Healing & recovery
A powerful fragment of thymosin beta-4 that acts like your body's repair signal—speeding up healing of muscles, tendons, and tissues by promoting cell migration and new blood vessel growth right where you need it most.
Start here
TB-500 is a lab-made fragment of thymosin beta-4, a protein your body uses as a repair signal after injury. It is studied for speeding the healing of muscles, tendons, and other tissues by encouraging cells to migrate to damaged areas and by promoting angiogenesis (the growth of new blood vessels) where repair is under way. It is taken by injection and is a research compound, not FDA approved, with evidence from moderate (Phase 1-2) human trials.
Think of TB-500 as your body's 'come here and help' signal for healing. When you get injured, your body naturally releases thymosin beta-4 to start the repair process. TB-500 is a synthetic version of the most active part of this protein. It works by telling your cells to migrate to the injury site, promoting the growth of new blood vessels to bring oxygen and nutrients, and reducing inflammation so healing can happen properly. It also helps prevent excessive scar tissue formation, so you heal with more functional tissue instead of stiff scar tissue. It's like giving your body's repair crew a megaphone and extra supplies 1.
TB-500 (Ac-LKKTETQ) is a lab-made heptapeptide (a chain of seven amino acids) that matches the active region (positions 17-23) of thymosin beta-4 (Tβ4). Its main action is to bind G-actin monomers (single building blocks of the cell's inner scaffold). This controls actin polymerization (how those blocks join into filaments) and lets cells reshape their scaffold so they can move. TB-500 raises actin production and encourages the building of extracellular matrix proteins (the material that holds tissues together) by switching on receptors on the cell surface. It stimulates angiogenesis (growth of new blood vessels) through the VEGF/Akt/eNOS pathway (a chain of signals that builds blood vessels), which helps endothelial progenitor cells (young blood-vessel-lining cells) mature and form vessels. It lowers inflammation by reducing macrophage infiltration (fewer immune cells flooding in) and turning down pro-inflammatory cytokines (inflammation signals), including TGF-β and IL-10. Its anti-fibrotic (anti-scarring) effect comes from blocking the change of fibroblasts (the cells that build connective tissue) into myofibroblasts (scar-making cells), partly through its N-terminal sequence Ac-SDKP. The peptide also protects nerves by reducing apoptosis (programmed cell death), promoting oligodendrogenesis (the making of new cells that insulate nerves), and supporting the maturing of neural stem cells. Together, these effects make it a broad tissue repair and regrowth agent 1.
Evidence check
Some human studies
It has been tested in people, but only in small or early-stage studies. Promising, but not yet proven the way an approved medicine is.
Every numbered marker on this page links to one of the 12 sources at the bottom.
Healing Speed
Accelerates tissue repair through cell migration and angiogenesis—one of the most effective peptides for injury recovery
Tissue Repair
Regenerates muscle, tendon, and ligament tissue by promoting new blood vessel formation and reducing inflammation
Anti-Scarring
Stops fibroblasts (repair cells) from turning into myofibroblasts (scar-forming cells), reducing scar tissue and keeping tissue flexible
The most-asked question
The research-reported range is 2–2.5 mg, twice weekly. Studies used different doses for different situations — find yours:
Tissue repair, Recovery
2-2.5 mg
Research peptide with no human trials of the fragment; 9 loading doses used in practice 6.
Ongoing recovery
2-2.5 mg
Maintenance dose used in practice following the loading phase 6.
The ceiling: 10 mg per week (higher doses not well-studied and unlikely to provide additional benefits) 6
Reconstitution, in plain words
Peptides usually arrive as a freeze-dried powder in a small vial. “Reconstitution” just means adding sterile water back in so you can measure a dose. Here's how it works for TB-500:
If you have a 5mg vial and add 2mL of BAC water, you get a concentration of 2.5mg/mL. So every 1mL (100 units on an insulin syringe) equals 2.5mg of TB-500.
For a 2.5mg dose at 2.5mg/mL concentration: draw 1mL (100 units on a standard insulin syringe). For a 5mg dose: draw the full 2mL or use a larger vial reconstituted accordingly.
Three quick questions — your vial, your water, your dose — and it tells you the exact syringe mark. “Find dose amount” is preloaded with TB-500's recorded schedule.
Injection sites & technique
Subcutaneous (under the skin) injection (just under the skin)—the easiest and most common method. Some users prefer injecting near the injury site, though systemic (affecting the whole body) administration works well too.
