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IGF-1 vs TB-500 (Thymosin Beta-4)

IGF-1 and TB-500 (Thymosin Beta-4) are studied in overlapping research areas, which is why they are frequently compared. This is a neutral side-by-side reference drawn from published preclinical literature and laboratory handling data.

Shared research areas:Musculoskeletal
Class70-residue single-chain protein (native IGF-1), three disulfide bondsSynthetic fragment of Thymosin Beta-4
Molecular weight7648.7 g/mol4963.5 g/mol
CAS numberNot assigned / not specified77591-33-4
Purity spec≥99%≥99%
Research areasHormonal & Endocrine, Musculoskeletal, MetabolicTissue Regeneration, Musculoskeletal, Cardiovascular
Primary diluentDilute acetic acid for initial dissolutionBacteriostatic water (0.9% benzyl alcohol)
Working windowShort — days rather than weeks — and shorter still with repeated handling.Commonly worked with for 2–4 weeks at 2–8 °C.
Lead degradation routeMisfolding and irreversible denaturation — the dominant failure mode.Methionine sulfoxide formation — the dominant chemical degradation route, detectable as an earlier-eluting shoulder on RP-HPLC and a +16 Da species on LC-MS.
Freeze–thawPoorly tolerant. Repeated freeze-thaw denatures the folded structure permanently, so aliquot for single use rather than relying on any freeze tolerance.Aliquot after reconstitution. Repeated cycles risk both concentration effects and progressive oxidation from headspace air introduced at each opening.
Light sensitivityNo specific light requirement beyond normal practice.Store reconstituted vials protected from light; methionine oxidation is accelerated by light and dissolved oxygen.

How they actually differ

Comparing the two: IGF-1 is 70-residue single-chain protein (native igf-1), three disulfide bonds, while TB-500 (Thymosin Beta-4) is synthetic fragment of thymosin beta-4 — different molecular classes with different handling consequences; they call for different primary diluents (dilute acetic acid for initial dissolution versus bacteriostatic water (0.9% benzyl alcohol)); their leading degradation routes differ (misfolding and irreversible denaturation for IGF-1, methionine sulfoxide formation for TB-500 (Thymosin Beta-4)), so the storage precautions that matter are not the same; their practical working windows differ once reconstituted. The sections below set out each in full.

IGF-1 — origin

IGF-1 is the native insulin-like growth factor — a folded 70-amino-acid protein stabilised by three internal disulfide bonds. It is the downstream messenger produced after growth hormone acts, and it is handled as a protein rather than a short peptide. This is the native sequence, distinct from the long-acting LR3 analogue.

TB-500 (Thymosin Beta-4) — origin

TB-500 corresponds to the active region of Thymosin Beta-4, a 43-residue actin-sequestering protein present in virtually every mammalian cell type and abundant in wound fluid and platelets. Research interest followed the observation that the protein's activity in tissue-organisation models is largely retained by a short fragment of it.

IGF-1 research themes

IGF-1 receptor signalling

Studied as the native ligand for the IGF-1 receptor and its downstream proliferation and survival pathways.

Satellite cell activation

Examined in muscle research models for its role in satellite-cell behaviour and anabolic signalling.

Native versus analogue

Compared with IGF-1 LR3, whose reduced binding-protein affinity gives a longer active window — a contrast studied directly in the literature.

TB-500 (Thymosin Beta-4) research themes

Actin sequestration

The defining studied mechanism: binding G-actin and influencing the polymerisation equilibrium that governs cell motility.

Cell migration models

Investigated in models where directed cell movement into a tissue defect is the measured endpoint.

Cardiac and corneal repair models

Two of the better-populated preclinical literatures for the parent protein.

Inflammation modulation

Studied for effects on inflammatory signalling in tissue-injury models.

IGF-1 handling

  • Dissolve first in dilute acetic acid, then dilute into the working buffer — never expect plain water to take it up fully.
  • Use a carrier protein and low-bind labware to prevent adsorptive loss.
  • Aliquot for single use; do not re-freeze reconstituted protein.

TB-500 (Thymosin Beta-4) handling

  • Minimise headspace exposure — each opening introduces oxygen that drives methionine oxidation.
  • Keep reconstituted vials out of direct light, including bench lighting over long sessions.
  • Introduce diluent against the vial wall; the cake is light and can be dispersed by a direct stream before it dissolves.

Both third-party tested

Every Popular Peptides batch of IGF-1 and TB-500 (Thymosin Beta-4) is independently tested by HPLC and LC-MS with a published Certificate of Analysis. Enter a lot number to pull the COA for a specific vial.

IGF-1 reference

TB-500 (Thymosin Beta-4) reference

Related comparisons

IGF-1 and TB-500 (Thymosin Beta-4) are supplied strictly as research chemicals for in-vitro laboratory and research use only. They are not intended for human or animal consumption, diagnostic, or therapeutic use. This comparison summarizes published preclinical literature and laboratory handling data; it is not medical advice, not a claim of efficacy, and not usage guidance.