Thymosin Alpha-1

Thymalfasin, Tα1, TA1, Zadaxin (brand)

Checked Oct 28, 2026

The short answer

No human evidence yet for immune support and fewer infections in healthy adults

D for that use: no controlled trial has tested it for fewer infections in healthy adults, so a placebo effect cannot be ruled out.

Approved?: Approved outside the US for: chronic hepatitis B and C, and as an immune adjunct in some other diseases (regulators in more than 35 countries, per the review cited; not a US FDA approval).
Safety: B, characterized: Injection-site irritation is the most common effect and the trials in sick patients reported few serious problems; long-term use in healthy people has not been studied.

We tried it. This is what happened.

Thymosin alpha-1: a block, not a habit PausedAn immune peptide with real human data, run as a defined block and then stopped cleanly.

The full answer: what it is for, the dose, the units

What people take it for: People take it for immune support: fewer colds, faster recovery when run down or travelling. It is also a prescription drug in more than 35 countries, for chronic hepatitis B and C, not in the US.

Does it work for immune support and fewer infections in healthy adults? D, no human evidence yet. Result: not tested in humans.

D for that use: no controlled trial has tested it for fewer infections in healthy adults, so a placebo effect cannot be ruled out. Where it was tested, hepatitis B (10 randomized trials) is rated very low to low certainty, and the largest sepsis trial (1,106 people) found no mortality benefit.

Approved outside the US for: chronic hepatitis B and C, and as an immune adjunct in some other diseases (regulators in more than 35 countries, per the review cited; not a US FDA approval). That does not carry over to boosting immunity or preventing colds in healthy people. Thymosin alpha 1: A comprehensive review of the literature (PMC7747025), statement on approval in more than 35 countries. No national agency page was opened, so no agency or year is printed.

Highest evidence for any use: A for chronic hepatitis B (10 randomized trials, certainty very low to low).

Safety: B, characterized. Injection-site irritation is the most common effect and the trials in sick patients reported few serious problems; long-term use in healthy people has not been studied.

Do not use if: Caution/avoid in autoimmune disease, organ-transplant or other immunosuppressed states (theoretical interference), and known hypersensitivity.

Could it be placebo? No controlled trial tests it for fewer infections in healthy adults, so a placebo effect cannot be ruled out for that use; in hepatitis B and sepsis the trials measured objective outcomes against control groups.

The dose people use, and the units to draw

Trials gave 0.8 to 1.6 mg per injection, mostly 1.6 mg twice a week in hepatitis B and 1.6 mg every 12 hours in sepsis; the one named clinician statement for wellness use is about 2.5 mg twice a week.

Source	Dose	How often and how	Who it was for	Link
Zadaxin (thymalfasin) prescribing information, as reproduced by RxList (page last updated 6/28/2021)	1.6 mg (900 mcg/m2); patients under 40 kg 40 mcg/kg	Subcutaneous injection twice a week for 6 to 12 months; not intravenous	Chronic hepatitis B (the page also gives 1.6 mg for cancer protocols)	Dosing section: 'The recommended dosage of Zadaxin is 1.6 mg (900 ug/m2) twice a week for 6 to 12 months'
Chien et al., Hepatology 1998 (randomized controlled trial)	1.6 mgUse this dose	Subcutaneous injection twice a week for 26 weeks or 52 weeks	98 adults with chronic hepatitis B; untreated control group	Abstract
Iino et al., J Viral Hepat 2005 (randomized clinical trial)	0.8 mg or 1.6 mg	24 weeks of monotherapy; injection frequency not stated in the abstract	316 Japanese adults with chronic hepatitis B	Abstract
Gravenstein et al., J Am Geriatr Soc 1989 (double-blind placebo-controlled trial)	900 mcg/m2	Subcutaneous injection twice a week for eight doses, given with the 1986 influenza vaccine	90 men aged 65 to 99; endpoint was flu-vaccine antibody response	Abstract, first paragraph
Tuthill et al., Int Immunopharmacol 2023 (randomized pilot, preliminary report)	1.6 mgUse this dose	Subcutaneous injection twice a week for 8 weeks, then 4 months of follow-up	Hemodialysis patients, 194 randomized to Ta1 or no Ta1 (open label); COVID-19 prevention	Abstract, Procedures
Wu et al., Crit Care 2013 (ETASS, single-blind randomized trial)	1.6 mgUse this dose	Subcutaneous injection twice a day for 5 days, then once a day for 2 days	361 ICU patients with severe sepsis	Methods, Study drug administration and sepsis management
Wu et al., BMJ 2025 (TESTS, double-blind placebo-controlled phase 3 trial)	1.6 mgUse this dose	Subcutaneous injection every 12 hours for up to 7 days	1,106 adults with sepsis at 22 centres in China	Methods, Procedures: '1.6 mg of lyophilised thymosin a1 powder dissolved in 1 mL of sterilised water every 12 hours'
ClinicalTrials.gov NCT04487444 (randomized phase 2, terminated)	1.6 mgUse this dose	Subcutaneous injection daily for 1 week, added to standard of care	COVID-19 treatment; 56 enrolled; stopped for slow enrollment and the PI moving institutions; no results posted	Arms and Interventions
Andrew Huberman and Dr. Mark Hyman, Huberman Lab, 'How to Improve Your Vitality & Heal From Disease'	No dose stated		Mentioned as a peptide for immune function when getting a cold, an immune issue or COVID	about 2:19:15, auto-transcript, verify by ear
Dr. Abud Bakri on Huberman Lab, 'Peptides: The Science, Uses & Safety', Jun 1 2026	about 2.5 mg	Twice a week, time of day not important, 'as a prophylactic'	Bakri's description of his own use when travelling and working hospital wards; he calls it not FDA approved and a self-experiment	about 1:38:00, auto-transcript with no speaker labels, verify by ear