Timing
Morning or evening—timing doesn't significantly affect TB-500's effectiveness. What matters most is consistency. Pick a schedule that works for your lifestyle and stick with it.
TB-500 can be injected regardless of food timing. It doesn't seem to affect absorption either way, so fit it into whatever routine works for you.
TB-500 pairs exceptionally well with BPC-157—they're often called the 'healing stack' because they work through different but complementary mechanisms. Inject at different sites if using both. Space injections at least 15-30 minutes apart to track individual effects 6.
The honest list
These show up most often. They usually fade as your body adjusts.
A little pink or red area where you injected is totally normal. It's just your skin reacting to the needle and solution 6.
What to do Rotate injection sites between belly, thigh, and arm. A cool compress can help. Usually fades within 24-48 hours.
Some users feel a bit tired after injections, especially in the first week. Your body is mobilizing healing resources 6.
What to do Inject in the evening if fatigue bothers you. Stay well-rested and this typically improves after the first week.
Occasional headaches have been reported, usually mild and in the first few days of use 6.
What to do Stay well-hydrated and rest if needed. These typically resolve within the first week as your body adjusts.
Some users notice mild warmth or flushing at the injection site or generally, usually brief.
What to do This typically passes within 30 minutes. Not a cause for concern unless it's severe or persistent.
Worth knowing about, but most people never see these.
Some users report brief lightheadedness shortly after injection, possibly related to blood pressure changes 6.
What to do Sit or lie down for a few minutes after injection. If it persists, consider reducing dose.
Mild nausea has been reported by some users, usually resolving quickly.
What to do Eat a light meal before or after injection. If persistent, reduce dose or consult your provider.
Rare, but if any of these happen, stop and contact a medical professional.
Rare, but possible with any peptide. 9 Watch for hives, significant swelling (especially face/throat), or difficulty breathing.
What to do STOP immediately and seek emergency medical care. This is extremely rare but requires immediate attention.
Week by week
Is it right for you?
TB-500 is a research compound, not an FDA-approved medication. Never start, stop, or change your dosing without guidance from a qualified healthcare provider. This information is for educational purposes only—not medical advice.
May increase bleeding at injection sites. TB-500 promotes angiogenesis (growth of new blood vessels), which could in theory affect clotting. Monitor closely.
NSAIDs reduce inflammation, which is part of the healing process TB-500 supports. They may make it less effective—use sparingly.
Steroids can impair healing. If you're on long-term steroids, discuss with your doctor.
TB-500 supports wound healing in diabetics but monitor blood sugar as healing processes can affect glucose.
Excellent pairing—the classic 'healing stack.' BPC-157 works in different ways, and together they give broad tissue repair support. Inject at different sites.
Safe to combine for comprehensive tissue repair. GHK-Cu focuses on skin and collagen while TB-500 works on deeper tissue healing.
Can be combined for stronger muscle recovery. Both help tissue repair in different ways.
Safe to stack for overall recovery. Peptides that trigger growth hormone release complement TB-500's healing effects.
Complementary—collagen provides building blocks while TB-500 promotes the repair process.
Safe and potentially helpful. Omega-3s help calm inflammation in ways that complement healing.
Supports collagen synthesis (making new collagen, the protein in skin and joints) and healing. Good addition to a recovery protocol.
Anti-inflammatory but work differently than NSAIDs. Generally considered safe to combine.
If you've pulled a hamstring, strained your back, or torn a muscle, TB-500 helps accelerate the healing process by promoting cell migration to the injury site and supporting new blood vessel growth. It's especially useful for injuries that just won't seem to fully heal 15.
Tendons and ligaments are notoriously slow healers because they have poor blood supply. TB-500 promotes angiogenesis (new blood vessel formation) and helps repair these stubborn connective tissue injuries—think Achilles tendonitis, tennis elbow, or rotator cuff issues 5.
After surgery, your body needs to repair a lot of tissue quickly. TB-500 supports wound healing, reduces inflammation, and may help minimize scar tissue formation. Some protocols use it alongside traditional recovery to potentially speed up the healing timeline 14.
Some people just heal slowly—whether due to age, diabetes, or other factors. TB-500 helps regulate the inflammatory response and promotes the cellular processes needed for tissue repair. It essentially tells your body to focus healing resources where they're needed most 1.
