STUDresearch · Peptide

Thymosin Alpha-1

Also known as

Tα1 · Ta1 · TA1 · Thymalfasin · Zadaxin · Thymosin α1 · Thymosin alpha 1 · Thymosin-α1 · T alpha 1 · thymosin a1

Community talk. May be wrong. Not medical advice. Not a protocol. Not for human or animal use.

Peptide Lots of talk Systemic SubQ / IM Immune peptides

Systemic — circulating immune-modulating thymic peptide (T-cell / innate–adaptive host defense), not a local soft-tissue repair agent like TB-500 or BPC-157.

What people say Thymosin alpha-1, or thymalfasin, is a defined 28-amino-acid immune-modulating peptide. It is distinct from TB-500/TB4, Thymalin extract, Thymogen and thymulin. Doses people talk about

One sinusitis self-report50 mcg initially, then 1 mg per dose

Over roughly two weeks, followed by two more 1 mg doses in one week before stopping because of symptoms; route was not stated in the post.

Clinical-label anchor1.6 mg SubQ twice weekly

The most repeated chronic outpatient thymalfasin schedule, generally spaced about 3–4 days.

Single-dose human PK range0.8–6.4 mg SubQ once

Healthy-volunteer research exposures used to characterize concentration-time behavior, not a self-use ladder.

Clinical indication, pharmaceutical formulation and research-vial self-report must remain distinct; the rows are examples, not a progression.

Half-life & effect duration

Half-life in the body: Under-the-skin injectionAbout 2 hours; under 3 hours in the small study
Felt duration people report: Shorter experiencesDizziness 1–4 hours after use, or brief joint / hand sensations
Benefit claimsTwo clear-sinus days or months of allergy relief after courses
Other accountsNo similar adverse effects; one stopped and felt recovered a week later

Timing context & sources

How it may feel Often judged by illness patterns rather than a buzz. One poster stopped after dizziness, heartburn, dark mucus and feeling ill, then felt well a week later but could not tell benefit from reaction; other users reported no such effects, transient pain or clearer sinuses.

Cycles people discuss The preserved record spans twice-weekly months-long clinical courses, 4–12-week community blocks and short daily inpatient or illness pulses. These settings and goals are not one interchangeable cycle. Timing Time of day is described as flexible; twice-weekly use is commonly spaced about 3–4 days, and users judge illness patterns rather than a pre-workout or same-day buzz. Short daily illness pulses are a separate reported context. Stacks LL-37, KPV, Thymalin, BPC-157 and TB products appear beside TA1 in community talk; oncology and hepatitis combinations are separate clinical contexts. Multi-agent accounts cannot isolate TA1. Access talk 2026 shelves: Telehealth/compounded 1.6 mg charts still get sold; RUO 10 mg vials are the gray-market default. A withdrawn nomination is not a bulks-list approval. Labs people mention CBC / WBC: 2026 clinic-adjacent posts treat a low-ish WBC as why they even look at TA1 — not a scoreboard that proves the peptide worked. Watch for Autoimmune / complex immune caution: Immune-modulating peptide — poor fit for unsupervised use in active autoimmune disease, transplant immunosuppression, or complex immunotherapy without clinical oversight; some clinic pages start lower (e.g. ~1 mg 2×/week) and watch for flares.

Tap a line to jump into the full notes. Research only — may be wrong.

Timing context & sources

Half-life in the body

Serum elimination half-life was under 3 hours after SubQ TA1 in a small healthy-volunteer study.

Nine healthy volunteers received 900 µg/m² SubQ in a randomized crossover of three formulations; mean Tmax was 1–2 hours and no accumulation was seen across five daily doses.

Small study, formulation-dependent exposure and an upper-bound rather than exact half-life; it does not determine immune-effect or symptom duration.

