Thymosin Alpha-1 Dosage Chart & Schedule Guide.

No, and this is the single most common mix-up. They share the word 'thymosin' only because both were originally pulled from the same crude thymus extract in the 1960s and 70s; they are structurally and functionally unrelated. Ta1 is a 28-amino-acid, N-terminally acetylated peptide (MW 3,108) that signals to immune cells and pushes T-cell maturation. TB-500 is a fragment of thymosin beta-4, an actin-binding protein involved in cell migration and tissue repair. Different molecules, different targets, completely different dosing. Nothing you read about TB-500 dosing applies here.

Not in the United States. A DailyMed search for thymalfasin returns zero approved labels. The manufacturer states Zadaxin is approved in more than 30 countries for chronic hepatitis B, and in some markets for hepatitis C and as an adjunct in cancer care (FDA notes it is unable to independently verify those foreign approvals), but in the US it holds only orphan-drug designations without marketing approval. On the compounding side, thymosin alpha-1 sat in Category 2 of the interim 503A bulks list from 2023, the nomination was withdrawn in September 2024, and FDA’s Pharmacy Compounding Advisory Committee reviewed it on 4 December 2024 and voted against adding it to the 503A bulks list, citing insufficient evidence of effectiveness and safety for the uses reviewed. It was not part of the July 2026 peptide vote that cleared BPC-157 and TB-500. US access has narrowed as a result.

The pharmaceutical product is a 1.6 mg vial reconstituted with exactly 1.0 mL of sterile water: the whole vial is one dose, injected as a full 1 mL subcutaneously. Research vials are usually 5 mg or 10 mg. At 5 mg reconstituted with 2 mL of bacteriostatic water you get 2,500 mcg/mL, so 1.6 mg is 0.64 mL, or 64 units on a U-100 syringe, and a 5 mg vial covers three doses with a little left. Note the label uses plain sterile water and says to use it immediately; bacteriostatic water is what makes a multi-dose vial practical, kept at 2–8°C.

It genuinely doesn't matter. Ta1 has no circadian dependence, doesn't touch the growth-hormone axis, and has no food interaction, unlike GH secretagogues where fasted timing is load-bearing. What matters is the interval: two fixed days spaced 3 or 4 apart. Pick days you'll actually keep, like Monday and Thursday, and stop optimising the clock.

Most people feel nothing, ever, and that is the expected outcome rather than a failure. Ta1 isn't stimulating and has no acute subjective signature. In the registration trials the endpoint wasn't symptoms at all; it was virologic response measured 12 months after finishing treatment. If you want to know whether it's doing anything, take a CBC with differential before you start and repeat it, and keep a plain count of infections and sick days across the course. Chasing a sensation with this compound leads straight to over-dosing.

There are no documented pharmacokinetic interactions, and the label's only stated caution is against combining with other immune-modulating drugs and against mixing anything in the same syringe. So a GLP-1, TRT or a repair peptide are not pharmacological conflicts. The real interaction to respect is with immunosuppressants (systemic steroids, biologics, transplant drugs), where Ta1 is actively pushing against what that medication is prescribed to do. Note the label also says drug interactions have not been fully evaluated, so this is absence of evidence rather than evidence of safety.

There is no controlled trial support for any of those uses, and the acute COVID data is genuinely mixed. One pilot trial gave 1.6 mg daily for seven days and saw a non-significant trend toward faster lymphocyte recovery. A separate retrospective analysis of 275 patients using 1.6 mg twice weekly found no difference in CD4+ or CD8+ recovery and actually reported longer viral shedding in the treated group (14 vs 11 days). Treat claims about post-viral syndromes as unproven marketing, not as an evidence-based indication.

The label's own design is a course, not a cycle: six continuous months, 52 doses, without interruption, then stop. There's no published evidence for indefinite use, and equally no data suggesting tachyphylaxis or receptor downregulation that would require a washout. The strongest argument for stopping at six months is simply that the trial response was measured 6–12 months after treatment ended, so staying on forever isn't replicating anything that was ever tested. If you're considering a second course, the sensible move is to re-measure your baselines first.