TB-500 Research: What Animal Tests Found | TB-500 Safe
Researchers measured wounds, tendons, hearts, brains, and muscle. Nearly all tests used rodents, horses, or cells.
Here’s the short version. As of 2026, no completed human test of TB-500 had been published [16].
Animal findings can't show what a shot does in you. Some papers tested TB-500; others tested the full body protein.
One form may not behave like the other. A result for one may not fit the other.
A 2026 review found faster tissue repair in animals [20]. It found few sound safety checks in people.
That leaves no firm count of benefit or harm. The review also warned about vials sold without normal drug checks.
For you, two gaps remain. TB-500 human tests are missing, and a label may hide a vial's true contents.
What TB-500 changed while tissue repaired
TB-500 copies one stretch of Thymosin Beta-4, numbered 17 through 23 [1]. The numbers identify that stretch in the full protein.
Researchers found five changes. Each one still needs a human test.
- New blood vessels grew. Cells kept making a chemical that fed that growth [13].
- Repair cells made room to move. Two proteins, called MMP-2 and MMP-9 in the paper, cleared damaged material [1].
- A swelling signal fell. Human cells made less IL-8, a chemical that calls in swelling, after irritation [15].
- Heart and brain cells lived longer. Blood flow was poor in those tests [5][6].
- Immune cells changed jobs. In sick mice, cells that drive swelling fell. Cells that clear damage rose [22].
These Thymosin Beta-4 changes may help explain faster animal repair. New vessel growth also raises the cancer concern.
Notice who was tested. A mouse or dish can't show what your body would do.
The TB-500 side effects page covers that concern. Human studies haven't answered it.
How TB-500 moved repair cells in tests
TB-500 tests watched repair cells move toward hurt tissue. Researchers also saw new small blood vessels grow [1][15].
The tests covered muscle, tendon, heart, brain, and eye tissue. Animals and cells in dishes were used.
No TB-500 study showed the same changes in people. So the findings can't predict your result.
For you, the missing human check matters most. Without it, a shot's effect stays unknown.
What TB-500 changed in animal wounds and organs
More than two dozen animal studies reported changes. The clearest measures came from wounds, ligaments, hearts, and brains.
Skin wounds closed faster. Treated rat wounds closed 42–61% more over 4–7 days [3].
Old and diabetic mice showed much the same result [2]. No person was part of those tests.
Knee ligaments grew stronger. Researchers put 1 microgram of Thymosin Beta-4 at a cut rat ligament.
A microgram means one part in a million of a gram. Four weeks later, the collagen was more even [9].
Thymosin Beta-4 use in horses drew a sports ban. Tests found TB-500 in blood and urine taken from horses [18].
Mouse muscle grew more repair fibers. Mice got 150 micrograms of Thymosin Beta-4 twice weekly for 6 months.
Their grip didn't improve, and their hearts didn't pump better [11]. More new tissue didn't mean better function.
Researchers also watched mouse muscle cells in a dish. The cells moved toward wounds and closed gaps faster [10].
Damaged rat hearts lost less tissue. Rats got 5.37 milligrams of Thymosin Beta-4 for every kilogram of rat weight.
The damaged area was 43% smaller at 28 days [6]. In mice, Thymosin Beta-4 helped more heart cells survive [5].
Rats with brain injury moved better. A 30 milligrams-per-kilogram Thymosin Beta-4 shot began 6 hours after injury [7].
A rat stroke test tried 2–12 milligrams for each kilogram. Its best calculated amount was 3.75 milligrams per kilogram [8].
Rat and mouse hair grew more. Thymosin Beta-4 woke resting hair roots and moved their cells [4].
Some mice were bred to make extra protein. Those mice also grew more hair.
Every result here came from animals or dishes. The amounts and shot sites varied.
They don't make a human care plan. See the amounts used in each TB-500 study.
What changed in tendons and ligaments
The strongest study cut a rat knee ligament. Researchers put 1 microgram of full protein into surgical glue [9].
A microgram means one part in a million of a gram. The glue held the protein against the cut.
After 4 weeks, the ligament was stronger. Its collagen fibers lay more evenly.
Horse use of TB-500 later led to drug tests in racing [18]. No human tendon test has checked TB-500.
If your tendon hurts, keep the animal in mind. A rat ligament can't promise how your tendon will heal.
What TB-500 changed in hurt muscle
Mouse studies tracked cells that rebuild muscle. Thymosin Beta-4 drew those cells toward hurt spots [10].