Per-injection amounts in the trials run from 0.8 mg (one arm of Iino 2005) to 1.6 mg, with the highest total in sepsis at 1.6 mg every 12 hours for 7 days (TESTS 2025); the one wellness statement from a named clinician is about 2.5 mg twice a week (Bakri), above any trial per-injection amount.

Examine returned no thymosin alpha-1 page we could open, and Peter Attia's site search returned nothing for thymosin or thymalfasin, so neither gives a dose. Dr. Craig Koniver on Huberman Lab (episode on peptide and hormone therapies, about 1:42) states a dose for his patients, but he runs peptide clinics, so it is excluded under the no-seller rule. The prior page text about community protocols (daily doses, on-off cycles, bursts during illness) had no named non-seller source and is removed. No verified dose statement found for acute-illness bursts.

Reported by the named source, never prescribed by us.

How many units do I draw?

To turn a dose in mg into syringe units, use the calculator: enter the vial's mg, the water you add in mL, and the dose in mg. Open the dose calculator

Why it might work

Subcutaneous injection → thymic and immune-cell targeting
Thymosin alpha-1 (Tα1) is a 28-amino-a
Toll-like receptor 9 (TLR9) activation on dendritic cells
Tα1 is shown to bind and signal throug
T-cell maturation and Th1 polarization
Tα1 augments thymic processing of imma
NK cell and cytotoxic T-lymphocyte (CTL) upregulation → antiviral and antitumor immune response
In immunocompromised patients (HBV
Assumed outcome in healthy users: enhanced baseline immune surveillance
Wellness users assume the sick-populat

Assumed pathway, not shown in people.

Mechanism is comparatively well-characterized for a peptide (it is an approved drug abroad, so 'assumed' applies mainly to the healthy-user use case). Thymosin Alpha-1 acts as an agonist at Toll-like receptors, principally TLR2 and TLR9 (with TLR4 also implicated), on myeloid and plasmacytoid dendritic cells. This drives dendritic-cell and T-cell maturation/differentiation (CD4+/CD8+) and modulates cytokines (IFN-gamma, IL-2, IL-10), shifting immune tone rather than simply ramping it up. It is best described as an immune MODULATOR/restorer, which is why its clearest wins are in immune-suppressed states.

The trials, claim by claim

Result tags show how each randomized trial came out, not its letter: the TESTS sepsis trial is A with 'did not work', and the hepatitis B review is A with 'mixed' because the trials were positive on virological response but the Cochrane review rates certainty very low to low.

Approved as a prescription drug (thymalfasin/Zadaxin) in dozens of countries for chronic hepatitis B and C, a regulatory approval grounded in human RCTs.

Result: mixed

International marketing approval (not US) plus hepatitis B RCTs from 1991 to 2018. A September 2026 Cochrane review of 10 of them (1,349 people) rated the evidence very low to low certainty, so the approval rests on more than the trials prove. The A rating reflects that multiple RCTs exist, not that they are strong.

