TB-500 vs Thymulin Analog (PAT)
A powerful fragment of thymosin beta-4 that acts like your body's repair signal—speeding up healing of muscles, tendons, and tissues by promoting cell migration and new blood vessel growth right where you need it most.
Synthetic thymulin-derived nonapeptide with potent analgesic and anti-inflammatory properties
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Quick comparison
Dose range
TB-500
2–2.5 mg
Thymulin Analog (PAT)
1 mcg–50 mcg mcg
Frequency
TB-500
Twice weekly
Thymulin Analog (PAT)
Once daily
Administration
TB-500
Subcutaneous injection
Thymulin Analog (PAT)
Intraperitoneal injection
Cycle length
TB-500
4-6 weeks
Thymulin Analog (PAT)
Ongoing/indefinite
Onset speed
TB-500
Moderate (1-2 weeks)
Thymulin Analog (PAT)
Moderate (1-2 weeks)
Evidence level
TB-500
Moderate human trials (Phase 1-2)
Thymulin Analog (PAT)
Strong human trials (Phase 3 or FDA approved)
Benefit ratings
Healing Speed
Tissue Repair
Anti-Scarring
Pain Relief
Anti-Inflammatory
Neuroprotection
Compound specifications
TB-500
Molecular formula
C38H68N10O14
Molecular weight
889.01 g/mol
Half-life
2-3 days (systemic)
Bioavailability
High via subcutaneous injection (~100%)
CAS number
885340-08-9
Thymulin Analog (PAT)
Molecular formula
C37H62N12O15
Molecular weight
858.9 Da
Half-life
Effects peak at 1-2 hours; diminish by 3-4 hours post-single dose
Bioavailability
Effective via intraperitoneal and intracerebroventricular routes in preclinical models
CAS number
Not assigned
Dosing compared
TB-500
Subcutaneous
2-2.5 mg
Twice weekly · Loading phase, 4-6 weeks
Research peptide with no human trials of the fragment; [9] loading doses used in practice [6].
2-2.5 mg
Once weekly · Maintenance after loading
Maintenance dose used in practice following the loading phase [6].
Thymulin Analog (PAT)
Best suited for
TB-500
Athletes Recovering from Muscle Injuries
If you've pulled a hamstring, strained your back, or torn a muscle, TB-500 helps accelerate the healing process by promoting cell migration to the injury site and supporting new blood vessel growth. It's especially useful for injuries that just won't seem to fully heal [1][5].
Tendon and Ligament Problems
Tendons and ligaments are notoriously slow healers because they have poor blood supply. TB-500 promotes angiogenesis (new blood vessel formation) and helps repair these stubborn connective tissue injuries—think Achilles tendonitis, tennis elbow, or rotator cuff issues [5].
Post-Surgical Recovery
After surgery, your body needs to repair a lot of tissue quickly. TB-500 supports wound healing, reduces inflammation, and may help minimize scar tissue formation. Some protocols use it alongside traditional recovery to potentially speed up the healing timeline [1][4].
Chronic Inflammation and Slow Healers
Some people just heal slowly—whether due to age, diabetes, or other factors. TB-500 helps regulate the inflammatory response and promotes the cellular processes needed for tissue repair. It essentially tells your body to focus healing resources where they're needed most [1].
Thymulin Analog (PAT)
Neuropathic pain research
Thymulin Analog (PAT) is particularly well-suited for individuals focused on neuropathic pain research. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Anti-inflammatory therapy development
Thymulin Analog (PAT) is particularly well-suited for individuals focused on anti-inflammatory therapy development. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Novel analgesic mechanism investigation
Thymulin Analog (PAT) is particularly well-suited for individuals focused on novel analgesic mechanism investigation. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Cytokine-mediated pain pathway studies
Thymulin Analog (PAT) is particularly well-suited for individuals focused on cytokine-mediated pain pathway studies. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Side effects
TB-500
Common
- Injection site redness
- Mild fatigue or lethargy
- Mild headache
- Slight flushing
Uncommon
- Head rush or lightheadedness
- Temporary nausea
Serious
- Allergic reaction
Thymulin Analog (PAT)
Common
- Injection Site Reaction
- Transient Immune Modulation
- Mild Sedation
- Short Duration of Action
Uncommon
- Potential Immune Suppression
- CNS Effects with Central Administration
Serious
- Unintended Immune Stimulation
Safety & evidence
TB-500
Evidence level
Moderate human trials (Phase 1-2)
FDA status
Research compound
Safety overview
TB-500 has shown a good safety profile across preclinical studies and limited human research. It's a fragment of thymosin beta-4, a naturally occurring protein in your body involved in healing. Most side effects are mild and transient, primarily injection site reactions. However, large-scale clinical trials are still needed to fully establish its safety profile in humans [1].
Contraindications
- Pregnancy or planning to become pregnant
- Currently breastfeeding
- Active cancer or history of cancer
- Known allergy to peptide components
- Children and adolescents
Thymulin Analog (PAT)
Evidence level
Strong human trials (Phase 3 or FDA approved)
FDA status
Research compound
Safety overview
Thymulin Analog (PAT) is a synthetic 9-amino acid peptide (pGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn) that is a research compound ONLY—NOT approved for human use. No serious adverse effects have been documented in extensive preclinical studies spanning 17+ years. However, this is a critical limitation: all data comes from animal models (primarily rats and mice). Zero completed human clinical trials exist. The peptide has not undergone human Phase 1 safety testing. No manufactured batches meet pharmaceutical standards. PAT's primary mechanism—alpha-7 nAChR potentiation—could theoretically affect multiple organ systems, but human safety data is absent. As an immune-modulating compound, prolonged high-dose use could theoretically suppress protective immunity, though animal studies show no adverse effects at therapeutic doses. Individual responses in humans are completely unknown.
Contraindications
- Not approved for human use
- Potential immune modulation concerns with chronic use
- Unknown drug-drug interactions
- Pregnancy and lactation (insufficient safety data)
Which is right for you?
Choose TB-500 if...
- Accelerating injury recovery
- Tendon and ligament healing
- Reducing chronic inflammation
- Post-surgical recovery support
Choose Thymulin Analog (PAT) if...
- Neuropathic pain research
- Anti-inflammatory therapy development
- Novel analgesic mechanism investigation
- Cytokine-mediated pain pathway studies