# TB-500 / Thymosin beta-4

Healing/actin peptide, almost always stacked with BPC; tumour-metastasis biology is a concern.

- Page: https://peprank.xyz/peptides/tb-500-thymosin-beta-4
- Category: Recovery, joints & healing (Research peptide)
- Also known as: Tβ4; TB4 (full 43-aa); TB-500 (LKKTETQ fragment, ~889 Da); 'Wolverine' with BPC-157
- Routes: Injection
- Sequence: SDKPDMAEIEKFDKSKLKTETQEKNPLPSKETIEQEKQAGES (thymosin β4, 43 aa, N-acetyl; commonly sold 'TB-500' is often the Ac-LKKTETQ (17-23) fragment, not the full protein)
- Safety tier: Strict: Avoid · Balanced: Avoid · Evidence only: Caution
- Risk axes (0 none to 3 severe): Seen harm 1, Mechanism 2, Data gap 3, Silent harm 3, Product 3
- Positive: 50% of 52 graded reports glowing or positive, shrunk toward the 49% all-report average by 8 reports' weight
- Rank: #34 of 61 research peptides
- Graded reports: 52 (Glowing 14, Positive 12, Mixed 7, Nothing 9, Negative 3, Bad reaction 7)
- Evidence: Small human studies — For TB-500; small human trials of full Tβ4 (eye drops, IV phase 1)
- Access: Grey market
- Onset: In the BPC stack, pain relief is reported within 1-3 weeks; solo TB-500 users report much less consistent results.
- Lasts: Dosed 2-3 times a week; users report effects outlasting a single injection by several days, and healed injuries stay healed.
- Cost per month: ≈ €15–73 (at 140–710 mcg/day, Semax Polska at €3.39/mg)
- Dose users report: 500–570 mcg/day (median 500 mcg, n=9)
- Updated: 2026-10-30

**Why Avoid under the strict bar:** Tβ4 has a well-documented pro-angiogenic and pro-metastatic role in cancer biology, and the fragment actually sold has no human safety data.

## What users report

Rarely used alone, so praise is mostly for the BPC+TB stack: injuries back in weeks instead of months, chronic knee/shoulder pain gone. Solo users are less consistent, and some report TB-500 made a tendinopathy worse or caused emotional blunting. One user who carried on with TB-500 alone after stopping BPC woke with hives, a closing throat and swollen lips and needed an ambulance; others report flu-like first-dose reactions, months of headaches or leg swelling, which they blame on contaminated vials as often as on the peptide. Vendors mostly sell the 7-aa fragment while the research is on full Tβ4.

**Effects:** faster soft-tissue recovery; less chronic joint pain; flexibility / range of motion

**Downsides:** lethargy, headache; emotional blunting (anecdotal); flu-like reactions (often contamination)

**Risks:** Tβ4 promotes tumour cell migration, angiogenesis and metastasis in models and is overexpressed in many cancers; TB-500 fragment has zero human exposure data (FDA); Generic: grey-market endotoxin; product often isn't the molecule studied

**Typical use:** 2-2.5 mg twice weekly for 4-6 weeks loading, then 1-2 mg weekly.

**Getting it:** Research-peptide vendors only. Many vials sold as 'TB-500' test as full-length Tβ4 (about 4921 Da) and vice versa. Covered by the Oct 2026 HHS enforcement discretion; banned in sport by WADA.

**Stacked with:** BPC-157 (The 'Wolverine' stack; most TB-500 use is this pair, often as a pre-mixed vial.); GHK-Cu and KPV ('GLOW' and 'KLOW' blends add these for skin and anti-inflammatory effects.); Growth hormone or GH secretagogues (Added by lifters for post-surgery healing; several said HGH did more than the peptides.)

## Risk profile

- **Seen harm 1/3:** FDA found no human exposure data and zero FAERS reports; the TGA's hypersensitivity cases could not be split between TB-500 and BPC-157, and the one serious first-hand report (whole-body hives) also involved grey-market BPC-157. Isolated and confounded.
- **Mechanism 2/3:** Full-length thymosin beta-4 is pro-angiogenic and pro-migratory, and its overexpression inside melanoma cells raised metastasis in mice; but exogenous Tβ4 suppressed a mouse lung cancer, and the seven-residue TB-500 fragment did not even promote fibroblast wound closure in vitro. Credible, not demonstrated.
- **Data gap 3/3:** No human data, toxicology or carcinogenicity study exists for the TB-500 fragment; full-length Tβ4 has a 40-person IV phase 1 and small eye-drop trials, which do not transfer, and vials sold as either often test as the other.
- **Silent harm 3/3:** Promotion of an existing tumour would be silent and delayed.
- **Product 3/3:** Grey-market injectable vials, frequently mislabelled between the fragment and full-length Tβ4.
- **Never if:** Active cancer or a history of cancer; Pregnancy or breastfeeding (no human reproductive data)

