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What Are the Most Studied Peptides?

Not all peptides are created equal when it comes to evidence. Some have thousands of published studies, multiple clinical trials, and decades of clinical use. Others have a handful of animal experiments and a lot of online enthusiasm.

Not all peptides are created equal when it comes to evidence. Some have thousands of published studies, multiple clinical trials, and decades of clinical use. Others have a handful of animal experiments and a lot of online enthusiasm. Knowing where a peptide falls on this spectrum is one of the most important factors in evaluating whether it's worth your attention.

This guide ranks the most studied peptides by publication volume, clinical trial data, and real-world evidence — giving you a clear picture of which peptides have earned their reputations and which are still building their cases.

Table of Contents

How We Ranked: Publication Volume, Trials, and Clinical Use

We evaluated peptides across three dimensions:

  1. Publication volume: Total number of published, peer-reviewed papers (via PubMed and Google Scholar)
  2. Clinical trial data: Number and quality of human clinical trials (via ClinicalTrials.gov)
  3. Regulatory/clinical status: Whether the peptide has FDA approval, is approved in other countries, or is in active clinical use

A peptide with 5,000 PubMed citations and FDA approval sits in a fundamentally different evidence category than one with 50 citations and no human data. Both may be interesting, but the confidence you can place in their effects is not comparable.

Tier 1: Thousands of Studies, FDA-Approved, Decades of Data

Insulin

Publications: 400,000+ (PubMed) Clinical trials: Thousands Status: FDA-approved since 1982 (recombinant); used clinically since 1922

Insulin is the most studied peptide in history, by an enormous margin. It's a 51-amino-acid peptide hormone that regulates blood sugar, and it has been the backbone of diabetes treatment for over a century. Virtually every aspect of insulin — its structure, mechanism, pharmacokinetics, formulations, delivery methods, and long-term effects — has been exhaustively studied.

While insulin may not be what most people think of when they hear "peptides" in the wellness context, it sets the standard for what comprehensive peptide evidence looks like.

Semaglutide (and GLP-1 Agonists)

Publications: 6,000+ for semaglutide specifically; 30,000+ for GLP-1 agonists as a class Clinical trials: 100+ registered trials for semaglutide Status: FDA-approved (Ozempic 2017, Rybelsus 2019, Wegovy 2021)

Semaglutide has generated more research in the past 7 years than most peptides accumulate in decades. The STEP and SUSTAIN trial programs alone enrolled over 25,000 participants. The SELECT cardiovascular outcomes trial added 17,604 more. Post-marketing surveillance now covers millions of users.

The GLP-1 class as a whole — including liraglutide, dulaglutide, exenatide, and tirzepatide — represents one of the most thoroughly studied peptide drug families in pharmacology. Evidence spans type 2 diabetes, obesity, cardiovascular disease, NASH, kidney disease, neurodegeneration, and addiction.

Oxytocin

Publications: 20,000+ (PubMed) Clinical trials: 500+ Status: FDA-approved for labor induction; studied extensively for social behavior, bonding, and psychiatric conditions

Oxytocin is a 9-amino-acid peptide hormone with a dual role: it stimulates uterine contractions during labor (its FDA-approved use) and acts in the brain as a neuromodulator involved in social bonding, trust, empathy, and pair bonding.

The behavioral research on oxytocin is massive — covering autism spectrum disorder, social anxiety, PTSD, couple bonding, maternal behavior, and more. While many of the behavioral effects are nuanced and context-dependent (not as simple as "the love hormone" headlines suggest), the volume of research is staggering.

Substance P

Publications: 25,000+ (PubMed) Clinical trials: 200+ Status: Not a drug itself, but its receptor (NK1) is a drug target; aprepitant (an NK1 antagonist) is FDA-approved for nausea

Substance P is an 11-amino-acid neuropeptide involved in pain transmission, inflammation, and nausea. It was one of the first neuropeptides discovered (1931) and has been studied extensively as both a signaling molecule and a drug target. While substance P itself isn't administered as a drug, understanding its biology has led to multiple therapeutic applications.

