LL-37 Dosing: 125mcg/Day for 50 Days

LL-37 is the only human cathelicidin antimicrobial peptide — a 37-amino-acid peptide with broad-spectrum antimicrobial activity and potent immune-modulating properties. No human clinical trials exist for injectable LL-37. This is not medical advice.

Quick Reference: Standard Protocol

For the full LL-37 peptide profile and vendor pricing, see our LL-37 peptide page. For benefits, see our LL-37 benefits guide.

Cycling Details

The standard protocol runs approximately 50 days of continuous daily injections, followed by 4 weeks off. One 5 mg vial at 125 mcg/day provides 40 doses — most users purchase 2 vials per cycle to cover the full 50 days.

The washout period allows the immune system to return to baseline and prevents potential desensitization. Some community members use an acute protocol (125-200 mcg daily for 2-4 weeks) during active immune challenges, while the full 50-day cycle serves as preventive/maintenance use.

Vitamin D3 synergy: Virtually all community protocols include Vitamin D3 (5,000-10,000 IU daily) because Vitamin D directly upregulates endogenous LL-37 production via the VDRE in the cathelicidin gene (Liu et al., 2006). Aim for serum 25(OH)D of 50-80 ng/mL. Many add Vitamin K2 (100-200 mcg MK-7) alongside high-dose D3.

Enhanced Protocol (Community)

Some protocols reference 200 mcg daily for 6-8 weeks based on the International Peptide Society's published guidelines. This uses 8 units per injection instead of 5.

Routes of Administration

Subcutaneous (standard): Abdomen, love handles, or thighs. Rotate injection sites. Morning injection preferred to align with immune circadian rhythms. Absorption is not affected by meals.

Reconstitution Quick Reference

Math: 5,000 mcg / 2 mL = 2,500 mcg/mL. 125 mcg / 2,500 = 0.05 mL = 5 units. One vial provides 40 doses (40 days). Swirl gently — LL-37 is a delicate peptide. Refrigerate immediately, use within 28 days.

For step-by-step reconstitution instructions, see the BPC-157 reconstitution guide — same technique applies.

Where These Numbers Come From

LL-37 dosing is entirely community-derived. No pharmacokinetic studies exist for subcutaneous injection in humans.

LL-37 demonstrates antimicrobial activity at concentrations as low as 1-16 mcg/mL against a broad range of pathogens, disrupting bacterial membranes through electrostatic interactions (Durr et al., 2006). LL-37 expression is directly regulated by Vitamin D through the VDRE in the cathelicidin gene promoter (Wang et al., 2004).

LL-37 can disrupt established bacterial biofilms — reducing biofilm formation by 50-80% in vitro against S. aureus and P. aeruginosa (Overhage et al., 2008). Beyond direct killing, LL-37 recruits immune cells and modulates TLR signaling (Kahlenberg & Kaplan, 2013).

The 125 mcg daily dose appears to be a conservative starting point extrapolated from in vitro effective concentrations, natural production rates, practical vial math (5 mg vial = 40 doses at 125 mcg), and community tolerance reports.

Stacking Protocols

Start one peptide at a time to assess tolerance. Use different injection sites when combining. Align cycle lengths for simplicity.

Side Effects & Safety

• Injection site redness/stinging — most commonly reported, typically mild
• Transient warmth or swelling at injection site
• Mild flu-like symptoms — first 1-3 days, possible immune activation response
• Herxheimer-like reactions — reported by some, possibly from microbial die-off
• Autoimmune caution — LL-37 overexpression is associated with psoriasis and rosacea; exercise extreme caution with these conditions (Morizane & Gallo, 2012)
• No human clinical safety data for injectable LL-37
• Pregnancy/nursing — no safety data; avoid

Frequently Asked Questions

What is the standard LL-37 dose?

125 mcg subcutaneous daily in the morning, for 50 days straight followed by 4 weeks off. Draw 5 units from a 5 mg vial reconstituted with 2 mL BAC water.

How long should an LL-37 cycle last?

Approximately 50 days continuous, then 4 weeks off. One 5 mg vial provides 40 doses at 125 mcg/day — purchase 2 vials per cycle.

How do I reconstitute LL-37?

Add 2 mL BAC water to a 5 mg vial (2,500 mcg/mL). 125 mcg = 5 units on insulin syringe. Swirl gently, refrigerate, use within 28 days.

Should I take Vitamin D with LL-37?

Yes — Vitamin D directly regulates natural LL-37 expression. Most protocols include 5,000-10,000 IU D3 daily, targeting serum 25(OH)D of 50-80 ng/mL.

Can I stack LL-37 with Thymosin Alpha-1?

Yes — this is the most popular immune peptide stack. LL-37 provides innate immune support (direct antimicrobial, biofilm disruption); TA-1 enhances adaptive immunity (T-cell maturation). Non-overlapping pathways.

Is LL-37 effective against biofilms?

In vitro research shows significant anti-biofilm activity. Whether SC injection achieves tissue concentrations sufficient for biofilm disruption in vivo is unknown.

Related Guides

• LL-37 peptide page — vendor pricing and full profile
• LL-37 Benefits Guide — antimicrobial, immune, and wound healing benefits
• Thymosin Alpha-1 Dosing Guide — adaptive immune peptide for stacking
• KPV Dosing Guide — anti-inflammatory peptide for immune protocols
• Peptide Stacking Guide — principles for combining immune peptides
• Calculate Your LL-37 Cycle Cost — estimate vials needed and total cost

References

For educational and research purposes only. This is not medical advice. No human clinical trials exist for injectable LL-37. All protocols are community-developed.