Naing et al., Cochrane Database Syst Rev 2026, Thymosin-alpha-1 for chronic hepatitis B

Status

NOT FDA-approved in the United States. It holds FDA orphan-drug DESIGNATION (hepatitis B, hepatocellular carcinoma, melanoma, DiGeorge), which is a development incentive, not marketing approval. In the US it is investigational/gray-market.

Designation-vs-approval distinction confirmed across regulatory summaries and the comprehensive literature review; full US marketing approval was never obtained.

PMC7747025. Thymosin alpha 1: a comprehensive review

For sepsis, the largest and best-designed RCT (TESTS, n=1,106, multicentre, double-blind, placebo-controlled, phase 3) found NO clear reduction in 28-day all-cause mortality. Subgroup signals pointed both ways (possible benefit at 60 and over, possible harm under 60) and are hypothesis-generating only.

Result: did not work

Published phase-3 RCT (BMJ, 2025). A high-quality negative primary result. Prespecified subgroups pointed both ways (possible benefit at 60 and over and in diabetes, possible harm under 60), which is hypothesis-generating only. A 2025 meta-analysis of 11 sepsis trials was positive overall but not in its high-quality or multicenter subsets.

PubMed PMID 39814420. TESTS sepsis phase 3 trial

Studied during COVID-19 in two small randomized open-label pilots: NCT04487444 was stopped early for slow enrollment with no results posted, and NCT04428008 in dialysis patients has only a preliminary report.

Two small registered pilots: one terminated early for slow enrollment (NCT04487444), one completed in dialysis patients with a preliminary report (NCT04428008). Net signal weak and confounded by pandemic-era standard of care.

ClinicalTrials.gov NCT04487444, thymalfasin for COVID-19

The marketed healthy-user benefit ('boosts immunity / fewer colds' in well people) is essentially unproven by controlled trials; nearly all rigorous evidence is in DISEASED or immune-compromised populations.

Result: not tested in humans

No placebo-controlled trial demonstrates the everyday immune-resilience claim in healthy adults; that gap is the honest center of the page.

NCT06821100, thymalfasin before COVID-19 boosters in older adults (ongoing, no results)

A September 2026 Cochrane review of 10 randomized trials in chronic hepatitis B (1,349 people) rated the evidence for thymosin-alpha-1 on mortality, serious adverse events, quality of life and histology very low to low certainty.

Result: mixed

Cochrane systematic review; the A grade is for the review as evidence about the evidence.

Naing et al., Cochrane Database Syst Rev 2026

In TESTS, prespecified subgroups pointed in opposite directions: possible harm under age 60 (HR 1.67) and possible benefit at 60 and over (HR 0.81) for 28-day mortality, with no overall effect.

Result: did not work

Phase 3 RCT subgroup analysis, hypothesis-generating.

Wu et al., BMJ 2025 (TESTS)

Risks and the label warnings

Adverse events

In thousands of treated subjects the dominant adverse event is mild, transient injection-site reaction (redness, swelling, pain), generally resolving within hours to days and occurring in under ~5% of patients in hepatitis studies (markedly lower than interferon). Combined with interferon, rarer systemic effects (fever, fatigue, myalgia, nausea, neutropenia) have been reported, but these track largely to the interferon partner.

Contraindications

Caution/avoid in autoimmune disease, organ-transplant or other immunosuppressed states (theoretical interference), and known hypersensitivity. Not established as safe in pregnancy, breastfeeding, or children outside specific clinical indications. Use with immunosuppressants or other immunomodulators should be physician-supervised. None of this is formal label guidance for US use because it is not FDA-approved here.

Theoretical concerns

As an immune modulator acting on Toll-like receptors (TLR2/TLR9) and driving T-cell and dendritic-cell activation, the theoretical concern is unwanted immune stimulation in people with autoimmune disease or those on immunosuppression (e.g., transplant recipients). Whether it could aggravate autoimmune conditions in otherwise-healthy biohackers is unstudied. It is described in the literature as immune-modulating rather than blindly immune-activating, which somewhat tempers this concern.

What nobody knows yet

Long-term (multi-year) safety in HEALTHY users taking it for general immune resilience is essentially uncharacterized, trial safety data come from limited-duration courses in sick patients. Gray-market product identity/purity is a major real-world unknown: US-sold 'research' vials are unregulated, and community reports describe wide sourcing-quality variance and storage failures. Optimal dose, frequency, and cycling for non-clinical use are unvalidated.