TB-500 has shown a good safety profile across preclinical (animal or lab studies, not human trials) studies and limited human research. It's a fragment of thymosin beta-4, a naturally occurring protein in your body involved in healing. Most side effects are mild and transient, primarily injection site reactions. However, large-scale clinical trials are still needed to fully establish its safety profile in humans 1.
TB-500 has been used extensively in equine medicine and has been the subject of multiple human clinical trials for conditions like dry eye, wound healing, and cardiac repair. Phase 1-2 trials have shown it to be well-tolerated, but Phase 3 data is limited. 8 Always work with a healthcare provider when using research compounds 2.
Keeping it good
Keep your TB-500 powder in the refrigerator (36-46°F / 2-8°C) for short-term storage or in the freezer (-4°F / -20°C) for long-term storage. Store in the original sealed vial away from light. Properly stored powder can remain stable for 2+ years when frozen.
Once mixed with bacteriostatic water, refrigerate at 36-46°F (2-8°C). Never freeze the reconstituted solution—freezing destroys the peptide. Keep away from light and use within 28 days.
Not our opinion — the published record
2012
This comprehensive review showed that thymosin beta-4 plays a vital role in tissue repair and regrowth. It protects cells from damage, reduces inflammation, helps cells move to injured areas, and helps form new blood vessels. The peptide also reduces scar formation by stopping fibroblasts (repair cells) from turning into scar-producing cells.
Goldstein AL, Hannappel E, Sosne G
2015
This update summarized decades of research showing TB4's effectiveness in directing stem cell maturation (stem cells are cells that can become many types of cells) and tissue repair. Several clinical trials showed benefits for eye injuries, skin wounds and heart repair. The peptide shows potential for new uses including kidney and liver disease, spinal cord injury and bone healing.
Goldstein AL, Kleinman HK
2012
In brain injury models, thymosin beta-4 showed strong neuroprotective (nerve-protecting) effects. It reduced cell death, decreased inflammation, and promoted blood vessel formation, wound healing and stem cell maturation (stem cells are cells that can become many types of cells). The research gives a scientific basis for possible use in treating traumatic brain injury.
Xiong Y, Mahmood A, Meng Y, et al.
2023
This study revealed TB4's strong anti-scarring effects. It works by reducing the flood of inflammatory cells into the tissue (infiltration), lowering TGF-beta levels (a signal that drives scarring), and preventing fibroblasts from converting to myofibroblasts (scar-producing cells). The fragment at its start, Ac-SDKP (the N-terminal fragment), not only prevents fibrosis (scarring) but can actually reverse existing scar tissue.
Kleinman HK, Kulik V, Goldstein AL
2018
Researchers found that TB4 significantly improves blood vessel formation by boosting the function of endothelial progenitor cells (young cells that build the lining of blood vessels). It works through the VEGF pathway (a blood-vessel growth signal), which is crucial for delivering nutrients and oxygen to healing tissue. When transplanted into damaged heart tissue, TB4-treated cells formed blood vessels much better.
Zhao Y, Song J, Bi X, et al.
2026
Peptide Dosing Protocols
2026
Thymosin-β4 and its derivatives (e.g. TB-500) are listed under S2.2 of the prohibited-substances list (growth factors and growth factor modulators, which are substances that change growth signals), and are prohibited at all times, in and out of competition, as non-specified substances.
World Anti-Doping Agency
2015
A randomised, placebo-controlled Phase II trial in human subjects (people were assigned by chance to the drug or a placebo, in a mid-stage trial). The formulation was safe and well tolerated, with no significant adverse events reported and no subject withdrawing because of an adverse effect of the study formulation.
Sosne G, Ousler GW
2026
Regulator evaluation dated 5/15/2026 of TB-500, described as the seven-amino-acid synthetic fragment of thymosin beta-4 (amino acids 17-23, N-acetylated, meaning it has a small chemical cap on one end). It states that thymosin beta-4 and TB-500 are not the same substance. The FDA found no clinical studies or human exposure data using TB-500 by any route, no clinical PK/PD studies in humans (studies of how the body handles the drug and what it does), no FAERS reports (the FDA's database of side-effect reports) and no published case reports of adverse events. Potential safety risks in humans are unknown. As an injectable peptide (under the skin or into a muscle), TB-500 may pose a significant risk of immunogenicity (triggering an unwanted immune response), possibly made worse by aggregation (peptide clumping) and peptide-related impurities. The consequences of an immune response can range from antibody responses with no apparent clinical manifestations to life-threatening reactions.
