
Thymosin Alpha-1 (Injectable)
Immune-modulating peptide for chronic infections and immune support.
The pepti Pen cartridge for this treatment is sold out right now. The vial is the same medication at our best price.
All-in monthly price
No membership fee · this is the full price · free shipping · avg 4-week supply
Add in-depth bloodwork
Optional — add a physician-reviewed at-home blood panel to your plan.
Your sex-hormone baseline plus the safety markers that matter on therapy — blood counts, liver and kidney function — from one painless upper-arm device. Matched to your sex (PSA for men; progesterone & FSH for women). No needle, no clinic, physician-reviewed.
This treatment requires licensed provider review and approval. Treatment is not guaranteed. If prescribed, medication is fulfilled by a licensed U.S. pharmacy where permitted by law. Compounded medications are not FDA-approved or FDA-cleared.

Reviewed by Dr. Gene, MD · Board-certified Family Medicine
Every Pepti prescription is reviewed by a licensed U.S. physician before it's dispensed — and only provided if clinically appropriate.
Thymosin Alpha-1 (Injectable)
Thymosin Alpha-1 is a naturally occurring peptide that plays a critical role in immune system regulation. It enhances the function of T-cells, dendritic cells, and natural killer cells. FDA-approved in over 35 countries for hepatitis B and C, and widely used off-label for immune support in chronic infections, autoimmune conditions, and as an adjunct to cancer immunotherapy.
About a 4-week supply supply at the standard prescribed dose — your physician confirms exact dosing.
A licensed US physician reviews your intake and prescribes when appropriate.
Compounded fresh at a US pharmacy and shipped cold-chain to your door.
Every order ships free — medication, physician care and refills, one all-in price.
Amounts shown are per unit. Compounded fresh at a US FDA-registered pharmacy.
Every batch independently tested
Every medication batch dispensed through Pepti is independently tested by a qualified third-party laboratory for applicable quality and safety standards before the pharmacy releases it. Batches are tested to the same standard used by 503B outsourcing facilities.
Confirms the finished preparation is free of viable microorganisms.
Screens for endotoxins that can cause fever or inflammatory reactions.
Verifies the labeled concentration of the active peptide is what is in the vial.
Checks the active peptide against impurities and degradation products.
Confirms the peptide in the vial is the correct molecule.
Confirms the solution sits within the range specified for injection.
Checks the finished vial for visible and sub-visible particles.
Confirms the vial seal holds so sterility is maintained through the beyond-use date.
- Lot 100526-THY-10
Tested 2026-10-07 · Biolink Life Sciences Carolinas
Sterility
Sterile
Endotoxin
<2 EU/mL
Potency
99.7%
- Lot 100526-THY-2
Tested 2026-10-07 · Biolink Life Sciences Carolinas
Sterility
Sterile
Endotoxin
<2 EU/mL
Potency
100.1%
- Lot 092826-THY-10
Tested 2026-09-30 · Biolink Life Sciences Carolinas
Sterility
Sterile
Endotoxin
<2 EU/mL
Potency
99.1%
How Thymosin Alpha-1 is prescribed.
- Adults whose physician is supporting immune function
- Patients with recurring infections or chronic immune stress
- People who want an immune peptide with a long clinical history
Your physician decides whether Thymosin Alpha-1 is appropriate for you after reviewing your intake and labs.
Inject 0.25 mL (25 units) subcutaneously once daily Monday through Friday.
- Licensed physician review of your intake, history, and labs
- Medication compounded to your prescription by a PCAB-accredited, FDA-registered pharmacy
- Every batch independently tested before release
- Sterile syringes and alcohol prep pads for injectables
- Tracked delivery to your door, refills on schedule
- Message your physician anytime; dose changes without an appointment
- Store refrigerated (36–46°F / 2–8°C) at all times, including before first use.
- One vial is your monthly supply. A fresh vial ships every 28 days on your refill schedule, so you're always well inside the beyond-use date on your label.
