LL-37 (Cathelicidin) vs Melanotan II

Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.

LL-37 (Cathelicidin)Melanotan II
CategoryPeptidesPeptides
Standard DoseResearch indicates 50-100 mcg daily via subcutaneous injection for immune support.Research indicates 250-500 mcg daily via subcutaneous injection during loading, reducing to 250 mcg 2-3 times weekly for maintenance.
TimingMorning administration preferred for immune support. Topical application directly to wound sites.Administer 4-6 hours before UV exposure for optimal tanning synergy. Can be taken at any time of day.
Cycle Duration4-8 week cycles. Short-term use preferred due to limited long-term safety data.Loading phase 1-2 weeks, then maintenance as long as desired. Pigmentation fades gradually upon discontinuation.
Evidence Levelanimal_plus_anecdotalmoderate_human

Mechanism

LL-37 is a 37-residue amphipathic helical antimicrobial peptide, the only human cathelicidin, that kills bacteria by forming tetrameric channels that perforate cytoplasmic membranes. Beyond direct antimicrobial activity, it modulates innate immunity through formyl-peptide receptor 2 (FPR2), induces chemotaxis of neutrophils and monocytes, upregulates CXCR4 and IL-8, and neutralizes bacterial endotoxins (LPS). It also promotes wound healing through keratinocyte migration and angiogenesis.

Standard Dosing

Research indicates 50-100 mcg daily via subcutaneous injection for immune support.

Timing

Morning administration preferred for immune support. Topical application directly to wound sites.

Cycle Duration

4-8 week cycles. Short-term use preferred due to limited long-term safety data.

Side Effects

  • Injection site pain and redness
  • Localized inflammation
  • Potential mast cell activation

Contraindications

  • Active autoimmune conditions (particularly lupus — LL-37 is implicated in SLE pathophysiology)
  • Pregnancy and breastfeeding
  • Psoriasis (may exacerbate)

Best Stacking Partners

KPVThymosin Alpha-1BPC-157
B

Melanotan II

Peptides

Mechanism

Melanotan II is a synthetic cyclic analog of alpha-melanocyte-stimulating hormone (alpha-MSH) that non-selectively agonizes melanocortin receptors MC1, MC3, MC4, and MC5. MC1R activation stimulates eumelanin synthesis through tyrosinase upregulation, producing tanning. MC3R activation in the CNS increases libido and produces erectile responses. MC4R activation suppresses appetite. The cyclic structure provides enhanced in vivo stability (half-life 1-2 hours) and increased blood-brain barrier permeability compared to linear alpha-MSH.

Standard Dosing

Research indicates 250-500 mcg daily via subcutaneous injection during loading, reducing to 250 mcg 2-3 times weekly for maintenance.

Timing

Administer 4-6 hours before UV exposure for optimal tanning synergy. Can be taken at any time of day.

Cycle Duration

Loading phase 1-2 weeks, then maintenance as long as desired. Pigmentation fades gradually upon discontinuation.

Side Effects

  • Nausea (common, especially during loading)
  • Facial flushing
  • Spontaneous erections
  • Appetite suppression
  • Darkening of existing moles (monitor closely)
  • Fatigue
  • New nevus formation

Contraindications

  • History of melanoma or atypical moles
  • Active skin cancer
  • Pregnancy and breastfeeding
  • Addison's disease
  • Pheochromocytoma

Best Stacking Partners

PT-141

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