Evidence Grade B — Strong clinical evidence. 575 published studies, 345 human. 61 registered clinical trials.
Medically reviewed by a licensed medical professional
Thymosin alpha-1 is an immune-modulating peptide originally isolated from the thymus gland. It has been studied extensively across conditions including hepatitis B, liver cancer, sepsis, and as a vaccine adjuvant. Its regulatory status varies widely by jurisdiction — it is used clinically in parts of Asia, Europe, and South America but has not been reviewed by the FDA or EMA.
Thymosin Alpha-1 is also known by these brand and alternate names:
575 published studies: 345 human, 185 animal, 123 in-vitro, 76 reviews
Thymosin alpha-1 has been studied across multiple indications including hepatitis B, hepatocellular carcinoma, sepsis, and as a vaccine adjuvant. A meta-analysis of hepatitis B trials reported a statistically significant treatment effect, but the largest individual Phase III trial did not reach significance.
The compound has been the subject of extensive clinical research but has not met FDA or EMA approval standards for any indication. Its regulatory status varies widely by jurisdiction — approved in over 35 countries, primarily in Asia and parts of Europe and South America. See also Thymalfasin (#74).
Research suggests thymosin alpha-1 may activate toll-like receptors on dendritic cells and influence T-cell differentiation. A meta-analysis of hepatitis B trials reported a significant treatment effect, though the pivotal Phase III trial did not confirm efficacy. The proposed immunomodulatory mechanisms are based on a combination of in vitro, animal, and clinical studies of varying quality.
Research suggests thymosin alpha-1 has been studied across multiple conditions including hepatitis B, liver cancer, sepsis, and as a vaccine adjuvant. A meta-analysis of hepatitis B trials reported a statistically significant treatment effect, but the largest individual Phase III trial did not reach significance. The largest sepsis trial (TESTS, 1,106 patients) was definitively negative on its primary endpoint. The disconnect between wide international approval (35+ countries) and rejection by the FDA and EMA reflects inconsistent efficacy across rigorous trials. The peptide is well-characterised scientifically and the mechanism (working through toll-like receptors on dendritic cells) is well-described, but clinical outcomes have not consistently matched the preclinical promise.
PeptideTrace tracks 61 registered clinical trials for Thymosin Alpha-1 sourced from ClinicalTrials.gov.
The Safety and Effectiveness of a Type of Interleukin-2 Plus Zidovudine Plus Thymosin in HIV-Positive Patients With and Without Symptoms of Infection
A Trial of Thymalfasin in Adult Patients With Hepatocellular Carcinoma
AI-assisted Subtyping-directed Precision Treatment in Acute Aortic Dissection
A Study Evaluating Neoadjuvant Chemotherapy, Concurrent Chemoradiotherapy Combined With Dual Immune Checkpoint Blockade in Patients With Locally Advanced Non-Small Cell Lung Cancer
Phase II Trial of Neoadjuvant Thymalfasin, PD-1 Inhibitor, and Chemoradiotherapy for cStage III GEJ Adenocarcinoma
Thymosin Alpha-1 (Ta1, thymalfasin) is a 28-amino acid peptide first isolated from Thymosin Fraction 5 by Allan Goldstein at the University of Texas Medical Branch in 1972. Sequence: Ac-SDAAVDTSSEITTKDLKEKKEVVEEAEN. Molecular weight: 3,108.28 Da. CAS: 62304-98-7. Molecular formula: C129H215N33O55. Half-life approximately 2 hours. Tmax approximately 1.3 hours (SC). Brand name: Zadaxin (SciClone Pharmaceuticals). Approved in approximately 35+ countries including China and Russia. FDA orphan drug designation only, not FDA approved for general use. Endogenously produced by asparagine endopeptidase cleavage of prothymosin alpha (113-amino acid precursor). Listed here as research_compound for grey-market/unapproved-jurisdiction context.
Research suggests Ta1 acts primarily as an agonist of TLR2 and TLR9 on myeloid and dendritic antigen-presenting cells, with additional activity at TLR3, TLR4, and TLR7. Downstream signaling involves the NF-kappaB, p38 MAPK, and JNK/AP1 pathways. It stimulates dendritic cell maturation and antigen presentation, activates indoleamine 2,3-dioxygenase (IDO) for immune tolerance, promotes T-cell differentiation (CD4+, CD8+, CD3+), enhances Th1 responses with increased IFN-gamma, IL-2, IL-3 production, upregulates MHC class I molecules, and enhances NK cell cytotoxicity. Research also suggests PTEN-mediated inhibition of the PI3K/Akt/mTOR pathway in breast cancer models.
Hepatitis B: A meta-analysis of 5 RCTs (Chan et al., 2001; N=353) found OR 2.67 (95% CI 1.25-5.68) for virological response at 12 months post-treatment. The Chien et al. RCT (1998; N=98) showed 40.6% complete response vs 9.4% control (P=0.004). However, the Phase III Mutchnick trial (1999; N=97) did not confirm efficacy (14% vs 4%, P=0.084). Sepsis: The ETASS trial (Wu et al., 2013; N=361) showed 26.0% vs 35.0% 28-day mortality (P=0.049 log-rank). The definitive TESTS trial (BMJ 2025; N=1,106, double-blind, placebo-controlled) found HR 0.99 (95% CI 0.77-1.27), P=0.93, no significant benefit overall, though a diabetes subgroup showed HR 0.58 (95% CI 0.35-0.99). Cancer: Phase II trials in NSCLC, HCC, and melanoma research suggest reduced chemotherapy toxicity and improved quality of life. FDA granted orphan drug status for HCC, melanoma, and DiGeorge anomaly.
The information on this page is provided for educational and research reference purposes only. This is not medical advice. Always consult a qualified healthcare professional before making any health-related decisions.
Vancomycin is marketed as Vancocin and Firvanq (approved 1958, with oral solution Firvanq approved 2018). It is the standard treatment for serious MRSA infections (bloodstream infections, endocarditis, pneumonia, bone infections) and is first-line for severe C. difficile colitis. Vancomycin requires therapeutic drug monitoring — blood levels must be checked regularly to ensure the dose is effective without causing kidney damage or hearing loss. The rise of vancomycin-resistant enterococci (VRE) and occasional vancomycin-intermediate S. aureus (VISA) strains represent ongoing challenges. Despite being nearly 70 years old, vancomycin remains irreplaceable for many serious infections, though newer alternatives like daptomycin and the lipoglycopeptides offer advantages in specific settings.
Zilucoplan is marketed as Zilbrysq (approved October 2023) for anti-acetylcholine receptor antibody-positive generalised myasthenia gravis in adults. Administered as a daily subcutaneous self-injection. In the RAISE trial, zilucoplan showed statistically significant improvements in both activities of daily living and quantitative muscle strength scores compared to placebo, with improvements evident from week one. Its key differentiator from existing complement inhibitors (eculizumab, ravulizumab) is the self-injectable format — those alternatives require hospital-based intravenous infusions. As with all complement inhibitors, patients require meningococcal vaccination before starting treatment due to increased susceptibility to meningococcal infection.
Daptomycin is marketed as Cubicin (approved September 2003). It is indicated for complicated skin and soft tissue infections and S. aureus bloodstream infections including right-sided endocarditis. Administered as a once-daily intravenous infusion. A key limitation is that daptomycin cannot be used for pneumonia — lung surfactant inactivates the drug. In the bacteraemia trial, daptomycin was non-inferior to vancomycin with significantly lower rates of kidney problems (11% versus 26%). Creatine kinase (CK) levels must be monitored during treatment, as daptomycin can cause muscle toxicity. Generics became available after patent expiry, significantly reducing cost.
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