Thymosin alpha-1 10 mg vial dosage

What Thymosin alpha-1 is

Class:

Immune-modulating peptide (28 amino acids)

Also called:

Thymalfasin, Zadaxin, Ta1

Used for:

Licensed in a number of countries, classically for chronic hepatitis B. Sold online for general immune support.

Human evidence:

Strong human evidence. Sixty-four randomised controlled trials across 864 records, including a multicentre randomised trial in the BMJ in 2025 with 28-day all-cause mortality as its primary outcome. The rating reflects the design and volume of evidence, not its direction: that trial found no clear evidence of a mortality benefit in sepsis.

US status:

Research use only. Not FDA-approved: FDA's December 2024 briefing to its Pharmacy Compounding Advisory Committee states that it has approved no drug product containing thymosin alpha-1, and that it is not approved in Japan or Europe except Italy. It is sold in some other countries as Zadaxin (SciClone Pharmaceuticals); the company reports approvals across the Asia-Pacific region, Latin America, Eastern Europe and the Middle East, which FDA says it cannot independently verify in every country named.

The full picture, with every study: Thymosin alpha-1 guide.

How to mix a 10 mg Thymosin alpha-1 vial

For this vial: 1 mL of bacteriostatic water makes 10 mg/mL, so 1.6 mg is 16 units (0.16 mL) on a U-100 insulin syringe. Pick a different volume from the units table if you want bigger or smaller draws; the number of doses stays the same.

1. Wipe the rubber stoppers of both the peptide vial and the bacteriostatic water vial with an alcohol swab and let the alcohol dry. ^[3][4]
2. With a new sterile needle and syringe, draw up the amount of bacteriostatic water you have chosen for the dilution. ^[3][4][5]
3. Inject the water into the peptide vial by aiming the stream against the inside glass wall, which helps prevent foaming. ^[6]
4. Swirl or roll the vial gently until the powder has fully dissolved; do not shake it. Do not inject the solution if it is cloudy or has particles in it. ^[3][4][6]
5. Label the vial with the date and time it was mixed, the amount of water added and how long it can be used after mixing. ^[3]
6. Store the mixed vial in the refrigerator at 2-8°C (36-46°F) and do not freeze it. ^[6]

Step by step with pictures: how to reconstitute peptides. About the water itself: bacteriostatic water.

Storing Thymosin alpha-1 vials

• Freeze-dried (lyophilized) peptide keeps far longer than peptide in solution; peptide suppliers advise storing the powder at -20°C away from bright light. ^[7]
• Protect peptide vials from heat and light. ^[7][8]
• Avoid repeated freeze-thaw cycles; a prescription peptide label also says not to freeze a vial once it has been mixed. ^[6][7]
• Once a multi-dose vial, such as bacteriostatic water, has been opened (needle-punctured), date it and discard it within 28 days unless its manufacturer states another date. ^[9][10]

More detail: peptide storage and shelf life.

Injecting safely

• Clean the injection site with an alcohol swab and let the skin dry completely before injecting. ^[11][12]
• Pinch up a fold of skin and fat (not muscle) and insert the needle at a 45- to 90-degree angle: 90 degrees where there is enough fatty tissue, 45 degrees where there is little. ^[11][12][13]
• Pulling back on the plunger (aspiration) is not necessary for a subcutaneous injection, because the chance of the needle being in a blood vessel is small. ^[11]
• Inject slowly, at roughly 10 seconds per mL. ^[11]
• Common sites are the belly, the thigh and the upper arm; rotate sites, keeping each injection at least 1 inch (2.5 cm) from the last. ^[6][11][12]

Hygiene and warning signs

• Use a new sterile needle and syringe for every injection and every time you enter a vial; never reuse them. ^[5][9][12]
• Never share needles, syringes or pens with anyone, even if the needle is changed; unsafe injection practices spread hepatitis B, hepatitis C and HIV. ^[5][8][9]
• Put used needles and syringes in a sharps disposal container straight away (FDA-cleared if possible), never loose in the trash, recycling or toilet, and dispose of the container following your community's guidelines. ^[14][15]
• Contact a health care provider if the injection site shows signs of infection, such as redness, swelling, red streaks or a fever. ^[12]

Where to inject: subcutaneous injection sites.

How Thymosin alpha-1 works

• Thymosin alpha-1 is a 28-amino-acid peptide with an acetyl group on its first amino acid. It was first isolated in 1977 from a calf thymus extract (thymosin fraction 5); the synthetic drug version, thymalfasin, has the same sequence. ^[16]
• It modifies immune responses, at least in part by acting on Toll-like receptor 9 on dendritic cells and immature immune (lymphoid) cells. ^[16]
• Injected under the skin in healthy men, it was absorbed quickly, peaking in blood after about 2 hours with a serum half-life of about 2 hours, and did not build up over 5 days of daily dosing. ^[16]

What the Thymosin alpha-1 research found

Human evidence: strong human evidence. Each result says what was studied.

