Side-by-side · Research reference

IGF-DESvsLL-37

Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.

AAnimal-StrongHUMAN-REVIEWED8/60 cited

BHuman-MechanisticHUMAN-REVIEWED15/35 cited

IGF-DES

IGF-1 Analogue · Truncated N-Terminal

~10×Potency vs IGF-1

ReducedIGFBP binding

ResearchStatus

Injection (local or systemic) · Research protocols onlyBredehöft 2008

LL-37

Cathelicidin · Human AMP

Broad-spectrumAntimicrobial activity

Membrane disruptionPrimary mechanismLu 2026 He 2026

Innate immunityHost defense rolePinheiro 2026 Zhang 2026

Endogenous · Secreted at inflammation sites

01Mechanism of Action

Parameter

IGF-DES

LL-37

Primary target

IGF-1 receptor (IGF1R)Shields 2007

Bacterial membranes · Phosphatidylserine-exposed cellsHe 2026 Lu 2026

Pathway

IGF1R activation → PI3K/Akt & MAPK signaling → protein synthesis, proliferation

hCAP-18 precursor → Proteinase-3 cleavage → LL-37 release → Membrane insertion/disruption

Downstream effect

Enhanced muscle protein synthesis, myoblast differentiation, reduced apoptosis, cell proliferation

Membrane permeabilization, cytokine induction, autophagy, phagosome-lysosome fusion, chemotaxisAhmad 2026 Zhang 2026

Feedback intact?

Unknown — no human endocrine feedback data

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Origin

Synthetic truncation of native IGF-1 — removal of N-terminal Gly-Pro-Glu tripeptideBredehöft 2008

Endogenous human cathelicidin (37-AA fragment, residues 134–170 of hCAP-18)

Antibody development

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02Dosage Protocols

Parameter

IGF-DES

LL-37

Research dose range

10–100 ng/mL (in vitro); μg doses (animal models)

Highly context-dependent; no standardized human protocol.

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Route

Subcutaneous or intramuscular (local injection favored)

Local delivery maximizes tissue-specific uptake.

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Frequency

Variable — daily to multiple times daily in research

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Evidence basis

Animal models + in vitro only

In vitro, animal models, human observational

Human data

None — no clinical trials

—

Half-life

Shorter than IGF-1 due to reduced IGFBP binding

Rapid tissue uptake, limited systemic circulation.

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Endogenous expression

—

Constitutive in neutrophils, epithelial tissues

Upregulated during infection and inflammation.Pinheiro 2026

Exogenous (experimental)

—

Dose varies by study; antimalarial ~10–50 μM in vitro

No FDA-approved exogenous formulation.

Plasma levels (malaria)

—

Elevated in infected patients and miceHe 2026

Exogenous administration reduced parasitemia in murine models.He 2026

03Metabolic / Fat Loss Evidence

Parameter

IGF-DES

LL-37

Primary mechanism

Indirect via muscle hypertrophy → metabolic rate elevation

—

Direct lipolysis

Minimal evidence — IGF-1 axis primarily anabolic, not lipolytic

—

Prostate model

Inhibited BPH cell proliferation when combined with vitamin D3 analogueCrescioli 2002

Context-specific anti-proliferative effect, not fat loss.

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04Side Effects & Safety

Parameter

IGF-DES

LL-37

Hypoglycemia risk

Theoretical — IGF-1 axis enhances glucose uptake

—

Mitogenic risk

Chronic IGF-1 receptor activation may promote cell proliferation, potential tumor growthCrescioli 2002

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Injection site reaction

Expected — erythema, irritation, local swelling

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Edema / Fluid retention

Possible via sodium retention (IGF-1 axis effect)

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Human safety data

Absent — no human trials, all effects theoretical or extrapolated

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Unknown long-term effects

No chronic dosing studies in humans; endocrine, metabolic consequences unknown

—

Cytotoxicity (high dose)

—

Membrane disruption in host cells at supraphysiological concentrations

Pro-inflammatory signaling

—

Can exacerbate inflammation in certain contexts (context-dependent)Pinheiro 2026

Biofilm formation risk

—

LL-37-DNA complexes may stabilize dental plaque biofilmsTanabe 2026

Theoretical cancer risk

—

Immunomodulatory roles in tumor microenvironment under investigation

Absolute Contraindications

IGF-DES

·Active malignancy or history of cancer (mitogenic risk)
·Pregnancy / lactation (no safety data)
·Hypoglycemia disorders

LL-37

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Relative Contraindications

IGF-DES

·Diabetes mellitus (unpredictable glucose effects)
·Renal or hepatic impairment (clearance unknown)
·Edema-prone conditions (heart failure, nephrotic syndrome)

LL-37

·Active autoimmune disease (theoretical immune dysregulation)

05Administration Protocol

Parameter

IGF-DES

LL-37

1. Research context only

Des(1-3)IGF-1 has no approved human protocol. All administration details are derived from animal or in vitro research and should not be construed as medical guidance.

LL-37 is constitutively expressed in neutrophils and epithelial cells, cleaved from hCAP-18 by proteinase-3 at sites of infection or inflammation.

2. Reconstitution (if lyophilized)

Sterile water or bacteriostatic water per research protocol. Gently swirl; do not shake. Store reconstituted peptide at 2–8 °C.

Synthetic LL-37 and derivatives (e.g., SAMP-12aa) tested in vitro and animal models. Administered via topical, intraperitoneal, or intravenous routes in research settings.

3. Injection site

Subcutaneous (abdomen, thigh) or intramuscular (deltoid, vastus lateralis). Local injection to target tissue (e.g., muscle group) may enhance regional uptake.

LL-37 is resistant to pepsin degradation at gastric pH. Synthetic short peptides designed to retain this stability while reducing toxicity.Lu 2026

4. Timing

Frequency and timing vary by research design. Post-exercise or fasted state may theoretically enhance muscle uptake.

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5. Needle gauge

27–31G insulin syringe for subcutaneous; 25–27G for intramuscular.

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6. Monitoring

Glucose monitoring essential (hypoglycemia risk). No established IGF-1 or safety labs for human use.

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06Stack Synergy

IGF-DES

+ BPC-157

Moderate

View BPC-157 →

Des(1-3)IGF-1 promotes myoblast differentiation and protein synthesis, while BPC-157 enhances tissue repair, angiogenesis, and collagen synthesis. Both act on distinct pathways (IGF1R vs gastric pentadecapeptide mechanisms) to support muscle recovery and connective tissue integrity. Synergy is mechanistic but lacks direct co-administration studies.

Des(1-3)IGF-1: Research dose post-workout (local IM)
BPC-157: 250–500 mcg SQ, daily or twice daily
Frequency: Daily or per research protocol
Primary benefit: Accelerated muscle repair, enhanced hypertrophy, connective tissue support

+ TB-500

Moderate

View TB-500 →

TB-500 (Thymosin Beta-4 fragment) promotes cell migration, angiogenesis, and wound healing via actin regulation. Des(1-3)IGF-1 drives protein synthesis and myoblast proliferation. Combined, these peptides may synergistically enhance muscle recovery, repair, and hypertrophy through complementary anabolic and regenerative pathways. No direct human co-administration data.

Des(1-3)IGF-1: Research dose post-workout (local IM)
TB-500: 2–5 mg SQ, 2× weekly
Frequency: Per research cycle
Primary benefit: Muscle hypertrophy, injury recovery, vascular support

LL-37

— no documented stacks