Posted by ReBel on Dec 28th 2025
Popular Peptides and Their Functions
Peptides are short chains of amino acids that act as signaling molecules in the body, regulating processes like tissue repair, cellular growth, immune modulation, metabolism, and hormonal signaling. Research—primarily in preclinical and early clinical studies—shows that different peptides interact with specific biological pathways, influencing recovery, adaptation, regeneration, and systemic homeostasis. Understanding how these peptides function can provide insight into their mechanisms and potential applications in research contexts.
1. Tissue & Connective Tissue Repair
BPC-157 (Body Protection Compound‑157)
Research shows BPC-157 promotes angiogenesis, fibroblast proliferation, and collagen deposition, supporting tendon, ligament, and muscle healing. Preclinical studies indicate stabilization of extracellular matrix remodeling and improved cellular migration at injury sites. Research suggests modulation of nitric oxide pathways and protective effects against oxidative stress. Studies indicate enhanced recovery in gastrointestinal tissues and epithelial layers. Multi-tissue support optimizes recovery after injury. Research suggests systemic anti-inflammatory effects that enhance tissue homeostasis.
TB-500 (Thymosin Beta-4 Fragment)
TB-500 facilitates cytoskeletal organization and cell migration, supporting tissue remodeling and repair. Preclinical studies indicate increased angiogenesis and vascularization at sites of soft tissue injury. Research shows enhanced muscle repair, tendon adaptation, and epithelial regeneration. TB-500 modulates extracellular matrix signaling and reduces inflammation. Studies suggest synergistic potential when combined with peptides like BPC-157. Research indicates improved tissue resilience during healing.
GHK-Cu
GHK-Cu stimulates collagen synthesis and fibroblast proliferation, supporting connective tissue maintenance. Research shows it modulates NF-kB signaling, reducing oxidative stress and inflammation. Preclinical studies suggest benefits in skin, tendon, and tissue regeneration. Research indicates enhanced angiogenesis and tissue remodeling. Studies show systemic anti-inflammatory effects and improved wound healing. GHK-Cu may indirectly support recovery environments for injured tissue.
Follistatin 344
Research indicates Follistatin 344 inhibits myostatin and activin pathways, promoting skeletal muscle regeneration. Preclinical studies show activation of satellite cells and support for fiber hypertrophy. Research suggests reduced muscle catabolism and improved adaptive remodeling during recovery. Studies indicate synergy with GH-axis peptides to enhance repair. Follistatin may optimize cellular regeneration signaling in damaged tissues. Preclinical models suggest potential benefits for muscle recovery after stress or injury.
GLOW (GHK-Cu + BPC-157 + TB-500)
GLOW combines multiple tissue-repair peptides for synergistic effects. GHK-Cu enhances collagen synthesis and reduces inflammation, BPC-157 promotes angiogenesis and ECM stabilization, and TB-500 improves cytoskeletal reorganization. Research suggests combined activation of multiple pathways may accelerate recovery of tendons, ligaments, muscles, and epithelial tissues. Preclinical evidence indicates improved vascularization, cell migration, and matrix remodeling. Multi-pathway support enhances systemic tissue homeostasis. Studies show GLOW may be more effective than any single peptide alone for repair-focused research.
KLOW (GHK-Cu + BPC-157 + TB-500 + KPV)
KLOW adds KPV for additional anti-inflammatory and epithelial support. Research shows synergistic activation of angiogenesis, extracellular matrix remodeling, fibroblast proliferation, and immune modulation. Preclinical studies indicate accelerated recovery in connective tissue, muscle, and epithelial layers. KLOW may improve vascularization and cytoskeletal dynamics while reducing local inflammation. Research suggests multi-pathway targeting enhances overall tissue regeneration efficiency. Studies indicate potential support for systemic healing environments.
