PinnyPeptide

B7-33 vs TB-500

Side-by-side comparison: effects, dosing ranges, side effects, regulatory status, and reconstitution.

Peptide A

B7-33

Muscle Growth

Single-chain relaxin peptide analog with anti-fibrotic and cardioprotective activity.

Peptide B

TB-500

Healing & Recovery

Synthetic fragment of Thymosin Beta-4 with potent tissue repair activity.

Typical vial

2 mg

Typical dose

1000-2000 mcg

Half-life

~2-3 hours

FDA status

Not FDA approved.

Typical vial

5 mg

Typical dose

2000-5000 mcg

Half-life

~6-8 hours

FDA status

Not FDA approved for human use.

B7-33 effects

  • Anti-fibrotic action in heart, lung, kidney tissue
  • Activates RXFP1 receptor via cGMP signaling arm
  • Vasodilatory effects
  • May support tissue remodeling and scar prevention
  • Reduces collagen deposition in injury models

TB-500 effects

  • Promotes wound healing and tissue repair
  • Reduces inflammation and fibrosis
  • Stimulates new blood vessel growth
  • Supports cardiac repair after ischemic injury
  • Enhances cell migration through actin upregulation

B7-33 side effects

  • Human safety data essentially absent
  • Theoretical: hypotension from vasodilation
  • Injection-site reactions
  • Possible effect on uterine / cervical tissue (relaxin family)

TB-500 side effects

  • Injection site irritation
  • Temporary head rush or lightheadedness
  • Mild lethargy
  • Headache

B7-33 dosing ranges

Research / anti-fibrotic

1-2 mg · Daily (SubQ or IV in preclinical work) · Per research protocol

TB-500 dosing ranges

Acute injury healing

2000-5000 mcg · Twice weekly · 4-6 weeks

Maintenance and recovery

2000 mcg · Once weekly · 4-8 weeks

B7-33 vs TB-500 — common questions

What is the difference between B7-33 and TB-500?

B7-33: Single-chain relaxin peptide analog with anti-fibrotic and cardioprotective activity. Typical dose 1000-2000 mcg. TB-500: Synthetic fragment of Thymosin Beta-4 with potent tissue repair activity. Typical dose 2000-5000 mcg. Both fall under the Muscle Growth and Healing & Recovery categories.

Can you stack B7-33 and TB-500?

Stacking B7-33 with TB-500 is a protocol-design question best raised with a clinician — it depends on your goal, current bloodwork, and whether both peptides target overlapping mechanisms. Both peptides should be tracked independently with separate injection sites and timing. PinnyPeptide supports multi-peptide stacks with automatic injection site rotation.

Which is dosed more frequently, B7-33 or TB-500?

B7-33 is typically dosed: Daily (SubQ or IV in preclinical work) for Research / anti-fibrotic. TB-500 is typically dosed: Twice weekly for Acute injury healing; Once weekly for Maintenance and recovery.

Are B7-33 and TB-500 FDA approved?

B7-33: Not FDA approved. TB-500: Not FDA approved for human use.

Tracking either of these?

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