Reviewed by the PeptideMind Team · Updated July 15, 2026

Thymosin Alpha 1 Dosage Guide, Benefits & Side Effects

Thymosin Alpha 1 is approved abroad (not FDA) for chronic hepatitis B and studied for restoring T-cell counts, vaccine response, and sepsis survival.

Chemical Makeup

Amino Acids

Thymosin Alpha 1

Ser

Position 1

Asp

Position 2

Ala

Position 3

Ala

Position 4

Val

Position 5

Asp

Position 6

Thr

Position 7

Ser

Position 8

Ser

Position 9

Glu

Position 10

Ile

Position 11

Thr

Position 12

Thr

Position 13

Lys

Position 14

Asp

Position 15

Leu

Position 16

Lys

Position 17

Glu

Position 18

Lys

Position 19

Lys

Position 20

Glu

Position 21

Val

Position 22

Val

Position 23

Glu

Position 24

Glu

Position 25

Ala

Position 26

Glu

Position 27

Asn

Position 28

Amino acid sequence

SerinePosition 1

Aspartic acidPosition 2

AlaninePosition 3

AlaninePosition 4

ValinePosition 5

Aspartic acidPosition 6

ThreoninePosition 7

SerinePosition 8

SerinePosition 9

Glutamic acidPosition 10

IsoleucinePosition 11

ThreoninePosition 12

ThreoninePosition 13

LysinePosition 14

Aspartic acidPosition 15

LeucinePosition 16

LysinePosition 17

Glutamic acidPosition 18

LysinePosition 19

LysinePosition 20

Glutamic acidPosition 21

ValinePosition 22

ValinePosition 23

Glutamic acidPosition 24

Glutamic acidPosition 25

AlaninePosition 26

Glutamic acidPosition 27

AsparaginePosition 28

As seen on

Thymosin Alpha 1 Dosage Guide for Immune & GutBPC-157 Dosage Calculator

Thymosin Alpha 1 is often called the 'BPC-157 of the immune system' because it's so widely used to support healthy immune function.

Vial size

10 mg

Bacteriostatic water

2 mL

Dosing

1.5 mg

Frequency

Weekly (2×)

Cycle

6–12 weeks

Benefit

Immune & Gut

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What is Thymosin Alpha 1?

Thymosin Alpha-1 is a naturally occurring peptide from the thymus gland that helps restore and balance immune function. It works by activating immune cells (like dendritic cells) that help train the rest of the immune system to respond appropriately. Its lab-made version, Thymalfasin, is approved in over 35 countries for chronic hepatitis B and is used clinically for immune deficiencies, severe infections, and as a supportive cancer treatment.

Longevity

Research targets include cellular aging, senescence, and long-term healthspan.

Immunity

Research targets include immune cell activity, inflammatory response, and infection defense.

Immunity

thymo

Immunity

Is Thymosin Alpha 1 FDA approved?

Thymosin Alpha 1 is not an FDA-approved drug. It is intended for research purposes only and is not approved for human consumption, diagnostic, or therapeutic use.

Research Use Only

Thymosin Alpha 1 has not been evaluated by the FDA for safety or efficacy in humans.

No Clinical Oversight

Not manufactured under FDA-regulated quality or clinical standards.

Unregulated Sourcing

Purity, dosing, and sourcing are not verified through FDA testing or oversight.

A smartphone screen displaying FDA status for a drug, indicating "FDA approved drug: No" and "Classification: Research use only." A banner notes "Research Only" with the disclaimer "not for human use," emphasizing its intended use for laboratory and analytical purposes.

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Based on current scores, this vendor ranks highest across those criteria.

Protide Health

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How Does Thymosin Alpha 1 Work?

It attaches to pathogen-sensing receptors on immune cells, triggering a signal that helps immune cells mature properly and boosts the release of infection-fighting messengers. At the same time, it helps keep the immune response balanced so it doesn't become excessive or overly inflammatory.

Binds pathogen-sensing receptors

Attaches to receptors that sense pathogens on immune cells.

Matures immune cells

Helps immune cells mature and boosts infection-fighting messengers.

Keeps the response balanced

Helps keep the immune response from becoming excessive or overly inflammatory.

How to reconstitute Thymosin Alpha 1

View guide

The materials you'll need and step-by-step instructions for safely mixing Thymosin Alpha 1 with bacteriostatic water.

Materials needed

Your Thymosin Alpha 1 vial (lyophilized)

Alcohol swabs

Bacteriostatic sterile water

3 mL syringes (Luer Lock tip)

25G or 27G needles (Luer Lock). Other gauges may also be acceptable.

