Controls
0.0 / 5.0 s in-zone
Click "Start Level" below to begin.
Most stem cells prefer low oxygen (about 2–8%) — the physiologic "sweet spot."
Growth factors are the "go" signals — moderate dosing keeps expansion under control.
Passage counts how often we've split the culture — later passages edge toward Hayflick's limit and instability.
Tip: 2–8% O₂ · moderate GF · early passage tends to keep the niche stable.