Testosterone helps close growth plates.
You still growing??–watch out.[/quote]
Testosterone itself can not cause fusing of the growth plates, however, your body manufactures test, then aromatizes some of it to estrogen.
Estrogen itself will not fuse the growth plates DIRECTLY, it will however accelerate the sequence that controls the growth plate.
This speeds up the proliferative exhaustion Which in turn causes the plate to fuse earlier than it should have. So its more like Estrogen fuses growth plates, but only indirectly.
Technically more testosterone without any control over the aromatase will cause more estrogen to be produced. But trib is no where near strong enough to cause that. I might be worried if he wanted to inject Test, but anything but actual steroids will have no effect.