2. Growth Hormone & Anabolic Pathway Peptides
Sermorelin
Sermorelin stimulates endogenous GH release. Research suggests support for IGF-1 mediated tissue repair and muscle adaptation. Preclinical studies indicate enhanced protein synthesis and lean mass support. Research shows potential benefits for connective tissue remodeling. Studies suggest systemic anabolic signaling improvements. Preclinical evidence indicates potential recovery optimization in stress or injury models.
Tesamorelin
Research indicates Tesamorelin enhances GH release and may improve visceral fat metabolism. Preclinical studies show increased protein synthesis and tissue adaptation. Research suggests potential support for lean mass preservation. Studies indicate systemic anabolic and recovery signaling improvements. Preclinical evidence suggests synergy with other GH peptides. Research also shows potential metabolic regulation benefits.
Ipamorelin
Research shows Ipamorelin stimulates GH release via pituitary somatotrophs. Studies suggest downstream IGF-1 activation supports tissue repair, protein synthesis, and lean mass maintenance. Preclinical models indicate support for connective tissue adaptation and recovery signaling. Research shows minimal impact on cortisol or prolactin levels. Studies suggest potential synergistic effects with GHRH analogs. Preclinical evidence indicates systemic anabolic support for protein turnover.
GHRP-2
GHRP-2 binds ghrelin receptors to stimulate GH secretion. Research suggests activation of IGF-1 pathways may enhance muscle repair and lean mass maintenance. Preclinical studies indicate protein synthesis and catabolism regulation. Research shows potential modulation of appetite and metabolic signaling. Studies suggest improved systemic recovery signaling. Preclinical evidence supports combined use with GH-releasing analogs for enhanced effects.
CJC-1295
Research indicates CJC-1295 stimulates GH release, elevating IGF-1 levels. Preclinical studies show enhanced protein synthesis and tissue repair. Research suggests support for connective tissue adaptation and systemic anabolic signaling. Studies indicate potential improvements in lean mass maintenance. Preclinical evidence shows optimized pulsatile GH release may improve recovery pathways. Research also suggests synergy with other GH axis peptides.
CJC-1295 (no DAC) + Ipamorelin
Studies show the combination enhances GH pulsatility and IGF-1 signaling. Preclinical models suggest synergistic effects on tissue repair, protein synthesis, and lean mass support. Research shows activation of pituitary and peripheral receptors may improve systemic anabolic adaptation. Studies indicate connective tissue recovery and metabolic signaling benefits. Research suggests improved efficiency in GH-mediated pathways. Preclinical evidence indicates multi-pathway activation may optimize recovery.
IGF-1 LR3
Research shows IGF-1 LR3 activates IGF-1 receptor pathways, promoting cellular proliferation and protein synthesis. Preclinical studies indicate enhanced tissue repair and muscle hypertrophy. Research suggests systemic anabolic support and lean mass maintenance. Studies indicate potential satellite cell activation and adaptive remodeling. Preclinical models show improved recovery signaling. Research suggests enhanced systemic tissue homeostasis.
3. Metabolic & Weight Management Peptides
Semaglutide
Research shows Semaglutide is a GLP-1 receptor agonist that enhances insulin secretion in response to glucose and supports glycemic control. Studies suggest it slows gastric emptying, modulates hypothalamic appetite circuits, and reduces caloric intake. Clinical research indicates benefits in obesity and type 2 diabetes populations. Preclinical studies show improved nutrient partitioning and systemic energy regulation. Research suggests potential secondary benefits for tissue recovery. Studies indicate favorable metabolic adaptation over time.
Tirzepatide
Studies suggest Tirzepatide activates GLP-1 and GIP receptors, enhancing insulin secretion, glucose tolerance, and energy regulation. Preclinical research indicates modulation of adipocyte metabolism and appetite signaling. Clinical trials show significant reductions in body weight and improved glycemic control. Research suggests synergistic effects on nutrient partitioning and fat mobilization. Preclinical studies indicate potential indirect support for tissue repair. Research shows multi-pathway metabolic regulation may optimize energy balance.
