What is it? TB-500 is a healing peptide (a synthetic version of a protein your body naturally makes) that comes as a freeze-dried powder in a small glass vial.
What does "reconstitution" mean? It just means mixing the powder with water so you can inject it. You add bacteriostatic water (BAC water) — sterile water with a tiny preservative that keeps it safe for weeks.
Loading vs. maintenance? TB-500 uses higher doses at first ("loading phase") to build up levels in your body, then lower doses to maintain them.
What are mcg and mg? Weight measurements: 1 mg (milligram) = 1,000 mcg (micrograms). Your vial is labeled in mg, but doses may be shown in mcg.