NEW YORK (Reuters) -Online weight-loss company Noom has begun offering smaller doses of compounded versions of Novo Nordisk's Wegovy as the U.S. drugs regulator clamps down on mass production of copies of the in-demand medicine.

Noom will offer its version of compounded semaglutide - the active ingredient in Wegovy and diabetes drug Ozempic - as part of a program personalized for patients, which it says will comply with changing U.S. Food and Drug Administration regulations.

Demand for the new generation of highly effective but pricey weight-loss drugs has catapulted sales at Noom and rival telehealth sites including Hims & Hers, WeightWatchers and Ro over the past two years. 

Taking small doses of the weight-loss drugs, sometimes referred to as micro-dosing, has become popular due to the high cost and side effects of the medicines.

For hundreds of dollars less than the name brand drugs, patients could access doctors and pharmacy-made versions based on semaglutide or tirzepatide, the main ingredient in Eli Lilly's ( LLY ) rival Zepbound and Mounjaro, due to a regulatory exception allowing them during drug shortages.

However, the FDA declared the shortages over and its sunset deadline for compounded versions of Wegovy is May 22.

Noom offers its compounded semaglutide at a starting price of $149 for the first month. A 2.5 milligram vial of Wegovy or Zepbound costs $349, according to Novo and Lilly websites.

Analysts have said the telehealth companies must pivot to working with branded drugs in order to survive after WeightWatchers filed for bankruptcy.

Jeffrey Egler, Noom's chief medical officer, said providers would determine if patients need a smaller dose because of concerns about gastrointestinal side effects, or to boost adherence or help keep lost weight off, for example.

Noom CEO Geoff Cook said the move would not conflict with regulations. "There is a personalized, and there has always been a personalized, exception," Cook said.

Novo Nordisk said it is illegal to make or sell semaglutide copies in the U.S. with only rare exceptions.

"As the FDA has warned, compounders cannot evade federal compounding laws by selling knockoff semaglutide drugs with manipulated, unnecessary, and pretextual changes to doses and ingredients," a Novo Nordisk spokesperson said in a statement.

DOSING

Noom's documents show that a personalized approach could start with half the typical starter 0.25-milligram dose of Wegovy and gradually increase to about half the FDA-approved maximum dose of 2.4 mg over 20 weeks.

Noom said the move is not meant to capitalize on the microdosing trend, saying patients could increase their dose to the target, just more slowly.

Noom said it will continue selling branded Novo Nordisk drugs as well as Lilly's Zepbound.

Clinical trials of Wegovy and Zepbound have shown the drugs can lead to reductions of 15% to 20% of a person's body weight.

A recent study suggests that half the usual dose of semaglutide may be as effective a weight-loss tool as current dosing.

While compounders can create copies for individuals of doses not available in branded drugs, ongoing FDA reviews of whether tirzepatide and semaglutide fall into a category of drugs too complex to qualify for any compounding could put an end to the practice, said Rosalie Hoyle, a research scientist at Avalere.

"As it stands today, compounders still can technically make a personalized dose of semaglutide and tirzepatide," she said.