Introduction
If you’ve been considering taking weight loss drugs to lose weight or manage your type 2 diabetes, you’re in luck. There’s currently a wide array of effective medicines available. You must already know about Ozempic, made with semaglutide, which has been flying off the shelves for its efficacy. There’s also the equally popular tirzepatide, among a sea of other weight loss drugs.
With all these options, it can be dizzying to choose which one is the most suitable medicine for you. Which one is better, semaglutide or tirzepatide? Read on as we compare the two blockbuster drugs, how they work, and which one is more effective.
Semaglutide and Tirzepatide: An overview
It hasn’t been long since semaglutide (Ozempic, Wegovy, and Rybelsus) and tirzepatide (Mounjaro, Zepbound) received FDA approval.
In 2017, Ozempic was the first semaglutide brand to receive FDA approval. It received approval for improving blood sugar control in adults with type 2 diabetes, in addition to diet and exercise.
Rybelsus, meanwhile, received FDA approval in 2019 for improving blood sugar control in adults with type 2 diabetes. It was the first GLP-1 receptor agonist FDA-approved in the US that you don’t need to inject.
Wegovy, meanwhile, was the first semaglutide brand that received FDA approval for weight loss. It was the last semaglutide to receive FDA approval, in 2021. Wegovy received approval for chronic weight management in adults with obesity or overweight adults with at least one weight-related condition.
This was in addition to a lower-calorie diet and higher physical activity. Some examples of these weight-related conditions are type 2 diabetes, high blood pressure, or high cholesterol.
The approval marked an important time in medicine. It was the first weight management drug since 2014 to receive approval for adults who are obese or overweight.
It would receive a secondary FDA approval in 2022 to cater to pediatric patients aged 12 years and above. This was for those with an initial BMI at the 95th percentile or greater for age and sex. In addition, they must have a lower-calorie diet and higher physical activity.
Not long after, in May 2022, tirzepatide, under its brand name Mounjaro, received initial FDA approval for type 2 diabetes. A new version of the drug, named Zepbound, would receive FDA approval in November 2023 for treating obesity.
How they work
In our gut is a hormone, glucagon-like peptide-1, or GLP-1 for short. Whenever we finish eating and our blood sugar levels are high, GLP-1 triggers the release of insulin, regulating these.
Semaglutide is a glucagon-like peptide-1 receptor agonist, or GLP-1 Ra. Whenever blood sugar levels are high, it responds in the same way, performing the same action.
At the same time, semaglutide also delays gastric emptying, when food exits the gut and enters the small intestine. Because digestion is slower, you don’t think about food as much and you feel fuller for longer. With fewer food cravings and a curbed appetite, people on semaglutide lose a considerable amount of weight. The drug also signals to the brain that you’re already full.
Tirzepatide is also a GLP-1 receptor agonist, but it’s also a dual-acting glucose-dependent insulinotropic polypeptide (GIP). Similarly, it stimulates the pancreas to release insulin when your blood sugar levels are high. In addition, it also delays gastric emptying. At the same time, it also decreases the amount of sugar produced by your liver.
Semaglutide and tirzepatide are both incretin mimetics as they mimic GLP-1, which is an incretin. An incretin is a metabolic hormone that triggers a reduction in blood glucose levels.
Eligibility: Who can take semaglutide and tirzepatide?
If you’d like to take semaglutide or tirzepatide, you first need to meet certain diagnostic criteria.
For Ozempic, Rybelsus, and Mounjaro, for example, patients must have a type 2 diabetes diagnosis.
Doctors may also prescribe Ozempic for heart disease as it has additional approval for lowering the risk of cardiovascular problems. They may also prescribe it for those dealing with insulin resistance.
Wegovy and Zepbound users, on the other hand, need to be overweight or obese, with one weight-related health condition. They must have a BMI of 27 or greater or 30 or greater, along with one weight-related health condition.
Although drugmaker Novo Nordisk markets these semaglutide and tirzepatide brands differently, they both offer blood sugar regulation and weight management. It’s no wonder many doctors choose to prescribe Ozempic, Rybelsus, or Mounjaro off-label for weight loss.
Dosage and administration
Your doctor will typically start you on a low dose, gradually increasing this to maintenance levels as your body adjusts.
For Ozempic, Mounjaro, Wegovy, and Zepbound, you inject them once weekly subcutaneously (under the skin) regardless of meals. You can inject them in either the abdomen, the thigh, or the upper arm. These come in injectable dosing pens.
You take Rybelsus, meanwhile, orally once daily on an empty stomach and come in tablet format.
Side effects of Tirzepatide and Semaglutide
Just like any drug, Ozempic, Wegovy, Rybelsus, Mounjaro, and Zepbound all come with potential side effects.
