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.
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Subcutaneous
Route
4 recommended
Sites
Twice weekly
Frequency
Preparation
Bacteriostatic water (BAC water)—the preservative keeps it safe for multiple uses
Insulin syringes (29-31 gauge)—thin needles mean less discomfort
Alcohol swabs for cleaning vial tops and injection sites
Your TB-500 powder vial
Pro tip
Prepare all supplies on a clean surface before you begin. Having everything ready makes the process smoother and more sterile.
Mixing
Wash your hands thoroughly with soap and water. Gather all supplies on a clean, flat surface.
Remove the plastic cap from the peptide vial and wipe the rubber stopper with an alcohol swab. Let it air dry.
Draw the appropriate amount of bacteriostatic water into a sterile syringe.
Insert the needle into the vial at an angle, aiming at the inside wall of the vial. Slowly push the plunger to let the water trickle down the glass wall -- do NOT squirt directly onto the powder.
Once all water is added, gently swirl the vial in a slow circular motion. Never shake the vial, as this can damage the peptide bonds.
Continue swirling until the powder is completely dissolved and the solution is clear. If particles remain, let the vial sit for a few minutes and swirl again.
Label the vial with the date of reconstitution, the peptide name, and the concentration (e.g. 250mcg per 0.1mL).
Example calculation
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.
Dose calculation
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.
Pro tip
Always add the bacteriostatic water slowly, letting it run down the side of the vial. Never shake the vial -- swirl gently to avoid damaging the peptide.
Location
Site 01
Abdomen
Pinch the skin 2 inches from navel. Avoid the area directly around the belly button. Rotate between left and right sides.
Site 02
Outer Thigh
Middle third of the outer thigh. Keep at least 4 inches above the knee and below the hip. Alternate legs each injection.
Site 03
Near the injury site (within a few inches, not directly into it)
Follow your provider's instructions for this injection site. Rotate sites regularly to prevent tissue damage.
Site 04
Upper Arm
Back or outer area of the upper arm. This site may require assistance from another person for proper technique.
Rotate between 4 sites to prevent tissue buildup and ensure consistent absorption.
Pro tip
Rotate your injection sites with each dose to prevent lipohypertrophy (buildup of fatty tissue). Keep a simple log of where you last injected.
Step by step
Wash your hands thoroughly with soap and water
Clean the injection site with an alcohol swab and let it air dry completely
Pinch about an inch of skin to create a fold
Insert the needle at a 45-90 degree angle (45 if you're lean, 90 if you have more tissue)
Push the plunger slowly and steadily
Wait 5 seconds before removing the needle
Apply light pressure if needed—don't rub
Pro tip
This peptide uses subcutaneous injection (just under the skin)—the easiest and most common method. some users prefer injecting near the injury site, though systemic administration works well too.. Inject at a 45-90 degree angle into pinched skin. Aspirate before injecting to ensure you haven't hit a blood vessel.
Timing
Optimal timing
Best time
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.
With food?
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.
Stacking notes
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].
Sample daily schedule
Morning (or consistent time that works for you)
2-2.5 mg injection
Site: Rotate between belly, thigh, and near injury site
Inject twice weekly, spacing doses 3-4 days apart (e.g., Monday and Thursday). A typical loading phase uses 4-5 mg total per week for 4-6 weeks, followed by maintenance of 2-4 mg weekly if continued.
Dosing tiers
Dose
2-2.5 mg
Frequency
Twice weekly
Duration
Loading phase, 4-6 weeks
Research peptide with no human trials of the fragment; [9] loading doses used in practice [6].
Dose
2-2.5 mg
Frequency
Once weekly
Duration
Maintenance after loading
Maintenance dose used in practice following the loading phase [6].
Preservation
Before mixing
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.
After mixing
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.
Shelf life after mixing
28 days
Signs of degradation
Discard the vial immediately if you notice any of these:
Cloudy or hazy appearance (should be crystal clear)
Visible particles floating or settled at the bottom
Color changes—any yellowing or discoloration means toss it
Unusual smell—fresh solution should have little to no odor
Important
When to stop
Any signs of allergic reaction—stop immediately and seek medical help
Persistent headaches or fatigue that don't improve after the first week
Significant injection site reactions that spread or don't heal
Any side effect that feels serious or really concerns you
Your injury has healed satisfactorily
Your research protocol/cycle is complete
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.