- Protect from light. Wipe the stopper with an alcohol pad before every draw.
- Dispose of syringes in the sharps container per the included instructions.
A typical course of Thymosin Alpha-1.
Everything published
about Thymosin Alpha-1.
How it is described to work, pathway by pathway. What the research shows and what it does not. Where it stands with the FDA, dated and sourced.
Read the referencepeer-reviewed, each verified on PubMed
mechanism, evidence, dosing, safety, FAQ
2026 · checked against fda.gov, not memory
How Thymosin Alpha-1 works, and what the research shows.
Thymosin Alpha-1 is a 28-amino-acid peptide produced by the thymus gland.
It enhances T-cell maturation, dendritic cell function, and NK cell activity.
Used in 35+ countries for immune modulation.
Thymosin Alpha-1 has substantial human use: as thymalfasin (Zadaxin) it is approved in over 30 countries for chronic hepatitis B and C and as an immune adjuvant, and randomized trials have studied it in severe infections and sepsis with signals of benefit in immune-compromised patients.
It is not FDA-approved in the US, where it is available through compounding pathways under physician direction.
References
- Dominari A, Hathaway Iii D, Pandav K et al.. Thymosin alpha 1: A comprehensive review of the literature · World J Virol (2020) · PMID 33362999
- Pierluigi B, D'Angelo C, Fallarino F et al.. Thymosin alpha1: the regulator of regulators? · Ann N Y Acad Sci (2010) · PMID 20536444
- Wu J et al.. The efficacy and safety of thymosin α1 for sepsis (TESTS): multicentre, double blinded, randomised, placebo controlled, phase 3 trial · BMJ (2025) · PMID 39814420
- Wu J et al.. The efficacy of thymosin alpha 1 for severe sepsis (ETASS): a multicenter, single-blind, randomized and controlled trial · Crit Care (2013) · PMID 23327199
- Naing C et al.. Thymosin-ɑ1 for people with chronic hepatitis B · Cochrane Database Syst Rev (2026) · PMID 42713852
- Chien RN et al.. Efficacy of thymosin alpha1 in patients with chronic hepatitis B: a randomized, controlled trial · Hepatology (1998) · PMID 9581695
- Yang YF et al.. Comparison of the efficacy of thymosin alpha-1 and interferon alpha in the treatment of chronic hepatitis B: a meta-analysis · Antiviral Res (2008) · PMID 18078676
- Ciancio A et al.. Thymosin alpha-1 with peginterferon alfa-2a/ribavirin for chronic hepatitis C not responsive to IFN/ribavirin: an adjuvant role? · J Viral Hepat (2012) · PMID 22233415
- Maio M et al.. Large randomized study of thymosin alpha 1, interferon alfa, or both in combination with dacarbazine in patients with metastatic melanoma · J Clin Oncol (2010) · PMID 20194853
- Liu Y et al.. Thymosin Alpha 1 Reduces the Mortality of Severe Coronavirus Disease 2019 by Restoration of Lymphocytopenia and Reversion of Exhausted T Cells · Clin Infect Dis (2020) · PMID 32442287
- Camerini R, Garaci E. Historical review of thymosin α 1 in infectious diseases · Expert Opin Biol Ther (2015) · PMID 26098768
- Gravenstein S, Duthie EH, Miller BA, Roecker E, Drinka P, Prathipati K, Ershler WB. Augmentation of influenza antibody response in elderly men by thymosin alpha one. A double-blind placebo-controlled clinical study · J Am Geriatr Soc (1989) · PMID 2642497
- Carraro G, Naso A, Montomoli E, Gasparini R, Camerini R, Panatto D, et al.. Thymosin-alpha 1 (Zadaxin) enhances the immunogenicity of an adjuvated pandemic H1N1v influenza vaccine (Focetria) in hemodialyzed patients: a pilot study · Vaccine (2012) · PMID 22178096
- Niu W, Li Z, Li Z et al.. A Prospective and Randomized Control Study on Effects of Thymalfasin for Injection on Perioperative Immune Function and Long-term Prognosis of Patients with Colorectal Cancer · Biotechnol Genet Eng Rev (2024) · PMID 37248723
Citations are provided for educational purposes. They do not constitute medical advice. Always discuss any peptide protocol with your prescribing physician.
