The Evidence Library
What the research actually shows.
Every peptide we recommend — tier-rated by confidence. No marketing copy.
Most supplement sites tell you what to buy. We're telling you what we know — and how confident we are about it. Every peptide here is tagged by evidence tier so you can see the difference between decades of peer-reviewed research and emerging clinical practice. Read it. Bring questions. Ask your doctor.
— Confidence Tiers —
🟢 Strong evidence — Decades of peer-reviewed research, FDA-approved or close, well-established mechanism
🟡 Growing evidence — Solid research base, common in longevity practice, mechanism well-understood
🟠 Emerging evidence — Smaller body of research, common in practice but data still developing
— Background —
Quick Explainers
Growth Hormone (GH)
A hormone produced by the pituitary gland that regulates tissue growth, cell repair, metabolism, sleep quality, body composition (muscle vs fat), and skin elasticity. GH levels peak in your 20s and decline roughly 1-2% per year after 30 — by age 60, most people have less than half the GH they had at 25. "Growth hormone support" peptides don't inject synthetic GH; they signal your body to produce more of its own. That's safer, more natural, and follows your body's own rhythm.
Relevant forIpamorelin, CJC-1295, Sermorelin, Tesamorelin
GLP-1 / GIP / Glucagon (the weight peptide family)
GLP-1 (glucagon-like peptide-1) is a hormone your gut releases after eating that signals fullness, slows stomach emptying, and improves insulin response. GIP (glucose-dependent insulinotropic polypeptide) works alongside GLP-1 for blood sugar control. Glucagon (the third) increases fat burning and energy expenditure. Modern weight peptides activate different combinations: semaglutide hits GLP-1 only, tirzepatide hits GLP-1 + GIP, retatrutide hits all three.
Relevant forSemaglutide, Tirzepatide, Retatrutide
Permeation Enhancer
A compound added to oral peptide formulations that temporarily opens the gut wall so the peptide can absorb before being destroyed by stomach acid. Without one, most peptides are destroyed before reaching the bloodstream. With one, oral bioavailability can rise from less than 1% to 1-10% — enough to be clinically effective. SNAC is the most well-known (used in Rybelsus, the oral semaglutide).
Relevant forOral peptide formulations (Rybelsus, Mycapssa)
Peptide vs Coenzyme
Peptides are short chains of amino acids that act as signaling molecules — they tell your cells what to do. Coenzymes (like NAD+) aren't peptides; they're helper molecules that enzymes need to function. We include NAD+ and its precursors (NMN, NMNH, Liposomal NR) in our protocols because they do similar work at the cellular level — energy, repair, longevity — and serious practitioners treat them as part of the same toolkit. Honest framing matters: NAD+ is a coenzyme, not a peptide, but it belongs in this conversation.
Relevant forNAD+, NMN, NMNH, Liposomal NR
— Category —
Skin
GHK-Cu (Copper Peptide) 🟢 Strong
Why this recommendation
Decades of peer-reviewed research support GHK-Cu for skin barrier repair, inflammation, collagen synthesis, and wound healing. One of the most-studied peptides for skin in existence — discovered in 1973 and validated across hundreds of studies since.
Primary useRosacea, fine lines, skin barrier, hair density
NoteVitamin C and strong retinoids can deactivate it when applied together.
Matrixyl (Palmitoyl Pentapeptide-4) 🟢 Strong
Why this recommendation
Well-established topical peptide with decades of cosmetic research. Acts as a signal peptide to stimulate collagen production through a different mechanism than GHK-Cu — often layered with it in advanced serums.
Primary useFine lines, collagen stimulation, anti-aging skincare
NoteTopical only — no systemic action.
Argireline (Acetyl Hexapeptide-8) 🟢 Strong
Why this recommendation
Extensively studied topical peptide for expression lines. Works by relaxing facial muscle contraction at the synaptic level — often called "topical Botox" because of the mechanism similarity.
Primary useExpression lines (forehead, around eyes)
NoteWorks on surface expression lines, not deeper structural aging.
TB-500 (Thymosin Beta-4 Fragment) 🟡 Growing
Why this recommendation
Extensive preclinical research on tissue repair, deeper wound healing, and scarring. Growing use in regenerative medicine practice for skin healing post-procedure. Most data is animal-based; human clinical research is still developing.
Primary usePost-procedure healing, deeper scarring, tissue repair
NoteNot FDA-approved. Discuss with a peptide-knowledgeable physician.
— Category —
Healing & Recovery
BPC-157 (Body Protection Compound) 🟡 Growing
Why this recommendation
Extensive animal research and growing human data support BPC-157 for gut healing, joint and tendon repair, and systemic tissue regeneration. Derived from a protective compound naturally found in human gastric juice — one of the few peptides with documented oral absorption.
Primary useGut healing, joint pain, tendon/ligament injury, post-surgery recovery
NoteNot FDA-approved. Capsule form works (rare for peptides). Sub-Q form generally faster.
