Peptides TB-500 Cheat Sheet: Why Your Vial Is Probably TB-4, Mass-Action Dosing, and the Wolverine Pairing

For research and laboratory use only. Not for human consumption. Dosing figures below are research reference points, not protocols.

The short version: Two things about TB-500 trip up almost everyone. First, the vial labeled "TB-500" in your hand is probably not TB-500, it's TB-4, a different and larger molecule. That sounds like a problem but mostly isn't, and this post explains why. Second, TB-500 breaks the daily-dosing habit most peptides train you into. It works by mass action, which means bigger doses twice a week beat small doses every day. Get those two things right and the rest is straightforward.

The label problem, explained

TB-500 was originally defined as a 7 amino acid fragment of thymosin beta-4 (the LKKTETQ sequence, around 800 Da). But doping-control analysis of commercial vials found that most products sold as "TB-500" actually contain full-length TB-4, the complete 43 amino acid protein at around 4,900 Da. The fragment is harder to synthesize and less commercially available, so the full molecule is what ships.

Here's why it mostly doesn't matter, and the one case where it does:

	TB-500 (7 aa fragment)	TB-4 (full 43 aa)
Actin-binding repair	Yes	Yes
Cell migration, angiogenesis	Yes	Yes
Anti-fibrotic (Ac-SDKP)	No	Yes
Scar reduction	Limited	Yes

Both share the actin-binding domain, so for general repair, cell migration, and new vessel formation they behave the same. The difference is the Ac-SDKP fragment that only the full TB-4 molecule carries, which suppresses TGF-beta signaling and gives anti-fibrotic, scar-reducing activity. So if scar reduction is your actual goal, you want TB-4, which is most likely what you already have.

How to check: look at the COA. Roughly 4,900 Da or 43 amino acids listed means TB-4. Around 800 Da or 7 amino acids means the fragment. If the COA doesn't specify, assume TB-4.

What it does, and how it differs from BPC-157

TB-500 and BPC-157 solve different halves of the same problem, which is why they're paired so often. BPC-157 drives local repair at the injury site: perfusion, vascular supply, the roads. TB-500 handles logistics: getting the right cells to the right place and organizing them into functional tissue instead of scar. It works by binding G-actin monomers one-to-one, building a reserve pool that cells deploy for migration, division, and reorganization. Without that reserve, cells respond sluggishly to repair signals.

The dosing reframe: mass-action, not daily

This is the part that matters most for results. TB-500 is mass-action, not catalytic. You need milligram bolus doses to bind enough actin to build the reserve, so 2 to 4 mg twice weekly outperforms smaller daily doses. The peptide itself clears in hours, but the actin pools it creates persist for days until cells draw on them. Peak concentration drives the binding event; the downstream effect sustains itself between doses. Dosing daily wastes material chasing a threshold that bolus dosing hits cleanly.

Dosing (research context)

Phase	Dose	Frequency	Units (U-100)
Loading (wk 1 to 4)	2 to 4 mg	2 to 3x/week	40 to 80 units
Maintenance (wk 5 to 8)	2 to 4 mg	1 to 2x/week	40 to 80 units
Off-cycle	0 mg	—	4 to 8 weeks before re-cycling

The loading-then-maintenance structure is the protocol, not a suggestion. Loading front-loads during the early-to-mid remodeling window when tissue architecture is being set, and maintenance consolidates collagen organization after. Running a flat dose continuously misses that architectural window.

Reconstitution

Spec	Value
Vial	10 mg
Water	2.0 mL bacteriostatic
Concentration	5 mg/mL
1 unit (U-100)	50 mcg

Conversions: 2 mg = 40 units, 4 mg = 80 units. For 4 mg boluses, a 100-unit syringe makes the draw easier.

Supply

A standard 6-week course (4 weeks loading plus 2 weeks maintenance, around 20 mg) runs about 2 vials. A heavier 8-week course at higher loading (around 36 mg) runs about 4 vials. Annual budget for 2 to 3 cycles lands around 6 to 12 vials.

Storage

Lyophilized vials store frozen at -20 °C, dry and dark, stable 12+ months. Reconstituted, refrigerate at 2 to 8 °C protected from light; avoid freeze-thaw.

Practical notes

Inject near the injury when possible. The peptide doesn't stay local (it enters systemic circulation regardless of site), but local injection still offers a modest delivery advantage. Cycle length is 6 to 8 weeks standard, with a 4 to 8 week off-cycle before repeating if the injury isn't fully healed. Once remodeling is underway, continued dosing has diminishing returns; this is a repair signal, not a maintenance compound. Side effects are limited to occasional injection-site reactions and rare mild lethargy lasting 12 to 24 hours, so hydrate and schedule around a rest day if you're sensitive.

The Wolverine pairing

TB-500 plus BPC-157 is the classic structural-repair stack: perfusion plus migration covers both halves of the repair process. Both peptides also anchor the GLOW and KLOW blends if you'd rather run them in a fixed ratio. Arizen also carries a dedicated BPC-157 + TB-500 blend for the pairing.

Contraindications

Absolute: active cancer or malignancy within 2 years (TB-500 promotes angiogenesis and cell migration), pregnancy or breastfeeding, proliferative retinopathy, and planned or recent surgery within 2 weeks. Relative: concurrent corticosteroid use, severe cardiovascular disease, active autoimmune conditions, and therapeutic anticoagulation. Note also that TB-500 is WADA-prohibited under class S0 and detectable in testing, so anyone subject to anti-doping rules should not use it.

Where to source

All Arizen Biolabs compounds, with current links and code PROFIT, are in the pinned Complete Product Guide.

Research use disclaimer: All compounds referenced here are intended for research and laboratory use only. Nothing in this post is intended for human consumption or as medical guidance. Dosing figures, where listed, are research reference points only.

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