Introduction: What are Dulaglutide and Semaglutide?
Dulaglutide and semaglutide are both medications known as glucagon-like peptide-1 receptor agonists. These drugs act by imitating a hormone that regulates satiety called glucagon-like peptide-1(GLP-1), which is naturally released from the small intestine. Both are peptides, a chain of amino acids, including peptides used for muscle growth, tendon repair, healing and gut health.
Semaglutide is available in two forms approved by the FDA: Ozempic and Wegovy, both branded by Novo Nordisk. Ozempic is primarily prescribed for type 2 diabetes and helps manage blood sugar. Wegovy is the primary weight-loss formulation approved for obese people over the age of 12, especially those who have obesity-related side effects. Ozempic is also sometimes prescribed for obesity, mainly because its approval had widespread media coverage. Both forms of semaglutide are taken by injections that gently puncture the skin [1, 2].
Dulaglutide, branded under the name Trulicity, is a once-weekly injectable drug that also mimics the action of GLP-1 in the human body. Dulaglutide is primarily used to treat type 2 diabetes and can be used from the age of 10. It is also injected by an under-the-skin injection [3].
Similarities Between Dulaglutide and Semaglutide
Dulaglutide and semaglutide are GLP-1 receptor agonists used to treat type 2 diabetes. They achieve this by the same mechanism: stimulating the release of insulin and suppressing the release of glucagon. Dulaglutide and semaglutide also increase the time for food to leave your stomach, which is an additional way that these drugs help reduce your blood sugar [2, 4].
Both dulaglutide and semaglutide are administered once a week, which is convenient for patients because they only have to worry about the injection once a week. Both are primarily injectable medications, although semaglutide can also be taken as a tablet called Rybelsus [2, 4, 5].
Regarding their benefits, dulaglutide and semaglutide can effectively reduce HbA1c levels, a measure of long-term blood sugar and body weight in patients with type 2 diabetes [4, 6].
In terms of safety, both drugs have comparable side effects. Gastrointestinal problems such as nausea are the most common in dulaglutide and semaglutide [4, 5].
Economic efficiency in lowering healthcare costs is another important factor, especially in chronic diseases such as type 2 diabetes and obesity. Therefore, the advantages of prescribing the medication over the long term have to be worth the money compared to the healthcare and societal costs of these diseases. Both dulaglutide and semaglutide have demonstrated cost-effectiveness in type 2 diabetes. However, just how much better they are than the status quo depends on the specific country you are looking at [7, 8].
Differences Between Dulaglutide vs Semaglutide
There are subtle differences between dulaglutide vs Semalutide in how these drugs affect glycated hemoglobin (HbA1c), a marker of blood sugar, body weight, and long term treatment outcomes.
Regarding glycaemic control, semaglutide was more effective at reducing HbA1c levels than dulaglutide. Specifically, semaglutide 2.0 mg reduced HbA1c by 0.44% points more than dulaglutide 3.0 mg and by 0.28% points more than dulaglutide 4.5 mg [9]. This demonstrates that per mg drug, semaglutide is much more effective.
In terms of weight reduction, semaglutide also outperforms dulaglutide, according to a study sponsored by Novo Nordisk. Two milligrams of semaglutide a week reduced body weight by 3kg more than three milligrams of dulaglutide and by 2kg more than 1.5 times the dose of dulaglutide [9]. This finding was consistent even when just 1mg of semaglutide was administered [10].
The long-term feasibility of taking semaglutide is also higher than that of taking dulaglutide. In a randomised control trial in the US, semaglutide was more acceptable across patients, and over 67% of patients improved after a year of taking semaglutide compared to only 56% for dulaglutide [11].
Therefore, while dulaglutide and semaglutide are effective and approved treatments for type 2 diabetes, semaglutide can offer more significant reductions in HbA1c and body weight with better tolerance and longer effects.
Side Effects Dulaglutide vs Semaglutide
Both dulaglutide and semaglutide have side effects that can range from mild to severe and form an important consideration when deciding to take dulaglutide vs semaglutide.
Common side effects of dulaglutide include nausea, diarrhoea, and discomfort from stomach stretching. These side effects are usually mild to moderate and diminish over time [12]. In some rare cases, dulaglutide can cause skin reactions, indicating its widespread effects [12].
Similar side effects have been reported from using semaglutide. Nausea, vomiting, constipation, and diarrhoea are all common and relatively mild side effects that will get better over time [13]. Semaglutide has been linked to facial ageing, also known as ‘Ozempic face’. However, this side effect is not from semaglutide but rather from rapid weight loss after taking semaglutide in the form of Ozempic.
Both dulaglutide and semaglutide are given as one-a-week injections, which was found to reduce the frequency of side effects and increase patient tolerability in a recent meta-analysis of weight loss peptides [14].