Thymosin Alpha-1 Dosage Chart and Calculator: Protocol, Trials
Thymosin alpha-1 dosage chart: units per dose by vial size for the 1.6 mg common protocol, a calculator, and what sepsis, pancreatitis and hepatitis B trials used.
The short version
Thymosin alpha-1 is not FDA-approved, so there is no US label dose. Community and licensed-drug-label sources converge on 1.6 mg by subcutaneous injection, twice weekly, for a course of roughly 3-12 months depending on the use. That is common practice for general immune support, not a dose any US regulator has established. Every published randomised trial also used 1.6 mg subcutaneous, but all were in hospitalised patients with sepsis, severe pancreatitis or chronic hepatitis B. None was in healthy adults, the group it is marketed to online.
- The common protocol is 1.6 mg subcutaneous, twice weekly, for roughly 3-12 months depending on use. It is not US-established, though it matches the trial and licensed-label dose.
- Every trial dose is also 1.6 mg subcutaneous - only the frequency and course length differ by condition.
- The 2025 BMJ sepsis trial (TESTS) dosed 1.6 mg every 12 hours for 7 days and found no mortality benefit.
- No randomised trial has tested any dose in healthy adults for general immune support, which is the marketed use.
Thymosin alpha-1 has no FDA-approved product or label in the United States, so there is no US label dose to state. This page reports the protocol community and licensed-label sources commonly describe. It then reports what four published randomised trials gave their own patients. Every one of those patients was hospitalised, and none was a healthy adult taking it for general immune support. For the wider evidence and why legal status depends on where you are, see the main thymosin alpha-1 guide.
US legal status - Research use only
Not FDA-approved. Holds marketing approval in a number of other countries as a licensed prescription medicine, where its own label would govern dosing - not this page.
AU legal status - Not on the ARTG
No registered product on the ARTG.
Regulators reach their own conclusions on their own timelines. Where these two disagree, the difference is the point - not an error.
Thymosin alpha-1 dosage: the common protocol
Community and licensed-drug-label sources describe 1.6 mg by subcutaneous injection, twice weekly (spaced 3-4 days apart), for a course of roughly 3-12 months depending on the use. This is common practice, not a dose any US regulator has established.
Common protocol
What is commonly used, not a dose established in trials. No regulator has set a dose for Thymosin alpha-1. Sources differ, so the ranges below span them.
- Dose per administration
- 1.6 mg
- How often
- twice weekly, subcutaneous injection, spaced 3-4 days apart
- Route
- Subcutaneous injection
- Cycle length
- 13-52 weeks
- Common vial size
- 1.6 mg
- Timing
- Injections spaced 3-4 days apart (e.g. Monday and Thursday).
Both community/practitioner and licensed-drug sources converge on the same 1.6 mg twice-weekly dose; what differs is course length, which sources describe as 3-6 months for general immune-support use versus 6-12 months for the licensed chronic hepatitis B indication. A third source (peptidedosage.org) separately describes a lower, unconverging 300-500 mcg daily community 'immune support' regimen that I did not use here because it disagreed materially with the two sources above.
Plan a cycle in the protocol builder or work out injection volume in the dosage calculator.
The common Thymosin alpha-1 dose is 1.6 mg, twice weekly, subcutaneous injection, spaced 3-4 days apart. From a 1.6 mg vial mixed with 1 mL of bacteriostatic water, 1.6 mg is 100 units (1 mL) on a U-100 insulin syringe.
Thymosin alpha-1 1.6 mg vial: units per dose
Full 1.6 mg vial page: mixing, doses per vial, how long it lasts →
| Water added | Concentration | 1 unit = | 1.6 mg |
|---|---|---|---|
| 1 mL | 1.6 mg/mL | 16 mcg | 100 units |
| 2 mL | 0.8 mg/mL | 8 mcg | over 100 units |
| 3 mL | 0.53 mg/mL | 5.33 mcg | over 100 units |
Thymosin alpha-1 5 mg vial: units per dose
Full 5 mg vial page: mixing, doses per vial, how long it lasts →
| Water added | Concentration | 1 unit = | 1.6 mg |
|---|---|---|---|
| 1 mL | 5 mg/mL | 50 mcg | 32 units |
| 2 mL | 2.5 mg/mL | 25 mcg | 64 units |
| 3 mL | 1.67 mg/mL | 16.67 mcg | 96 units |
Thymosin alpha-1 10 mg vial: units per dose
Full 10 mg vial page: mixing, doses per vial, how long it lasts →
| Water added | Concentration | 1 unit = | 1.6 mg |
|---|---|---|---|
| 1 mL | 10 mg/mL | 100 mcg | 16 units |
| 2 mL | 5 mg/mL | 50 mcg | 32 units |
| 3 mL | 3.33 mg/mL | 33.33 mcg | 48 units |
All Thymosin alpha-1 vial sizes: 1.6 mg · 5 mg · 10 mg
Units are on a standard U-100 insulin syringe (100 units = 1 mL), rounded to the nearest half unit - half-unit marks are on 0.3 mL syringes. Water volumes are examples: more water means more units per dose, not more doses per vial. For any other vial or dose, use the calculator below.
