Wolverine stack (BPC-157 + TB-500): what studies say

What it is

Wolverine is the name under which the store sells a pre-filled pen that combines two research peptides, BPC-157 and TB-500. The name is a marketing label and not a scientific one. BPC-157 is a synthetic peptide of 15 amino acids, a partial copy of a protein found in human gastric juice, studied mostly in rats (Staresinic 2003). TB-500 is a product name. Doping-control laboratories found that its key ingredient was a 7-amino-acid segment of the natural 43-amino-acid peptide thymosin beta-4, the part that binds the cell protein actin (Ho 2012). Some products sold under the name contain the full peptide instead. Neither compound is an approved medicine anywhere (Tham 2026). The two are studied in the same injury models, tendon, skin and blood vessels, and each has been reported to promote new blood vessels and the migration of repair cells, which is the usual argument for pairing them (Hsieh 2017, Philp 2003). Whether they add anything to each other has been tested in one published animal study and in 4 patients of a small case series.

What the studies looked at

• The pair. 32 male rats, 12 weeks old, had the Achilles tendon cut and repaired and were split into 4 groups of 8: control, BPC-157 at 10 µg per kg per day, TB-500 at 60 µg per kg per day, or both, injected into the abdomen for 4 weeks. The tendons were then pulled to breaking point and examined under the microscope (Biçer 2026). In a retrospective chart review at one clinic in Florida, 4 of 16 knee-pain patients had received injections of both BPC-157 and thymosin beta-4 into the knee and 12 had received BPC-157 alone. They were asked by phone, 6 months to a year later, to rate their pain (Lee 2021).
• BPC-157 alone. Cut rat tendons (Staresinic 2003), new vessel growth in chick embryo membranes, in human vessel-lining cells and in rats with a blocked leg artery (Hsieh 2017), a toxicology programme in four species (Xu 2020) and a study of how fast it is cleared in rats and dogs (He 2022).
• Thymosin beta-4 alone. Full-thickness wounds in rats (Malinda 1999), incisions and sponge implants to study scarring (Ehrlich 2010), the 7-amino-acid fragment in cell migration and vessel-sprouting assays (Philp 2003), 40 healthy volunteers given intravenous doses (Ruff 2010) and 73 patients with venous leg ulcers given a gel (Guarnera 2010).
• Reviews. A systematic review of every human BPC-157 study up to June 2026 (Poolton 2026), an orthopaedic review of all three substances (Tham 2026) and a sports-medicine review of unapproved peptides (Mendias 2026).

What the studies say

The pair in rats. The TB-500 group had a higher maximum load to failure than controls (p < 0.05) and better tissue scores on two scales (Bonar p = 0.016, Movin p = 0.017). The combination group scored better than controls on the Movin scale (p = 0.040) but did not differ in strength. The BPC-157 group had numerically better scores that did not reach significance. The authors wrote that the combination "did not confer additional benefits compared to either agent alone" and suggested the two peptides may act through shared pathways, a hypothesis they said needs confirmation (Biçer 2026).

The pair in people. Of the 4 patients who received both peptides, 3 (75 %) reported significant improvement and 1 reported none. Of the 12 who received BPC-157 alone, 11 (91.6 %) reported improvement. No validated pain or function scale was used (Lee 2021).

BPC-157 alone. Daily injections of 10 µg or 10 ng per kg improved the strength, function and microscopic structure of cut rat tendons over 14 days (Staresinic 2003). It increased vessel density in chick membranes and cell assays, sped up blood-flow recovery in rats with a blocked leg artery and raised the vessel receptor VEGFR2 (Hsieh 2017). The toxicology programme found no serious toxicity in mice, rats, rabbits or dogs; the only finding was a fall in blood creatinine in dogs at 2 mg per kg that reversed within 2 weeks (Xu 2020). In rats and dogs the peptide left the blood with a half-life under 30 minutes (He 2022).

Thymosin beta-4 alone. In rats it increased the regrowth of skin over a wound by 42 % at day 4 and by as much as 61 % at day 7, and 10 pg stimulated keratinocyte migration 2 to 3-fold in a dish (Malinda 1999). Incisions healed narrower and with minimal scarring, and implants that received 100 µg on days 2, 3 and 4 contained better-organised collagen at day 14 (Ehrlich 2010). In people, intravenous doses of 42 mg to 1260 mg, once and then daily for 14 days, caused infrequent, mild or moderate adverse events (Ruff 2010), and a 0.03 % gel was associated with complete healing of venous ulcers within 3 months in about 25 % of patients, with safety similar to placebo (Guarnera 2010).

What the researchers flagged

• No extra effect from the pair. The only controlled test of the two peptides together found no additional benefit over either alone, in 8 rats per group over 4 weeks (Biçer 2026).
• No controlled human trial of the blend. The only human data on the pair are 4 patients in an uncontrolled phone survey (Lee 2021). The 2026 systematic review found just 3 human BPC-157 studies with 30 participants in total, all of poor methodological quality, and rated the certainty of the evidence as very low (Poolton 2026).
• Which TB-500. The published human trials of thymosin beta-4 used the full peptide. The 7-amino-acid fragment sold as TB-500 has no published human trial, and reviewers warned against treating the two as equivalent (Tham 2026).
• Fixed ratio. The rat study used 10 µg of BPC-157 for every 60 µg of TB-500, a ratio of 1 to 6 by weight. No study has tested whether other ratios behave the same (Biçer 2026).
• Short half-life and product quality. BPC-157 disappeared from animal blood within about half an hour (He 2022), and reviewers raised concerns about the identity, purity, concentration and sterility of peptides sold online (Tham 2026, Mendias 2026).
• Sport. The 2026 Prohibited List names BPC-157 as a non-approved substance (class S0) and "Thymosin-β4 and its derivatives e.g. TB-500" as growth factors (class S2), both banned at all times (WADA 2026).