Rost et al.: Pharmacokinetics of thymosin alpha1 after subcutaneous injection of three different formulations in healthy volunteers (opens in a new tab)Full PubMed abstract inspected: randomized three-way crossover in nine healthy volunteers after 900 µg/m² SubQ TA1, comparing Zadaxin, Timosina and a Hoffmann-La Roche formulation; mean Tmax 1–2 hours, elimination half-life under 3 hours and no accumulation after five daily doses.Small healthy-volunteer study; exposure differed by formulation, and the abstract gives an under-three-hour bound rather than each exact estimate. It does not measure felt or immune-effect duration.

Felt duration people report

Reports span transient sensations within hours, symptoms over weeks, no comparable adverse effects and claimed benefits lasting days to months; no single felt window is credible.

The main poster noted dizziness 1–4 hours after doses and stopped after several weeks, feeling recovered a week later but uncertain about cause. Other commenters reported brief joint/hand sensations, two clear-sinus days or months of allergy relief after short courses.

Multiple self-selected reporters, unverified products, different schedules, unclear routes and illnesses; symptom changes are not parent pharmacokinetics or evidence of efficacy.

Thymosin Alpha 1 Experiences (opens in a new tab)Complete visible archived thread inspected, including miki4you's initial two-week 50 mcg-to-1 mg account and same-author update after two more 1 mg doses, one week off and unresolved benefit-versus-reaction interpretation; also Ynkwmh's 500 mcg plus 1 mg same-day pain/numbness update, Puzzled-Towel9557's 1.6 mg weekly nurse-administered account, and contrary no-side-effect/allergy reports.Different reporters, products, conditions and schedules with incomplete route reporting; perceived sinus changes and symptoms cannot establish causality, prevalence or an efficacy duration.

What people say 12

Illness bounce-back (community): Users report fewer long “always sick” stretches, shorter colds, or better training continuity through cold season — heavily confounded by sleep, vitamin D, training load, and multi-peptide stacks. forum
Longevity / immunosenescence: Age-related immune decline and “immune optimization” clinic marketing — community volume is high; large healthy-aging outcome RCTs for research vials are not the evidence base. forum
vs Thymalin: Thymalin is a multi-peptide thymic extract (Russian tradition, often paired with Epitalon); Tα1 is a single defined 28-aa sequence with pharma monographs — not interchangeable products. forum
vs LL-37 / KPV: Forums often cast Tα1 as adaptive / T-cell side and LL-37 or KPV as antimicrobial or anti-inflammatory complements in “immune season” stacks. forum
Long-COVID / mast-cell adjacent anecdotes: Scattered forum claims (energy, PEM, inflammatory calm) exist; no controlled self-use proof and some users report poorer fit than anti-inflammatory peptides. anecdote
Chronic hepatitis B (historical trials): Classic regimen ~1.6 mg SC twice weekly; complete virological response rates around ~40% in some older cohorts at 6–12 months; treatment of HBV with Tα1 alone is now largely obsolete after direct-acting antivirals. trial
Oncology adjunct: Metastatic melanoma phase II randomization (Maio et al.) tested DTIC ± IFN-α ± Tα1 at 1.6 / 3.2 / 6.4 mg arms; durable responses and PFS trends discussed with little incremental Tα1-only toxicity vs partner drugs. trial
Chemo / IO loading talk: Clinic and trial writeups describe short daily loading (e.g. 1.6–3.2 mg QD for several days before chemo or before RT + PD-1) then twice-weekly maintenance — lymphocyte-count shifts reported in some series. trial
Critical illness / sepsis / COVID-era: Small RCTs and retrospectives used intensive daily or multi-day SC schedules; some Chinese series used high daily mg totals; mortality or immune-marker shifts are mixed and setting-dependent — not a wellness protocol. trial
Vaccine response: Research interest in older-adult vaccine enhancement (including registered COVID-vaccine adjuvant-style studies at standard 1.6 mg twice weekly). trial
vs TB-500 / Tβ4: Tα1 = immune / host-defense framing; TB-500 and full thymosin β4 = soft-tissue repair / actin / mobility framing — same “thymosin” word family, different jobs. forum
Tolerability reputation: As a single agent, generally lacks the high-dose IL-2 / interferon-style flu storm; injection-site reactions dominate safety summaries. trial