One test watched mouse muscle cells in a dish. The open gap between them closed faster.
Another Thymosin Beta-4 study ran for 6 months. Mice got 150 micrograms twice weekly [11].
A microgram means one part in a million of a gram. More new fibers grew in their muscles.
Yet their grip didn't improve, and their hearts didn't pump better. Better-looking tissue didn't mean better function.
That split matters for you. Human tests haven't checked workout tears or sore muscles.
What TB-500 changed in hurt hearts
A blocked heart vessel injured the rats. They got 5.37 milligrams of Thymosin Beta-4 for every kilogram of rat weight.
After 28 days, damaged heart tissue was 43% smaller [6]. Their hearts also pumped better.
Blood tests found less heart damage. In mice, Thymosin Beta-4 helped more heart cells survive [5].
Nobody knows if people would get that result. If you have heart trouble, these aren't care instructions.
Your doctor has human heart facts this treatment lacks. Rat findings can't guide your heart care.
What changed after brain injury
Young male rats had a brain injury. A 30 milligrams-per-kilogram Thymosin Beta-4 shot began 6 hours later [7].
Those rats moved and learned better. They also lost less brain tissue.
The 30 milligrams-per-kilogram amount beat 6 milligrams per kilogram. A stroke test then tried 2–12 milligrams per kilogram [8].
At day 56, its best calculated amount was 3.75 milligrams per kilogram. No human brain test has used TB-500.
You can't turn rat amounts into your own plan. The animals and injuries were watched closely in a lab.
What TB-500 changed in rat and mouse hair
Rat and mouse tests found more hair growth. Cells around each hair root woke and moved [4].
Some mice were bred to make extra Thymosin Beta-4. Those mice grew more hair too.
TB-500 copies the stretch tied to cell movement. Human hair proof is still missing.
If hair loss concerns you, these animal tests offer no answer. They can't say whether your hair would change.
TB-500 vs BPC-157: which tissues were tested
BPC-157 is a peptide, or short protein piece. Rat tests mostly covered the gut, tendons, and ligaments.
TB-500 comes from a different protein, Thymosin Beta-4. Its tests tracked repair cells moving toward wounds.
Those tests also tracked new blood vessels. BPC-157 studies asked different questions about different injuries.
No published study compared the two head to head. Read what TB-500 and BPC-157 each changed.
TB-500 and BPC-157: what the pair hasn't proven
No study gave TB-500 and BPC-157 together [1][21]. Researchers haven't checked whether the pair helps, clashes, or adds risk.
No TB-500 study has tested what adding BPC-157 might do. Animal work can't fill that gap.
The papers also give no human result for the pair. A claim about using both needs a human study.
What TB-500 changed after injury, and what stayed unknown
Rodent and horse tests found faster repair. They covered tendon, ligament, muscle, and nearby tissue [3][9][10][21].
Some tissue changes were large. Yet no human trial found a safe amount.
The world sports drug-testing group bars TB-500 [18]. Long-term harm in people remains unknown.
A 2026 review warned against treating animal findings as human proof [20]. That warning still fits these papers.
What human TB-500 tests have and haven't done
As of 2026, no completed human TB-500 test had been published. ClinicalTrials.gov, a public study list, shows a planned test.
The listing doesn't say whether that test finished or found anything. A listed plan isn't a published result.
Human safety work tested Thymosin Beta-4 instead. One brief study gave Thymosin Beta-4 by vein to 54 healthy people [16].
No serious harm appeared. Single amounts reached 25 micrograms for each kilogram of body weight.
Repeat amounts ran from 0.5–5.0 micrograms per kilogram for 10 days. Blood levels took 0.5–2.08 hours to fall by half.
That time doesn't show how long TB-500 lasts. The study used Thymosin Beta-4, not the copied stretch.
Another study used 0.1% Thymosin Beta-4 eye drops for 28 days [23]. Problems were reported by 5.6% with treatment and 13.9% with placebo.
A placebo has no study drug. The higher placebo number doesn't show why problems happened.
Neither study tested a TB-500 shot. They can't prove those shots are safe.
How TB-500 differs from other peptides
TB-500 may move repair cells toward wounds. It may also help new blood vessels form.
BPC-157 has mostly been tested near hurt tissue. GHK-Cu is a peptide, or short protein piece, that carries copper.
GHK-Cu may affect collagen, the strong material in tissue. Other peptides affect growth hormone, a body signal for growth.
No human study compared these substances head to head.