TB-500
TB-500 is the name sold for thymosin beta-4, a natural repair protein the body keeps in nearly every cell. Some sellers use the name for a short piece of it instead. It helps cells move toward an injury. Most of what is known comes from animal studies, and it is not approved anywhere.
What it’s studied for
- Dry eyeStudied in humans
In a human trial of thymosin beta-4 eye drops, eye discomfort fell about a quarter versus placeboplaceboAn inactive version given to some trial participants so the real effect can be measured fairly.. source
- WoundsStudied in animals or lab
In animal studies, skin wounds closed faster, with less scarring. source
- Tendons and ligamentsStudied in animals or lab
In an animal knee-ligament study, the healing fibers were better organized and held up better at 4 weeks. source
2 more uses studied
- HeartStudied in animals or lab
In animal studies after a heart attack, more heart cells survived and the damaged area was smaller. source
- Injury healing in peopleUnknown
No human trial has tested it for muscle, tendon or ligament healing, the main reason people look into it.
New here? Three things worth knowing first
What’s a peptidepeptideA short chain of amino acids. Proteins are long chains; peptides are short ones, usually under 50 amino acids.? A short chain of amino acids, the building blocks of protein. Many act like messengers in the body.
Why the vial has to be mixed. It ships as a dry powder. You add bacteriostatic waterbacteriostatic waterSterile water with a little benzyl alcohol that stops bacteria growing, so a mixed vial lasts days or weeks. Often called BAC water., and the amount you add decides how many unitsunitsMarks on an insulin syringe. On a U-100 syringe, 100 units = 1 mL. How many units equal a dose depends on how much water was added. on the syringe equal one dose. The calculator does that math.
SubcutaneoussubcutaneousUnder the skin, into the fat layer. The usual route for peptide injections. Often shortened to sub-Q. injection, Once daily. Subcutaneous means into the fat layer just under the skin. It uses a small insulin syringe. Any word with a dotted underline on this page opens a short definition.
Dosage guidelines
Two patterns are described. One is 250 to 500 mcg once a day alongside BPC-157. The other is 2 to 2.5 mg twice a week for 4 to 6 weeks, sometimes followed by a dose every 1 to 2 weeks.
The doses below come from published reference protocols and, where they exist, the human trials. Tap a row to load it into the calculator.
Figures reviewed against their sources in October 2026. Where a trial or approved label sets a schedule, it is shown first; where a label sets one fixed dose, the FAQ below says so.
Daily, with BPC-157. 250 to 500 mcg once a day, paired with 250 to 500 mcg of BPC-157. Runs 4 to 8 weeks for new injuries, 8 to 12 for old ones.
Active healing (Wolverine stack) · 250–500 mcg TB-500 a day (with 250–500 mcg BPC-157), once daily · 4–8 weeks for acute injuries; 8–12 weeks for chronic ones
| Step | Dose per injection | Draw to | |
|---|---|---|---|
| 1 | 250 mcg (0.25 mg) | 5 units | |
| 2 | 500 mcg (0.5 mg) | 10 units |
Doses marked “between 5-unit marks” sit between the 5-unit lines on a 1 mL syringe; the 1-unit lines on a 0.5 mL or 0.3 mL syringe make them easier to read.
Units are for a 10 mg vial mixed with 2 mL of water. Change the vial in the calculator
Full protocol details
Other protocols described
- Acute injury. Follows the loading pattern: 2 to 2.5 mg twice a week for 4 to 6 weeks.
- Chronic injury. Follows the loading pattern for longer: 2 to 2.5 mg twice a week for 6 to 8 weeks.
- Post-surgical. 4 to 6 mg a week in all for 4 to 6 weeks, with no split given. Described as run with the surgeon's approval.
Mixing in the protocols: 5 mg vial + 2 mL bacteriostatic water · 250 mcg per 10 units (daily stack dosing).
Other forms: Oral use is not described: unlike BPC-157, thymosin beta-4 is not stable in the stomach.
