Peptide Comparison

Thymosin Alpha-1vsThymopentin (TP-5)

Your immune system's master trainer—a naturally occurring thymus peptide that wakes up tired immune cells, helps your body fight infections, and keeps your defenses sharp as you age.

Immune-boosting pentapeptide fragment that enhances T-cell function and dendritic cell maturation

ImmuneImmune

At a Glance

Quick
comparison

Dose Range

Thymosin Alpha-1

1.6–3.2 mg

Thymopentin (TP-5)

1–2 mg

Frequency

Thymosin Alpha-1

Twice weekly

Thymopentin (TP-5)

Once daily

Administration

Thymosin Alpha-1

Subcutaneous injection

Thymopentin (TP-5)

Subcutaneous injection

Cycle Length

Thymosin Alpha-1

8-12 weeks

Thymopentin (TP-5)

4-6 weeks

Onset Speed

Thymosin Alpha-1

Moderate (1-2 weeks)

Thymopentin (TP-5)

Moderate (1-2 weeks)

Evidence Level

Thymosin Alpha-1

Moderate human trials (Phase 1-2)

Thymopentin (TP-5)

Moderate human trials (Phase 1-2)

Efficacy

Benefit
ratings

Thymosin Alpha-1
Thymopentin (TP-5)

Immune Activation

Thymosin Alpha-195%
Thymopentin (TP-5)0%

Infection Fighting

Thymosin Alpha-192%
Thymopentin (TP-5)0%

Immune Balance

Thymosin Alpha-188%
Thymopentin (TP-5)0%

Immune Enhancement

Thymosin Alpha-10%
Thymopentin (TP-5)85%

Cardiovascular Support

Thymosin Alpha-10%
Thymopentin (TP-5)75%

Post-Recovery Support

Thymosin Alpha-10%
Thymopentin (TP-5)80%

Technical Data

Compound
specifications

Thymosin Alpha-1

Molecular Formula

C129H215N33O55

Molecular Weight

3108.32 g/mol

Half-Life

Approximately 2 hours

Bioavailability

High when injected subcutaneously (rapid absorption, peak at ~2 hours)

CAS Number

62304-98-7

Thymopentin (TP-5)

Molecular Formula

C30H49N9O9

Molecular Weight

679.8

Half-Life

30 seconds to few minutes in plasma

Bioavailability

Sustained release via subcutaneous route

CAS Number

69558-55-0

Protocols

Dosing
tiers

Thymosin Alpha-1

starting

1.6 mg

Twice weekly

4 weeks

This is the standard clinical dose used in most research trials. Start here to assess your tolerance and response. The 1.6 mg dose (sometimes listed as 900 mcg/m2) has decades of safety data behind it.

standard

1.6 mg

Twice weekly

8-12 weeks

The most common protocol used in clinical trials for hepatitis and cancer support. Inject on consistent days (like Monday/Thursday) for best results. This duration allows meaningful immune enhancement.

advanced

1.6 mg daily for 7 days, then twice weekly

Daily initially, then twice weekly

12+ weeks

Used in some severe infection and critical care protocols. The daily loading phase rapidly boots immune function, followed by maintenance. Only under medical supervision for serious conditions.

Thymopentin (TP-5)

Applications

Best
suited for

Thymosin Alpha-1

Chronic Hepatitis B or C Support

Thymosin Alpha-1 has its strongest clinical evidence here. Multiple trials show it helps clear viral loads and normalize liver enzymes, especially when combined with antiviral medications. It's approved in over 30 countries specifically for hepatitis treatment.

Cancer Treatment Support

When used alongside chemotherapy, Thymosin Alpha-1 may help maintain immune function that chemo tends to suppress. Research in lung cancer, melanoma, and liver cancer shows improved outcomes when added to standard treatments. It helps your immune system keep fighting even during tough treatments.

Age-Related Immune Decline

As you age, your thymus shrinks and produces less thymosin naturally—a process called immunosenescence. Supplementing with Thymosin Alpha-1 may help compensate, keeping your immune defenses more youthful and responsive. Think of it as replacing what your body makes less of over time.

Severe Infection Recovery

In sepsis and critical infections, Thymosin Alpha-1 has shown promise for reducing mortality by helping restore immune balance. It's particularly interesting because it modulates immunity rather than just boosting it—calming overreaction while enhancing pathogen-fighting ability.

Thymopentin (TP-5)

Immune System Enhancement

Thymopentin directly increases T-cell function and promotes dendritic cell maturation, making it ideal for people seeking to boost immune response naturally

Cardiac Health Support

Clinical trials show thymopentin improves ejection fraction and exercise capacity in elderly heart failure patients while enhancing immune markers

Post-Surgery Recovery

Helps restore immune function after major surgery and protects important immune responses during recovery period

Safety Profile

Side
effects

Thymosin Alpha-1

Common

  • Injection site reactions
  • Mild fatigue
  • Flu-like symptoms

Uncommon

  • Mild fever
  • Lymph node awareness

Serious

  • Allergic reaction

Thymopentin (TP-5)

Common

  • Local injection site reaction
  • Mild fatigue
  • Transient fever

Uncommon

  • Muscle aches
  • Mild headache

Serious

  • Allergic reaction

Research Status

Safety
& evidence

Thymosin Alpha-1

Evidence Level

Moderate human trials (Phase 1-2)

FDA Status

FDA approved for other use

Safety Overview

Thymosin Alpha-1 has one of the most extensive safety records of any peptide, with decades of clinical use across multiple countries. Studies consistently report minimal side effects—mostly limited to mild injection site reactions. The 2-hour half-life means it doesn't accumulate in your system. It's been used safely in thousands of patients with hepatitis, cancer, and other serious conditions.

Contraindications

  • xOrgan transplant recipients on immunosuppressants
  • xActive autoimmune disease flares
  • xKnown allergy to thymosin peptides
  • xPregnancy or breastfeeding
  • xChildren under 18 without medical supervision

Thymopentin (TP-5)

Evidence Level

Moderate human trials (Phase 1-2)

FDA Status

Research compound

Safety Overview

Thymopentin is well-tolerated with minimal side effects reported in clinical trials. Most adverse events are mild and local. No serious safety concerns have emerged from decades of clinical use in China and Europe.

Contraindications

  • xPregnancy and breastfeeding
  • xActive malignancy (without medical supervision)
  • xSevere immunosuppression
  • xHypersensitivity to peptide medications

Decision Guide

Which is
right for you?

Choose Thymosin Alpha-1 if...

  • Immune system strengthening
  • Chronic infection support
  • Cancer adjunct therapy
  • Healthy aging immune support

Choose Thymopentin (TP-5) if...

  • Immune system strengthening
  • Recovering from illness or surgery
  • Managing autoimmune conditions
  • Supporting cardiac health in elderly patients
Peptide ProThymosin Alpha-1 vs Thymopentin (TP-5) — Peptide Comparison | Peptide Initiative