How many 1.6 mg vials a cycle takes
| Scenario | Dose | Doses a week | Weeks | Total | 1.6 mg vials |
|---|---|---|---|---|---|
| Low end of the common protocol | 1.6 mg | 2 | 13 | 41.6 mg | 26 |
| High end of the common protocol | 1.6 mg | 2 | 52 | 166.4 mg | 104 |
Whole vials, rounded up. Plan a cycle with your own numbers in the protocol builder. Keep mixed vials cold and use them within the window in how long reconstituted peptides last; where to inject: subcutaneous injection sites.
Thymosin alpha-1 doses used in human studies
What the trials found
The 2025 BMJ trial (TESTS) is the newest, largest and most rigorous test. It was a multicentre, double-blinded, placebo-controlled phase 3 trial with 28-day all-cause mortality as its primary outcome. Its conclusion was that the trial “found no clear evidence to suggest that thymosin α1 decreases 28 day all cause mortality in adults with sepsis”. No secondary or safety outcome differed significantly between groups Wu 2025 - Wu J, Pei F, Zhou L et al. The efficacy and safety of thymosin α1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial. BMJ. 2025;388:e082583., in the references below.
The other three trials:
- ETASS (2013, sepsis): 28-day mortality was 26.0% in the treated group and 35.0% in the control group, a relative risk of 0.74. This did not reach conventional statistical significance on the primary nonstratified analysis (P = 0.062) Wu 2013 - Wu J, Zhou L, Liu J et al. The efficacy of thymosin alpha 1 for severe sepsis (ETASS): a multicenter, single-blind, randomized and controlled trial. Crit Care. 2013;17(1):R8., in the references below.
- Pancreatitis (2022): no significant difference in the development of infected pancreatic necrosis between groups Ke 2022 - Ke L, Zhou J, Mao W et al. Immune enhancement in patients with predicted severe acute necrotising pancreatitis: a multicentre double-blind randomised controlled trial. Intensive Care Med. 2022;48(7):899-909., in the references below.
- Hepatitis B (2006): a modest treatment response. The authors describe the overall response rate as “still less ideal” and call for further study of more effective approaches You 2006 - You J, Zhuang L, Cheng HY et al. Efficacy of thymosin alpha-1 and interferon alpha in treatment of chronic viral hepatitis B: a randomized controlled study. World J Gastroenterol. 2006;12(41):6715-21., in the references below.
The dose used where it is a licensed medicine
Writing in the BMJ, the TESTS trial authors describe the conventional therapeutic dose of thymosin alpha-1 as 1.6 mg twice weekly. That is the dose used for cancers and viral hepatitis in countries where it is licensed. They note the drug’s half-life as 1.5 hours Wu 2025 - Wu J, Pei F, Zhou L et al. The efficacy and safety of thymosin α1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial. BMJ. 2025;388:e082583., in the references below. This describes foreign licensed-product dosing, reported inside a fetched trial publication. It is not an FDA-reviewed dose, and it does not apply to a vial sold as a US research chemical.
What is not established
- No FDA-approved dose exists. Thymosin alpha-1 has no US label of any kind.
- No trial has tested healthy adults or general immune support, which is what the online market sells it for. Every dose above comes from hospitalised patients with a specific acute or chronic illness, under clinical monitoring.
- The trials do not agree on a single schedule. Four different frequency-and-duration combinations appear across four conditions. None was tested in the population or for the purpose it is marketed for.
- The common protocol above is current community and licensed-label practice, not a US trial finding. Each source is recorded, but no US regulator has established that dose.
Reconstitution and injection volume: use the calculator, not a guess
The injection volume for a target amount depends on how a specific vial was reconstituted. This page cannot know that for any given vial. The dosage calculator walks through vial strength, diluent volume and target amount. It performs the math; it does not tell you what dose to use.
Who should not use thymosin alpha-1
Thymosin alpha-1 has no FDA-reviewed label in the US, so there is no FDA contraindication list to point to. The trial populations were all hospitalised and monitored by clinical staff, which tells you nothing about self-directed use outside that setting. Anyone pregnant, breastfeeding, immunocompromised, on other medications, or with a diagnosed medical condition has no US regulator-reviewed information to weigh a decision against.
Thymosin alpha-1 side effects and risks
Within the trials themselves, no serious drug-related adverse events were reported and safety outcomes did not differ significantly from placebo. The risk that matters for a US buyer is different. Material sold as a research chemical has no FDA-reviewed manufacturing standard, no verified purity, identity, or concentration, and no clinician supervising the dose or watching for a reaction.
Related
Thymosin alpha-1 dosage calculator
Preset to a 1.6 mg vial and 1,600 mcg, the low end of the common protocol. Enter your own vial size, water and dose to get the syringe units to draw.
Your vial
Printed on the vial. There is no standard size - enter what yours says.