Clean technique checklist
Wash hands thoroughly with soap and water before handling supplies
Swab vial tops and injection site with alcohol and let dry
Never touch the needle tip or allow it to contact non-sterile surfaces
Use a new syringe and needle for each injection
Dispose of used sharps in a proper sharps container
Store reconstituted peptides according to the storage instructions above
Published research
Goldstein AL, Hannappel E, Sosne G · 2012
This comprehensive review showed that thymosin beta-4 plays a vital role in tissue repair and regeneration. It protects cells from damage, reduces inflammation, promotes cell migration for healing, and helps form new blood vessels. The peptide also reduces scar formation by preventing fibroblasts from becoming scar-producing cells.
Goldstein AL, Kleinman HK · 2015
This update summarized decades of research showing TB4's effectiveness in directing stem cell maturation and tissue repair. Multiple clinical trials demonstrated benefits for eye injuries, skin wounds, and cardiac repair. The peptide shows potential for new applications including kidney and liver disease, spinal cord injury, and bone healing.
Xiong Y, Mahmood A, Meng Y, et al. · 2012
In brain injury models, thymosin beta-4 showed remarkable neuroprotective effects. It reduced cell death, decreased inflammation, promoted blood vessel formation, wound healing, and stem cell differentiation. The research provides scientific foundation for potential use in treating traumatic brain injury.
Kleinman HK, Kulik V, Goldstein AL · 2023
This study revealed TB4's powerful anti-scarring effects. It works by reducing inflammatory cell infiltration, lowering TGF-beta levels, and preventing fibroblasts from converting to myofibroblasts (scar-producing cells). The N-terminal fragment Ac-SDKP not only prevents fibrosis but can actually reverse existing scar tissue.
Zhao Y, Song J, Bi X, et al. · 2018
Researchers discovered that TB4 significantly improves blood vessel formation by enhancing the function of endothelial progenitor cells. It works through the VEGF pathway, which is crucial for delivering nutrients and oxygen to healing tissues. When transplanted into damaged heart tissue, TB4-treated cells showed much better blood vessel formation.
Peptide Dosing Protocols · 2026
World Anti-Doping Agency · 2026
Thymosin-β4 and its derivatives (e.g. TB-500) are listed under S2.2, growth factors and growth factor modulators, and are prohibited at all times — in and out of competition — as non-specified substances.
Sosne G, Ousler GW · 2015
A randomised, placebo-controlled Phase II trial in human subjects. 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.
U.S. Food and Drug Administration (Mathew B, Mattingly A, Rupp T, Albuquerque E, Benedict A, Kneeream E, Kasim S) · 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). States that thymosin beta-4 and TB-500 are not the same substance. FDA found no clinical studies or human exposure data using TB-500 via any route, no clinical PK/PD studies in humans, no FAERS reports and no published case reports of adverse events; potential safety risks in humans are unknown. As an injectable peptide (SC/IM), TB-500 may pose a significant risk for immunogenicity, potentially amplified by aggregation and peptide-related impurities; consequences of an immune response can range from antibody responses with no apparent clinical manifestations to life-threatening reactions.
Renke G, Chinellato L · 2026
Open-access review (Int J Mol Sci 2026). Describes TB-500 as the synthetic acetylated fragment corresponding to a key sequence of thymosin beta-4, and states the TB-500 fragment reproduces some of thymosin beta-4's effects, focusing on promoting new vessels and cell migration. In its safety section on thymosin beta-4 (the full protein), it reports no difference in adverse events vs placebo in ulcer studies and, with systemic use, rare reports of mild headaches.
Rahman OF, Lee SJ, Seeds WA · 2026
Open-access review (JAAOS Global Research & Reviews 2026). Describes TB-500 as a synthetic peptide fragment derived from thymosin beta-4 whose active segment promotes actin polymerization, progenitor cell recruitment and enhanced cellular migration; preclinical studies and veterinary use have suggested benefit in tendon and muscle repair with anti-inflammatory effects and proangiogenic activity. Lists distinct primary pathways for BPC-157 and TB-500. Notes a current lack of clinical trials.
Moiz A, O'Keefe EL, O'Keefe JH · 2026
Open-access review (Missouri Medicine 2026). Describes TB-500 as a synthetic peptide fragment replicating the active, acetylated region of thymosin beta-4, frequently co-administered with BPC-157 in unregulated fitness regimens to accelerate wound healing and muscular recovery. States no human safety or efficacy trials exist for elective cosmetic or athletic use, raises concern about unmonitored systemic use and occult tumour cells, and notes WADA prohibits TB-500 at all times.
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