TB500

• Week 1-2: Little change yet; some report redness or mild headache
• Week 2-4: Users report first gains: less stiffness, easier training
• Week 4-8: Users report the most progress; course ends after week 6
• Week 8-12: On break until week 10; then judge the injury
• Side effects: 911: face or throat swelling; see a doctor: infection, new lump

More on each stage

Week 1-2

No human study has measured this. Most people feel little yet. Some report redness where they inject, or a mild headache or tiredness on shot days.

Week 2-4

Community reports say first improvements usually show up around weeks 2-3: less stiffness, aches calming in more than one spot, easier training. Results vary from person to person.

Week 4-8

Users report the most progress by weeks 4-6. The store course ends after week 6 (12 shots, 24 mg, so plan on 3 vials); week 7 starts your 4-week break. In rats, a torn knee ligament healed stronger at 4 weeks.

Week 8-12

You are on the break until the end of week 10. Judge the injury then. If it still needs help, start another 6-week round. If nothing changed after a full round, see a doctor about the injury before trying again.

Side effects

Usually mild: injection-site redness, sometimes a headache or tiredness. Stop and get help for face or throat swelling, trouble breathing, or a hot, spreading red patch.

Based on what people report in the community sources below. Results vary, and many responses are anecdotal.

• Skin wounds and ulcers

  Clinical trial

  In a 73-patient trial on leg ulcers, a 0.03% thymosin beta-4 skin gel may have sped healing, and about 1 in 4 patients healed fully within 3 months. This used a skin gel of the full-length protein, not TB500 shots.3

• Faster skin regrowth over wounds in rats

  Animal/lab study

  In rats with skin wounds, thymosin beta-4 increased new skin growing over the wound by 42% versus salt water at day 4 and by up to 61% at day 7, and treated wounds shrank at least 11% more by day 7. Full-length protein, not TB500 shots.7

• Eye surface healing

  Clinical trial

  Thymosin beta-4 eye drops (0.1%) cut eye discomfort by 35% versus placebo in a small severe dry-eye trial. In another trial they healed a stubborn corneal sore in 6 of 10 patients versus 1 of 8 on placebo. Eye drops, not shots.45

• Ligament and tendon repair

  Animal/lab study

  In rats with a cut knee ligament, a single dose placed in the gap gave neater collagen fibres and a stronger ligament at 4 weeks.9

• Muscle repair

  Animal/lab study

  Injured mouse muscle makes more thymosin beta-4, and the peptide drew muscle repair cells toward the injury in lab tests.10

• Heart repair after a heart attack

  Animal/lab study

  In mice, thymosin beta-4 helped heart muscle cells survive a heart attack and improved heart function afterwards.11

• Whole-body recovery and looser joints

  Community report

  Users report aches easing in several places at once, better flexibility, and faster bounce-back after training or surgery.25

What it has been studied for

• Leg (venous) ulcers that will not heal: skin gel of full-length thymosin beta-43Clinical trial
• Severe dry eye: 0.1% eye drops4Clinical trial
• Corneal sores that will not heal (neurotrophic keratopathy): 0.1% eye drops5Clinical trial
• Heart attack recovery: IV thymosin beta-4 was safety-tested in healthy volunteers for this; not tested in patients111Human study
• Ligament injury9Animal/lab study
• Wound healing in diabetic and older animals (the TB500 piece itself was tested)8Animal/lab study
• Knee pain: doctor-given knee injections of BPC-157 plus thymosin beta-4 in 4 patients6Human study

Your body already makes a protein called thymosin beta-4 in most cells and releases it where you are hurt. TB500 is sold as a lab-made form of it. Anti-doping labs found that TB500 products contain its active piece, 7 building blocks (amino acids) long, though some sellers use the name for the full 43-block protein. That piece grabs the cell's inner scaffolding (actin), which lets repair cells crawl into damaged tissue. Animal studies also show new blood vessels, less inflammation, and less scarring. People take it for whole-body repair rather than fixing one spot.

