Peptide Comparison
GramicidinvsThymalin
Historic 15-amino-acid linear pentadecapeptide antibiotic with alternating D- and L-amino acids — the first commercially produced antibiotic discovered by René Dubos in 1939, forming monovalent cation-selective transmembrane channels in bacterial membranes, FDA-approved as a topical/ophthalmic antimicrobial component of Neosporin and related preparations
Russian thymic peptide complex that rejuvenates immune function and supports healthy aging
At a Glance
Quick
comparison
Dose Range
Gramicidin
0.025–0.25 mg/mL
Thymalin
5–10 mg
Frequency
Gramicidin
Multiple times daily
Thymalin
Once daily
Administration
Gramicidin
Topical application (primary clinical route)
Thymalin
Intramuscular injection
Cycle Length
Gramicidin
8-12 weeks
Thymalin
4-6 weeks
Onset Speed
Gramicidin
Rapid (hours to days)
Thymalin
Moderate (1-2 weeks)
Evidence Level
Gramicidin
Strong human trials (Phase 3 or FDA approved)
Thymalin
Limited human trials
Efficacy
Benefit
ratings
Energy
Immune
Immune Restoration
Longevity Support
Disease Prevention
Technical Data
Compound
specifications
Gramicidin
Molecular Formula
C₉₉H₁₄₀N₂₀O₁₇ (gramicidin A)
Molecular Weight
1,882.3 Da (gramicidin A); Gramicidin D mixture: ~1,880-1,900 Da average
Half-Life
Local tissue persistence: hours to days at topical application sites (protease-resistant D-amino acid structure); systemic half-life: not applicable (hemolytic — never administered systemically); single channel lifetime: ~1 second (open/close kinetics in electrophysiology)
Bioavailability
Topical: local tissue concentrations at application site; systemic absorption negligible through intact skin and eye; oral bioavailability: not applicable (not used orally for systemic effect; would cause GI hemolysis); intrinsically resistant to proteases due to D-amino acid content
CAS Number
11029-61-1 (gramicidin A); 1405-97-6 (gramicidin D mixture)
Thymalin
Molecular Formula
Complex mixture; active dipeptide EW: C16H19N3O5
Molecular Weight
Polypeptide complex; components 250-1000 Da; active dipeptide EW ~321 Da
Half-Life
Not precisely characterized for complex; immune effects persist weeks post-administration
Bioavailability
High via intramuscular or subcutaneous injection
CAS Number
63958-90-7
Protocols
Dosing
tiers
Gramicidin
Thymalin
Applications
Best
suited for
Gramicidin
Topical treatment of bacterial conjunctivitis and external eye infections (FDA-approved)
Gramicidin is particularly well-suited for individuals focused on topical treatment of bacterial conjunctivitis and external eye infections (fda-approved). Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Prophylaxis and treatment of superficial skin infections, minor cuts, scrapes, and burns (OTC topical preparations)
Gramicidin is particularly well-suited for individuals focused on prophylaxis and treatment of superficial skin infections, minor cuts, scrapes, and burns (otc topical preparations). Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Research into ion channel biophysics, single-channel electrophysiology, and membrane transport mechanisms
Gramicidin is particularly well-suited for individuals focused on research into ion channel biophysics, single-channel electrophysiology, and membrane transport mechanisms. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Combination topical antimicrobial therapy providing Gram-positive coverage alongside polymyxin B for Gram-negatives
Gramicidin is particularly well-suited for individuals focused on combination topical antimicrobial therapy providing gram-positive coverage alongside polymyxin b for gram-negatives. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Thymalin
Aging Adults Seeking Immune Support
Thymalin is especially valuable for people over 55 whose thymus gland has naturally shrunk with age. By stimulating thymic function, it helps restore the immune training center that your body relies on to fight infections and stay healthy.
Longevity and Anti-Aging Protocols
Clinical studies tracking patients for 6-8 years showed Thymalin reduced mortality by 2.0-2.1-fold. Combined with Epitalon, the mortality reduction reached an impressive 4.1-fold, making this combination one of the most studied longevity peptide protocols.
Seasonal Illness Prevention
Research shows Thymalin cuts respiratory infection rates by 2.0-2.4-fold. A short 10-day course before cold and flu season can significantly boost your immune defenses for months afterward.
Safety Profile
Side
effects
Gramicidin
Common
- Ophthalmic stinging/burning
- Local skin irritation
- Temporary blurred vision
- Contact sensitization
Uncommon
- Superinfection
Serious
- Hemolytic toxicity with systemic absorption
Thymalin
Common
- No side effects in most patients
- Mild injection site reaction
Uncommon
- Transient low-grade fever
- Mild flu-like symptoms
- Temporary headache
Serious
- Severe allergic reaction
Research Status
Safety
& evidence
Gramicidin
Evidence Level
Strong human trials (Phase 3 or FDA approved)
FDA Status
FDA approved for this use
Safety Overview
Gramicidin is a cyclic peptide antibiotic derived from Bacillus brevis with a 70+ year track record of topical safety. It functions as a pore-former in bacterial membranes and shows minimal systemic absorption when applied to intact skin or mucous membranes, making it extremely low-toxicity for localized use. The primary safety concern is sensitization reactions in 1-5% of users with prolonged exposure, not organ toxicity. Gramicidin is FDA-approved for topical antibacterial applications and generally well-tolerated across age groups.
Contraindications
- xKnown hypersensitivity to gramicidin or any component of topical/ophthalmic formulations
- xSystemic administration by any route — gramicidin is hemolytic and toxic to red blood cells; strictly topical/ophthalmic use only
- xDeep puncture wounds or severe burns requiring systemic antimicrobial coverage
- xProlonged use on large open wounds — even topical gramicidin may cause hemolysis if absorbed systemically through extensive denuded skin
Thymalin
Evidence Level
Limited human trials
FDA Status
Research compound
Safety Overview
Thymalin has an excellent safety profile based on over 40 years of clinical use in Russia. Most patients experience zero side effects, and the peptide complex has been described as 'practically non-toxic' in research literature. It has been used safely in thousands of patients, including elderly populations over extended periods.
Contraindications
- xActive thymic tumors or malignancies
- xKnown hypersensitivity to animal-derived peptide products
- xPregnancy and breastfeeding (insufficient safety data)
- xSevere uncontrolled autoimmune disease without medical supervision
Decision Guide
Which is
right for you?
Choose Gramicidin if...
- Topical treatment of bacterial conjunctivitis and external eye infections (FDA-approved)
- Prophylaxis and treatment of superficial skin infections, minor cuts, scrapes, and burns (OTC topical preparations)
- Research into ion channel biophysics, single-channel electrophysiology, and membrane transport mechanisms
- Combination topical antimicrobial therapy providing Gram-positive coverage alongside polymyxin B for Gram-negatives
Choose Thymalin if...
- Immune system restoration in aging adults
- Longevity and healthy aging support
- Reducing infection frequency and severity
- Multi-system health optimization