Doses people talk about 21

Community / clinic “immune support” default: 1.5–1.6 mg SC 2×/week is by far the most copied lifestyle-adjacent schedule; some round research vials to ~1.5 mg for syringe math. forum
Milder clinic band: 0.8–1.6 mg per injection twice weekly appears in some provider writeups as a start or maintenance band. forum
Higher twice-weekly talk: 1.6–3.2 mg 2–3×/week for “chronic conditions” or more aggressive immune-support marketing; some pages float up to ~5 mg per injection — less standardized than 1.6 mg BIW. forum
Acute short daily block (community/clinic): ~1.6 mg daily for ~7–14 days around acute infection narratives, then often back to BIW or stop. forum
Month-on seasonal pattern (clinic/community): Five injections per week for ~4 weeks (often described as weekday dosing), then ~3 months off, ~3 such cycles per year — one repeated “pulse” template outside pure 1.6 mg BIW. forum
Uncertainty: Gray-market fill accuracy and peptide identity vary — labeled mg is not guaranteed delivered active Tα1; third-party COA/mass talk is the usual quality checkpoint. forum
mg not mcg (unit fail): 2026 protocol pages keep shouting that 1.6 mg is 1,600 mcg — copying a BPC 250–500 mcg screenshot onto TA1 is a recurring underdose. forum
Conservative start camp: 0.8 mg SubQ twice weekly for 2–4 weeks, then 1.6 mg BIW, shows up as the “feel out autoimmune/irritation” chart. forum
3×/week camp: 1.6 mg three times weekly (or 1.6–3.2 mg 2–3×/week) is the louder “chronic immune” marketing band — less standardized than 1.6 mg BIW. forum
RUO 10 mg vial math: Gray-market 10 mg lyophilizates are the 2026 stock photo; people still aim the draw at ~1.6 mg per shot, not “use the whole 10 mg.” forum
Chronic / longer clinic framing: ~1.6 mg 2–3×/week for ~3–6 months appears in educational/clinic dosage videos and blogs for chronic infection or autoimmune-adjacent talk — not a validated DIY standard. forum
Weekly total at anchor: ~3.2 mg/week on classic BIW 1.6 mg. trial
Single-dose PK band: Healthy-volunteer SC studies used roughly 0.8–6.4 mg single doses; monograph multiple-dose talk extends to higher multi-day totals in research settings. trial
Oncology-style higher BIW: ~3.2 mg twice weekly (sometimes with chemo timing) is a recurring “oncology support” chart figure; melanoma trial arms also tested 1.6 mg and 6.4 mg with DTIC ± IFN. trial
Chemo peri-cycle example: Writeups describe ~1.6 mg daily for the 4 days immediately before cycle 1 of chemo, then shift to twice-weekly dosing through treatment — clinical-protocol style, not wellness charts. trial
Critical-illness intensive: Review literature cites multi-mg daily multi-day schedules — e.g. 1.6 mg twice daily for 5 days then daily; other sepsis/COVID series used 1.6 mg three times weekly, every other day, or daily for short courses; some Chinese critical-care reports used much higher daily totals (e.g. ~10 mg/day for ≥7 days) — hospital context only. trial
Melanoma trial dose ladder: Large randomized study arms included Tα1 1.6 mg, 3.2 mg, and 6.4 mg with DTIC ± interferon — useful as evidence of human multi-mg exposure, not a self-use ladder. trial
Framing: Discussed clinical and community research ranges only — not medical advice, not a prescription, not a consumption guide. forum
Standard clinical anchor (most repeated): 1.6 mg subcutaneously twice weekly (e.g. Monday/Thursday or Tuesday/Friday), spaced ~3–4 days — Zadaxin / thymalfasin chronic hepatitis B labeling and the default chart across forums and clinic pages. trial
Weight-based pediatric/small adult label math: Patients under ~40 kg: ~40 µg/kg instead of fixed 1.6 mg (also expressed as ~900 µg/m² in some monographs). trial
IO / RT loading example: Retrospective series used 1.6 or 3.2 mg once daily for 7 consecutive days before hypofractionated RT + PD-1; lymphocyte subset increases reported after the load. trial