Peak

Not established in humans for TB500 under the skin. Full-length thymosin beta-4 given by IV drip peaked in the blood within 3 to 15 minutes.

Half-life

Not established in humans for TB500. Full-length thymosin beta-4 by IV had a half-life of about 0.5 to 2 hours, getting longer at higher doses.

Cleared

Not established in humans. IV thymosin beta-4 did not build up over 10 daily doses. In rats given TB500, a small breakdown piece was still found up to 72 hours later.

Half-life is how long it takes the body to remove half of a dose.2113

Twice a week. Any time of day. Space the two shots 3 to 4 days apart, such as Monday and Thursday. 2 days a week (for example Monday and Thursday). Units are for a 10 mg vial mixed with 1 mL water (10 mg per mL).

• Lower end · conservative minor-injury dose

  2 mg twice weekly

  A conservative healing dose some use for minor injuries and joint discomfort without a distinct loading phase.25

• Most common · loading + maintenance structure

  4-8 mg per week (loading), then 2-4 mg per week (maintenance)

  The community-standard loading-then-maintenance structure biohackers built for tendon, ligament, and systemic repair — usually stacked with BPC-157 as the Wolverine protocol.25

• Higher end · aggressive post-surgical protocol

  5-10 mg, 2-3 times weekly

  An aggressive post-surgical or severe-injury protocol a minority report — higher than most community members use.25

Research protocols

• Healthy volunteers, IV safety study (40 people, full-length thymosin beta-4)

  One IV dose of 42, 140, 420, or 1,260 mg, then the same dose daily for 14 days. Well tolerated; no dose-limiting side effects or serious adverse events.1

• Healthy volunteers, IV safety study (84 people, lab-made human thymosin beta-4)

  Single IV doses of 0.05 to 25 mcg per kg of body weight, or 0.5 to 5 mcg per kg once a day for 10 days. No serious adverse events.2

• Leg ulcer trial (73 patients)

  Thymosin beta-4 gel on the ulcer at rising strengths, compared with placebo. 0.03% looked most promising; about 1 in 4 patients healed fully within 3 months.3

• Severe dry eye trial (9 patients)

  0.1% thymosin beta-4 eye drops 6 times a day for 28 days.4

• Rat knee ligament study

  1 mcg of thymosin beta-4 in fibrin glue placed once into the ligament gap; checked at 4 weeks.9

• Racehorse doping-control study

  A single dose of TB500 containing 10 mg of Ac-LKKTETQ was given to horses so labs could learn to detect it.14

• Biohacking community (Peptide Protocol Wiki, 120 reports; not a study)

  Two popular plans: 2 to 5 mg twice a week for 4 to 8 weeks, or a loading phase of 4 to 8 mg a week split into 2 or 3 shots for 4 to 6 weeks, then 2 to 4 mg a week. The store plan (2 mg twice a week, 4 mg a week) is a starting point, and you can step up toward 5 mg a shot if you need more.25

TB-500 (a 7-amino-acid fragment) is not the same molecule as the full-length Thymosin Beta-4 used in clinical research, so trial results may not transfer. The loading/maintenance structure is community-derived, with no basis in published human studies. TB-500 is not FDA-approved.

Dosing guidance built from the cited research and community reports. It is not a prescription.

1. 1
2. 2
3. 3
4. 4
5. 5
6. 6
7. 7
8. 8
9. 9
10. 10

On: 6 weeks Break: 4 weeks

A full course at the store pace takes 3 vials. A mixed vial keeps for up to 90 days.

Why the break helps

No study has tested whether breaks help with TB500. The break is a community habit with two practical reasons: it lets you see whether the injury holds up without the peptide, and it limits nonstop use of a compound that grows new blood vessels and has no long-term human safety data (the longest injected human dosing studied was 14 days, by IV). Community runs are usually 4 to 8 weeks.

