Feb 28 (Reuters) - Eli Lilly ( LLY ) launched an ad

campaign on Friday, cautioning patients against the risks of

unapproved weight-loss drugs in its latest attempt to fend off

competition from copies of its weight-loss drug.

The ad, asking patients to "be a healthy skeptic", was

released soon after a commercial from telehealth firm Hims &

Hers', selling a compounded weight-loss drug, premiered

at the Super Bowl.

WHY IT MATTERS

The ad is aimed at unproven and sometimes counterfeit

products sold online and elsewhere, which claim to offer

weight-loss benefits.

But it also marks the latest in a public back-and forth

between weight-loss drugmakers and companies selling compounded

versions of the drugs, whose sales are permitted when the

original drugs are in short supply.

Hims, which offers compounded versions of Novo Nordisk's

Wegovy, drew criticism from some lawmakers for

omitting safety information about the customized medicines in

their advertisement.

Novo had released an ad earlier this month asking patients

to "check before you inject".

"Before anything goes into your body, be skeptical of what's

in it, be skeptical of where it comes from, be skeptical of who

oversees its production," said Lilly's ad.

CONTEXT

Compounding facilities create medicines by combining,

mixing or altering drug ingredients. While federal regulations

allow compounded versions to be sold to meet demand if a drug is

in short supply, these drugs are not approved by the U.S. Food

and Drug Administration.

Lilly's Zepbound and Novo's Wegovy were recently removed

from the U.S. FDA's shortage list, which means that compounding

pharmacies selling hundreds of thousands of doses of the drugs

are running out of time to produce them.

Novo and Lilly have also sued several medical spas and

compounding pharmacies for selling products claiming to contain

their respective drugs, semaglutide and tirzepatide.