Retatrutide
Retatrutide is a triple agonist (GLP-1, GIP, glucagon). Research shows simultaneous activation produces robust metabolic effects. GLP-1 improves insulin secretion, glucose tolerance, and satiety; GIP enhances adipocyte insulin sensitivity; glucagon promotes lipolysis and energy expenditure. Preclinical studies indicate significant body weight reduction and improved systemic metabolism. Early clinical trials suggest superior outcomes compared to GLP-1 mono-agonists. Research shows Retatrutide may preserve lean mass while mobilizing fat, optimizing nutrient partitioning.
Cagrilintide
Research shows Cagrilintide modulates gastric emptying and satiety signaling via hypothalamic and brainstem pathways. Preclinical studies indicate complementary effects with GLP-1 signaling. Research suggests benefits for reduced caloric intake, improved body composition, and metabolic efficiency. Studies indicate indirect support for recovery by optimizing systemic energy balance. Research suggests improved nutrient utilization. Preclinical models show synergistic potential with GLP-1 receptor agonists.
AOD 9604
Research indicates AOD 9604 selectively activates lipolytic pathways in adipocytes without full GH receptor activation. Preclinical studies show fat mobilization while sparing protein metabolism. Research suggests potential benefits for body composition optimization and metabolic efficiency. Studies indicate indirect support for systemic recovery via energy regulation. Preclinical evidence indicates potential synergy with other metabolic peptides. Research shows consistent fat oxidation signaling in models.
Cartalax
Preclinical research suggests Cartalax may influence energy regulation, appetite signaling, and adipocyte metabolism. Research indicates potential effects on systemic fat oxidation and metabolic efficiency. Studies suggest indirect support for tissue repair through improved energy homeostasis. Research shows potential modulation of peripheral nutrient signaling. Preclinical models suggest supportive systemic effects for recovery-focused research.
4. Immune Support & Infection Modulation
Thymosin-alpha-1
Research shows Thymosin-alpha-1 enhances T-cell maturation and modulates cytokine production, improving adaptive immune responses. Preclinical studies suggest increased antiviral and antibacterial defense. Research indicates potential reduction of inflammation and support for tissue repair through immune modulation. Studies suggest enhanced natural killer (NK) cell activity and improved systemic immune balance. Preclinical models indicate support for recovery after infection or immune stress. Research shows potential synergy with tissue repair peptides through inflammation regulation.
LL-37
LL-37 is an antimicrobial peptide that supports epithelial defense and innate immunity. Research indicates it enhances chemotaxis, recruits immune cells, and modulates cytokine signaling. Preclinical studies show broad-spectrum antimicrobial activity and potential support for tissue integrity. Research suggests indirect support for recovery by protecting injured tissues from secondary infection. Studies indicate modulation of local inflammatory pathways. Preclinical evidence suggests synergy with other immune or tissue-repair peptides.
VIP (Vasoactive Intestinal Peptide)
Research shows VIP modulates immune responses by reducing pro-inflammatory cytokines and enhancing anti-inflammatory pathways. Preclinical studies indicate support for vascular tone and tissue perfusion. Research suggests indirect support for tissue repair through inflammation regulation and improved nutrient delivery. Studies show potential modulation of immune cell activity. Preclinical evidence suggests VIP may improve systemic homeostasis during recovery. Research indicates benefits in both acute injury models and chronic inflammation contexts.
5. Cellular Health & Longevity
Epithalon / NA Epithalon Amidate
Research indicates Epithalon regulates telomerase activity, supporting DNA repair and genomic stability. Preclinical studies suggest reduced oxidative stress and improved cellular longevity. Research shows modulation of senescence pathways and potential protection against cellular aging. Studies suggest enhanced mitochondrial function and stress adaptation. Preclinical evidence indicates potential systemic benefits for recovery and tissue homeostasis. Research suggests neuroprotective and adaptive signaling support.