Sharps container (optional)

Remove the caps

Remove the caps from both your Thymosin Alpha 1 vial and your bacteriostatic water vial.

Sanitize the rubber stoppers

Wipe down the rubber stoppers on both vials with alcohol swabs and let them dry for about 3 minutes.

Attach the needle

Take your 3 mL syringe and needle. Twist the needle's plastic hub into the Luer Lock tip on the syringe to secure it.

Draw the bac water

Pull back on the plunger to draw your desired volume of bacteriostatic water. If you overfill, just push the excess back in until you reach the right marker on the syringe.

How much bac water? Thymosin Alpha 1 typically comes in a 10 mg vial. We recommend 2 mL of bacteriostatic water, though anywhere between 1 mL and 3 mL is acceptable. For larger vials you can use up to 5 mL — more bac water makes microdosing easier, but insulin needles usually max out at 1 mL per injection. That means a lot of bac water might force you into multiple injections to hit your target dose. Unless you're microdosing, 2 mL per vial is a solid rule of thumb.

Insert the needle into the Thymosin Alpha 1 vial

With the bac water in your syringe, insert the needle into the Thymosin Alpha 1 vial at a slight angle to avoid pressure buildup.

Use a thin needle: Stick to 25G or higher to avoid damaging the rubber stopper. Higher gauge means a thinner needle.

Release the water gently

Let the water run gently down the side of the vial. Don't inject it forcefully.

Heads up: Sometimes the plunger pushes itself in as soon as the needle enters the vial. Hold the plunger back so you have full control over how fast the bac water enters.

Swirl to dissolve

Avoid shaking. Gently swirl, flip, and roll the vial to dissolve the powder.

Be patient: This usually takes 2 to 5 minutes of consistent swirling, mixing in a circular motion, and gently flipping the vial up and down. The water needs to run through the powder many times to fully dissolve it. Don't shake or get aggressive with it.

Check for full dissolution

The solution should be clear with no visible particles. If it's cloudy or clumpy, wait a minute and repeat the swirling step.

Cap, dispose, and store

Once you're done, cap the needle and dispose of it (ideally in a sharps container). Store the reconstituted Thymosin Alpha 1 vial in the fridge whenever it's not in use. It will stay good for approximately 30 days.

How to Store Thymosin Alpha 1

Keep the dry powder well below freezing for the long term, or refrigerate it for shorter periods, staying dry. Once mixed with liquid, refrigerate and use within a week, and don't freeze it once mixed.

Lyophilized Storage

Below -18°C long-term, or 2–8°C short-term, kept desiccated.

Reconstituted Storage

Refrigerate at 2–8°C, use within 7 days.

Handling Notes

Do not freeze the reconstituted peptide.

A smartphone displaying a "Storage Guide" for peptides, indicating a safe storage temperature range of 2–8°C, with warnings to keep away from light, heat, and freezing. The background is light blue, and additional tips on protecting the peptides are visible below the temperature range.

What Are the Benefits of Thymosin Alpha 1?

What research says it may help with, and how it works in the body.

immunity

: It has helped elderly people and dialysis patients build a stronger antibody response to vaccines for illnesses like H1N1 flu and COVID-19.
: It helps restore levels of a key type of immune cell and reduces infections that take advantage of a weakened immune system.
: It has received FDA orphan drug status for DiGeorge syndrome, a rare condition, because it helps restore the function of T-cells, key immune cells.

inflammation

: It lowers several inflammation-signaling proteins in the body by 40-60%.
: It helps manage conditions where the immune system mistakenly attacks the body and causes inflammation.
: When paired with interferon, a natural antiviral protein, it becomes more effective at fighting viruses.

recovery

: It helps the immune system bounce back after the physical stress of surgery.
: It helps counter the temporary weakening of the immune system that can follow intense exercise training.

antiaging

: It supports the function of the thymus gland, part of the immune system that naturally shrinks and weakens with age.
: It helps slow the natural decline in immune strength that happens as people get older.

What Are the Side Effects of Thymosin Alpha 1?

Who should avoid it, warning signs to watch for, and what to know before combining it with other compounds.

Who Should Avoid It

: Organ transplant recipients (risk of graft rejection)
: Pregnancy and breastfeeding

Stop Right Away If You Notice

: Signs of graft rejection in transplant recipients
: Persistent injection site reactions or infection signs
: Unusual immune system hyperactivity
: Severe allergic reactions (rare)

Milder Signs to Watch For

Yellow, brown, or collapsed powder (heat/moisture degradation)Persistent cloudiness or particles post-reconstitutionNon-professional sourcing or unclear labeling

Was it helpful?Yes

How Long Should a Thymosin Alpha 1 Cycle Last?