Daily, with BPC-157
Active healing (Wolverine stack)
- Dose
- 250–500 mcg TB-500 a day (with 250–500 mcg BPC-157)
- How often
- Once daily
- Timing
- Any time; no fasting
- Route
- Subcutaneous
- How long
- 4–8 weeks for acute injuries; 8–12 weeks for chronic ones
- Break
- No cycling required; stopped or reduced once healed
Traditional loading
- Dose
- 2–2.5 mg twice a week (4–5 mg a week)
- How often
- Twice weekly (Monday/Thursday or Tuesday/Friday)
- Route
- Subcutaneous
- How long
- 4–6 weeks
Maintenance
- Dose
- 2–2.5 mg
- How often
- Once every 1–2 weeks, as needed
- Route
- Subcutaneous
For general maintenance the figure given is 2–2.5 mg every 2 weeks.
Acute injury
- Dose
- 4–5 mg a week
- How often
- Twice weekly at 2–2.5 mg, as in the loading pattern
- Route
- Subcutaneous
- How long
- 4–6 weeks
Chronic injury
- Dose
- 4–5 mg a week
- How often
- Twice weekly at 2–2.5 mg, as in the loading pattern
- Route
- Subcutaneous
- How long
- 6–8 weeks
Post-surgical
- Dose
- 4–6 mg a week
- Route
- Subcutaneous
- How long
- 4–6 weeks
Weekly total; no split is given. Described as run with the surgeon's approval.
Cycle
4–8 weeks for acute injuries; 8–12 weeks for chronic ones; No cycling required; stopped or reduced once healed
When a step up happens
User reports describe stepping up only after progress has stalled for two weeks or more, and only if the previous step was tolerated. Everyone is different.
Timing: Any time; no fasting.
Peptide calculator
Already filled with this vial. Change anything you like.
How much is in your vial?
Check the label. The most common strengths:
Every 10 units = 0.5 mg.
5 units. 2 mL of BAC water
How the vial is mixed
The powder has to be dissolved in bacteriostatic (BAC) water before use. For a 10 mg vial this page uses 2 mL, which puts the usual dose on a round syringe mark: every 10 units is 500 mcg.
STEP 1Wipe both topsAlcohol pad on the peptide vial and the BAC water vial.
STEP 2Draw 2 mL of waterThat’s 2 full 1 mL syringes.
STEP 3Add it slowlyAim at the glass wall, not at the powder.
STEP 4Swirl, don’t shakeRoll gently until clear. Refrigerate after.What to watch for
- Tiredness or a flu-like feeling for a day or two early onReported by users
- Mild headacheReported by users
- Redness or irritation where the shot goes inReported by users
- A head rush or lightheaded feeling right after a shotReported by users
- A theoretical cancer concern: in lab and animal studies, high thymosin beta-4 levels are linked to tumor growthUnknown
Not for anyone with active cancer, a past cancer without a cancer doctor's input, or an allergy to thymosin peptides. It is banned in tested sport. Talk to a doctor first, especially if pregnant, breastfeeding, or living with an immune, autoimmune or heart condition.
Reasons to get medical help right away: trouble breathing, swelling of the face or throat, chest pain, fainting, or any severe or worrying reaction.