Gastrointestinal reactions account for 10% or more of semaglutide’s side effects. These include nausea, diarrhea, vomiting, constipation, and abdominal pain.
Other less common side effects of semaglutide include indigestion, belching, gassiness, gastroenteritis, or gastritis. Gastroenteritis is the short-term infection and inflammation of the digestive system, while gastritis is inflammation of the stomach lining.
Similarly, tirzepatide’s side effects are gastrointestinal, probably because of their nature as GLP-1 drugs which take effect in the gut. About 50% of patients reported nausea, vomiting, and diarrhea as the most common side effects of both semaglutide and tirzepatide.
Tirzepatide’s most common side effects include stomach pain, acid or sour stomach, belching, constipation, diarrhea, or an upset stomach.
The more serious side effects of semaglutide include allergic reactions, hypoglycemia, pancreatitis, kidney problems, and thyroid C-cell tumors. Meanwhile, tirzepatide’s includes changes in urine amount, decreased or blurred vision, or nausea and vomiting that won’t stop.
Semaglutide vs. Tirzepatide
On achieving desired HbA1c levels
Both semaglutide and tirzepatide can help patients reach their target HbA1c (hemoglobin A1C) levels. HbA1c measures their average blood sugar level over the past two to three months. Achieving desired A1C levels can help prevent diabetes complications like heart/blood vessel disease, kidney failure, and nerve/vision damage.
A comparative study revealed semaglutide lowered A1C levels by 1-2%, while tirzepatide reduced A1C levels by 2% to 2.5%.
For weight loss
Those on 0.5 or 1 mg of semaglutide lost 13.2-22 pounds. Meanwhile, those on 10 or 15 mg of tirzepatide lost between 15.4-28.6 pounds. Based on this data, tirzepatide was more effective in helping lower blood sugar levels and promoting weight loss.
On the flip side, it can also be linked to more gastrointestinal side effects if taken in higher doses. Patients on tirzepatide could also lose 17.7% of their initial body weight, versus those on semaglutide (12.4%).
On cardiovascular problems
As we’ve mentioned, studies found that Ozempic reduces the risk of cardiovascular problems in patients with type 2 diabetes and heart disease. Tirzepatide, meanwhile, has not yet received this indication, as studies are still being conducted on this.
Comparing price tags of Semaglutide and Tirzepatide
One US study found that Zepbound may provide greater value for money than Ozempic for weight reduction over 68-72 weeks.
For 72 weeks, a tirzepatide treatment costs roughly $17,500, while a semaglutide treatment costs around $22,800. This translates to a $985 cost with tirzepatide for 1% body weight reduction and a $1845 cost with semaglutide.
On side effects
The number of patients who reported side effects for semaglutide and for tirzepatide were not far from each other. However, more serious side effects were observed on tirzepatide (5.3% to 7%) versus those on semaglutide (2.8%).
All doses of both semaglutide and tirzepatide increased the risk for gastrointestinal side effects versus placebo. But the higher the dose of tirzepatide (15 mg), the higher the risk for developing nausea, diarrahea, and vomiting.
Semaglutide and its formats
Only semaglutide’s Rybelsus comes in tablet form and is taken orally. This provides an alternative to those who want the same benefits but are squeamish to inject themselves with a drug.
Use in pediatric patients
While semaglutide and tirzepatide are approved for adults, only Wegovy is FDA-approved to manage weight in children 12 and above.
Conclusion
Which is better, semaglutide or tirzepatide?
It appears that tirzepatide is superior to semaglutide in reducing A1C levels and providing greater value for money. Tirzepatide was also more effective in helping patients lose weight but at higher doses.
This also typically resulted in worsened side effects. Those who take tirzepatide were also found to be more likely to experience nausea, vomiting, or diarrhea.
Semaglutide has been proven to reduce the risk of cardiovascular problems, while tirzepatide has yet to receive this indication. Semaglutide is also the only active ingredient to have an oral variant, in Rybelsus. In addition, it has FDA approval for treating obesity in pediatric patients (Wegovy).
Both semaglutide and tirzepatide have advantages over the other. Although if efficacy is your standard for making one superior over another, tirzepatide will have to take the crown. Remember, though, that the most suitable medication for you will be determined by your doctor.
Note that any person will react differently to a drug. Should you encounter any side effects while taking semaglutide or tirzepatide, let your healthcare provider know.
Glossary of terms:
- GLP-1: Glucagon-like peptide-1 is a gut-based hormone involved in the secretion of insulin to lower blood sugar levels typically elevated after meals.
- GLP-1 Ra: Glucagon-like peptide-1 receptor agonist. It mimics the actions of GLP-1.