This breaks down how long a typical Thymosin Alpha 1 cycle runs and what research suggests happens at each stage. Research shows that staying on a peptide continuously, without a break, may make it less effective over time.

That's why most research protocols build in a break between cycles, often called a washout period, to let the body reset before starting again.

Week 1-2: Initial immune system activation
Week 2-6: Enhanced immune function, reduced infection risk
Week 6-12: Maximum immunomodulatory benefits
Week 0-0: Sustained immune support with continued use

Cheat Sheets Featuring Thymosin Alpha 1

See how Thymosin Alpha 1 fits into a broader research stack with these free downloadable cheat sheets. Each one includes reference dose ranges, dosing frequency, and half-life for every peptide it covers. For research purposes only.

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Immunity Peptide Cheat Sheet

15 peptides

Longevity Peptide Cheat Sheet

42 peptides

Master Peptide Cheat Sheet

78 peptides

Browse user-created protocols

Real protocols from the community that include Thymosin Alpha 1

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Other83 days

Immune and Autoimmune Support

Bryn

Longevity

thymo

Healing

kpv

Healing

bpc

Thymosin Alpha 1 Research References

It is an approved compound

4Research references

Thymosin Alpha 1

Thymosin Alpha 1 is an approved compound

COVID-19 Treatment Study

30% vs 11% mortality reduction in severe cases; lymphocyte restoration.

2020

Cytokine Storm Mitigation Study

40-60% reduction in pro-inflammatory cytokines (TNF-α, IL-1β, IL-6).

2020

Comprehensive Safety Review

11,000+ patients, 30+ trials; <1% serious adverse events.

2024

TESTS Phase 3 Sepsis Trial

1,106 patients; mixed overall results but subgroup benefits in elderly/diabetic populations.

2020

Frequently Asked Questions About Thymosin Alpha 1

Straight answers on reconstitution, dosing, and safety, everything you need to research with confidence. For research reference only.

Thymosin Alpha 1 (Tα1) is a naturally occurring 28-amino-acid peptide fragment derived from prothymosin alpha, originally isolated from thymus tissue. It acts as an immune modulator rather than a general stimulant: it works largely by engaging toll-like receptors (TLR2 and TLR9) on dendritic cells and macrophages, which helps recalibrate T-cell maturation and the Th1/Th2 balance rather than simply boosting immune activity in one direction. A synthetic version (thymalfasin, brand name Zadaxin) is an approved prescription drug in more than 30 countries (though not in the US or Canada) used mainly alongside interferon for chronic hepatitis B and C.

The clinical dosing pattern for Zadaxin/thymalfasin is 1.6 mg injected subcutaneously twice weekly, generally for 6 to 12 months in hepatitis treatment protocols; smaller patients (under ~40 kg) are sometimes dosed at roughly 40 mcg/kg twice weekly. In research and biohacking communities, people commonly follow this same 1.6 mg twice-weekly schedule, and some experiment with higher amounts (around 3.2 mg) based on anecdotal reports, though there is no published research supporting a benefit from doubling the dose, and immune signaling pathways don't necessarily scale linearly with peptide amount. Any dosing decision should be guided by a qualified healthcare provider, not general online information.

It is almost always given by subcutaneous injection — this is how it was administered in the major clinical trials and is the standard route reported by both clinical sources and peptide communities. Common injection sites include the abdomen, thighs, and upper arms, with site rotation recommended to reduce local irritation. The peptide is not considered orally bioavailable, so it is not taken as a pill.

The lyophilized (freeze-dried) powder is generally stable refrigerated at 2-8°C (36-46°F) for extended periods when kept dark and in original packaging. It's typically reconstituted with bacteriostatic water (or sterile/normal saline), added slowly down the side of the vial and swirled gently rather than shaken to avoid damaging the peptide. Once reconstituted, most guidance recommends keeping it refrigerated and using it within roughly 1-3 weeks, and never freezing the reconstituted solution, since ice crystals can degrade the peptide. Handling and cold-chain shipping quality are frequently cited as major factors affecting whether a given batch retains potency.

