TB-500 research hasn’t established healing in patients
The part copied from thymosin beta-4 interested scientists studying cell movement. Experiments usually gave thymosin itself. Moving cells haven’t proved human healing.
How TB-500 attaches to a protein involved in movement
TB-500 was made to study part of thymosin beta-4. Cell experiments didn't establish treatment for injured people. Inside cells, actin protein can join together in thin strands. Changes in the strands allow movement and changes of shape. Thymosin beta-4 temporarily holds actin apart in a 1:1 pair. Each pair contains one thymosin beta-4 and one actin [1]. Held actin can't join other actin to make strands. After release, actin can join those strands again. The laboratory copy contains the part that attaches to actin.
Changing a cell's shape doesn't prove your wound closes.
For the X-ray study, researchers used a specially made protein. Thymosin was joined with another protein part for examination. That protein helped researchers examine attachment, without treating patients. X-rays distinguished details 2 angstroms apart, far smaller than a hair’s width. The test showed a 1:1 pair with actin. The joined protein covered both ends of the actin. That prevented actin from joining into strands [2]. Other experiments treated animals or cells growing in dishes. Skin and muscle cells moved faster, as did cells lining vessels. More cells survived; fewer cells making scars remained. Inflammation, the sore and swollen response to injury, decreased too [10].
These findings prompt further study, rather than establishing treatment. Human trials haven't established benefits at amounts discussed for home use [1].
What thymosin beta-4 changed: TB-500 still lacks thymosin beta-4’s results
Most findings in this section concern thymosin beta-4 treatment. Thymosin beta-4 has a 43-amino-acid chain of small linked parts. At injuries, blood-clotting cells and some immune system cells release thymosin. Experiments found more cells moving toward damage and fewer dying. Thymosin may also reduce inflammation and germ growth. Small blood vessels may grow near an injury [10].
You still need results for the treatment your clinic offers.
Thymosin weighs about 4963 daltons; TB-500 weighs about 889 daltons [1]. These tiny protein weights are measured in daltons. Size doesn’t establish which treatment helps you. A review brought together findings from thymosin experiments. Treated tissue had fewer cells that pull wounds tight and leave scars. The treated areas gained blood vessels as well. These results prompted trials of thymosin for skin and eye wounds [10]. Those trials tested thymosin itself. Human trials of the shorter treatment remain uncompleted [1].
What happened to treated mouse and pig hearts
These were animal experiments, with results that didn't agree. Mice had a heart artery blocked, cutting off blood. Thymosin beta-4 changed proteins that help injured heart cells survive. Cell survival improved, and pumping became better in those hearts [4]. Pig hearts were injured by stopping and restarting their blood supply. Giving thymosin beta-4 didn't lessen the heart damage [1].
An animal gain doesn't settle your heart treatment.
Laboratory experiments found that thymosin beta-4 increased a vessel-growth protein [8]. Extra vessels could bring needed blood to an injured area. A tumor might also gain blood through those new vessels. The tumor questions raised by TB-500 research explain the uncertainty. The human tests don't measure this risk for you.
What can TB-500 change inside a moving cell?
Actin forms thin strands that help a cell change shape. The part of thymosin beta-4 that attaches to actin is in TB-500. Thymosin beta-4 holds actin in a 1:1 pair. Held actin can't join the strands until released. Experiments with thymosin beta-4 also found more surviving cells and new vessels. Inflammation decreased in animals or cells in dishes [2][10]. None establishes healing from the laboratory copy in people [1].
What heart benefit appeared in mice but not pigs?
People with heart injuries weren't treated in these experiments. After a blocked artery, treated mice kept more heart cells. Their hearts also pumped better with thymosin beta-4 [4]. Treated pigs had no clear reduction in damage from interrupted blood flow [1]. TB-500 hasn't completed human testing as a heart treatment [1].
What vessel growth raises a concern about TB-500?
Laboratory work examined cells that line blood vessels. Thymosin beta-4 helped those cells grow and move. Researchers also found more of a protein encouraging vessel growth [8]. A tumor might benefit from the extra blood supply. Human research hasn't established the size of any TB-500 risk [1].
What short safety tests and rat stroke tests showed
This human test was short and involved healthy people. Healing injuries wasn't part of the test. Researchers divided 40 volunteers into groups by chance. Some received thymosin beta-4; others received a placebo, a similar treatment lacking the tested protein. Phase 1 is the first stage of human safety testing. Separate groups received 42, 140, 420, or 1260 milligrams through veins. Researchers first tested a single dose, then daily treatment for 14 days. The summary doesn't describe the gap between these tests. Problems were few and described as mild or moderate. Symptoms weren't named, leaving you unable to judge how people felt. No reported harm prevented the planned increases in amount. Larger amounts produced higher blood levels [5].
That trial tested thymosin, without treating an injured knee.
Blocking an artery in the brain caused strokes in male rats. Groups of rats then received differing thymosin beta-4 amounts. Shots went into the abdomen, the space around the belly's organs. Rats given 2 and 12 milligrams per kilogram regained more nerve function. That means the rats did better on movement and response tests. Gains appeared from day 14 through day 56. No clear gain appeared at 18 milligrams per kilogram [9]. The tests don't establish that the rats fully recovered. You can check the amounts behind TB-500 claims. See also the question about TB-500 blood levels.
What did the volunteer safety trial miss about TB-500?
The volunteers received thymosin beta-4, rather than TB-500. In Phase 1, amounts reached 1260 milligrams without harm stopping increases [5]. Some volunteers reported problems, though the summary doesn't name them. The eye study often cited here treated mice [12]. The planned thymosin beta-4 heart-attack trial never enrolled patients [11]. Those studies don't prove TB-500 heals your injury.
What movement did the rats regain after stroke treatment?
The rats received thymosin beta-4 by shots into the abdomen. At 2 and 12 milligrams per kilogram, nerve tests improved. Researchers tested the rats' movement and responses after the strokes. Gains appeared from day 14 to day 56. Another group received 18 milligrams per kilogram, without a clear gain [9]. Better test results don't mean every movement returned to normal. TB-500 hasn't proved that it protects your brain [1].
What eye findings concerned inflammation?
Researchers examined injured eyes and cells grown in dishes. Thymosin beta-4 reduced substances that start inflammation inside cells [10]. Inflammation is the body's reaction to injury, often with sore, swollen tissue. Those tests mainly concerned thymosin. They don't show that TB-500 eases inflammation in people [1].