Common

• Redness, pain, or swelling where you injected

  What to do Rotate sites and use a fresh syringe every time. It usually fades on its own. If redness spreads or gets hot and painful, treat it as an infection (see below).

• Tiredness or a mild headache on shot days (community reports)

  What to do Rest and drink water. 2 mg is already the low end of what people use, so if it keeps happening, stop and talk to a doctor.

Stop and get help

• Allergic reaction: hives or rash, swelling of the face, lips, or throat, trouble breathing, or feeling faint. Emergency doctors describe this starting about 30 minutes after a shot from a new vial of a BPC-157/TB500 stack.

  What to do Stop and call 911 (or your local emergency number) right away. Report it to Poison Control at 1-800-222-1222.

• Infection at the injection site: redness that spreads, heat, pus, red streaks, or fever

  What to do Stop injecting and see a doctor the same day.

• A new lump, or a known growth getting bigger

  What to do Stop TB500 and see a doctor. Thymosin beta-4 helped tumours grow and spread in mice, so do not wait.

Do not use if

• You have cancer now, have had it, or have a strong family risk: in mice, melanoma cells making extra thymosin beta-4 grew larger tumours and spread to the lungs about 4 times as much.
• You are pregnant, trying to get pregnant, or breastfeeding: there is no safety data.
• You are under 18.
• You compete in a drug-tested sport: WADA bans thymosin beta-4 and TB500 at all times, in and out of competition.

Sources2328

Storage

Keep it

Keep the mixed vial in the fridge (2-8 °C / 36-46 °F), away from heat and light, and do not freeze it. Do not use it if it turns cloudy or changes colour.

How long

Use within 90 days of mixing. A mixed vial kept in the fridge holds its strength for 60-90 days, then slowly starts to lose potency. Wipe the rubber top with an alcohol swab before every draw.

Drawing your dose

Syringe: a 0.5 mL (50-unit) U-100 insulin syringe.

1. With this mix, every 1 unit line on a U-100 insulin syringe holds 0.1 mg (100 mcg). Draw to the 20-unit line for 2 mg, or to 50 units for 5 mg.
2. One 10 mg vial holds 5 shots of 2 mg (about 2.5 weeks at twice a week). The last draw can come up a little short, because a few drops stay in the vial; tilt the vial and pull from the lowest point.
3. Hold the syringe at eye level, flick out air bubbles, and push the plunger back to the exact line.
4. Pinch a fold of skin, insert the needle at 45 to 90 degrees, push slowly, and wait a few seconds before pulling out.
5. Use a new sterile syringe every time and never share one.
6. Some people inject near the sore area; others use the belly because TB500 is meant to work through the whole body.

• BPC-157

  The store's Wolverine stack. BPC-157 is usually aimed at one sore spot, while TB500 is used for the whole body. In rats, BPC-157 helped a cut Achilles tendon heal fully. In a small knee-injection chart review, 3 of 4 people given both peptides improved.17626

• GHK-Cu

  Part of the store's Glow stack. GHK-Cu raises collagen and elastin and supports skin repair, while thymosin beta-4 moves repair cells into wounds and reduces scarring. They have not been tested together.1820

• KPV

  Part of the store's KLOW stack. KPV turned down the NF-kB inflammation switch and reduced gut inflammation in mice, adding a calming effect alongside TB500's repair. They have not been tested together.1920

Interactions

• Cancer treatment, especially drugs that block blood-vessel growth (such as bevacizumab)

  Thymosin beta-4 grows new blood vessels and helped tumours spread in mice, which could in theory work against these drugs.

  What to do Do not use TB500 during cancer treatment unless your oncologist approves.

• Blood thinners and immune-suppressing medicines

  No interaction studies exist. A community safety guide advises caution with both.

  What to do Ask the doctor who prescribes them first. Report unusual bruising or bleeding.

