TB-500 (Thymosin Beta-4) vs Tesamorelin

Side-by-side comparison of mechanisms, dosing, interactions, and stacking potential.

TB-500 (Thymosin Beta-4)Tesamorelin
CategoryPeptidesPeptides
Standard DoseResearch indicates 2-2.5 mg administered twice weekly via subcutaneous injection.Research indicates 2 mg administered once daily via subcutaneous injection (FDA-approved dose for HIV lipodystrophy).
TimingNo strict timing requirements. Can be administered at any time of day. Systemic action means injection location is not critical.Morning administration on empty stomach. Consistent daily timing recommended.
Cycle DurationLoading phase: 4-6 weeks. Total cycle: 8-16 weeks.26+ weeks in clinical trials. Long-term use is common; effects are not sustained after discontinuation.
Evidence Levelanimal_plus_anecdotalStrong (FDA-approved indication), Moderate (longevity)

Mechanism

TB-500 is a synthetic fragment of Thymosin Beta-4, a 43-amino acid protein that sequesters G-actin monomers, preventing premature polymerization and facilitating cellular migration and morphological changes essential for wound healing. It upregulates actin to promote cell migration, proliferation, and differentiation of stem/progenitor cells at injury sites. TB-500 also enhances angiogenesis, reduces inflammation, and promotes tissue remodeling through increased re-epithelialization and vascular density.

Standard Dosing

Research indicates 2-2.5 mg administered twice weekly via subcutaneous injection.

Timing

No strict timing requirements. Can be administered at any time of day. Systemic action means injection location is not critical.

Cycle Duration

Loading phase: 4-6 weeks. Total cycle: 8-16 weeks.

Side Effects

  • Temporary lethargy
  • Head rush upon injection
  • Injection site irritation
  • Mild headache

Contraindications

  • Active cancer (angiogenesis concern)
  • Pregnancy and breastfeeding
  • Recent myocardial infarction

Best Stacking Partners

BPC-157GHK-CuGH Secretagogues
B

Tesamorelin

Peptides

Mechanism

Tesamorelin is an FDA-approved synthetic 44-amino acid GHRH analog with a trans-3-hexenoic acid modification at the N-terminal tyrosine that confers resistance to DPP-IV degradation. It binds GHRH receptors on anterior pituitary somatotrophs, stimulating endogenous GH production and secretion while maintaining pulsatile release patterns. Tesamorelin selectively reduces visceral adipose tissue (15-20% reduction in trials) while preserving subcutaneous fat, and markedly increases plasma GH and IGF-1 levels with once-daily dosing.

Standard Dosing

Research indicates 2 mg administered once daily via subcutaneous injection (FDA-approved dose for HIV lipodystrophy).

Timing

Morning administration on empty stomach. Consistent daily timing recommended.

Cycle Duration

26+ weeks in clinical trials. Long-term use is common; effects are not sustained after discontinuation.

Side Effects

  • Injection site reactions (erythema, pruritus)
  • Arthralgia
  • Peripheral edema
  • Myalgia
  • Paresthesia
  • Elevated blood glucose

Contraindications

  • Active cancer or pituitary tumors
  • Pregnancy (Category X)
  • Hypersensitivity to GHRH analogs
  • Disruption of hypothalamic-pituitary axis from surgery/radiation
  • Active cancer
  • Pregnancy
  • Pituitary surgery or disease

Best Stacking Partners

IpamorelinAOD-9604

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