Rapamycin (Sirolimus) vs Thymosin Alpha-1 (Zadaxin)
Both are used for immunity. Here's how they compare on human evidence, mechanism, safety and availability — in plain English.
| Rapamycin (Sirolimus) | Thymosin Alpha-1 (Zadaxin) | |
|---|---|---|
| Human evidence | ★★★★★ | ★★★☆☆ |
| Legal status | Off-Label, FDA Approved | Prescription, Not Approved |
| How it works | Binds FKBP12 to inhibit mTOR complex 1 — flipping cells from growth to maintenance (autophagy, stress resistance, less senescence). What mTOR is and why dialling it down matters → the mTOR pathway. The compound-specific nuance is… | Immunomodulator activating Toll-like receptors (TLR9/2) and T-cell maturation; approved in ~35 countries for hepatitis B/C and as a vaccine adjuvant. |
| In plain English | Rapamycin dials the "grow" switch (mTOR) down periodically, flipping cells into "clean and repair." It extends lifespan in every animal tested — the single most reliable longevity drug — but human data is still coming in. Taken weekly, not… | Tunes up the immune system's T-cells — approved in many countries (not the US) for chronic infections and used to bolster immunity. |
| Bottom line | The most compelling longevity drug we have; still needs human RCTs (PEARL, others ongoing). | Real immunotherapy abroad; investigational in the US. |
| Availability | Prescription only | Prescription only |
Which is better for immunity?
Rapamycin (Sirolimus) has the stronger human-evidence rating (★★★★★ vs ★★★☆☆), but the right choice still depends on your goal, tolerance and budget.
Full breakdowns: Rapamycin (Sirolimus) · Thymosin Alpha-1 (Zadaxin).
Common questions
Is Rapamycin (Sirolimus) or Thymosin Alpha-1 (Zadaxin) better for immunity?
Rapamycin (Sirolimus) has the stronger human-evidence rating (★★★★★ vs ★★★☆☆), but the right choice still depends on your goal, tolerance and budget.
What's the difference between Rapamycin (Sirolimus) and Thymosin Alpha-1 (Zadaxin)?
Rapamycin (Sirolimus): The most compelling longevity drug we have; still needs human RCTs (PEARL, others ongoing). — Thymosin Alpha-1 (Zadaxin): Real immunotherapy abroad; investigational in the US.