• Human studyIn the TESTS trial (2025), 1,106 adults with sepsis at 22 centres in China were randomised to thymosin alpha-1 or placebo every 12 hours for 7 days. Deaths by day 28 were 23.4% against 24.1%, no clear benefit, and no secondary outcome differed significantly. ^[17]
• Human studyAn earlier single-blind trial (2013) of 361 adults with severe sepsis found 28-day deaths of 26.0% with thymosin alpha-1 against 35.0% in controls, a borderline result (P = 0.062 in the main analysis). A marker of immune-cell function, monocyte HLA-DR, rose more on treatment. ^[18]
• Human studyIn a 2022 double-blind trial of 508 people with predicted severe acute necrotising pancreatitis, 14 days of thymosin alpha-1 did not reduce infection of the damaged pancreas (15.7% against 18.1% on placebo). ^[19]
• Human studyIn a 2006 randomised study of 62 people with chronic hepatitis B, complete response was 31.0% on thymosin alpha-1 against 45.5% on interferon alpha at the end of 6 months' treatment, and 48.3% against 27.3% six months later; neither difference was statistically significant. ^[20]
• Regulator reviewIn a placebo-controlled, double-blind hepatitis B trial reviewed by FDA, undetectable virus levels 6 months after treatment were 20% on thymosin alpha-1 against 21% on placebo. FDA's 2024 review concluded there was a lack of evidence of effectiveness for all 12 uses it assessed. ^[16]

Thymosin alpha-1 side effects and risks

• Regulator reviewAcross most clinical studies, at 1 to 16 mg under the skin for up to 12 months, FDA found no significant adverse events attributable to thymosin alpha-1. The most common reactions were irritation, redness or discomfort at the injection site. ^[16]
• Regulator reviewRarer reports in published studies include flares of the liver enzyme ALT in people with chronic hepatitis B, thyroid-stimulating hormone abnormalities in people with chronic hepatitis C, and nipple pain. ^[16]
• Regulator reviewIn stem-cell transplant recipients, one study reported fatal immune haemolytic anaemia with graft failure. FDA flags a possible risk in people whose immune system is deliberately suppressed: in stem-cell transplant recipients, for example, it could cause or worsen graft-versus-host disease. ^[16]
• Human studyIn the 2025 sepsis trial, no safety outcome differed significantly from placebo, and the 2013 sepsis trial recorded no serious drug-related adverse event. ^[17][18]
• Human studyIn the 2006 hepatitis B study, no side effects occurred in the thymosin alpha-1 group, unlike the interferon group. ^[20]

Other things to know

• The 2025 BMJ multicentre trial found no clear evidence that it decreases 28-day all-cause mortality in adults with sepsis, and no secondary or safety outcome differed significantly.
• Every trial is in hospital medicine: sepsis, severe necrotising pancreatitis, chronic hepatitis. There is no randomised trial of general immune support in healthy adults.
• Legal status genuinely differs by country. Importing an unapproved medicine carries consequences that depend on where you live.

Reported side effects and what the studies measured: Thymosin alpha-1 side effects.

Where this vial size comes from

Thymosin alpha-1 is sold as a 10 mg vial by the pages below, each checked on the date shown. I list them as evidence that this size exists, not as a recommendation to buy from them.

• BioEdge Research LabsvendorLists it as: "Thymosin Alpha 1 (10mg)" - single 10mg vial option · checked 2026-09-28
• Loti LabsvendorLists it as: "Thymosin Alpha 1 10mg" - "10mg lyophilized powder with ≥98% purity" · checked 2026-09-28

The doses come from the sourced common protocol on the Thymosin alpha-1 dosing page, and every number on this page is arithmetic on those doses and this vial size.

Other Thymosin alpha-1 vial sizes

• 1.6 mg vial
• 5 mg vial
• 10 mg

Where to buy Thymosin alpha-1 for research

Sold for research use only. Listed by Spartan Peptides and BioEdge Research Labs; compare them on my vendors page or see the listing on the Thymosin alpha-1 page.

Questions

How much water do I add to a 10 mg Thymosin alpha-1 vial?

There is no single correct amount: water changes how many units a dose is, not how many doses the vial holds. With 1 mL the vial is 10 mg/mL and 1.6 mg is 16 units (0.16 mL) on a U-100 insulin syringe. The units table gives 1, 2, 5 mL.

How many doses are in a 10 mg Thymosin alpha-1 vial?

6 doses at 1.6 mg.

How long does a 10 mg Thymosin alpha-1 vial last?

At 1.6 mg a dose and twice weekly, about 3 weeks. How long a mixed vial keeps is a separate limit; see storage below.

How many 10 mg vials do I need for a cycle?

5 vials at 1.6 mg 2 times a week for 13 weeks; 17 vials at 1.6 mg 2 times a week for 52 weeks.

What does 1 unit equal in a 10 mg Thymosin alpha-1 vial?

100 mcg with 1 mL, 50 mcg with 2 mL, 20 mcg with 5 mL of bacteriostatic water, on a U-100 syringe.