## Top reports

- Glowing, recovery, 750 mcg/day blend: “2 weeks ago today I injured my shoulder doing bench. Massive bruise, couldn't sleep. No benching. Today I am doing CGBP with 225 for reps pain free and threw up a single at 255. No. Pain. BPC-157/TB500 FTW. 750 mcg daily.” — [@FLEXjss on X](https://x.com/FLEXjss/status/2071923075814207919)
- Glowing, recovery, 500 mcg/day each with BPC-157, 5 days/week: “Week 3: This is when everything changed. The pain dropped off almost completely. By the end of week three I’d say I was about 95 percent better.” — [r/Biohackers](https://www.reddit.com/r/Biohackers/comments/1plfyya/my_experience_with_tb500bpc157/)
- Glowing, recovery: “No side effects for me. Had bad tennis elbow for almost a year that was significantly affecting my workout routines. After 1 month of TB-500/BP-157 daily pain completely gone.” — [@thehammer303 on X](https://x.com/thehammer303/status/2031392377014018392)
- Glowing, recovery: “I used BPC-157 and TB 500 (known as the “Wolverine Stack”) to fix my chronic back pain (I’m also a retired disabled veteran). It prevented me from having major back surgery. I can now squat 405 (5x5 workout program) after a 10 year “hiatus” from powerlifting.” — [@ShadowLord_Maul on X](https://x.com/ShadowLord_Maul/status/2023571885976678635)
- Glowing, recovery: “After running BPC157 and TB500 for 3 weeks, my shoulder pain (which has bothered me for over a year) has absolutely vanished and gives me no pain while doing pressing movements anymore. None! I'm not sure if this is placebo or if it's legit” — [@ItIsMikeFitz on X](https://x.com/ItIsMikeFitz/status/1951756160777809958)

## Cheapest in Europe

- [Semax Polska](https://semaxpolska.com/en/tb-500-10-mg/) (PL): TB-500 10 mg + bacteriostatic water, €34, €3.39/mg
- [XL Peptides](https://xlpeptides.com/product/tb-500-5mg/) (GB): TB-500 5mg Research Peptide, €23, €4.54/mg
- [Baltic Peptides](https://balticpeptides.com/product/tb-500/) (LT): TB-500 (TB4) 10mg, €55, €5.50/mg
- [Particle Peptides](https://particlepeptides.com/en/buy-peptides/110-thymosin-beta-4-tb-500-10mg-with-mannitol.html) (SK): Thymosin Beta-4 (TB-500) 10mg with Mannitol, €78, €7.80/mg
- [Europa-Peptide](https://europa-peptide.de/en/shop/tb500/) (PL): TB500 5mg, €40, €7.98/mg

## Studies

- [Ruff et al. 2010: randomized, placebo-controlled single and multiple dose study of intravenous thymosin beta-4 in healthy volunteers](https://pubmed.ncbi.nlm.nih.gov/20536472/) (rct, n=40, 2010): Full-length synthetic Tβ4 at 42-1260 mg IV daily for 14 days caused only mild or moderate adverse events and no dose-limiting toxicity; it says nothing about the TB-500 fragment.
- [Guarnera et al. 2010: the effect of thymosin treatment of venous ulcers (phase 2)](https://pubmed.ncbi.nlm.nih.gov/20536470/) (rct, n=73, 2010): Topical Tβ4 was as well tolerated as placebo; the 0.03% dose may speed healing, with about 25% of ulcers fully closed within 3 months.
- [Sosne & Ousler 2015: thymosin beta-4 ophthalmic solution for dry eye, phase II trial](https://pubmed.ncbi.nlm.nih.gov/26056426/) (rct, n=72, 2015): 0.1% Tβ4 eye drops missed both primary endpoints but improved several secondary signs and symptoms of dry eye, with no safety concerns.
- [Malinda et al. 1999: thymosin beta-4 accelerates wound healing](https://pubmed.ncbi.nlm.nih.gov/10469335/) (animal, 1999): Topical or injected Tβ4 increased re-epithelialisation by 42-61% and wound contraction in rats, partly by stimulating keratinocyte migration.
- [Cha et al. 2003: role of thymosin beta-4 in tumor metastasis and angiogenesis](https://doi.org/10.1093/jnci/djg100) (animal, 2003): Raising Tβ4 in tumour cells increased their migration, blood-vessel formation and metastasis in mice, the main reason for the cancer concern.

## Sources

- [Role of thymosin beta-4 in tumor metastasis and angiogenesis (JNCI 2003)](https://doi.org/10.1093/jnci/djg100)
- [Tumor progression is mediated by thymosin-beta4 through a TGFbeta/MRTF axis (Mol Cancer Res 2018)](https://doi.org/10.1158/1541-7786.mcr-17-0715)
- [FDA risk note: TB-500 fragment, no human exposure data](https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks)