tuneTypical Dose
1.6 mg twice weekly
Peptide
Thymosin Alpha-1
thymosin alpha-1
Evidence TierCWADA NOT PROHIBITED
watchEffect Window
Weeks to 3 months depending on endpoint
check_circleCompliance
WADA NOT PROHIBITED
Overview
Clinical Summary
Thymosin alpha-1 is an immunomodulatory peptide derived from thymic proteins. It is used clinically in some settings to enhance immune responsiveness, with evidence varying by indication and region.
Studies suggest improved immune function measures and reduced severity or duration of certain infections when used as adjunct therapy. It may enhance vaccine response in some populations. Minority research explores adjunct roles in cancer immunotherapy and chronic viral infections, with heterogeneous evidence. Benefits depend on clinical context, dosing protocols, and patient immune status rather than general wellness use.
Immune pathway modulation via T-cell and antigen-presentation signaling.
Outcomes
What This Is Expected To Influence
Primary Outcomes
- Possible sepsis mortality and immune-marker improvement (low certainty)
Secondary Outcomes
- Liver inflammation response in small chronic hepatitis studies
- No proven benefit as broad prophylactic immune support
Safety
Contraindications and Interactions
Contraindications
- Pregnancy/lactation
- Known hypersensitivity
- Unsupervised autoimmune conditions
Side effects
- Injection site discomfort
- Transient flu-like symptoms
Interactions
- Interferon-based therapies
- Other immune modifiers
Avoid if
- Healthy users
- Non-protocol wellness use
Evidence
Study-level References
thymosin-alpha-1-SRC-001Meta-analysis
Sourceopen_in_newhttps://pubmed.ncbi.nlm.nih.gov/27633969/ doi:10.1186/s12879-016-1823-5
Population: Sepsis patients (19 RCTs, 530 patients in mortality subset)
Dose protocol: Heterogeneous Tα1 regimens
Key findings: Pooled mortality reduction signal (RR 0.59) and APACHE II improvement reported. Low evidence quality noted.
Notes: Quality and protocol consistency limitations reduce clinical certainty.
Paper content
Pooled mortality reduction signal (RR 0.59) and APACHE II improvement reported; low evidence quality noted.
thymosin-alpha-1-SRC-002Meta-analysis
Sourceopen_in_newhttps://pubmed.ncbi.nlm.nih.gov/25532482/ doi:10.1016/j.ijid.2014.12.032
Population: Sepsis
Dose protocol: Multiple RCTs
Key findings: Trend toward mortality reduction (pooled RR 0.68) in early synthesis, again with methodological caveats.
Notes: Highlights possible benefit but low-confidence evidence due trial quality.
Paper content
Trend toward mortality reduction (pooled RR 0.68) in early synthesis, again with methodological caveats.
thymosin-alpha-1-SRC-003Double-blind placebo-controlled pilot trial
Sourceopen_in_newhttps://pubmed.ncbi.nlm.nih.gov/8873009/ doi:10.1111/j.1600-0676.1996.tb00729.x
Population: 19 patients with chronic HCV
Dose protocol: 900 mcg/m2 SC twice weekly x 6 months
Key findings: No significant ALT or viral clearance benefit. One ALT responder relapsed by month 6.
Notes: Demonstrates very limited efficacy in this setting.
Paper content
No significant ALT or viral clearance benefit; one ALT responder relapsed by month 6.
thymosin-alpha-1-SRC-004Narrative review.
Sourceopen_in_newSimonova MA, Ivanov I, Shoshina NS, Komyakova AM, Makarov DA, Baranovskii DS, Klabukov ID, Telepenina KP, Atiakshin DA, Shegay PV, Kaprin AD, Stepanenko VN. Aging and Thymosin Alpha-1. Int J Mol Sci. 2025;26(23):11470. doi:10.3390/ijms262311470. PMID:41373628.
Population: Aging populations with thymic involution and immune decline.
Dose protocol: Review of thymosin alpha-1 immunomodulatory evidence in aging
Key findings: Thymosin alpha-1 has immunomodulatory, anti-inflammatory, and antioxidant properties relevant to age-related immune decline. Introduces Refnot hybrid therapeutic concept. No controlled human aging data reported.
Notes: Adds aging-focused mechanistic context but does not upgrade clinical confidence.
Paper content
This review examines thymosin alpha-1 in the context of age-related immune decline driven by thymic involution. The peptide demonstrates immunomodulatory, anti-inflammatory, and antioxidant properties that could theoretically counteract immunosenescence. The paper also presents Refnot, a hybrid therapeutic combining thymosin alpha-1 with TNF-alpha, as a strategy for age-related immune dysfunction with reduced toxicity compared to TNF alone. While the mechanistic rationale for thymosin alpha-1 in aging is well-articulated, the review acknowledges that additional research is needed on long-term safety and efficacy in elderly populations. No controlled human aging trials with thymosin alpha-1 monotherapy are reported.
thymosin-alpha-1-SRC-005Prospective phase II clinical trial.
Sourceopen_in_newXu H, Li F, Li B, Yang D, Liu T, Xia Y, Hua H, Li Q, Wang J, Liu H, Xu Z. Neoadjuvant immunochemotherapy plus thymalfasin in locally advanced gastric cancer: a prospective clinical trial. BMC Med. 2026;24:143. doi:10.1186/s12916-026-04740-z. PMID:41749205.
Population: Adults with stage III gastric or gastroesophageal junction adenocarcinoma.
Dose protocol: Thymalfasin added to anti-PD-1 plus SOX chemotherapy for 9 weeks neoadjuvant in stage III gastric cancer
Key findings: 30% pathological complete response, 56.7% major pathological response. CD8+ T cell expansion and immune gene upregulation observed. Grade 3+ toxicity 26.7%.
Notes: Single-arm design limits attribution to thymalfasin specifically. Promising signal for cancer immunotherapy adjunct use.
Paper content
This phase II trial evaluated thymalfasin (thymosin alpha-1) added to anti-PD-1 immunochemotherapy as neoadjuvant treatment for stage III gastric cancer. The 30-patient cohort achieved a 30% pathological complete response rate and 56.7% major pathological response, with nearly two-thirds reaching ypN0 status. At median 14-month follow-up, only one relapse occurred. Flow cytometry showed CD8+ T cell expansion with increased CD69 expression and reduced HLA-DR-positive T cells, suggesting immune remodeling. RNA sequencing revealed thymalfasin-associated upregulation of antigen processing, presentation, and type I interferon signaling genes. Grade 3+ toxicity was 26.7%. The single-arm design without a control group limits attribution of benefit to thymalfasin specifically, but the response rates and immune profiling data support further investigation in randomized trials.