U.S. Food and Drug Administration (Mathew B, Mattingly A, Rupp T, Albuquerque E, Benedict A, Kneeream E, Kasim S)
If this isn't the right fit
Your questions
Thymosin beta-4 is the full 43-amino-acid protein naturally produced in your body. TB-500 is a synthetic 7-amino-acid fragment (the 'active region') that contains most of the healing benefits. Think of it like using the key part of a larger molecule. TB-500 is easier to synthesize and more stable, which is why it's commonly used in research 1.
You can inject near the injury site (within a few inches), and some users believe this provides localized benefits. However, TB-500 works systemically—it spreads throughout your body via your bloodstream. Subcutaneous (under the skin) belly injections work just as well because the peptide naturally migrates to where it's needed. Don't inject directly INTO injured tissue 1.
Most users notice reduced inflammation and improved flexibility within 1-2 weeks. Significant healing improvements typically appear by weeks 3-4 for muscle injuries. Tendon and ligament injuries take longer—expect 4-8 weeks for noticeable progress. The more severe the injury, the longer it takes.
This combination is very popular 12 and often called 'the healing stack.' They work through different mechanisms: TB-500 promotes cell migration and blood vessel formation, 1011 while BPC-157 works more locally and affects growth factors differently. Together they provide comprehensive tissue repair support. Inject at different sites 6.
Possibly, yes. TB-500 can help restart the healing process in chronic injuries by promoting cell migration, new blood vessel formation, and tissue remodeling. However, very old injuries with significant scar tissue may have limited improvement. It's worth trying, especially combined with physical therapy 1.
Yes, TB-500 (and thymosin beta-4) are prohibited by WADA (World Anti-Doping Agency) and most sports organizations under the category of peptide hormones and growth factors. Athletes subject to drug testing should not use TB-500 7.
Some users report improved overall recovery from exercise and general well-being. However, TB-500 is primarily studied for injury healing. 111 If you're looking for general recovery support without an injury, other peptides like BPC-157 or growth hormone secretagogues (compounds that prompt your body to release growth hormone) might be more appropriate.
TB-500 stops fibroblasts (repair cells) from turning into myofibroblasts, the cells that make too much scar tissue. It also lowers TGF-beta, a major driver of fibrosis (excess scar tissue). The result is that injured tissue heals with more normal, working tissue rather than stiff scar tissue 4.
TB-500 is a synthetic fragment of thymosin beta-4, a naturally occurring healing protein found in nearly all human and animal cells. The fragment reproduces the parent protein's active region, which promotes cell migration, blood-vessel formation, and reduced inflammation at injury sites. In research settings it's studied for muscle, tendon, and ligament recovery — it acts systemically (affecting the whole body), traveling through the body rather than working only where injected. See the full profile below for mechanism and studies, or the TB-500 vs thymosin beta-4 comparison for how the fragment differs from the full protein 1.
Research protocols typically run in two phases: a loading phase of 2–2.5mg injected subcutaneously (under the skin) twice weekly (commonly 4–6 weeks), then a maintenance phase of 2–2.5mg once weekly. Athletes and bodybuilders researching recovery generally follow the same structure — the loading phase during active injury recovery, maintenance after. TB-500's long half-life (how long it stays active in your body) is why dosing is weekly rather than daily. See the dosing protocol page for schedules, timing, and adjustment guidance 6.
Reported side effects in research use are generally mild: injection-site redness, temporary fatigue or lethargy, mild headache, and slight flushing are the most common. Less commonly, a brief head rush or lightheadedness and temporary nausea have been reported shortly after injection. As with any peptide, allergic reaction is possible 9 and is the one serious reaction to watch for — discontinue and seek medical care for signs like difficulty breathing or significant swelling. The safety section below covers management for each 6.
12 sources
Every numbered marker on this page points to one of these. Same sources, same numbering as the TB-500 research profile on Peptide Initiative.
Want the deep science?
Every claim on this page traces back to the research database behind Peptide Initiative — studies, citations, clinical trial data, and the technical detail we deliberately left out here.
Open the research profileThis guide is education, not medical advice. TB-500 is a research compound that is not FDA-approved for human use. Talk to a clinician before taking anything.
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