Thymosin Beta-4 vs Ziconotide (Prialt)
The body's natural healing peptide that accelerates tissue repair and reduces inflammation
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
Thymosin Beta-4
2–5 mg
Ziconotide (Prialt)
2.4–19.2 mcg/day
Frequency
Thymosin Beta-4
Twice weekly
Ziconotide (Prialt)
Continuous intrathecal infusion
Administration
Thymosin Beta-4
Subcutaneous injection
Ziconotide (Prialt)
Intrathecal infusion by implanted or external microinfusion pump — NOT for intravenous use
Cycle length
Thymosin Beta-4
8-12 weeks
Ziconotide (Prialt)
Ongoing/indefinite
Onset speed
Thymosin Beta-4
Moderate (1-2 weeks)
Ziconotide (Prialt)
Moderate (1-2 weeks)
Evidence level
Thymosin Beta-4
Moderate human trials (Phase 1-2)
Ziconotide (Prialt)
Strong human trials (Phase 3 or FDA approved)
Benefit ratings
Wound Healing
Inflammation Reduction
Tissue Regeneration
Pain Relief
Opioid Alternative
Neuropathic Pain
Compound specifications
Thymosin Beta-4
Molecular formula
C212H350N56O78S
Molecular weight
4963
Half-life
Dose-dependent (increases with higher doses)
Bioavailability
100% (subcutaneous and intravenous)
CAS number
77591-33-4
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
Thymosin Beta-4
Subcutaneous injection
2-5 mg (community injectable practice for 'TB-500')
Once or twice weekly · 4-6 week loading phase, then weekly maintenance
Documented community/research-practice injectable dosing for tissue repair; thymosin beta-4 has ~100% bioavailability by the subcutaneous route [1]. Not an FDA-approved use.
Topical ophthalmic (eye drops)
0.1% (1 mg/mL) RGN-259 solution, 1 drop
Several times daily (e.g. up to 5x/day) · 4 weeks
0.1% RGN-259 ophthalmic solution used in phase III neurotrophic keratopathy and dry-eye trials, applied as eye drops several times daily for ~4 weeks [5].
Intravenous injection
450-1200 mg
IV push daily for the first 3 days, then weekly · Total of 7 doses over ~5 weeks
Doses studied in the RGN-352 acute myocardial infarction clinical program, given IV after PCI [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
Thymosin Beta-4
Post-Surgery Recovery
Accelerates healing of surgical wounds and reduces post-operative inflammation and scarring
Chronic Wound Management
Helps pressure ulcers, venous stasis ulcers, and other slow-healing wounds progress faster
Tissue Regeneration
Supports repair of damaged tissues from injury, burns, or degenerative conditions
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
Thymosin Beta-4
Common
- Injection site redness
- Injection site swelling
Uncommon
- Temporary mild headache
- Mild bruising at injection site
- Transient fatigue
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
Thymosin Beta-4
Evidence level
Moderate human trials (Phase 1-2)
FDA status
Research compound
Safety overview
Thymosin Beta-4 is a naturally occurring peptide found in all cells and body fluids in the human body. Clinical trials have demonstrated excellent safety even at very high doses. IV studies showed doses up to 1260 mg were well tolerated with no serious adverse events.
Contraindications
- Active systemic infections
- Severe immunosuppression
- Hypersensitivity to thymosin or any component
- Pregnancy (insufficient safety data)
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 Thymosin Beta-4 if...
- Recovering from injuries or surgery
- Improving wound healing speed
- Reducing inflammation
- Minimizing scar formation
Choose Ziconotide (Prialt) if...
- Severe chronic pain management
- Opioid-refractory neuropathic pain
- Cancer-related intractable pain
- Reducing systemic opioid dependence