HealthRX.com · Printable medication review sheet
Thymosin alpha-1 switch record: the before and after products side by side
Fill in both products from their labels, line by line, and note why the switch was made, so a clinician or pharmacist can see whether the two are even the same substance. The facts block lists the FDA records that matter for that comparison.
Both products, from their labels
| Field | Product before | Product after |
|---|---|---|
| Name exactly as labelled | ||
| Ingredient form: free base, acetate or not stated | ||
| Maker or pharmacy, and country | ||
| Lot number | ||
| Route and formulation | ||
| Concentration as printed | ||
| Goal it was used for | ||
| Dates used |
Why the switch happened
Diagnosis or treatment goal
Who recommended the change
Gap or overlap between the two products
Other medicines, vaccines and immune treatments
FDA records to compare the products against
- FDA has approved no drug product containing thymosin alpha-1.[1]
- FDA says Zadaxin, a finished product sold in other countries, cannot be used interchangeably with Ta1 or thymalfasin.[1]
- Ta1 free base and Ta1 acetate count as different bulk drug substances.[1]
- A crossover study in 9 healthy adults found that blood exposure differed between three Ta1 products.[1]
- On December 4, 2024, 4 advisory committee members voted yes and 17 voted no, with none abstaining, on placing Ta1 free base on the 503A bulks list; the vote on Ta1 acetate was the same.[2]
- FDA's category 2 page, current as of 04/22/2026, lists Ta1 as nominated but withdrawn and says compounded Ta1 may pose a significant immunogenicity risk for some routes.[3]
For the clinician or pharmacist
- Is there evidence for the new product in my specific condition, by this route?
- Was it made by a licensed manufacturer or pharmacy, and in which country?
- Does stopping the old product need a taper or any other step?
- Which outcome will we measure, and when, to judge the change?
Keep a trail
- Keep both labels and the packaging
- Write down any new symptom with the date it started
- Report a suspected side effect or quality problem to FDA MedWatch
Sources for the facts on this sheet
- U.S. Food and Drug Administration. FDA Briefing Document: Evaluation of Thymosin Alpha-1 (Ta1)-Related Bulk Drug Substances (Ta1 free base and Ta1 acetate), Pharmacy Compounding Advisory Committee meeting of December 4, 2024. Accessed 2026-10-18. https://www.fda.gov/media/183820/download
- U.S. Food and Drug Administration, Center for Drug Evaluation and Research. Final Summary Minutes of the Pharmacy Compounding Advisory Committee Meeting, December 4, 2024. Accessed 2026-10-18. https://www.fda.gov/media/185642/download
- U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks. Accessed 2026-10-18. https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
This sheet records information for a conversation with your prescriber or pharmacist. It does not replace their instructions or the medication's prescribing information.