KPV 🟠 Emerging
Why this recommendation
A small anti-inflammatory peptide derived from alpha-MSH. Emerging research on gut inflammation and IBD; growing use in gut-health and skin-inflammation practice. Small molecule size allows real oral absorption.
Primary useGut inflammation, IBD support, skin inflammation
NoteSmaller body of clinical research than BPC-157. Often stacked with BPC-157.
— Category —
Energy & Mitochondrial
MOTS-c 🟡 Growing
Why this recommendation
A mitochondrial-derived peptide discovered in 2015. Solid research on metabolism, insulin sensitivity, and cellular energy production. One of the most promising peptides in longevity research right now.
Primary useEnergy, metabolic health, insulin sensitivity, exercise capacity
NoteNewer peptide — research base is solid but smaller than older peptides.
SS-31 (Elamipretide) 🟡 Growing
Why this recommendation
In active clinical trials for mitochondrial diseases. Strong mechanism on cardiolipin protection within mitochondria. Used in age-related muscle loss and cardiovascular research.
Primary useMitochondrial dysfunction, energy, cardiovascular support
NoteIn clinical trial phase for several indications — emerging but well-mechanism-supported.
— Category —
Weight & Metabolic
Semaglutide 🟢 Strong
Why this recommendation
FDA-approved (Ozempic, Wegovy, Rybelsus). Among the most-studied weight-loss and diabetes medications in recent history. Massive clinical trial base.
Primary useWeight loss, blood sugar regulation, appetite suppression
NotePrescription required. Discuss with your doctor.
Tirzepatide 🟢 Strong
Why this recommendation
FDA-approved (Mounjaro, Zepbound). Dual GLP-1 and GIP agonist — often produces stronger weight-loss effect than semaglutide. Extensive clinical trial data.
Primary useWeight loss, blood sugar regulation
NotePrescription required. Discuss with your doctor.
Retatrutide 🟡 Growing
Also known as: Reta (informal nickname) and GLP-3 (community nickname — though technically a misnomer)
Why this recommendation
Eli Lilly's triple agonist hitting GLP-1, GIP, AND glucagon receptors simultaneously. Phase 2 trial data has shown weight-loss results that exceed both semaglutide and tirzepatide. Currently in Phase 3 trials with FDA approval expected in 2026-2027. The "GLP-3" nickname stuck in the longevity community because it follows the progression (semaglutide = single, tirzepatide = double, retatrutide = triple) — but there's no actual GLP-3 receptor.
Primary useWeight loss (potentially stronger than semaglutide/tirzepatide)
NoteNot yet FDA-approved. Currently in clinical trials. Watch this one closely.
AOD-9604 🟠 Emerging
Why this recommendation
A fragment of human growth hormone studied for fat metabolism without the broader growth hormone effects. Some research supports targeted fat-loss action; less robust clinical data than semaglutide/tirzepatide.
Primary useTargeted fat loss, particularly stubborn fat areas
NoteSmaller research base. Often used alongside other protocols.
Tesamorelin 🟢 Strong
Why this recommendation
FDA-approved for HIV-related visceral fat reduction (brand: Egrifta). Well-studied growth-hormone-releasing hormone analog with strong evidence for reducing visceral (belly) fat specifically.
Primary useVisceral belly fat, growth hormone support
NotePrescription required. Best results when paired with diet/exercise.
— Category —
Sleep
DSIP (Delta Sleep Inducing Peptide) 🟠 Emerging
Why this recommendation
Discovered in 1977 and studied primarily in Russian and Eastern European research over the decades. Research suggests effects on sleep onset and deep-sleep architecture; mechanism is less precisely characterized than newer sleep aids.
Primary useFalling asleep, stress-related insomnia
NoteSmaller Western research base. Used in practice for decades with good safety profile.
Epitalon (Epithalon) 🟡 Growing
Why this recommendation
Extensive Russian research over multiple decades on sleep architecture, telomerase activation, and circadian rhythm. One of the more-studied longevity peptides outside the Western clinical trial system. Mechanism is well-explored.
Primary useDeep sleep, telomere support, circadian rhythm reset
NoteMost clinical research is Russian — Western research is still developing.
— Category —
Brain & Cognitive
Selank 🟡 Growing
Why this recommendation
Russian-developed peptide with decades of clinical use in Russia for generalized anxiety. Provides anti-anxiety effects without sedation or dependency. Growing Western interest backed by solid mechanism research.
Primary useAnxiety, focus under pressure, mood support
NoteUsed intranasally for best absorption. Most clinical data is Russian.
Semax 🟡 Growing
Why this recommendation
Russian-developed ACTH fragment with decades of clinical use for stroke recovery, cognitive support, and neuroprotection. Strong mechanism research; widely used in clinical practice in Russia.