What else could explain the result

Biohackers rarely run it alone: it is commonly stacked with BPC-157, TB-500, thymosin beta-4, KPV, or LL-37, and frequently started at the same time as sleep, diet, sauna, vitamin D, or other immune-support changes, all of which muddy attribution of any 'fewer colds' effect. In the clinical literature, hepatitis and cancer benefits were often measured in COMBINATION with interferon or chemotherapy, so monotherapy magnitude is harder to isolate.

Is the vial what it says?

Cross-checked across a peer-reviewed comprehensive literature review (PMC7747025), the published TESTS phase-3 sepsis RCT (PubMed 39814420), ClinicalTrials.gov registrations (NCT04487444, NCT04428008), the September 2026 Cochrane review of hepatitis B trials (PMID 42713852), and regulatory summaries confirming international approval but US orphan-DESIGNATION-only status. Community-sentiment items are summarized as anecdote, not quoted.

Half-life and storage

Half-life: Short: peak blood level at roughly 1-2 hours with an elimination half-life of about 2-3 hours, and no meaningful accumulation between twice-weekly doses. The short half-life is why dosing is repeated rather than once-and-done; experimental Fc-fusion constructs (Tα1-Fc, ~25 h in mice) exist specifically to extend it but are not the marketed product.

Once mixed: Supplied as a lyophilized (freeze-dried) powder; reconstitute with bacteriostatic or sterile water and keep refrigerated after mixing. As a peptide it is sensitive to heat, light, repeated freeze-thaw, and agitation, gentle swirling rather than shaking. Community reports specifically cite storage failures (degraded/inactive vials) as a real-world problem, and unregulated 'research' supply makes correct cold-chain handling and verified content uncertain.

What I noticed, and what people report

Case study

Thymosin alpha-1: a block, not a habit PausedAn immune peptide with real human data, run as a defined block and then stopped cleanly.

What people report

Volume of reports: moderate. A real body of reports, fairly consistent.

Moderate-to-high for a peptide: it is a long-discussed compound with substantial forum activity (r/Peptides and similar), and at least one analysis claimed its threads out-engage even BPC-157/TB-500. Practitioner (longevity/functional-medicine clinic) discussion is also relatively heavy because of its drug pedigree.

Reasonably consistent in direction but modest in magnitude: users commonly report fewer or shorter infections, less seasonal illness, and a vague 'more resilient' feeling over 2-4 weeks. Reports are tempered by frequent acknowledgement that the effect is subtle, hard to self-measure, and easily confounded, and by complaints about sourcing/storage rather than about the molecule failing.

Mixed credibility: a meaningful share of online content is vendor- or affiliate-adjacent and was discounted. However, the underlying compound has genuine peer-reviewed and regulatory backing, so the anecdote sits on top of a real (if disease-focused) evidence base, unusual for this category. The healthy-user signal still remains anecdote, not proof.

Anecdote: many users report getting sick less often or recovering faster from colds/flu after a few weeks of use, while describing the effect as subtle and hard to quantify.
Anecdote: it is generally praised as one of the better-tolerated peptides, with stinging/redness at the injection site being the most common complaint and few systemic effects.
Anecdote: recurring frustration centers on sourcing and storage, users report wide quality variance between vendors and worry about degraded or under-dosed gray-market vials rather than about the peptide itself.
Anecdote: people with autoimmune tendencies are noticeably cautious in community discussion, with some reporting they avoid it or stop it out of concern about over-stimulating an already-active immune system.

Reports are anecdote, not proof.

Can you tell if it is working?

Partly trackable

No non-blood tracker exists, the only objective readout is immune bloodwork (ALC, CD4/CD8, NK), and even that moves only from a depleted baseline.

Bloodwork

Partly measurableConfidence: Plausible

A lab moves, but it's noisy, indirect, or off-target, treat it as a hint, not proof.

Thymosin-alpha-1 acts directly on immune cells (promotes thymic T-cell output, reverses T-cell exhaustion via lower PD-1/Tim-3), so its action CAN surface on routine labs as rising lymphocyte and CD4/CD8 counts. But this is documented only when there is a baseline deficit to correct (lymphopenia, low CD4), and only in critically ill cohorts (severe COVID, sepsis). In an immunocompetent person with normal counts there is usually nothing measurable to move, so blood cannot confirm the everyday immune-resilience claim.