Full side-effect list and who should avoid it
In published research
- Full-length thymosin beta-4 up to 1,260 mg intravenously: no dose-limiting toxicity, rare mild to moderate side effects
- 84 volunteers, repeated intravenous dosing: no dose-limiting toxicity or serious adverse events, no build-up
- Eye-drop trial: no adverse events in 72 people over 32 days
- Animal toxicology: no significant adverse effects up to 100 mg/kg
- No long-term human safety data. The FDA found no human exposure data for the 7-amino-acid fragment sold under the same name
What users report
- Common: tiredness for 1–2 days early on or during loading, mild headache, injection-site redness or irritation
- Less common: head rush or lightheadedness right after injection, a flu-like feeling at the start, nausea
Theoretical concerns
- In lab and animal studies high thymosin beta-4 levels are linked to tumor growth and spread, so there is a theoretical cancer concern
Not for
- Active cancer or tumors
- A history of cancer without an oncologist's input
- Known allergy to thymosin peptides
- Tested athletes (WADA S0)
Use caution with
- Pregnancy or breastfeeding
- Severe immune deficiency
- Active autoimmune disease
- Heart and circulation conditions
- Precancerous conditions or unexplained masses
- No set bloodwork panel; healing is described as tracked with a physician or physical therapist, with imaging clearance from an oncologist if there is any cancer history
How the body handles it
- Intravenous full-length protein: levels rise in proportion to dose, with half-life lengthening at higher doses
- No build-up with repeat intravenous dosing
- No published data after injection under the skin; the 10-day half-life figure has no source
Supplies
What 12 weeks of the schedule above takes, counted dose by dose.
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Stacking
The community pairs TB-500 most often with BPC-157, and sometimes GHK-Cu, but no pairing has been tested in a trial.
- BPC-157Reported by users
Known as the Wolverine stack: BPC-157 is described as building blood supply, and TB-500 as moving repair cells in and lowering scarring. The cancer caution applies to both.
- GHK-CuReported by users
Described as a good match: TB-500 for moving repair cells and less scarring, GHK-Cu for rebuilding collagen, the protein that gives tissue its strength.
Also used alongside it, with no interactions described: GLP-1 drugs, growth-hormone peptides and testosterone therapy.
Go deeper
Every study, community report and source behind this page.
What the studies show20 findings, each with its evidence label
Status, October 2026. TB-500 (thymosin beta-4) is not approved anywhere, and no product sold as TB-500 has been tested in a human trial; the FDA said on April 15, 2026 it would take it off its Category 2 compounding list, and an advisory committee voted 8–6 on July 23, 2026 to recommend it for the 503A bulks list, which is non-binding and not yet acted on. Source
How it works
Actin is the protein scaffolding cells use to change shape and move. In lab studies, thymosin beta-4 binds single actin unitsunitsMarks on an insulin syringe. On a U-100 syringe, 100 units = 1 mL. How many units equal a dose depends on how much water was added. one to one, holds them in reserve, and hands them to a partner protein, profilin, which feeds them to the growing ends of actin filaments. That is what lets a cell crawl toward an injury. The short fragment some sellers call TB-500 carries only this actin-binding region.
The full protein does not bind the surrounding tissue matrix and is small, so in animal studies it acted throughout the body rather than only where it was injected. In lab work, skin-cell migration rose 2 to 3 fold at as little as 10 picograms.
Other effects in animal and lab studies come from different parts of the full protein. Positions 17–23, the region the short fragment carries, are linked to new blood-vessel growth and hair growth. Positions 1–4 form Ac-SDKP, a fragment that lowered inflammatory signals and scarring in lung, liver, kidney and heart models. Positions 1–15 are linked to keeping cells alive. The full protein also drew stem and progenitor cells to injured tissue.
Benefits
Each one carries an evidence label, so you can see how much is actually known.
Wound healing
In animal studies of the full protein, skin closure rose 42% by day 4 and up to 61% by day 7, wounds contracted at least 11% more, and scarring was lower with breaking strength kept. source
Tendon and ligament
In an animal knee-ligament model, fibers were better organized and collagen fibrils thicker, with better mechanics at 4 weeks. source
Muscle
In an animal model of muscular dystrophy, more muscle fibers regenerated, but strength, heart function and fibrosis did not improve. source
Heart
In animal studies after a heart attack, heart-cell survival improved, infarcts were smaller and pumping measures better. source
Dry eye
In a phase 2phase 2A mid-stage human trial that tests dose and early effect in hundreds of people. Phase 3 confirms results in thousands. human trial of thymosin beta-4 eye drops, eye discomfort fell 27% against placeboplaceboAn inactive version given to some trial participants so the real effect can be measured fairly.. source
Spinal cord
After spinal cord injury in animals, myelin protein rose 57.8% and activated immune cells fell 36.9%. source
Hair growth
In animal studies, the full protein activated hair-follicle stem cells. source
Injury healing in people
No human trial has tested thymosin beta-4 for injury healing, the main reason people look into it.