Primary useFocus, memory, neuroprotection, cognitive support
NoteUsed intranasally for direct nose-to-brain delivery. Western research is growing but smaller than Russian data.
Dihexa 🟠 Emerging
Why this recommendation
Synthetic peptide developed specifically for cognitive enhancement and synapse formation. Promising preclinical research, but limited human clinical data. More experimental than the Russian neuropeptides.
Primary useMemory, cognitive enhancement
NoteSmaller clinical research base. Considered experimental.
Cerebrolysin 🟢 Strong
Why this recommendation
Used clinically in 50+ countries for stroke, dementia, and traumatic brain injury. Extensive European and Asian clinical research base. Not FDA-approved in the US, which limits availability.
Primary useStroke recovery, dementia support, cognitive function
NotePrescription required. Not available in US through standard channels.
— Category —
Hormone & Growth
Ipamorelin 🟡 Growing
Why this recommendation
Well-studied selective growth hormone secretagogue. Stimulates the body's own growth hormone production without affecting cortisol or other hormones — making it cleaner than older GH stimulants.
Primary useGrowth hormone support, recovery, body composition, anti-aging
NoteOften paired with CJC-1295 for amplified effect.
CJC-1295 🟡 Growing
Why this recommendation
Growth hormone-releasing hormone analog with extended half-life. Well-studied as a GHRH that produces sustained growth hormone release. Commonly paired with Ipamorelin in anti-aging practice.
Primary useGrowth hormone support, recovery, body composition
NoteTwo forms exist — with and without DAC (Drug Affinity Complex). The DAC version lasts longer.
Sermorelin 🟢 Strong
Why this recommendation
Historically FDA-approved growth hormone-releasing hormone for growth hormone deficiency. Decades of clinical use. A milder, longer-history alternative to CJC-1295.
Primary useGrowth hormone support, sleep, body composition
NotePrescription required in most cases.
— Category —
Longevity & Cellular
NAD+ (Nicotinamide Adenine Dinucleotide) 🟡 Growing
Why this recommendation
Core coenzyme involved in cellular energy production and DNA repair. Levels decline significantly with age. Strong growing research on NAD+ restoration for energy, metabolism, and cellular aging — one of the most-discussed longevity molecules in current research.
Primary useCellular energy, mitochondrial health, longevity, recovery
NoteNot technically a peptide — it's a coenzyme. Multiple delivery routes (IV, sub-Q, oral precursors).
NMN (Nicotinamide Mononucleotide) 🟡 Growing
Why this recommendation
Direct NAD+ precursor with strong recent research base, much of it from David Sinclair's lab at Harvard. Has documented oral absorption — one of the few longevity molecules that actually works in capsule form.
Primary useNAD+ restoration through oral supplementation
NoteCapsule form works. Quality varies widely between brands.
NMNH (Reduced NMN) 🟠 Emerging
Why this recommendation
Newer reduced form of NMN with emerging research suggesting potentially better bioavailability than standard NMN. Less data than NMN but increasing interest in the longevity research community.
Primary useNAD+ restoration with potentially higher absorption
NoteSmaller research base. Newer to the market.
Liposomal NR (Nicotinamide Riboside) 🟡 Growing
Why this recommendation
NR is the established NAD+ precursor sold commercially as Tru Niagen, with strong human clinical research. Liposomal delivery improves absorption compared to standard NR capsules.
Primary useNAD+ restoration, cellular energy
NoteOne of the most-researched NAD+ precursors available without prescription.
Thymosin Alpha-1 🟢 Strong
Why this recommendation
FDA-approved in several countries for hepatitis treatment. Extensive research on immune system support, particularly for aging immune function. Used clinically for decades.
Primary useImmune support, longevity, post-illness recovery
NotePrescription required in most cases.
— Category —
Hormonal Support (Women 50+)
PT-141 (Bremelanotide) 🟢 Strong
Why this recommendation
FDA-approved (brand: Vyleesi) for premenopausal female sexual dysfunction. Works on melanocortin receptors in the brain rather than blood flow — different mechanism than other libido drugs.
Primary useLibido, female sexual response
NotePrescription required. Side effects include flushing and nausea in some users.
Kisspeptin 🟡 Growing
Why this recommendation
Critical hormonal regulator that initiates the cascade leading to estrogen and testosterone production. Growing clinical research on fertility, hormone balance, and libido support.
Primary useHormonal cascade support, libido, fertility-adjacent issues
NoteNewer clinical use. Discuss with a hormone-knowledgeable practitioner.
Pine Pollen Tincture 🟠 Emerging
Why this recommendation
Traditional use in herbal medicine; growing modern interest as a natural source of plant-based testosterone and DHEA precursors. Considered more of an adaptogen than a peptide — less rigorous clinical research than synthetic peptides.
Primary useAdrenal support, hormone precursors, mild testosterone/DHEA support
NoteLess clinical research than peptides. Used as a gentler hormonal support option.
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