Tier 2: Hundreds of Studies, Clinical Trials, Strong Evidence

Thymosin Alpha-1

Publications: 1,500+ Clinical trials: 100+ Status: Approved in 30+ countries for hepatitis B/C and immune modulation

Thymosin alpha-1 has one of the strongest clinical evidence bases of any non-FDA-approved peptide (it's approved elsewhere but not by the US FDA as of 2026). It's been used in clinical practice since the 1990s for chronic hepatitis, cancer immunotherapy support, and immune system modulation. Clinical trials have enrolled thousands of patients.

Its evidence quality puts it in a different league from most peptides discussed in wellness contexts. Multiple randomized controlled trials support its efficacy for hepatitis B and C, and observational data supports immune-boosting effects in cancer patients and immunocompromised individuals.

GHK-Cu (Copper Peptide)

Publications: 400+ for GHK-Cu specifically; broader copper peptide research adds hundreds more Clinical trials: 20+ Status: Not FDA-approved as a drug; widely used in cosmetic products

GHK-Cu is the most studied topical anti-aging peptide. Loren Pickart's original research dates to the 1970s, and the body of work has grown steadily. The 2014 gene expression study showing GHK-Cu modulates 4,000+ human genes was particularly significant. Clinical studies demonstrate skin improvements, wound healing benefits, and anti-inflammatory effects.

The research comes from multiple independent groups worldwide, which strengthens confidence. It's not a single-lab phenomenon.

Natriuretic Peptides (BNP, ANP, NT-proBNP)

Publications: 30,000+ collectively Clinical trials: Thousands (as biomarkers and therapeutic targets) Status: BNP/NT-proBNP are FDA-cleared as diagnostic biomarkers for heart failure; nesiritide (synthetic BNP) was FDA-approved as a drug

Brain natriuretic peptide (BNP) and its amino-terminal fragment (NT-proBNP) are among the most clinically important peptide biomarkers in medicine. Every hospital in the developed world tests for them to diagnose and monitor heart failure. As diagnostic tools, they have an enormous evidence base.

Liraglutide

Publications: 5,000+ Clinical trials: 100+ Status: FDA-approved (Victoza 2010 for diabetes, Saxenda 2014 for weight management)

Liraglutide preceded semaglutide as a GLP-1 agonist and has its own substantial evidence base. The LEADER cardiovascular outcomes trial (9,340 patients), the SCALE weight management trials, and extensive post-marketing data make it one of the most thoroughly studied peptide drugs. It's somewhat overshadowed by semaglutide now, but the evidence is comprehensive.

Tier 3: Extensive Preclinical Research, Emerging Clinical Data

BPC-157

Publications: 100+ peer-reviewed papers Clinical trials: 1 registered (Phase 2, IBD, NCT05765396; results not yet published) Status: Not approved in any country; research peptide

BPC-157 occupies a unique position: massive preclinical evidence with zero published human clinical data. The 100+ animal studies — spanning tendon, muscle, gut, brain, heart, liver, and bone healing — make it one of the most studied research peptides. However, the majority comes from one research group at the University of Zagreb.

The evidence is unusual in its breadth and consistency of positive results. The absence of negative studies is noteworthy — though this could reflect publication bias. The registered Phase 2 trial represents a significant step toward human evidence.

Matrixyl (Palmitoyl Pentapeptide-4)

Publications: 50+ (including clinical studies and formulation research) Clinical trials: Multiple controlled studies Status: Cosmetic ingredient; not classified as a drug

Matrixyl has been in commercial skincare products since 2000 and has accumulated a reasonable clinical evidence base for a cosmetic ingredient. The research includes controlled human studies with objective wrinkle measurement. While the total publication count is lower than pharmaceutical peptides, the quality of evidence for its cosmetic claims is solid.

