Sept 5 (Reuters) - The U.S. Food and Drug Administration

is tightening oversight of imports of GLP-1 drug ingredients,

used for weight loss and diabetes, amid concerns that many of

the items may be adulterated and pose a safety risk.

The move comes as the FDA cracks down on unapproved

compounded drugs, which had filled the gap during shortages of

patented treatments. Soaring demand for Novo Nordisk

and Eli Lilly's ( LLY ) obesity drugs has fueled a booming

global market for cheaper, and sometimes even counterfeit

versions.

The health regulator said it had previously identified

serious concerns with compounded weight-loss drugs, including

dosing errors, use of unapproved salt forms and side effects,

with some requiring hospitalization.

As part of its heightened scrutiny, the FDA sent an import

alert on Friday authorizing detention without physical

examination (DWPE) at U.S. ports. This will allow the agency to

seize shipments that appear to be non-compliant with federal

requirements, without inspecting them on arrival.

Importers must now provide proof of quality and compliance

before their goods are released.

The FDA evaluated 48 manufacturing sites outside the U.S.

and found 21% of them as non-compliant.

The regulator will also maintain a separate "green list" -

identifying firms or products that have resolved compliance

concerns and are not subject to automatic detention at the

border.

Under the "green list", the agency identified sources in

Belgium, Canada, China and India, among others, meeting its

criteria, and hence are excluded from DWPE.