Two different pharmaceutical products are bioequivalent if they contain the same chemical compounds in the same proportions (ideally) and are absorbed and used by the body in such a way that they should have identical or very similar therapeutic and adverse effects. Basically, one should be just as safe and effective as the other.
Deeper dive
Bioequivalence comes into play with generic versus name brand drugs. For example, in theory, escitalopram manufactured by any pharmaceutical company should have the same effects on the body as any other, whether it’s officially the brand name Lexapro or a generic version. In reality, however, two supposedly bioequivalent products may have differences that impact therapeutic benefit or side effect risks, such as findings about differences in Wellbutrin generics that led to requests for post-market studies from the U.S. Food and Drug Administration. Further, since the standards for bioequivalence can vary across nations or agencies, such as the World Health Organization or FDA, it’s important for journalists to pay attention to what the standards are in any countries that export drugs into the U.S.