Sales pages pitch BPC-157 and TB-500 as a healing pair, often as if the choice were about which works faster. The question comes earlier. Neither has a published, controlled trial in people [7] [2]. Neither may be compounded by a US pharmacy, and both went before FDA's compounding advisers in July 2026 [1].
Two different peptides sold for the same promise
BPC-157 is a chain of 15 amino acids. FDA's briefing describes it as a fragment of a protein that has been found in gastric juice, and notes it is also called bepecin or PL-14736 [1]. It has nothing to do with thymosin.
TB-500 is shorter: 7 amino acids, a synthetic copy of amino acids 17 to 23 of thymosin beta-4 with an acetyl group added (Ac-LKKTETQ) [2]. Thymosin beta-4 itself is a 43-amino-acid protein. That difference matters, because most of the human research people quote for TB-500 used the full protein, not the fragment sold.
FDA also found that both names are used loosely. Different salts and forms are sold under the same common name, which FDA calls a safety risk because a patient "may be dosed with a different" substance than the one ordered [2].
Side by side: thin evidence on one side, none on the other
| BPC-157 | TB-500 | |
|---|---|---|
| Size | 15 amino acids [1] | 7 amino acids [2] |
| What it comes from | A fragment of a protein found in gastric juice, per FDA | A fragment of thymosin beta-4 (amino acids 17 to 23) |
| Published human studies | 3 uncontrolled studies, 30 people [7] | None [2] |
| Strongest human result | Symptom relief in small uncontrolled pilots; certainty very low | None |
| FDA status | Never approved; no 503A route; out of Category 2 since April 2026 | Never approved; no 503A route; out of Category 2 since April 22, 2026 |
| Use FDA evaluated, July 2026 | Ulcerative colitis [1] | Wound healing [2] |
| FDA briefing conclusion | Criteria "weigh against" listing | Criteria "weigh against" listing |
| Sport | Prohibited at all times, WADA S0 (non-approved substances) [12] | Prohibited at all times, WADA S2.3, "Thymosin-β4 and its derivatives e.g. TB-500" [12] |
BPC-157's human evidence: three small studies without a control group
A 2026 systematic review searched four databases to June 2026 for any human study of BPC-157. It found three, with 30 people in all: a knee-pain injection study (16), a bladder-instillation pilot for interstitial cystitis (12) and an IV safety pilot (2) [7]. All three reported improvement in most people and no treatment-related side effects. All were judged of poor quality, and the certainty of evidence was rated very low.
The individual reports show why. In the cystitis pilot, 10 of 12 patients reported their symptoms fully resolved, with no control group [8]. The cystitis pilot used BPC-157 made by a 503A compounding pharmacy. The IV pilot treated 2 people at a private clinic in Florida and looked at safety only [9]. Both were run by the same lead author.
There is one controlled trial, but it never reached a journal. FDA's briefing describes a 2005 meeting abstract of a randomized, placebo-controlled enema trial in 53 people with ulcerative colitis. FDA found its details too thin and called the data "inadequate to support the efficacy and safety" of BPC-157 for that use [1]. Whether any of this adds up to a treatment is covered in does BPC-157 work.
TB-500's human evidence: none for the fragment that is sold
FDA's 2026 review searched the medical literature and "did not identify data, such as clinical studies, on the use of TB-500 in humans" [2]. It found no human studies of how the body handles it and no case reports. The three references the nominator submitted were all studies of thymosin beta-4.
The thymosin beta-4 research is real but answers a different question. In one example, a 9-patient phase 2 trial of thymosin beta-4 eye drops for severe dry eye, discomfort fell 35.1% more than with the inactive drops at day 56 [11]. That was the full 43-amino-acid protein in an eye drop. It says nothing direct about a 7-amino-acid fragment injected under the skin.
| Study | Substance | Who and how many | Design | What it found |
|---|---|---|---|---|
| Poolton 2026 [7] | BPC-157 | 30 people across 3 studies | Systematic review of uncontrolled studies | Very low certainty; no treatment-related side effects reported |
| Lee 2024 [8] | BPC-157 | 12 patients with interstitial cystitis | Retrospective pilot, no control | 10 of 12 reported full symptom relief |
| Lee 2025 [9] | BPC-157 | 2 healthy adults | IV safety pilot | No side effects reported; safety only |
| Sosne 2015 [11] | Thymosin beta-4 (not TB-500) | 9 patients with severe dry eye | Randomized, double-masked eye-drop trial | Discomfort -35.1% vs inactive drops |
| Any study of TB-500 itself | TB-500 | None found by FDA [2] | None | Unknown |
Better for healing or tendons? No human study has tested either
The tendon and ligament claims come from animals. A 2025 systematic review of BPC-157 in sports medicine found 36 studies, 35 of them preclinical, and "no clinical safety data" [10]. Its one human study was a knee-pain report, not a tendon trial. For TB-500 there is nothing to review: FDA found no human data of any kind [2]. Back and joint pain claims are taken apart in BPC-157 for back pain and arthritis.
Safety: FDA's concerns are about what is unknown
FDA raised the same two concerns for both peptides. Injected peptides can trigger immune reactions, and impurities or clumping from manufacturing raise that risk. FDA also notes it can't rule out those risks without data on what each vial contains [1] [2].
BPC-157 has a few side-effect reports. In older enema studies in healthy people, the most common side effects were headache and flatulence, per FDA's summary of two meeting abstracts [1]. TB-500 has nothing to summarize, and FDA wrote that its potential risks in humans "are unknown" [2]. The longer safety review is on is BPC-157 safe.
Status: the same July 2026 meeting, no FDA decision yet
Neither peptide has ever been approved, and neither has a USP monograph or a place in an approved drug [1] [2]. Both sat in Category 2 of FDA's 503A list from 2023 and were moved to the "nominated but withdrawn" table in April 2026 when their nominations were withdrawn [4]. Leaving Category 2 is not a clearance. Neither is on the bulks list.
FDA still took both to its advisory committee on July 23, 2026. Its briefings said the criteria "weigh against" listing either one [1] [2]. FDA has posted no minutes, transcript or vote [3]. A trade journal reported that the committee voted 8 to 6, with 1 abstention, to recommend both, going against FDA's scientists [6]. A committee vote is advice to FDA, and FDA has issued no rule as of this update. The approval question is answered on is BPC-157 FDA approved, and the purchase question is answered as a matter of status on can you buy BPC-157 legally.
| Date | BPC-157 | TB-500 |
|---|---|---|
| September 29, 2023 | In 503A Category 2 [5] | In 503A Category 2 [5] |
| April 2026 | Moved out of Category 2; nominations withdrawn [4] | Moved out of Category 2 on April 22, 2026; nomination withdrawn [4] |
| July 23, 2026 | Advisory meeting; FDA briefing weighs against listing | Advisory meeting; FDA briefing weighs against listing |
| Now | No FDA vote record or decision posted | No FDA vote record or decision posted |
Taking them together: no study in people
Clinics often sell the two as a combination. No study has tested BPC-157 and TB-500 together in people, and with no human data on TB-500 alone there is nothing to build a combination claim on. What each one is, and why they are sold as a pair, is on the TB-500 page. How this site weighs evidence and status is in how we check.