What the science shows
Wound healing (1999)
Studied in animals or labApplied to the skin or injected, the full protein raised skin closure 42% at day 4 and 61% at day 7, increased wound contraction by at least 11%, and in lab work raised skin-cell migration 2 to 3 fold at 10 picograms. source
Scarring (2010)
Studied in animals or labIncisions healed narrower, with few scar-forming cells and organized mature collagen, while breaking strength was kept. source
Knee ligament (2013)
Studied in animals or labBetter fiber bundles, thicker collagen fibrils and better mechanics at 4 weeks. source
Heart repair (Nature, 2004)
Studied in animals or labAfter a blocked coronary artery, the protein switched on the ILK and Akt survival pathways, and more heart cells survived. source
Heart after loss of blood flow (2013)
Studied in animals or labSmaller infarcts, better pumping and lower injury markers. The change in vessel density was not significant. source
Muscular dystrophy model (2010)
Studied in animals or labMore regenerating fibers, with no gain in strength, heart function or fibrosis. source
Muscle-cell recruitment (2011)
Studied in animals or labThymosin beta-4 released after injury drew in muscle precursor cells. source
Phase 1 safety, intravenous (human, 2010)
Studied in humansPlaceboplaceboAn inactive version given to some trial participants so the real effect can be measured fairly.-controlled trial in healthy volunteers, escalating doses up to 1,260 mg of the full protein. No dose-limiting toxicity, rare mild to moderate side effects, and levels rose in proportion to dose. source
Phase 1 safety, recombinant (human, 2021)
Studied in humansRandomized, double-blind trial in 84 healthy volunteers, single and repeated intravenous doses. No dose-limiting toxicity or serious adverse events, and no build-up with repeat dosing. source
Dry eye, phase 2 (human, 2015)
Studied in humans72 people, 0.1% eye drops of the full protein. Discomfort fell 27% against placebo and corneal staining improved significantly, with no adverse events over 32 days. source
Spinal cord injury (2014)
Studied in animals or labEvery behavioral measure improved, with more surviving nerve and myelin cells, myelin protein up 57.8% and immune-activation markers down 36.9%. source
What has not been studied
UnknownThere are no human trials for muscle, tendon or ligament healing, the main real-world use, and none of a product sold as TB-500.
What the community reports5 user reports, a timeline and 5 pairings
What to expect
Some users describe tiredness or a flu-like feeling that passes within 24–48 hours.
Reported by usersPain and inflammation are described as easing, especially during a loading phase.
Reported by usersMuscle injuries are described as responding.
Reported by usersTendon and ligament function is described as improving from weeks 3–4, peaking at 6–8.
Reported by usersChronic injuries are described as responding here, less predictably.
Reported by usersIn two human safety trials, intravenous full-length thymosin beta-4 was well tolerated at doses far above those described for TB-500. There are no published data on how it behaves after an injection under the skin. The widely quoted 'about 10-day half-lifehalf-lifeHow long it takes for half of a compound to leave the body. A longer half-life usually means less frequent dosing.' does not come from any published study.
What people report
Gathered from user communities. Anecdotal: useful for what to expect, not proof.
Injury recovery
Faster recovery from tendon, ligament, muscle and post-surgical injuries, mostly alongside BPC-157: less pain in 1 to 2 weeks, function over 4 to 8. Shoulders, knees and elbows are the most discussed.
Where it fits
TB-500 is seen as better for body-wide inflammation and large areas, BPC-157 for specific sites.
Dosing patterns
The older pattern is a loading phase of 2 to 2.5 mg twice a week for 4 to 6 weeks, then 2 mg every 1 to 2 weeks. Many people stacking with BPC-157 now run 250–500 mcgmcgMicrogram, one thousandth of a milligram. 1 mg = 1,000 mcg. of each daily.