Absolute lymphocyte count (ALC)CBC with differential

Only informative if baseline is lymphopenic: ALC climbs back toward/into the normal range. In a user who starts with a normal count, expect little to no change, and a flat result is NOT proof of effect or failure.

Ta1 drives thymic T-cell output and expansion, restoring circulating lymphocytes in deficit states (shown in severe COVID and sepsis cohorts, PMID 32442287 / 23327199).

CD4+ and CD8+ T-cell countsLymphocyte subset panel (CD4/CD8 by flow cytometry) - orderable at LabCorp/Quest, usually needs a clinical indication

Only in those who begin low: rise in CD4+/CD8+ toward normal (COVID data showed restoration specifically when CD4 <650/uL or CD8 <400/uL). Effect is inconsistent or absent in non-lymphopenic subjects, and at least one COVID cohort saw no CD4/CD8 benefit.

Ta1 promotes T-cell maturation and reverses exhaustion, increasing helper/cytotoxic T cells when they are depleted.

Draw baseline

Before first dose - and critically, capture a documented ALC and CD4/CD8 count so you know whether a deficit even exists to correct. Without a low baseline there is usually nothing to track.

Retest

4-6 weeks (T-cell reconstitution takes weeks); draw at the same time of day and not during an acute illness.

Read this before you spend on labs

This only functions as verification if your baseline shows an immune deficit (lymphopenia or low CD4). In an immunocompetent person with normal counts, Ta1 typically produces NO measurable bloodwork change, and no placebo-controlled trial has shown the everyday immune-resilience claim in healthy adults via objective labs - so a flat retest does not confirm or refute the marketed benefit. Both surviving markers were validated only in critically ill deficit populations (severe COVID, sepsis), not healthy users. Lymphocyte counts are noisy (acute infection, physiologic stress, cortisol, diurnal variation, recent vaccination), and they track immune-cell NUMBERS, not the clinical endpoints that matter (viral clearance, fewer infections, survival). Results are inconsistent across cohorts. Grade is partial, not direct.

Bottom line

Thymosin-alpha-1 is a T-cell/immune modulator, so its only objective efficacy signal is immunologic and blood-borne (absolute lymphocyte count, CD4/CD8 ratio, NK cells), already captured, at partial strength, by the blood finding. Critically, those counts rise toward normal only from a lymphopenic/immunocompromised baseline (severe COVID, sepsis, hepatitis, cancer); in an immunocompetent person with normal counts there is typically nothing to move, so even the blood readout can look flat while the peptide is pharmacologically active. No consumer or standard-lab non-blood modality applies: urine, stool (fecal calprotectin/microbiome), sleep/HRV wearables, CGM, VO2max, DEXA, genetic testing, and body-composition metrics have no validated link to Tα1 efficacy in humans. The biohacker use case (immune resilience, fewer colds) is subjective and unproven by controlled trials, with no objective proxy. Disease-specific outcomes that do track it, HBV DNA / HCV RNA viral load, ALT/AST, seroconversion, antibody titers, are themselves blood/serum tests, not a separate modality. Honest bottom line: outside of blood immune counts read against a depleted baseline, there is no objective way to verify this peptide is working.

Logging baseline vs retest is the whole game. The Truth Tracker is our free log for bloodwork, DEXA, genetics, and wearable data, bring your own numbers.

How to track it

History

First documented human use: Human use dates to the late 1970s/early 1980s: Thymosin Alpha-1 was isolated from thymosin fraction 5 by Goldstein and colleagues in 1972 and entered human immunodeficiency and hepatitis studies within the decade. Unlike most gray-market peptides, controlled human trials are abundant, dozens of clinical trials, and it has been a marketed prescription drug (thymalfasin/Zadaxin) since the 1990s.

Update: an FDA advisory panel voted against this one in December 2024

On December 4, 2024 the FDA's Pharmacy Compounding Advisory Committee voted 17 to 4 against adding thymosin alpha-1 to the 503A Bulks List, so compounding pharmacies have no listed route to make it. It is not FDA-approved and has no application in the FDA's drug database. The approvals this page mentions are outside the US. That is a different regulator and a different question, and it does not carry over to a US prescription.