This changes how much you draw - never how many doses the vial holds.
100 units per mL. 1 unit = 0.01 mL. This is what almost every insulin syringe sold is, in every barrel size.
Capacity only. A 1 mL U-100 syringe holds 100 units - the scale decides that, not the barrel.
Draw this much
= 2 mL on a 1 mL U-100 syringe
- Concentration
- 800 mcg/mL
- Exact volume
- 2 mL
- Dose you actually get
- 1,600 mcg
- Doses per vial(unaffected by water volume)
- 1
- This dose needs 200 units, but a 1 mL U-100 syringe only holds 100. It will not fit in one draw - use less water, or a larger barrel.
Where to buy Thymosin alpha-1 for research
Each vendor is checked against my vendor checklist.
1.Spartan PeptidesFeatured
5 mg vial
- No FDA warning letter found
- Names its testing lab
2.BioEdge Research Labs
10 mg vial
- No FDA warning letter found
- Names its testing lab
- Batch COAs published
Common questions
What is the usual thymosin alpha-1 dose?
Community and licensed-drug-label sources both describe 1.6 mg by subcutaneous injection, twice weekly with injections spaced 3-4 days apart. The course lasts roughly 3-6 months for general immune-support use, or 6-12 months where it is a licensed chronic hepatitis B treatment. That is common practice reported by those sources, not a dose any US regulator has established. See the next question for what published trials used instead.
What dose of thymosin alpha-1 have human trials used?
Every randomised trial in this record used 1.6 mg by subcutaneous injection. The 2025 BMJ sepsis trial dosed it every 12 hours for 7 days. An earlier severe sepsis trial dosed it twice daily for 5 days, then once daily for 2 more days. A pancreatitis trial dosed it every 12 hours for 7 days, then once daily for a further 7 days. A hepatitis B trial dosed it twice weekly for 6 months.
Is there an FDA-approved thymosin alpha-1 dose?
No. Thymosin alpha-1 has no FDA-approved product or label in the United States. Where it is a licensed medicine in other countries, the conventional therapeutic dose described in the literature is 1.6 mg twice weekly. That is a foreign regulatory fact, not an FDA-reviewed one, and it does not apply in the US.
Do any of the trials test the way it is marketed online?
No. All four trials enrolled hospitalised patients: adults with sepsis in intensive care, patients with predicted severe acute necrotising pancreatitis, and patients with chronic hepatitis B. None enrolled healthy adults, and none tested general immune support, which is what online sellers market it for.
Did the sepsis trials show a benefit?
The newest and largest one did not. The 2025 BMJ trial, in 1,106 adults with sepsis, found no clear evidence that thymosin alpha-1 reduces 28-day mortality compared with placebo. An earlier, smaller 2013 trial found a relative risk reduction that did not reach conventional statistical significance by its primary test.
How do I work out reconstitution and injection volume?
That is arithmetic about a specific vial and diluent, not a dosing decision, and this page cannot know your vial. The dosage calculator works through concentration and draw volume for whatever amount you are looking at. It does the math; it does not tell you what dose to use.
What are the main risks?
In the trials themselves, no serious drug-related adverse events were reported and safety outcomes did not differ significantly from placebo. The risk on this site is different. Material sold as a research chemical in the US has no FDA-reviewed manufacturing standard and no verified purity or concentration. No clinician supervises the dose.
When should I stop and get medical care?
Get emergency care, and call 911 in the US, for a severe allergic reaction, chest pain, fainting, or any symptom that feels dangerous. Call Poison Control at 1-800-222-1222 if you have taken an unknown or excessive amount of anything sold as thymosin alpha-1. None of this is a substitute for a clinician who knows your history.
References (5 sources)
Bibliographic detail is fetched from PubMed, not written by me - so a citation here cannot drift from the paper it names. Study design comes from PubMed's own tags rather than my judgement.
- 1.Wu J, Pei F, Zhou L et al. The efficacy and safety of thymosin α1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial. BMJ. 2025;388:e082583.Randomised trialPMID 39814420full text
- 2.Wu J, Zhou L, Liu J et al. The efficacy of thymosin alpha 1 for severe sepsis (ETASS): a multicenter, single-blind, randomized and controlled trial. Crit Care. 2013;17(1):R8.Randomised trialPMID 23327199full text
- 3.Ke L, Zhou J, Mao W et al. Immune enhancement in patients with predicted severe acute necrotising pancreatitis: a multicentre double-blind randomised controlled trial. Intensive Care Med. 2022;48(7):899-909.Randomised trialPMID 35713670full text
- 4.You J, Zhuang L, Cheng HY et al. Efficacy of thymosin alpha-1 and interferon alpha in treatment of chronic viral hepatitis B: a randomized controlled study. World J Gastroenterol. 2006;12(41):6715-21.Randomised trialPMID 17075991full text
- 5.National Poison Control Center - 1-800-222-1222, free and confidential poisoning and overdose guidance, 24 hours a day.- America's Poison Centersother