• ACE-inhibitor blood-pressure pills (lisinopril, enalapril, and similar)

  The body cuts full-length thymosin beta-4 into a small peptide (Ac-SDKP) that ACE breaks down, so these pills raise its levels. This only applies if your vial holds the full-length protein, and whether it matters is unknown.

  What to do Tell your doctor you use TB500. Do not stop your blood-pressure medicine.

• Other peptides in a stack (BPC-157, GHK-Cu, KPV)

  Mixing several unregulated peptides has not been studied and in theory raises the chance of side effects.

  What to do Start one peptide at a time so you can tell which one causes a reaction.

Videos

• BPC-157 & TB-500: The Truth About the Wolverine StackDr. Alex Tatem · 2026
• I Analyzed the Wolverine Stack Evidence—Here's What I FoundDr. Chris Raynor | Not Your Everyday Ortho · 2026

Sources

1. 1Ruff et al., Ann N Y Acad Sci 2010 (IV thymosin beta-4, 40 healthy volunteers)Clinical trial
2. 2Wang et al., J Cell Mol Med 2021 (IV thymosin beta-4 phase 1, pharmacokinetics)Clinical trial
3. 3Guarnera et al., Ann N Y Acad Sci 2010 (venous ulcer trial, 73 patients)Clinical trial
4. 4Sosne et al., Cornea 2015 (severe dry eye phase 2 trial)Clinical trial
5. 5Sosne et al., Int J Mol Sci 2022 (neurotrophic keratopathy phase 3 trial)Clinical trial
6. 6Lee & Padgett, Altern Ther Health Med 2021 (knee injection chart review, 16 patients)Study
7. 7Malinda et al., J Invest Dermatol 1999 (rat wound healing)Study
8. 8Philp et al., Wound Repair Regen 2003 (TB-500 fragment in diabetic and aged mice)Study
9. 9Xu et al., Regul Pept 2013 (rat knee ligament)Study
10. 10Tokura et al., J Biochem 2011 (muscle repair cells in mice)Study
11. 11Bock-Marquette et al., Nature 2004 (heart repair in mice)Study
12. 12Cha et al., J Natl Cancer Inst 2003 (tumour growth and spread in mice)Study
13. 13Rahaman et al., J Chromatogr B 2024 (TB-500 breakdown in rats)Study
14. 14Ho et al., J Chromatogr A 2012 (TB-500 detection in horses)Study
15. 15Esposito et al., Drug Test Anal 2012 (identifies Ac-LKKTETQ in TB-500)Study
16. 16Delcourt et al., Drug Test Anal 2025 (thymosin beta-4 banned by WADA and racing bodies)Study
17. 17Staresinic et al., J Orthop Res 2003 (BPC-157, rat Achilles tendon)Study
18. 18Pickart & Margolina, Int J Mol Sci 2018 (GHK-Cu review)Review
19. 19Dalmasso et al., Gastroenterology 2008 (KPV in mouse colitis)Study
20. 20Goldstein et al., Expert Opin Biol Ther 2012 (thymosin beta-4 review)Review
21. 21Maar et al., Cells 2021 (thymosin beta-4 review, incl. cancer questions)Review
22. 22Hrenak et al., Curr Pharm Des 2015 (Ac-SDKP and ACE inhibitors)Review
23. 23FDA: Bulk drug substances that may present significant safety risks (TB-500 entry)Reference
24. 24emDocs ToxCard 2026: Peptide toxicity (emergency physicians)Practitioner
25. 25Peptide Protocol Wiki: TB-500 community protocols (120 reports)Community
26. 26Peptide Protocol Wiki: TB-500 overview (storage, stacks)Community
27. 27Peptide Protocol Wiki: TB-500 risks and interactionsCommunity
28. 28Peptide Protocol Wiki: TB-500 side effectsCommunity

Where people discuss it

• r/Peptides (subreddit)
• Peptide Protocol Wiki — TB-500 community (120 reports)

Some peptides, like semaglutide (Ozempic and Wegovy), are FDA-approved medicines. Most of the peptides people research are not. That label sounds like the FDA tested something and turned it down. Usually it means something else: nobody has paid for the studies the FDA needs to see. Here is why.