Final summary minutes of the December 4, 2024 meeting, approved February 21, 2025. Rechecked November 2, 2026: no FDA approval found.. FDA, PCAC final summary minutes, December 4, 2024

1972Thymosin Alpha-1 isolated from thymosin fraction 5 by Goldstein and colleagues.
1977Amino-acid sequence of the 28-residue peptide characterized; synthetic production enables human study.
1990sSynthetic thymalfasin (Zadaxin) reaches market in multiple countries for chronic hepatitis B; SciClone develops it commercially.
2004FDA grants orphan-drug designation (e.g., hepatocellular carcinoma), a development incentive, not US marketing approval.
2013ETASS trial: single-blind RCT suggesting a mortality reduction in severe sepsis, encouraging but not definitive.
2020-2021COVID-19 trials launched (ClinicalTrials.gov); outcomes mixed, and one registered trial was terminated early for slow enrollment.
2025TESTS phase-3 sepsis RCT (BMJ, n=1,106) reports NO clear 28-day mortality benefit, the most rigorous data to date, and negative on its primary endpoint.
Sep 2025A sepsis meta-analysis of 11 RCTs is positive overall (28-day mortality) but not in its high-quality or multicenter subsets.
Sep 9 2026A Cochrane review of 10 hepatitis B RCTs rates the evidence very low to low certainty.

All sources

Thymosin alpha 1: A comprehensive review of the literature (PMC7747025)(Peer-reviewed overview: mechanism (TLR2/9), 35+ country approval, orphan-drug designation, safety, indications.)
TESTS phase-3 sepsis RCT. PubMed PMID 39814420(Multicentre, double-blind, placebo-controlled phase 3 (n=1,106, BMJ 2025); NO clear 28-day mortality benefit.)
Naing et al., Cochrane Database Syst Rev 2026, Thymosin-alpha-1 for chronic hepatitis B (PMID 42713852)(10 RCTs, 1,349 people; evidence rated very low to low certainty. The body of hepatitis B evidence behind the international approval.)
ClinicalTrials.gov NCT04487444, thymalfasin for COVID-19(Registered human trial of thymosin alpha 1 in COVID-19; terminated early for slow enrollment (56 enrolled, no results posted).)
ClinicalTrials.gov NCT04428008, thymosin alpha 1 to prevent COVID-19 in dialysis patients(Completed Phase 2 in dialysis patients (189 enrolled); registry results and a preliminary report (Tuthill et al., PMID 36881981).)
Gu et al., Front Cell Infect Microbiol 2025, thymosin alpha 1 in sepsis meta-analysis (PMID 40969554)(11 RCTs, 1,927 patients; 28-day mortality OR 0.73 overall, not significant in high-quality or multicenter subsets.)
RxList, Zadaxin drug monograph, Dosage and Supply sections. Not a US FDA label: Zadaxin is not FDA-approved.(dose table)
Chien RN, Liaw YF, Chen TC, Yeh CT, Sheen IS. Hepatology 1998;27(5):1383-7. PMID 9581695. doi:10.1002/hep.510270527(dose table)
Iino S, Toyota J, Kumada H, et al. J Viral Hepat 2005;12(3):300-6. PMID 15850471. doi:10.1111/j.1365-2893.2005.00633.x(dose table)
Gravenstein S, Duthie EH, Miller BA, et al. J Am Geriatr Soc 1989;37(1):1-8. PMID 2642497. doi:10.1111/j.1532-5415.1989.tb01561.x(dose table)
Tuthill CW, Awad A, Parrigon M, Ershler WB. Int Immunopharmacol 2023;117:109950. PMID 36881981. doi:10.1016/j.intimp.2023.109950(dose table)
Wu J, Zhou L, Liu J, et al. Crit Care 2013;17(1):R8. PMID 23327199. doi:10.1186/cc11932. Dose in the Methods, 'Study drug administration' (PMC4056079)(dose table)
BMJ 2025;388:e082583. PMID 39814420. Dose in the Methods, Procedures (PMC11780596). Registry NCT02867267(dose table)
ClinicalTrials.gov NCT04487444, arms and interventions section(dose table)
Huberman Lab, Jun 1 2026, chapter 'Thymus, Age Shrinkage; Thymosin Alpha-1, Immune Function' begins 1:29:38; the dose answer is between about 1:37:48 and 1:38:24(dose table)
Huberman Lab, chapter 'Peptides, PT-141 (Vyleesi), BPC-157, Thymosin Alpha-1; Risks, Cycling' begins 2:17:08; thymosin alpha-1 discussed about 2:19:15 to 2:20:15(dose table)

Not medical advice. Grades reflect the evidence as of the date above and will change as data arrives. Reports from users are anecdote, not proof. Talk to a licensed clinician before you act on anything here.