studied in telomere maintenance and aging-related models. GHK-Cu’s human skin results vary by preparation and setting; Epitalon’s telomere findings do not establish human rejuvenation. No direct trial identified here ranks their effects on skin aging or longevity.
Epithalon, also called Epitalon, is the four-residue peptide AEDG studied in telomere and circadian biology. Thymosin alpha-1 is a separate N-acetylated 28-residue peptide with immune-cell experiments and controlled clinical trials. Its larger corrected sepsis trial did not establish a mortality reduction. Epitalon’s cellular and limited human-biomarker findings do not supply a human longevity benefit, and the two compounds have no direct clinical comparison in the sources reviewed here.
Bremelanotide and Melanotan II are related cyclic melanocortin peptides with different clinical evidence. The approved bremelanotide acetate injection improved desire and related distress in selected premenopausal women, while small Melanotan II studies measured pigmentation and acute erections in men. No selected head-to-head trial establishes a better or safer treatment.
Semax and bremelanotide are both short synthetic peptides related to hormone biology, but their studies ask different questions. Semax reports concern brain signaling and neurological illness; bremelanotide trials concern desire and related distress in premenopausal women with hypoactive sexual desire disorder, meaning persistent low desire that causes distress. No selected trial compares them for memory, stroke recovery or sexual symptoms.
Thymosin alpha-1 and LL-37 both participate in immune biology, but the selected clinical studies test different interventions. Thymosin alpha-1 was injected as an adjunct to sepsis care; synthetic LL-37 was applied to chronic leg ulcers. Larger trials did not establish the hoped-for overall mortality or ulcer-closure benefits, while earlier favorable findings and biological activity remain important to understand.