Argireline (Acetyl Hexapeptide-3)

Publications: 30+ Clinical trials: Several controlled studies Status: Cosmetic ingredient

Argireline has both mechanistic studies confirming its SNARE complex modulation and clinical studies showing wrinkle reduction. As a cosmetic peptide, its evidence base is above average. Multiple independent groups have studied it, adding confidence beyond the manufacturer's data.

Sermorelin

Publications: 200+ Clinical trials: Multiple (sufficient for prior FDA approval) Status: Previously FDA-approved for GH deficiency (withdrawn for commercial reasons, not safety); widely used in clinical practice

Sermorelin's evidence base includes the clinical data that supported its FDA approval, plus continued research in the growth hormone optimization space. It remains one of the better-studied growth hormone peptides.

Tier 4: Significant Research Interest, Growing Evidence

Epitalon

Publications: 30-40 (primarily from Khavinson's group) Clinical trials: Small human studies (published by the St. Petersburg Institute of Bioregulation and Gerontology) Status: Research peptide; not approved anywhere

Epitalon has interesting data on telomerase activation and lifespan extension in animal models. But the evidence is concentrated in one research group, independent replication is limited, and the human studies are small and not conducted to Western clinical trial standards.

MOTS-c

Publications: 100+ since its 2015 discovery Clinical trials: None registered for therapeutic use Status: Early research

MOTS-c has generated significant publication volume for a recently discovered peptide, reflecting its unique biology (mitochondrial-derived, exercise mimetic). Published in top-tier journals (Cell Metabolism, Nature), the research quality is high. But it's all preclinical.

Humanin

Publications: 300+ since 2001 discovery Clinical trials: Very limited Status: Early research

Humanin was the first mitochondrial-derived peptide discovered and has accumulated a substantial preclinical literature. Research spans neuroprotection, metabolic health, cardiovascular protection, and aging. Multiple independent groups worldwide have studied it, which adds credibility.

Selank and Semax

Publications: 100+ combined (predominantly Russian literature) Clinical trials: Several (primarily Russian) Status: Approved in Russia; not approved in US/EU

These nootropic peptides have a meaningful evidence base, though much of it is published in Russian-language journals and may not appear in standard PubMed searches. Russian clinical trials have enrolled hundreds of patients, but the trial methodology doesn't always meet Western standards for randomized controlled trials.

LL-37

Publications: 2,000+ Clinical trials: Limited therapeutic trials Status: Research stage for therapeutic use

LL-37 is the most studied human antimicrobial peptide. The basic science literature is extensive — LL-37's role in innate immunity, wound healing, and anti-microbial defense is well-characterized. Therapeutic applications (as a drug) are still in development.

Why Publication Volume Matters — and Why It's Not Everything

Publication volume provides a rough measure of how thoroughly a peptide has been studied. But it's not the only metric:

Quality matters more than quantity. One well-designed Phase 3 RCT with 10,000 patients provides more reliable evidence than 100 small animal studies. Semaglutide's clinical trial program alone constitutes stronger evidence than BPC-157's entire publication history, despite BPC-157 having more individual papers on healing.

Diversity of research groups matters. Findings that have been replicated by independent groups worldwide carry more weight than findings from a single lab, regardless of publication count. GHK-Cu research comes from groups across multiple countries. BPC-157 research is dominated by one group. This difference affects confidence.

Clinical vs. preclinical matters. A peptide with 50 human clinical studies is in a fundamentally different evidence category than one with 200 animal studies and zero human data.

Recency matters. Older research may use outdated methods. The peptide field moves fast — a peptide studied extensively in the 1990s may have evidence that needs updating with modern analytical methods.

For help evaluating peptide research yourself, see how to interpret peptide research papers and how to read peptide research.

