Assertion: collagen | /r/CapableOf | last after first injection
Facets:
Source sentences:
text: Patients may require retreatment 6 to 8 months after the first injection, 8 to 12 months after the second injection, and 12 to 18 months after the third injection, if not longer; many patients reported that collagen lasted 2 to 3 years after the first injection .