Semaglutide Vs Tirzepatide, and the Future of Weight Loss Drugs

When weight loss drugs first gained national prominence, everybody used the term “Ozempic.” To be precise, Ozempic is a drug used to treat diabetes, and it’s been on the market for decades. However, when its weight loss properties gained public attention, it became the De facto term for a weight loss injection. In fact, Wegovy is the name of the weight loss version, specifically a glucagon-like peptide receptor agonist (GLP-1), also known generically as semaglutide.

One of the main competitors to Ozempic is a drug named Mounjaro (tirzepatide). Like Ozempic, it acts on GLP-1 receptors, but it also targets GIP-1 receptors, which may provide additional benefits for diabetes management. This dual pathway is thought to enhance weight loss beyond what GLP-1 alone can achieve. Much like Ozempic, which was formulated at a higher dosage to create Wegovy and approved for weight loss, Moujaro has a more potent sister drug known as Zepbound, which is similarly approved for weight loss.

Is there a better option?

Of the two, the dual mechanism of GLP-1 and GIP-1 contained in Tirzepatide/Zepbound/ Mounjaro has a slightly better effectiveness profile.

In clinical trials, Semaglutide / Wegovy offered approximately one-third of patients 20% or slightly more body weight loss. On the other hand, Tirzepatide has increased that to about 26% body weight loss.

Similarly, and likely due to the same dual versus single-action properties, Tirzepatide appears to have a more favorable profile than semaglutide when it comes to long-term blood sugar control and reducing A1c.

Side effects

The side effect profile of both drugs is quite similar, with the majority of side effects revolving around gastrointestinal upset, including nausea and vomiting. With that said, because Tirzepatide affects both the GLP and GIP receptors, it may yield more side effects. For now, we have observed a relatively similar side effect profile between the two, which is mild in most patients, but can also be problematic for some.

To that end, patients should be aware of the side effect profile of the drug they are taking. Both cause significant and serious side effects, including gallbladder disease, pancreatitis, and a slowing of gastrointestinal movement known as gastroparesis. Typically, these improve or resolve when the patient stops the drug, but, of course, there is the possibility of more far-reaching problems.

These drugs may also cause some concerns due to the rapid weight loss that they provide. If not paired with proper diet and exercise, patients on these drugs may find that they lose a significant amount of muscle mass and bone density as they lose weight. This can cause more immediate concerns surrounding plateaus and limited weight loss, as well as longer-term worries in the form of osteopenia and osteoporosis.

A note on effectiveness

It’s important to cut through the hype of pharmaceutical marketing. Patients can indeed lose up to 20 or even 25% of their body weight using one of these two drugs. However, these results were observed only in a subset of patients during clinical trials, and we have learned from the past two years of widespread use that not everyone will experience what feels like miraculous weight loss from taking these drugs. In fact, some patients will not experience any weight loss at all.

The fact that we have both semaglutide and tirzepatide on the market gives us options to adjust the medication regimen and see what works. For example, if you’ve taken one before and it hasn’t worked, switching may be a good option. It’s also important to remember that rapid weight loss is not desired; slow and steady progress is ideal, and meaningful weight loss can still occur over several weeks. With that said, if you have experienced significant side effects with a GLP-1 medication before, you will likely experience similar side effects regardless of which drug you choose.

Cost

The cost of GLP-1 drugs has been a point of contention since they were introduced. On the one hand, many insurance companies, including those in Alabama, may not cover the cost of weight loss-specific formulations of these drugs, leaving patients to pay out-of-pocket for the medication. The cost of these drugs has been upwards of $1,000 a month.

During a period of significant drug shortages, the FDA authorized compounding pharmacies to fill the gap, allowing patients to obtain the drugs at a substantially lower cost. This shortage period is now over, and the brand-name drugs, with all their expenses, are the only authorized medications available on the market.

With that said, the drug maker behind the semaglutides Wegovy and Ozempic has tried to make various deals with distributors to reduce the price and spur drug sales. After a contentious relationship with an online purveyor, the drug has found a low-cost home with GoodRx, and patients may be able to buy it for as low as half the price. As of the writing of this article, there has been no such deal made with Eli Lilly and Zepbound.

Is one drug better than the other?

Fortunately, the competition between these two drugs – and future medications that will inevitably come out and eclipse them in popularity or effectiveness – offers patients a choice. Something else to consider is whether you have certain comorbidities that could benefit from treatment beyond obesity alone. For example, if you have a history of stroke or severe sleep apnea, some medications may be more suitable and offer a “double win.”

Patients can speak with the dedicated team at SAMPA or their prescribing doctor to determine which of the two currently most popular medications might be best for them.