How it may feel 11

First hours to several weeks: In one thread, the poster reported dizziness 1–4 hours after dosing, odd joint sensations, heartburn and dark mucus during two weeks of 50 mcg-to-1 mg use; after two more 1 mg doses the person stopped, felt recovered a week later and had no sinus symptoms but explicitly remained unsure whether TA1 helped or caused a bad/contaminated-product reaction. Other commenters reported no such effects, brief pain/numbness, clear sinuses or months-long allergy relief. forum
Weeks 1–2: Still subjectively quiet for many — people watch illness frequency, recovery from minor bugs, or training continuity rather than a daily mood/energy lift. forum
Weeks 3–4: Common first continue/stop checkpoint on a classic 1.6 mg twice-weekly block; some claim fewer colds or faster bounce-back, others notice nothing. forum
Weeks 4–8: Wellness / seasonal immune blocks often reassess here; clinic writeups may keep going if labs or clinical goals justify. forum
Pulsed annual patterns: Month-on / multi-month-off (including “1 month on, 3 months off, ~3×/year” clinic-style talk) — subjective residual benefit claims are mixed. forum
No daily buzz expectation: Unlike stimulants or GH secretagogues, Tα1 is usually judged by season illness, labs (lymphocyte subsets when monitored), or infection recovery — not a same-day “feel.” forum
Quiet vs “kitchen sink” (2026): Longevity-stack posts still add TA1 because it is trendy; pushback is “if you already run MOTS-c + SS-31 + NAD+ + BPC, what gap is this filling?” — no daily energy story to settle that. forum
Illness-season scoreboard: 2025–26 Reddit writeups still time “fewer colds / faster bounce-back” to ~3–6 weeks at 1.6 mg twice weekly — subjective, no home biomarker. forum
Autoimmune / flare watch: Users with complex immune history sometimes report feeling worse, not “boosted.” Community stop-rule is flare or new systemic illness, not a dose jump. anecdote
Months 2–6: Older HBV and many oncology-adjunct courses ran twice-weekly for ~6–12 months — endpoints were viral or cancer metrics, not “felt optimized.” trial
Intensive daily blocks: Critical-illness or short daily-load schedules are judged over days–weeks in hospital/clinic contexts, not lifestyle feel curves. trial

Around the dose 6

Clock: Any time of day. Copied pattern is Mon/Thu or Tue/Fri so shots sit ~3–4 days apart — not a pre-workout peptide. forum
Training: Illness-season / “don’t get sick in a training block” is the job. People do not pin TA1 to hit a PR. forum
After: They watch colds, bounce-back, and (if they draw labs) a CBC — not a same-day buzz. forum
Load then BIW: Short daily 1.6 mg around a bug, then back to twice-weekly, is the 2025–26 clinic-blog pattern. forum
Don’t copy BPC units: Milligrams. A 10 mg RUO vial is several 1.6 mg shots, not one mega-dose. forum
Stack discipline: Adding LL-37 + Thymalin + TA1 the same month is the “too many immune peptides” warning, not a named blend. forum

Cycles people discuss 10

Short immune / seasonal blocks: ~4–8 weeks twice-weekly is a very common community and wellness-clinic pattern. forum
Medium clinic blocks: ~8–12 weeks then reassess appears repeatedly in peptide-protocol pages. forum
8 on / 4 off style: Some stack guides describe ~8–12 weeks on with multi-week breaks for non-chronic goals. forum
Pulsed annual: Month-scale on, multi-month off (including 1 month on / 3 months off × ~3/year) — framed as immune “top-ups,” not continuous lifelong use. forum
Acute daily pulse then stop/BIW: 1–2 weeks daily around illness, then off or back to twice-weekly. forum
Re-runs: Before travel, contest prep stress, cold season, or after illness clusters — long-term continuous healthy-adult safety data for research vials is limited. forum
Not default lifelong daily: Even high-talk users usually treat Tα1 as blocks or BIW courses rather than indefinite daily injectable. forum
Long clinical courses (infection labeling): 6–12 months of twice-weekly SC dosing in older chronic hepatitis B monographs and clinic writeups. trial
Oncology duration: Often months (~6 months or through chemo / multi-cycle regimens); melanoma combo trials observed responses over ~12-month primary windows with longer follow-up. trial
Critical-illness courses: Days to ~1–2 weeks of daily or multi-daily dosing in inpatient literature — not a lifestyle cycle. trial