FOXO4
FOXO4 modulates apoptosis in senescent cells, supporting selective clearance of damaged or aged cells. Research shows activation of DNA repair pathways and regulation of oxidative stress. Preclinical studies indicate improved tissue homeostasis and systemic adaptation. Research suggests potential reduction in senescent cell burden during aging or chronic stress. Studies indicate indirect support for recovery through improved cellular environments. Preclinical evidence shows synergy with other longevity-supporting peptides.
MOTS-c
MOTS-c activates AMPK signaling, enhancing mitochondrial efficiency, energy metabolism, and stress resilience. Preclinical studies suggest improved systemic metabolic homeostasis. Research indicates support for cellular adaptation to energy stress and oxidative challenges. Studies show potential synergistic effects with metabolic peptides for energy utilization. Research suggests indirect support for tissue repair via improved energy availability. Preclinical models indicate mitochondrial protective effects.
SS-31
SS-31 targets the mitochondrial inner membrane to reduce ROS production and enhance ATP generation. Research shows support for cellular resilience and tissue energy supply. Preclinical studies indicate protection against oxidative stress-induced cellular damage. Research suggests potential improvements in systemic recovery and organ function. Studies show modulation of apoptotic signaling pathways. Preclinical evidence indicates potential synergistic support for longevity and metabolic peptides.
NAD+
NAD+ is essential for redox reactions, DNA repair, and mitochondrial function. Research indicates support for energy metabolism, cellular stress resilience, and tissue homeostasis. Preclinical studies suggest systemic improvements in metabolic efficiency and adaptation to stress. Research shows potential synergy with mitochondrial and anabolic peptides. Studies indicate indirect benefits for recovery and systemic repair. Preclinical evidence supports improved cellular energy balance and antioxidant defenses.
Pinealon
Research suggests Pinealon supports neuroprotection, mitochondrial function, and cellular adaptation to stress. Preclinical studies indicate modulation of neuronal pathways and oxidative stress. Research shows potential benefits for systemic energy metabolism and recovery under stress. Studies indicate indirect effects on tissue repair via improved neuroendocrine signaling. Preclinical models suggest anti-aging and resilience-promoting effects. Research suggests complementary effects when combined with mitochondrial peptides.
6. Hormonal & Neuroendocrine Signaling
Kisspeptin
Kisspeptin regulates GnRH neurons, initiating reproductive hormone cascades. Research shows modulation of LH and FSH signaling, supporting reproductive axis function. Preclinical studies indicate potential indirect support for systemic tissue adaptation via endocrine pathways. Research suggests improved hormonal balance and reproductive signaling. Studies indicate synergy with other reproductive peptides. Preclinical evidence shows indirect effects on recovery through hormonal regulation.
Oxytocin
Oxytocin modulates neuroendocrine signaling, social behavior, and stress responses. Research indicates potential indirect benefits for tissue repair via hormonal pathways. Preclinical studies suggest improved systemic adaptation and recovery under stress. Research shows anti-inflammatory and vascular effects. Studies indicate support for reproductive and emotional homeostasis. Preclinical evidence suggests potential synergy with immune and recovery peptides.
PT-141 (Bremelanotide)
PT-141 acts on melanocortin receptors to stimulate sexual arousal pathways. Research indicates potential neuromodulatory and vascular effects. Preclinical studies suggest indirect support for systemic adaptation through neuroendocrine pathways. Research shows complementary effects on hormonal signaling. Studies indicate modulation of vasodilation and tissue perfusion. Preclinical evidence suggests potential synergy with metabolic and hormonal peptides.
7. Cosmetic & Appearance
Melanotan II
Melanotan II activates melanocortin receptors, enhancing pigmentation. Research indicates potential modulation of melanogenesis and UV response. Preclinical studies show effects on skin protective pathways. Research suggests indirect benefits for tissue signaling and antioxidant responses. Studies indicate potential modulation of hormonal and metabolic pathways. Preclinical evidence suggests synergy with peptides that influence skin repair.