Side effects
Minimal for most. Tiredness or a mild flu-like feeling for 1 to 3 days at the start, mild headache, a head rush after injection, and injection-site irritation.
Hair
Some report incidental hair growth.
Stacking
How it is described alongside other compounds.
BPC-157 (Wolverine stack)
BPC-157 is described as building blood supply at the injury, and TB-500 as mobilizing repair cells and lowering scarring. 250–500 mcg of each daily under the skin, from day one; sharing a syringe and injection site is described. Both promote blood-vessel growth, so the cancer caution applies to each.
GLP-1 drugs
No interaction concerns described.
Growth-hormone peptides (CJC-1295, ipamorelin, sermorelin)
No interaction concerns described. GH peptides keep their fasted schedule; TB-500 can go at any time.
Testosterone therapy
No interaction concerns described.
GHK-Cu
Described as complementary: cell migration and lower scarring alongside collagen remodeling.
Common questions10 questions
Common questions
Does it need to go near the injury?
No. In animal studies the full protein spread throughout the body, so protocols describe any spot under the skin, usually the abdomen or thigh.
Is TB-500 the same as thymosin beta-4?
Usually, yes: products sold as TB-500 are normally the full 43-amino-acid protein. Some sellers use the name for a 7-amino-acid piece of it, the part that binds actin. The vial's certificate of analysis shows which.
Does it need cycling?
No hormonal reason is described, and it is not known to suppress the body's own production. Protocols run it while healing, 4 to 8 weeks and up to 8 to 12, then stop.
Can it start together with BPC-157?
Yes, from day one.
Does it need fasting?
No.
Does TB-500 cause cancer?
That has not been shown in healthy organisms. High levels of thymosin beta-4 are linked to spread in some tumors and are low in others, such as multiple myeloma. Its effects on blood vessels and cell movement could in theory help an existing tumor, which is why cancer is listed as a reason not to use it.
Why do some people feel tired after the first injection?
The cause is unclear; shifts in immune or inflammatory signaling are one suggestion. It passes within 24 to 48 hours.
Can it be taken by mouth?
No; it is not stable in the stomach, so protocols describe injection under the skin.
What does “minimum effective dose” mean?
It is the lowest dose that still produces the effect someone is after. User reports describe starting there and staying there for as long as it keeps working, rather than climbing toward the top of the range. Side effects tend to rise with dose, and the top of each range on this page is a ceiling people report, not a target.
When does the dose go up?
There is no trial schedule for TB-500. User reports describe staying on a dose while it is still working, and moving up only after progress has stalled for two weeks or more and side effects have settled. There is no prize for getting to the top dose fast. These are not quick fixes: most of what people report builds over weeks, not days.
Source material12 studies and documents
References
- Malinda KM, Sidhu GS, Mani H, et al. J Invest Dermatol. 1999;113(3):364-368. pubmed.ncbi.nlm.nih.gov/10469335/…
- Ehrlich HP, Hazard SW 3rd. Ann N Y Acad Sci. 2010;1194:118-124. pubmed.ncbi.nlm.nih.gov/20536458/…
- Xu B, Yang M, Li Z, et al. Regul Pept. 2013;184:1-5. pubmed.ncbi.nlm.nih.gov/23523891/…
- Bock-Marquette I, Saxena A, White MD, et al. Nature. 2004;432(7016):466-472. pubmed.ncbi.nlm.nih.gov/15565145/…
- Bao W, Ballard VL, Needle S, et al. Front Pharmacol. 2013;4:149. pubmed.ncbi.nlm.nih.gov/24348421/…
- Spurney CF, Cha HJ, Sali A, et al. PLoS ONE. 2010;5(1):e8976. pubmed.ncbi.nlm.nih.gov/20126456/…
- Tokura Y, Nakayama Y, Fukada SI, et al. J Biochem. 2011;149(1):43-48. pubmed.ncbi.nlm.nih.gov/20880960/…
- Ruff D, Crockford D, Girardi G, Zhang Y. Ann N Y Acad Sci. 2010;1194:223-229. pubmed.ncbi.nlm.nih.gov/20536472/…
- Wang X, Liu L, Qi L, et al. J Cell Mol Med. 2021;25(17):8222-8228. pubmed.ncbi.nlm.nih.gov/34346165/…
- Sosne G, Ousler GW. Clin Ophthalmol. 2015;9:877-884. pubmed.ncbi.nlm.nih.gov/26056426/…
- Cheng P, Kuang F, Zhang H, Ju G, Wang J. Neuropharmacology. 2014;85:408-416. pubmed.ncbi.nlm.nih.gov/24937047/…
- Philp D, Nguyen M, Scheremeta B, et al. FASEB J. 2004;18(2):385-387. pubmed.ncbi.nlm.nih.gov/14657002/…
Related
What is TB-500?
