TB-500 from Sixpex is basically a lab-made version of Thymosin Beta-4 (TB4). You usually get it as a 5mg or 10mg vial of powder, and you mix it up with bacteriostatic water before using it for research.

What It Is
Thymosin Beta-4 is a 43-amino acid peptide (C212H350N56O78S1, around 5kDa if you’re counting). Your body actually makes this stuff—it’s all over the place when you get hurt, especially around wounds and damaged tissue. 

What does it do?
It helps cells move and change by managing actin (that’s a protein involved in cell structure), helps new blood vessels grow, and even encourages stem cells to jump into action. In its research form, it comes freeze-dried, so you mix it with sterile water before using it under the skin or in the muscle. It lasts about two days in your body.

How People Use It
Researchers look at TB-500 for speeding up healing in tendons, ligaments, and muscles, cutting down swelling after injuries, and just generally helping athletes bounce back faster. It’s also popular among bodybuilders who want to heal strains or tears quickly, get more flexible, repair heart tissue, or even boost hair growth. Sometimes, people combine it with BPC-157 because together they seem to work even better.

Why People Like It
TB-500 gets attention for helping wounds close up fast and heal with less scarring. It drives new blood vessel growth by moving certain cells (EPCs) where they’re needed, and it keeps scar tissue and stiff, fibrous cells down. A lot of people say it helps with muscle stamina, makes joints move more smoothly, and lowers inflammation in the whole body—all without messing up your hormones.

Drawbacks and Side Effects
Most people just feel a bit tired, maybe a little dizzy, or get some redness where they inject (which fades quickly). There’s a rare, theoretical risk that it could help cancer spread (since it boosts new blood vessels), so you really shouldn’t use it if you’ve got any kind of cancer. At high doses, some folks get headaches or feel wiped out. Honestly, there’s not a ton of human research—most of what we know comes from animal studies. And, if you’re buying from places like Sixpex, you never really know what you’re getting, so quality is a concern.

How to Use It
To mix it, you add 2-3ml of bacteriostatic water to a 5mg or 10mg vial (so you’re getting about 2-5mg per ml). For a loading phase, most start with 4-8mg per week, split into 2mg doses two or three times a week, either injected near the injury or systemically. For maintenance, it’s 2-6mg a week. People usually do cycles: four to eight weeks on, then take four weeks off. You can inject it directly into a muscle for a local injury or under the skin of your belly for a systemic effect. Keep it in the fridge, and use a thin insulin syringe—29 to 31 gauge is the sweet spot.