Frequently Asked Questions

Is the most studied peptide necessarily the best? No. "Most studied" reflects research interest and funding, not superiority. Insulin is the most studied peptide because diabetes is one of the most common diseases. BPC-157 has less research not because it's less interesting but because it hasn't attracted the pharmaceutical investment that drives large clinical trials.

Why are some peptides more studied than others? Money and disease burden. Peptides that treat major diseases (diabetes, obesity, heart failure) attract pharmaceutical R&D investment, which funds clinical trials. Research peptides that address conditions like tendon healing or anti-aging have less commercial infrastructure supporting large-scale studies.

Does BPC-157 have enough evidence to use? That depends on your risk tolerance and the availability of alternatives. BPC-157 has extensive animal evidence — more than most research peptides. But zero published human clinical data. If you compare it to an FDA-approved drug, the evidence gap is enormous. If you compare it to other research peptides, it's actually among the better-studied options. The BPC-157 guide provides the full picture.

Which peptide has the strongest evidence for anti-aging? For FDA-approved, clinically validated anti-aging effects: semaglutide (for metabolic aging — weight, cardiovascular risk). For topical skin aging: GHK-Cu. For immune aging: thymosin alpha-1. No single peptide addresses all aging pathways with strong evidence.

Are there peptides that are over-studied or over-hyped? Some would argue oxytocin has been over-hyped as "the love hormone" — the behavioral effects are more nuanced than popular coverage suggests. In the wellness space, BPC-157's reputation may exceed its evidence base given the lack of human data. Neither is necessarily over-studied, but both have public perceptions that outrun the actual evidence in certain areas.

The Bottom Line

The most studied peptides are, unsurprisingly, the ones that treat major diseases and have attracted pharmaceutical investment: insulin, GLP-1 agonists, oxytocin, natriuretic peptides. These have thousands of studies, extensive clinical trials, and decades of real-world use.

Among peptides more relevant to the wellness and optimization space, thymosin alpha-1 and GHK-Cu stand out for having genuine clinical evidence from multiple independent groups. BPC-157 has impressive preclinical breadth but a conspicuous absence of human data. Growth hormone peptides have moderate clinical evidence. Newer discoveries like MOTS-c and humanin are scientifically exciting but years from clinical application.

When evaluating any peptide, ask three questions: How many studies? By how many groups? In humans? The answers will tell you where the peptide sits on the evidence spectrum — and how much confidence you can reasonably place in its reported effects.

References

  1. PubMed. National Library of Medicine. Search data accessed January 2026.
  2. ClinicalTrials.gov. National Institutes of Health. Registry data accessed January 2026.
  3. Wilding JPH, et al. "Once-Weekly Semaglutide in Adults with Overweight or Obesity." NEJM. 2021;384(11):989-1002.
  4. Pickart L, et al. "GHK Peptide as a Natural Modulator of Multiple Cellular Pathways in Skin Regeneration." BioMed Research International. 2015;2015:648108.
  5. Tuthill C, et al. "Thymalin and Thymosin Alpha 1 as Modulators of Immunity." Drugs Under Experimental and Clinical Research. 2002;28(3):109-131.
  6. Sikiric P, et al. "Brain-gut Axis and Pentadecapeptide BPC 157." Current Neuropharmacology. 2016;14(8):857-865.
  7. Lee C, et al. "The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis." Cell Metabolism. 2015;21(3):443-454.
  8. Hashimoto Y, et al. "A rescue factor abolishing neuronal cell death by a wide spectrum of familial Alzheimer's disease genes and Aβ." PNAS. 2001;98(11):6336-6341.
  9. Khavinson VK, et al. "Epithalon peptide induces telomerase activity and telomere elongation." Bulletin of Experimental Biology and Medicine. 2003;135(6):590-592.
  10. Robinson LR, et al. "Topical palmitoyl pentapeptide provides improvement in photoaged human facial skin." International Journal of Cosmetic Science. 2005;27:155-160.