Important safety information
+
Possible side effects
Do not use if you have
If you experience severe side effects, call 911 or go to your nearest emergency room.
5 mL multi-dose vial, Thymosin A-1 2 mg/mL (10 mg Thymosin A-1 per vial); as the Pen: 3 mL pre-filled Pen cartridge containing 15 mg Thymosin alpha-1
Frequently asked
about Thymosin Alpha-1 (Injectable).
Thymosin Alpha-1 is a naturally occurring peptide that plays a critical role in immune system regulation. It enhances the function of T-cells, dendritic cells, and natural killer cells. FDA-approved in over 35 countries for hepatitis B and C, and widely used off-label for immune support in chronic infections, autoimmune conditions, and as an adjunct to cancer immunotherapy. Thymosin Alpha-1 is prescription-only at Pepti: a licensed physician reviews your assessment and, if appropriate, prescribes it to be compounded by a state-licensed, FDA-registered pharmacy.
Thymosin Alpha-1 is $249 per month at Pepti as a vial, or $339 as a pre-filled pepti Pen. That is all-in: medication, physician review and ongoing care, shipping, and messaging. No membership, consult, or visit fees, and the price is the same in every state.
Thymosin Alpha-1 is commonly prescribed for: Adults whose physician is supporting immune function; Patients with recurring infections or chronic immune stress; People who want an immune peptide with a long clinical history. Whether it is appropriate for you is decided by the reviewing physician from your history, medications, and labs where required.
Yes. Thymosin Alpha-1 is prescription-only. The free online assessment takes about five minutes, a physician licensed in your state reviews it within 4 hours, and if approved the prescription goes to the pharmacy. If not approved, the medication charge is refunded.
No. Thymosin Alpha-1 can be prescribed from the assessment alone. Bloodwork is required only for the GLP-1s and growth-hormone secretagogues, and the intake tells you if a medication on your order needs it.
Thymosin Alpha-1 is a subcutaneous injection into the abdomen or thigh with a small insulin syringe. Your kit ships with sterile syringes and alcohol prep pads, and the exact dose and schedule are printed on the pharmacy label. Dosing videos are in your account. It is also available as a pre-filled pepti Pen for $339.
33 more questions about Pepti, answered.Show fewer
One vial is your monthly supply at the dose your physician prescribes. A fresh vial ships about every 28 days, and the date moves if your physician changes your dose. Store it as the pharmacy label directs, refrigerated.
Once per fill, $249 each time, when the next vial ships. It renews until you cancel, which you can do anytime from your account with no cancellation fee.
The compounded Thymosin Alpha-1 with sterile syringes and alcohol prep pads, free tracked shipping in an unbranded box with insulated packaging, the physician review, ongoing physician care and dose adjustments, and unlimited messaging.
Reported side effects of Thymosin Alpha-1 are usually mild: mild injection site reactions. The physician screens your history, medications, and allergies before prescribing, the medication-specific consent lists the known risks, and you can message your physician about anything you notice. Seek emergency care for severe symptoms.
Response varies by person, goal, and dose, and Thymosin Alpha-1 is prescribed for ongoing use rather than a short trial. Your physician sets expectations at approval, tracks how you respond through your account, and adjusts the dose without an appointment.
Yes. Request it from your account or the app; your physician approves or declines. If approved you pay for the additional medication at the pharmacy's cost and the new dose applies to your next shipment.
Yes. Add Thymosin Alpha-1 to a plan with another treatment and both go through one assessment and one physician review, shipping together on one schedule. Each keeps its own catalog price. The physician reviews the combination and can adjust it.
