TB-500 vs Ziconotide (Prialt)
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.
FDA-approved intrathecal analgesic derived from cone snail venom for severe chronic pain
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
Ziconotide (Prialt)
2.4–19.2 mcg/day
Frequency
TB-500
Twice weekly
Ziconotide (Prialt)
Continuous intrathecal infusion
Administration
TB-500
Subcutaneous injection
Ziconotide (Prialt)
Intrathecal infusion by implanted or external microinfusion pump — NOT for intravenous use
Cycle length
TB-500
4-6 weeks
Ziconotide (Prialt)
Ongoing/indefinite
Onset speed
TB-500
Moderate (1-2 weeks)
Ziconotide (Prialt)
Moderate (1-2 weeks)
Evidence level
TB-500
Moderate human trials (Phase 1-2)
Ziconotide (Prialt)
Strong human trials (Phase 3 or FDA approved)
Benefit ratings
Healing Speed
Tissue Repair
Anti-Scarring
Pain Relief
Opioid Alternative
Neuropathic Pain
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
Ziconotide (Prialt)
Molecular formula
C102H172N36O32S7
Molecular weight
2639.2 Da
Half-life
CSF: 4.6 hours; Plasma: 1.3 hours
Bioavailability
100% intrathecal; does not cross blood-brain barrier systemically
CAS number
107452-89-1
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].
Ziconotide (Prialt)
Intrathecal
point
2.4 mcg/day
Continuous infusion · Starting point
Ziconotide is pumped directly into the fluid around the spinal cord, using an implanted or external microinfusion device — it is NOT for intravenous administration [6]. The label starts at no more than 2.4 mcg per day (0.1 mcg per hour) [6]. Starting low matters here more than usual: the boxed warning is for severe psychiatric symptoms and neurological impairment, and the drug is contraindicated in anyone with a history of psychosis [6].
Until pain is controlled
Increase up to 2.4 mcg/day per step
No more than 2-3 times per week · Until pain is controlled
The dose is raised by up to 2.4 mcg per day at a time, no more often than 2 to 3 times a week [6]. This is one of the few genuine titrations in this library: the same patient climbs the ladder, rather than different patients being assigned different rungs. What you are titrating against is not just pain — the label directs frequent monitoring for cognitive impairment, hallucinations and changes in mood or consciousness, and discontinuation if serious neurological or psychiatric signs appear [6].
Ongoing/maintenance
Up to 19.2 mcg/day
Continuous infusion · Ongoing/maintenance
The recommended maximum is 19.2 mcg per day (0.8 mcg per hour), reached by about day 21 on the label's schedule [6]. Many people settle below it. Reported psychiatric events at clinical doses include hallucinations in 12%, paranoid reactions in 3%, hostility in 2%, delirium in 2%, psychosis in 1% and manic reactions in 0.4% — and the placebo-controlled trials found a higher incidence of suicide, suicide attempts and suicidal ideation on ziconotide than on placebo [6]. Slower is better tolerated than faster, and the ceiling is a ceiling, not a target.
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].
Ziconotide (Prialt)
Severe chronic pain management
Ziconotide (Prialt) is particularly well-suited for individuals focused on severe chronic pain management. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Opioid-refractory neuropathic pain
Ziconotide (Prialt) is particularly well-suited for individuals focused on opioid-refractory neuropathic pain. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Cancer-related intractable pain
Ziconotide (Prialt) is particularly well-suited for individuals focused on cancer-related intractable pain. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Reducing systemic opioid dependence
Ziconotide (Prialt) is particularly well-suited for individuals focused on reducing systemic opioid dependence. 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
Ziconotide (Prialt)
Common
- Dizziness
- Nausea
Uncommon
- Confusion and Memory Impairment
- Ataxia and Nystagmus
Serious
- Psychiatric Symptoms
- Elevated Creatine Kinase and Rhabdomyolysis
- Psychiatric Symptoms
- Rhabdomyolysis with Acute Renal Failure
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
Ziconotide (Prialt)
Evidence level
Strong human trials (Phase 3 or FDA approved)
FDA status
FDA approved (PRIALT, 2004) for the management of severe chronic pain in adults for whom intrathecal therapy is warranted and who are intolerant of or refractory to other treatment, including intrathecal morphine. Carries a BOXED WARNING for neuropsychiatric adverse reactions and is contraindicated in anyone with a pre-existing history of psychosis.
Safety overview
PRIALT carries a BOXED WARNING for neuropsychiatric adverse reactions: severe psychiatric symptoms and neurological impairment may occur, every patient must be monitored frequently for cognitive impairment, hallucinations or changes in mood or consciousness, and therapy must be discontinued if serious neurological or psychiatric signs appear. It is CONTRAINDICATED in anyone with a pre-existing history of psychosis [6]. The reported rates are specific: hallucinations 12%, paranoid reactions 3%, hostility 2%, delirium 2%, psychosis 1%, manic reactions 0.4%. The label also states that ziconotide may cause or worsen depression with risk of suicide in susceptible patients, and that the placebo-controlled trials showed a HIGHER incidence of suicide, suicide attempts and suicidal ideation on ziconotide than on placebo [6]. Beyond the box, the label warns about meningitis — patients and carers must know the signs, including fever, headache, stiff neck, altered mental status, nausea or vomiting and occasionally seizures — about patients becoming unresponsive or stuporous, about elevations in creatine kinase requiring periodic monitoring, and about opiate withdrawal: patients must NOT be abruptly withdrawn from their opiates but tapered over a few weeks and replaced with an equivalent oral dose [6]. Ziconotide itself can be stopped abruptly without withdrawal effects [6].
Contraindications
- A pre-existing history of psychosis — stated in the boxed warning and in the contraindications
- Known hypersensitivity to ziconotide or any formulation component
- Any concomitant treatment or medical condition that would make intrathecal administration hazardous
- Infection at the microinfusion injection site
- Uncontrolled bleeding diathesis
- Spinal canal obstruction that impairs circulation of cerebrospinal fluid
Which is right for you?
Choose TB-500 if...
- Accelerating injury recovery
- Tendon and ligament healing
- Reducing chronic inflammation
- Post-surgical recovery support
Choose Ziconotide (Prialt) if...
- Severe chronic pain management
- Opioid-refractory neuropathic pain
- Cancer-related intractable pain
- Reducing systemic opioid dependence