Immune Protocol
Cathelicidin (hCAP-18 / Synthetic Derivatives)Complete Dosing & Administration Guide
Human cationic antimicrobial protein-18 (hCAP-18) precursor and its synthetic derivative SAAP-148 — a next-generation 24-amino-acid cathelicidin-based peptide with broad-spectrum bactericidal activity against multidrug-resistant ESKAPE pathogens including MRSA biofilms, superior potency to its parent fragment LL-37, and retained efficacy under physiological salt and plasma conditions
Dose Range
0.5-5mg
Frequency
Once daily
Route
Topical application (primary research route)
Cycle Length
4-6 weeks
Dosing
How much
do I take?
Topical: Applied onto the skin as a cream, gel, or lotion — it works mainly where you put it.
Bioavailability Local — acts mainly at the skin; little reaches the bloodstream.
Standard Dose
0.5 mg/mL drops (about 100 microliters per application)
In a human phase 2a ear study, OP-145 drops at 0.5 mg per mL were applied to the affected ear twice daily for 2 weeks and were safe and well tolerated [4].
Timing
Best time to take
Apply Cathelicidin (hCAP-18 / Synthetic Derivatives) to clean, dry skin. For best results, use consistently at the same time(s) each day. Evening application is often preferred to allow overnight absorption, unless otherwise directed.
With food?
As a topical product, Cathelicidin (hCAP-18 / Synthetic Derivatives) is not affected by food intake. Apply to clean skin and allow adequate absorption time before covering the area.
If stacking
Cathelicidin (hCAP-18 / Synthetic Derivatives) should be used as directed by your healthcare provider. If combining with other medications or supplements, discuss potential interactions with your provider. Avoid combining with compounds that have overlapping mechanisms unless specifically guided by a medical professional.
Adjusting Your Dose
Increase if
- +You've tolerated the current dose for the recommended period without significant side effects
- +Therapeutic goals haven't been met at the current dose level
- +Your healthcare provider recommends dose escalation based on your response
- +Lab work or clinical assessments support a higher dose
Decrease if
- -Side effects are bothersome or impacting daily life despite management strategies
- -You experience any signs of an adverse reaction
- -Lab results indicate the need for dose reduction
- -Your healthcare provider recommends a lower dose based on your response
Signs of right dose
- ✓Therapeutic goals being met with minimal side effects
- ✓Stable and consistent response to treatment
- ✓Lab values or clinical markers trending in the right direction
- ✓Good tolerance with manageable or absent side effects
Dosing Calculator
Calculate Your Exact Dose
Step 1: Peptide Weight
Find the weight printed on your peptide vial label
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The peptide weight is printed on the label
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Administration
How do I
use it?
Reconstitution
What you need
- •Cathelicidin (hCAP-18 / Synthetic Derivatives) in its prescribed form
- •Clean, dry storage container
- •Measuring device if applicable (oral syringe, measuring cup)
- •Calendar or reminder app for dosing schedule
Injection
Route
Cathelicidin (hCAP-18 / Synthetic Derivatives) is administered Topical application (primary research route)—no injection required
Best sites
- •Not applicable—this is not an injectable formulation
Technique
- 1.Follow the specific administration instructions for your Cathelicidin (hCAP-18 / Synthetic Derivatives) formulation
- 2.Take or apply as directed by your healthcare provider
- 3.Store properly between uses according to package instructions
Storage
Signs of degradation
Sample Daily Schedule
Safety
Is it
safe?
Safety Profile
Cathelicidin peptides (natural and synthetic) are not FDA-approved and have no completed human clinical trials. Animal studies demonstrate broad-spectrum antimicrobial activity without systemic toxicity at therapeutic concentrations. However, concern exists regarding immunological tolerance—cathelicidin derivatives can trigger innate immune activation and inflammatory responses at high concentrations. The peptide's mechanism on immune cells is incompletely understood in humans, and effects on chronic immune signaling, tolerance development, or off-target immune activation remain uncharacterized. Bacterial resistance development to cathelicidin-based therapeutics is theoretically possible but not yet documented clinically.
Evidence is limited to in vitro antimicrobial activity assays, animal infection models, and preclinical immune cell studies. No human pharmacokinetics, dose-escalation studies, Phase 1 safety data, or clinical efficacy trials exist. Published research focuses on mechanism of antimicrobial action rather than safety profiling or tolerability in human use.
Common Side Effects
Experienced by some users
Local application site irritation
Mild redness, warmth, and stinging at the topical application site. Reflects the peptide's interaction with skin cells and local immune activation.
Management: Use appropriate formulation vehicle (hypromellose ointment). Apply to wound bed rather than intact skin. Monitor and reduce concentration if irritation is excessive.
Local inflammatory response
Transient increase in local inflammation including mild swelling and erythema around the treated area as immune cells are recruited via FPR2/ALX receptor activation.
Management: This is expected and generally beneficial — indicates immune cell recruitment to the infection site. Monitor for excessive inflammation. Should resolve within 24-48 hours.
Mild wound exudate increase
Increased wound exudate in the first 24-48 hours of treatment as biofilm disruption releases bacterial contents and immune infiltration increases.
Management: Change wound dressings as needed. Increased exudate initially is expected with biofilm disruption. Should normalize within 2-3 days as bacterial load decreases.
Less Common
- •Localized urticaria
- •Transient pain at injection site
These typically resolve with continued use or dose adjustment.
Stop and Seek Help If
- ×Severe or worsening side effects that don't improve with dose adjustment or supportive care
- ×Signs of an allergic reaction—rash, hives, swelling, or difficulty breathing
- ×Your healthcare provider recommends discontinuation based on your clinical response
- ×Development of any new medical condition that may be contraindicated with Cathelicidin (hCAP-18 / Synthetic Derivatives)
- ×Pregnancy or planning to become pregnant (unless specifically approved for use during pregnancy)
- ×Abnormal lab results or clinical markers that suggest adverse effects
Cathelicidin (hCAP-18 / Synthetic Derivatives) should only be started, adjusted, or discontinued under medical supervision. This information is for educational purposes only and does not replace professional medical advice. Never stop a prescribed treatment without consulting your healthcare provider first, as abrupt discontinuation may have consequences.
Interactions
With other peptides
- ✓May be used together under medical guidance.
- ✓May be used together under medical guidance.
- ✓May be used together under medical guidance.
With medications
- !High concentrations of divalent cations (Mg²⁺, Ca²⁺) in formulations — may reduce electrostatic membrane binding of cationic cathelicidin peptides - Use with caution—discuss with your healthcare provider.
- !Anionic surfactants or high-concentration albumin solutions — may sequester cationic peptides and reduce bioavailability - Use with caution—discuss with your healthcare provider.
- !Immunosuppressive medications without supervision — cathelicidin derivatives promote immune activation that may conflict with immunosuppressive goals - Use with caution—discuss with your healthcare provider.
With supplements
- ✓Multivitamins - Generally safe to take alongside Cathelicidin (hCAP-18 / Synthetic Derivatives). Space doses apart if taking oral formulations to ensure optimal absorption.
- ✓Electrolyte supplements - Helpful if experiencing any GI side effects that could lead to dehydration. Safe to combine.
Want the Full Picture?
View the complete Cathelicidin (hCAP-18 / Synthetic Derivatives) research profile including mechanism of action, clinical studies, effectiveness timeline, and FAQ.
View Full Cathelicidin (hCAP-18 / Synthetic Derivatives) Profile