PE-22-88
PE-22-88 is investigational and may support skin signaling and epidermal maintenance. Research suggests potential benefits for skin integrity and cellular adaptation. Preclinical studies indicate modulation of cellular repair pathways. Research shows indirect support for tissue homeostasis. Studies suggest potential synergy with antioxidant and tissue repair peptides. Preclinical evidence indicates protective effects against environmental stressors.
Glutathione
Glutathione acts as a central antioxidant, supporting detoxification and reduction of oxidative stress. Research indicates benefits for systemic tissue protection, skin health, and cellular resilience. Preclinical studies suggest enhanced recovery from oxidative damage. Research shows modulation of redox signaling and anti-inflammatory pathways. Studies indicate indirect support for tissue repair and metabolic efficiency. Preclinical evidence supports synergy with regenerative and mitochondrial peptides.
PTD-DBM
PTD-DBM modulates Wnt signaling, supporting hair follicle epithelial tissue regeneration. Research shows potential effects on epithelial tissue homeostasis and repair. Preclinical studies indicate improved cellular signaling in hair follicle and skin tissues. Research suggests indirect benefits for tissue repair and recovery. Studies indicate potential synergy with other regenerative peptides. Preclinical evidence suggests enhanced epithelial resilience.
Reference Table
| Category | Peptide | Primary Function | Primary Pathway | FDA Status |
|---|---|---|---|---|
| Tissue & Repair | BPC-157 | Tendon, ligament, soft tissue repair | Angiogenesis, fibroblast, ECM | Research Only |
| Tissue & Repair | TB-500 | Tissue remodeling, angiogenesis | Cytoskeleton, vascularization | Research Only |
| Tissue & Repair | GHK-Cu | Collagen synthesis, anti-inflammatory | ECM, NF-kB | Research Only |
| Tissue & Repair | Follistatic 344 | Muscle regeneration | Myostatin/activin inhibition | Research Only |
| Tissue & Repair | GLOW | Multi-pathway tissue repair | Angiogenesis + ECM + fibroblast | Research Only |
| Tissue & Repair | KLOW | Multi-pathway + anti-inflammatory | Angiogenesis + ECM + fibroblast + KPV | Research Only |
| GH/Anabolic | Ipamorelin | GH release | Pituitary GH axis | Research Only |
| GH/Anabolic | GHRP-2 | GH secretion | Ghrelin receptor → GH | Research Only |
| GH/Anabolic | CJC-1295 | GH/IGF-1 | GH/IGF-1 | Research Only |
| GH/Anabolic | CJC-1295 + Ipamorelin | GH/IGF-1 synergy | GH/IGF-1 | Research Only |
| GH/Anabolic | Sermorelin | GH release | GH release | Research Only |
| GH/Anabolic | Tesamorelin | GH release / metabolic | GH/IGF-1 | Research Only |
| GH/Anabolic | IGF-1 LR3 | Anabolic / protein synthesis | IGF-1 receptor | Research Only |
| Metabolic | Semaglutide | Glucose regulation / appetite | GLP-1 receptor | Approved |
| Metabolic | Tirzepatide | Glucose regulation / appetite | GLP-1/GIP receptor | Approved |
| Metabolic | Retatrutide | Multi-hormone metabolic regulation | GLP-1/GIP/Glucagon | Research Only |
| Metabolic | Cagrilintide | Satiety / gastric emptying | Amylin receptor | Research Only |
| Metabolic | AOD 9604 | Fat mobilization | GH fragment / adipocyte | Research Only |
| Metabolic | Cartalax | Energy regulation | Investigational | Research Only |
| Immune | Thymosin-alpha-1 | Immune modulation | T-cell / cytokine | Research Only |
Disclaimer: This content is provided for informational and research purposes only. The peptides discussed are not approved by the FDA for therapeutic use, and this information is not intended as medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional before undertaking any experimental or research protocols. Some peptides mentioned may also appear on the WADA banned substance list for competitive athletes.