The FDA doesn’t test drugs. Companies do.

The FDA does not run its own drug tests. A company that wants to sell a new medicine has to test it first, and pay for it. It studies the drug in animals, then in people: first 20 to 100 volunteers, then a few hundred, then up to 3,000. Then it sends all the results to the FDA. FDA scientists review them and decide whether the benefits outweigh the risks.

So approval always starts with a company asking for it. If no company applies, the FDA has nothing to review, however promising the research looks.

Those studies cost about a billion dollars

A study in the medical journal JAMA estimated that bringing one new drug to market costs a typical company about $1.1 billion. That figure includes the money spent on drug ideas that failed along the way, because many drugs that start human testing never make it.

A patent is how a company earns that money back

A patent is a right the government gives an inventor. For up to 20 years from the day the inventor applies, nobody else may make or sell the invention without permission.

For a drug company, that right is what makes the billion-dollar bet worth it. While the patent lasts, the company is the only seller, so it can charge enough to pay back the studies and the failures. When the patent runs out, other companies can sell cheap copies, called generics, and the price drops.

The FDA adds a shorter shield of its own. For 5 years after a brand-new drug is approved, no copycat version can apply for approval. That helps, but it is much shorter than a patent can last.

Why most peptides can’t be patented

To get a patent, an invention has to be new, and it has to be something people made, not something found in nature. Most popular peptides fail one test or both.

They come from nature. Many are copies or small pieces of molecules your body already makes. KPV is a 3-building-block piece of the hormone that tans your skin. BPC-157 is copied from a protein in stomach juice. In 2013 the US Supreme Court ruled that something that exists in nature, like a human gene, cannot be patented just because someone found it and pulled it out.

They aren’t new anymore. Many were first described in research papers decades ago. Scientists were already testing KPV in the 1980s. Once something has been published, it no longer counts as new, so nobody can patent it now, and any patents from back then have long since run out.

Without a patent, a company that paid for the studies would soon face rivals selling the same peptide without having paid for any research. Few companies will spend a billion dollars on a product anyone can copy. So nobody goes first, and the large human studies never happen.

The workaround: change the molecule

Drug companies do make peptide medicines, but they change the peptide first. A changed molecule is a new invention, so it can be patented. Semaglutide is a lab-made version of GLP-1, a gut hormone your body releases after meals, changed so one shot lasts a week. Tesamorelin (Egrifta) is the body’s own growth-hormone signal with a small fatty chain added. Both went through the full studies, and both are FDA-approved.

The natural versions, and the many peptides nobody has changed and patented, stay where they are: studied in labs and animals, used by the biohacking community, and never put through large human trials.

What this means for you

When a peptide is “not FDA-approved,” it usually means no company has paid for the large human studies. It does not mean the FDA tested it and found it harmful.

It also does not mean it is proven safe or proven to work. Without those studies, nobody knows the best dose for sure, or what rare or long-term side effects it may have. And the FDA does not check research peptides for purity or strength the way it checks approved medicines. That is why this page labels every finding by the kind of study behind it, and lists who should not use it.

Sources for this section

1. 1FDA: How drugs are developed and approved (the FDA does not test drugs; companies submit the evidence)
2. 2FDA: The drug development process, step 3: clinical research (study sizes for each phase)
3. 3Wouters, McKee & Luyten, JAMA 2020, corrected 2022: median cost to bring a new drug to market, $1.14 billion
4. 4US patent law, 35 U.S.C. § 154: a patent lasts 20 years from the filing date
5. 5FDA: Frequently asked questions on patents and exclusivity (5-year new chemical entity exclusivity)
6. 6US Supreme Court, Association for Molecular Pathology v. Myriad Genetics (2013): naturally occurring genes cannot be patented