Thymosin beta-4 is a 43-amino-acid protein (about 5 kDa) present in nearly every cell except red blood cells, and especially rich in platelets, white blood cells, plasma and wound fluid. It was discovered in the thymus in the 1960s; its international drug name is timbetasin. Products sold as TB-500 are usually this full-length protein, and that is what this page describes. Some sellers use the name for a 7-amino-acid fragment instead (Ac-LKKTETQ, the protein's positions 17–23), which carries only the actin-binding region. The certificate of analysis shows which one a vial holds: about 4,960 Da for the full protein, about 890 Da for the fragment. No human trial has used a product sold as TB-500. TB-500 is not approved anywhere. On April 15, 2026 the FDA said it would take it off its Category 2 compounding list, and on July 23, 2026 an FDA advisory committee voted 8–6 to recommend it for the 503A bulks list, a non-binding vote not yet acted on. It is prohibited in tested sport (WADA S0).
What people look into TB-500 for
Every line carries an evidence label, so you can see how much is actually known.
Wound healing: In animal studies of the full protein, skin closure rose 42% by day 4 and up to 61% by day 7, wounds contracted at least 11% more, and scarring was lower with breaking strength kept.source
Studied in animals or labTendon and ligament: In an animal knee-ligament model, fibers were better organized and collagen fibrils thicker, with better mechanics at 4 weeks.source
Studied in animals or labMuscle: In an animal model of muscular dystrophy, more muscle fibers regenerated, but strength, heart function and fibrosis did not improve.source
Studied in animals or labHeart: In animal studies after a heart attack, heart-cell survival improved, infarcts were smaller and pumping measures better.source
Studied in animals or labDry eye: In a phase 2phase 2A mid-stage human trial that tests dose and early effect in hundreds of people. Phase 3 confirms results in thousands. human trial of thymosin beta-4 eye drops, eye discomfort fell 27% against placeboplaceboAn inactive version given to some trial participants so the real effect can be measured fairly..source
Studied in humansSpinal cord: After spinal cord injury in animals, myelin protein rose 57.8% and activated immune cells fell 36.9%.source
Studied in animals or labHair growth: In animal studies, the full protein activated hair-follicle stem cells.source
Studied in animals or labInjury healing in people: No human trial has tested thymosin beta-4 for injury healing, the main reason people look into it.
UnknownMix and measure: a 10 mg vial
Go deeper
How it works, in plain words
Actin is the protein scaffolding cells use to change shape and move. In lab studies, thymosin beta-4 binds single actin unitsunitsMarks on an insulin syringe. On a U-100 syringe, 100 units = 1 mL. How many units equal a dose depends on how much water was added. one to one, holds them in reserve, and hands them to a partner protein, profilin, which feeds them to the growing ends of actin filaments. That is what lets a cell crawl toward an injury. The short fragment some sellers call TB-500 carries only this actin-binding region.
What did the study measure?
No single study is featured for TB-500; the human trials are linked from the uses above.
Sources
Side effects and who should avoid it
Side effects and limits, stated plainly. If anything here applies to you, talk to a doctor first.