Reported side effects are generally described as mild and temporary. The most common are injection-site reactions such as redness, swelling, or discomfort that typically resolve within hours to a few days. Less frequently reported effects include fatigue, headache, and mild gastrointestinal discomfort. Allergic reactions are considered rare. Clinical safety data from thousands of treated patients (including those with hepatitis, certain cancers, and other conditions) has generally shown a favorable tolerability profile, though this reflects supervised clinical use rather than unsupervised self-administration of unregulated research-grade material.

Its approved pharmaceutical use (as Zadaxin/thymalfasin) is primarily for chronic hepatitis B, often alongside interferon therapy, and it has also been studied for hepatitis C, certain cancers (as adjunct therapy), and immune-compromised conditions. In research and self-experimentation communities, it is discussed for general immune support, faster recovery from respiratory infections, and more recently as an area of interest for post-viral or long-COVID-related immune dysregulation, reflecting its role in normalizing T-cell profiles. These broader uses are investigational and not established medical treatments outside its approved indications.

As the prescription drug thymalfasin (Zadaxin), it is an approved medication in over 30 countries, but it is not FDA-approved in the United States. Outside of that approved pharmaceutical product, Thymosin Alpha 1 is widely sold online as a "research chemical" labeled not for human consumption, meaning it has not been evaluated by regulators for safety, purity, or efficacy when sourced this way. Buying it for personal use in that form carries legal and quality-control uncertainty, and product purity/potency can vary significantly between suppliers.

Yes — it is frequently combined in research contexts with peptides like BPC-157 and TB-500, particularly in "recovery" or "immune support" stacks, since BPC-157 and TB-500 are studied for tissue repair and angiogenesis-related pathways while Thymosin Alpha 1 targets immune/T-cell signaling. These combinations are sold as blended research products by some vendors, but there is limited controlled clinical research on the combined use of these peptides together, and any reported synergy is largely anecdotal rather than established in clinical trials.

Thymosin Alpha 1 Dosage Guide, Benefits & Side Effects

Chemical Makeup

Thymosin Alpha 1 Dosage Guide for Immune & GutBPC-157 Dosage Calculator

What is Thymosin Alpha 1?

Is Thymosin Alpha 1 FDA approved?

Our top-rated vendor

How Does Thymosin Alpha 1 Work?

How to reconstitute Thymosin Alpha 1

How to Store Thymosin Alpha 1

What Are the Benefits of Thymosin Alpha 1?

immunity

inflammation

recovery

antiaging

What Are the Side Effects of Thymosin Alpha 1?

Who Should Avoid It

Stop Right Away If You Notice

Milder Signs to Watch For

How Long Should a Thymosin Alpha 1 Cycle Last?

Cheat Sheets Featuring Thymosin Alpha 1

Browse user-created protocols

Thymosin Alpha 1 Research References

Frequently Asked Questions About Thymosin Alpha 1

What is Thymosin Alpha 1 and what does it do?

What dosage is typically used in research and clinical settings?

How is Thymosin Alpha 1 typically administered?

How should Thymosin Alpha 1 be reconstituted and stored?

What side effects are commonly reported?

What is Thymosin Alpha 1 commonly used for?

Is Thymosin Alpha 1 legal to buy, and is it approved for human use?

Is Thymosin Alpha 1 commonly stacked with other peptides?

Thymosin Alpha 1 Dosage Guide, Benefits & Side Effects

Chemical Makeup

Thymosin Alpha 1 Dosage Guide for Immune & GutBPC-157 Dosage Calculator

What is Thymosin Alpha 1?

Is Thymosin Alpha 1 FDA approved?

Our top-rated vendor

How Does Thymosin Alpha 1 Work?

Thymosin Alpha 1 Targeted areas

How to reconstitute Thymosin Alpha 1

How to Store Thymosin Alpha 1

What Are the Benefits of Thymosin Alpha 1?

immunity

inflammation

recovery

antiaging

What Are the Side Effects of Thymosin Alpha 1?

Who Should Avoid It

Stop Right Away If You Notice

Milder Signs to Watch For

How Long Should a Thymosin Alpha 1 Cycle Last?

Related peptides

Cheat Sheets Featuring Thymosin Alpha 1

Browse user-created protocols

Thymosin Alpha 1 Research References

Frequently Asked Questions About Thymosin Alpha 1

What is Thymosin Alpha 1 and what does it do?

What dosage is typically used in research and clinical settings?

How is Thymosin Alpha 1 typically administered?

How should Thymosin Alpha 1 be reconstituted and stored?

What side effects are commonly reported?

What is Thymosin Alpha 1 commonly used for?

Is Thymosin Alpha 1 legal to buy, and is it approved for human use?

Is Thymosin Alpha 1 commonly stacked with other peptides?