Timing 8

Why twice-weekly still dominates: Community and clinical practice treat immune-modulating effects as longer than plasma residence — BIW is the validated outpatient schedule, not continuous infusion or daily forever for chronic use. forum
Daily vs BIW debate: Reddit/clinic threads note that plasma is gone in a day, yet most labeling and trials still use BIW for chronic indications; daily is reserved for short intensive or loading contexts. forum
Timing of day: Morning vs evening is flexible; consistency and schedule adherence matter more than clock hour — no strong “training-time” requirement. forum
With other peptides: Short plasma half-life is why stacks keep Tα1 on its own BIW calendar while BPC may be daily and TB-500 multi-mg less-than-daily. forum
Monitoring talk: Some advanced users track illness logs or occasional lymphocyte subsets / CBC rather than “felt peak” timing. forum
Serum half-life: Approximately ~2 hours after subcutaneous thymalfasin (Zadaxin-style) in humans; sometimes summarized as <3 hours. trial
Peak (Tmax): Roughly ~1–2 hours post-SC dose. trial
Return toward baseline: Blood levels largely back toward baseline within ~24 hours; no meaningful accumulation shown with repeated twice-weekly SC dosing in PK writeups. trial

Stacks 12

Tα1 + KPV: Clinic blogs market the pair for immunity + NF-κB / gut-inflammatory calm; usually separate vials/schedules, not a fixed ratio blend. forum
Thymic pairing (Tα1 + Thymalin): Discussed for “full thymic” coverage — different molecules; combination is theoretically overlapping and largely unstudied head-to-head. forum
Repair adjacency (don’t get sick while healing): Tα1 next to BPC-157 and/or TB-500 during injury blocks — immune continuity while repair peptides run. forum
Wolverine-adjacent but not Wolverine: Wolverine = BPC + TB; GLOW = +GHK-Cu; KLOW = +KPV — Tα1 is sometimes added as a fourth immune agent, not a standard named blend component. forum
Longevity / mito stacks: Anecdotal pairings with Epitalon, GHK-Cu, SS-31, MOTS-c, sermorelin in multi-peptide longevity posts. forum
Micronutrient co-talk: Vitamin D, zinc, sleep, and training deload when people judge “fewer colds” outcomes. forum
Stack caution: Multiple immune peptides increase attribution noise and theoretical overstimulation risk talk, especially with autoimmune history. forum
Longevity kitchen sink (2026): TA1 dropped next to MOTS-c, SS-31, NAD+, and BPC in screenshot stacks — the honest counter is “name the gap.” forum
Epitalon / thymic season: Still paired with Epitalon or Thymalin as a “thymic year” pulse, not a daily GH-style pin. forum
Immune season stack: Tα1 + LL-37 appears often for infection-season / host-defense narratives (adaptive + antimicrobial framing). forum
Oncology clinical combos: Historical and ongoing trial pairings with interferon, dacarbazine, other chemo, and more recently PD-1 / radiotherapy contexts — clinical only. trial
HBV historical combos: Thymalfasin + interferon (and later nucleoside analogs in research) — superseded by modern antiviral standards for HBV care. trial