No. Compounded Thymosin Alpha-1 is not FDA-approved. It is prepared to your physician's prescription by a state-licensed, FDA-registered 503A pharmacy and every batch is independently tested before release.
Yes, when prescribed by a licensed physician and dispensed by a licensed pharmacy, which is how Pepti provides it in every state it serves. Research-use-only Thymosin Alpha-1 sold without a prescription is labeled not for human use and is a different product.
Thymosin Alpha-1 is a 28-amino-acid peptide produced by the thymus gland. At Pepti it is prescribed to support boosts immune function, supports t-cell activity, used for chronic infections, anti-inflammatory, enhances vaccine response. Individual response varies, and your physician sets expectations at approval.
Thymosin Alpha-1 is a 28-amino-acid peptide produced by the thymus gland. It enhances T-cell maturation, dendritic cell function, and NK cell activity. Used in 35+ countries for immune modulation. Compounded Thymosin Alpha-1 is not FDA-approved; it is prescribed off-label by a licensed physician after reviewing your assessment.
Thymosin Alpha-1 is prescribed for boosts immune function, supports t-cell activity, used for chronic infections, anti-inflammatory, enhances vaccine response. It is commonly requested by adults whose physician is supporting immune function; patients with recurring infections or chronic immune stress; people who want an immune peptide with a long clinical history. Whether it is appropriate for you is the reviewing physician's decision.
Thymosin Alpha-1 is studied for boosts immune function, supports t-cell activity, used for chronic infections, anti-inflammatory, enhances vaccine response. Those are the goals it is prescribed to support at Pepti; results vary by person, dose, and consistency, and no outcome is guaranteed. Your physician tracks how you respond through your account.
Thymosin Alpha-1 has substantial human use: as thymalfasin (Zadaxin) it is approved in over 30 countries for chronic hepatitis B and C and as an immune adjuvant, and randomized trials have studied it in severe infections and sepsis with signals of benefit in immune-compromised patients. It is not FDA-approved in the US, where it is available through compounding pathways under physician direction. References are listed on this page.
Thymosin Alpha-1 is generally not prescribed with: active cancer or history of cancer (unless approved by oncologist); pregnancy or breastfeeding; severe kidney or liver disease; known allergy to the peptide or excipients; active autoimmune disease (use with physician guidance). The physician screens for these in your intake, and anything that rules Thymosin Alpha-1 out means it is not prescribed and is refunded.
At Pepti. Complete the free assessment, a physician licensed in your state reviews it within 4 hours, and if appropriate Thymosin Alpha-1 is compounded by a state-licensed, FDA-registered pharmacy and shipped free to your door for $249 per month, all-in. Not prescribed means refunded.
Injectable vial: 5 mL at 2 mg/mL, containing 10 mg Thymosin α-1. Pepti Pen cartridge: 3 mL cartridge (300 units) at 5 mg/mL, containing 15 mg Thymosin α-1. One vial is your monthly supply at the prescribed dose, and a fresh one ships about every 28 days.
Yes. Thymosin Alpha-1 is available as a pre-filled pepti Pen cartridge for $339 per month, versus $249 as a vial. Same medication, same pharmacy; the reusable injector is free with your first pen order. Choose the format in the cart or ask your physician.
$249 per month covers the compounded Thymosin Alpha-1, the physician review, ongoing physician care including dose adjustments and refill review, unlimited messaging, and free tracked shipping. There is no membership, consult, visit, or refill fee; the only separate charges are optional at-home lab panels and a physician-approved dose increase billed at pharmacy cost.
Yes. Thymosin Alpha-1 is on Pepti's live catalog, which lists only treatments a partner pharmacy can compound and ship today. If a physician prescribes it, it ships; if it ever cannot be dispensed, the charge is refunded.
Thymosin Alpha-1 ships to 50 states, free and tracked, in insulated unbranded packaging. Eligibility is confirmed during the assessment from your shipping address.
$249 per month at Pepti as a vial, or $339 as a pepti Pen. That includes the compounded Thymosin Alpha-1, the physician review and ongoing care, free tracked shipping, and messaging, with no membership, consult, or visit fee. The price is the same in every state and every refill is the same price.
