Are there differences in the manufacturing process of Wegovy compared to other weight loss drugs?

Wegovy is made as a biologic medicine, meaning it uses recombinant technology to produce semaglutide, a protein-based drug. Mysimba and Orlistat, by contrast, are small-molecule tablets made by chemical synthesis. These differences influence regulation and supply but not day-to-day use for patients.

What makes Wegovy a biologic

Wegovy (semaglutide) belongs to a group of medicines known as biologics. These are typically large, complex molecules produced in living cells using recombinant DNA technology. Instead of being made through traditional chemical reactions in a lab, semaglutide is manufactured by programming cells — often yeast or bacteria — to produce the protein. The process is highly controlled, and even small changes in production can affect how the medicine works, which is why strict regulation applies to biologics.

How this differs from small-molecule drugs

Older weight-loss medicines like Orlistat or Mysimba (naltrexone/bupropion) are considered small molecules. These are made through standard chemical synthesis, where ingredients are combined and refined in predictable steps. They are generally simpler to produce and replicate, which makes manufacturing more straightforward and less costly. Unlike biologics, small molecules can often be copied as generics more easily once patents expire.

Why regulation is stricter for biologics

Because biologics are more complex, regulators such as the MHRA and EMA require detailed checks on manufacturing consistency. For semaglutide, the process must ensure that the protein structure, folding, and activity remain identical across every batch. This adds complexity and cost compared with drugs like Orlistat or Mysimba, but it also ensures safety and reliability. When copies of biologics are developed, they are known as biosimilars rather than generics, reflecting the fact that exact replication is not possible in the same way as with chemical drugs.

Supply implications

The complexity of biologic manufacturing partly explains why medicines like Wegovy and Mounjaro have faced global supply pressures. Production involves large-scale cell cultures, purification steps, and strict cold-chain storage. Any disruption in the process can limit availability. By contrast, small-molecule drugs such as Orlistat are easier to mass-produce and distribute, which is why shortages are less common.

Impact on patients

For patients, these manufacturing differences are largely invisible. What matters day to day is how the medicine is taken: Wegovy as a weekly injection pen, Orlistat as capsules with meals, Mysimba as daily tablets. The regulatory and supply challenges happen behind the scenes, handled by manufacturers, regulators, and the NHS. Still, knowing that biologics like Wegovy are more complex helps explain why they are more expensive and why rollouts can sometimes be slower than with older drugs.

NHS perspective

NICE acknowledged the higher cost of Wegovy in its appraisal but concluded that the benefits in weight reduction, metabolic health, and cardiovascular protection made it a cost-effective choice for NHS commissioning. The complexity of biologic manufacturing is factored into pricing negotiations, ensuring that patients can still access the medicine through specialist weight-management services.

The wider context

Yes, there are clear differences in how Wegovy is manufactured compared to older weight-loss drugs. Biologic production is more complex, tightly regulated, and more costly, while small-molecule medicines like Orlistat and Mysimba are simpler to produce. For patients, the practical experience may be the same — taking a medicine regularly to support weight loss — but behind the scenes the processes, regulations, and supply chains are very different.