Access talk 5

2026 shelves: Telehealth/compounded 1.6 mg charts still get sold; RUO 10 mg vials are the gray-market default. A withdrawn nomination is not a bulks-list approval. forum
Zadaxin ≠ research vial: Pharma thymalfasin 1.6 mg single-use is not the same product as a multi-mg RUO lyophilizate. forum
Not on the July 2026 PCAC seven. TA1 was not in that BPC/TB/KPV/MOTS-c/Semax/Epitalon batch. trial
Dec 4, 2024 PCAC: FDA proposed TA1 free base and acetate not go on the 503A bulks list. On the inclusion vote for acetate the count was 4 yes / 17 no. Nomination had already been withdrawn. trial
503B: 2025 nominated-substances tables put thymosin alpha-1 in Category 3 — not the interim-discretion Category 1 bucket. trial

Labs people mention 4

CBC / WBC: 2026 clinic-adjacent posts treat a low-ish WBC as why they even look at TA1 — not a scoreboard that proves the peptide worked. forum
CD4/CD8: Protocol sheets list lymphocyte subsets on longer immune blocks. forum
CRP: Named as a generic inflammation extra, not a TA1-specific marker. forum
No home “immune score”: Fewer colds is still how most logs judge it. forum

Storage notes 2

No mix instructions here: STUDresearch does not list reconstitution, diluent volumes, or syringe unit charts. People reconstitute many different ways and vial labels differ — that content creates more confusion than clarity. forum
Storage (general talk only): Unopened research products are usually kept cool, dry, and away from light per the seller label. Anything after first use is product-specific — follow the label, not a universal forum SOP. forum

Related 8

Watch for 14

Mild systemic: Transient fatigue, headache, low-grade malaise, or light flu-like notes in early weeks for a minority of users. forum
Autoimmune / complex immune caution: Immune-modulating peptide — poor fit for unsupervised use in active autoimmune disease, transplant immunosuppression, or complex immunotherapy without clinical oversight; some clinic pages start lower (e.g. ~1 mg 2×/week) and watch for flares. forum
Overstimulation narrative: Stacking multiple immune peptides (Tα1 + LL-37 + Thymalin etc.) raises community concern about too much concurrent immune push — evidence is soft but caution is common. forum
Source / quality risk: Research-chemical contamination, mislabel, underfill, or degraded peptide is a separate hazard from thymalfasin pharma controls. forum
Not zero risk: Favorable single-agent safety summaries across thousands of trial subjects do not equal a free pass for gray-market continuous self-experimentation. forum
When to stop talk: Progressive rash, significant systemic illness, or autoimmune flare symptoms → community consensus is stop and seek care rather than dose-escalate. forum
Unit mix-up harm: Treating 1.6 mg like a 1.6 mcg peptide chart is the practical underdose; treating a 10 mg RUO vial as one shot is the practical overdose scare. forum
Shipping / heat kill: 2026 user-experience roundups still blame dead peptide (warm shipping, fridge fail) before “TA1 does nothing.” forum
Injection site (most consistent): Redness, mild pain, swelling, or local discomfort — usually short-lived; rotate sites. trial
Rare labeled-style events: Older safety summaries note uncommon systemic reactions (e.g. transient muscle atrophy reports, polyarthralgia with hand edema, rash) in small minorities — still treat as real risk flags. trial
Combo confounders: With interferon or chemo — fever, myalgia, nausea, vomiting, neutropenia, and cytopenias are often driven by partner drugs, not Tα1 alone. trial
Regulatory: Indication approval and legal access vary by country; not a global “any immune goal” approved drug; U.S. general wellness use is not an FDA-labeled pathway. trial
Pregnancy / pediatric: Not a casual research-peptide topic — labeled weight-based pediatric math exists in monographs for medical contexts only. trial
PCAC is not a green light: December 2024 committee votes against 503A bulks-list inclusion are not “FDA approved immune peptide.” trial

Updated: 2026-09-01

Evidence mix Mostly community / anecdote tags Full: every bullet (trial + community). Use Scan for a faster bro-science read.

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Half-life & effect duration

Timing context & sources⌄

Half-life in the body

Felt duration people report

What people say 12

Doses people talk about 21

How it may feel 11

Around the dose 6

Cycles people discuss 10

Timing 8

More on what it is 7

Stacks 12

Access talk 5

Labs people mention 4

Storage notes 2

Related 8

Watch for 14

Timing context & sources