Yes. Pepti offers Thymosin Alpha-1 as a pre-filled pepti Pen cartridge for $339 per month, or as a vial for $249. The reusable injector is included free with your first pen order and tips come with every cartridge. Same medication, same pharmacy, physician-prescribed after a free online assessment.
Yes. Pepti prescribes Thymosin Alpha-1 online in 50 states after a free assessment reviewed by a physician licensed in your state. It is compounded by an FDA-registered pharmacy and shipped free, $249 per month all-in. Not prescribed means refunded.
Yes. At Pepti the entire process is telehealth: a five-minute online assessment, physician review within 4 hours, then Thymosin Alpha-1 ships from the pharmacy. No clinic visit and no video appointment in most cases. $249 per month, all-in.
Yes, for the real thing. Thymosin Alpha-1 sold without a prescription is research-use-only product labeled not for human use, with no physician, no pharmacy, and no verified testing. Pepti's Thymosin Alpha-1 is physician-prescribed, pharmacy-compounded, batch-tested, and $249 per month including the physician and shipping.
Pepti does, in 50 states, with named board-certified physicians, a state-licensed FDA-registered compounding pharmacy, independent batch testing, and one published all-in price of $249 per month with no membership or consult fee. Refunded if the physician does not prescribe.
It is legal to be prescribed Thymosin Alpha-1 online by a licensed physician and have it dispensed by a licensed pharmacy, which is how Pepti provides it. Buying it as a research chemical without a prescription is a different product and is not for human use. Compounded Thymosin Alpha-1 is not FDA-approved.
$249 per month at Pepti, or $339 as a pepti Pen, including the medication, the physician, and shipping. Refills are the same price and there is no membership fee.
Yes. Pepti has no clinics: the assessment, physician review, messaging, dose changes, and refills all happen online, and Thymosin Alpha-1 ships free from the pharmacy to your door in 50 states.
Start the free assessment at hellopepti.com, choose Thymosin Alpha-1, and answer the health questions. A physician licensed in your state reviews it within 4 hours. If approved, Thymosin Alpha-1 ships within 1-3 business days and arrives in 1-3 more; if not, the $249 is refunded.
No. Thymosin Alpha-1 can be prescribed from the assessment alone at Pepti. Bloodwork is required only for GLP-1s and growth-hormone secretagogues.
Pepti ships Thymosin Alpha-1 to 50 states, free and tracked, refrigerated in insulated packaging, directly from the pharmacy. Delivery is 1-3 business days after the pharmacy compounds it.
Questions people ask
about Thymosin Alpha-1 (Injectable).
- Thymosin Alpha-1: What It Is, Where to Get It Prescribed, and What It CostsThymosin Alpha-1 — 5 mL multi-dose vial, Thymosin A-1 2 mg/mL (10 mg Thymosin A-1 per vial). Specification, mechanism, dosing, formats, state availability and how to get it prescribed.
- Peptides for Immune Support: Thymosin Alpha-1, FORTIFY and the EvidenceWhat thymic peptides actually do to immune signalling, which ones have real clinical evidence behind them, what they cost, and who should not take an immune modulator.
- How Much Do Peptides Cost? Real Monthly Prices and What Drives ThemWhat prescription peptides actually cost per month, why single molecules price differently from four-peptide blends, which costs providers hide behind a low headline, and how to compare.
- Do You Need a Doctor to Get Peptides? Yes, and Here Is Exactly WhyPeptides used clinically are prescription medications. Why a prescriber is legally required, what your own doctor will likely say, and what a real review looks like online.
- How to Inject Peptides Safely: Step by Step, Units, Sites and MistakesA practical subcutaneous injection walkthrough: reading your sig, converting millilitres to insulin-syringe units, the ten steps, site rotation, what to do about bubbles and missed doses.
Read more about Thymosin Alpha-1 (Injectable).
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