Januvia and Jardiance are not the same medication. They contain different active ingredients, work through completely different mechanisms in the body, and are approved for different uses. Januvia (sitagliptin) belongs to a class called DPP-4 inhibitors, while Jardiance (empagliflozin) is an SGLT2 inhibitor. Both can lower blood sugar in people with type 2 diabetes, but the similarities largely end there.
How Each Drug Works
Januvia works by blocking an enzyme that breaks down hormones involved in insulin production. When you eat, your gut releases hormones that signal the pancreas to produce insulin. Januvia keeps those hormones active longer, so your pancreas releases more insulin when blood sugar rises after a meal. It also reduces the amount of sugar your liver releases into the bloodstream. The effect is tied to meals, meaning the drug primarily works when you’re eating.
Jardiance takes a completely different approach. Instead of targeting insulin, it works through the kidneys. Normally, your kidneys filter sugar out of the blood and then reabsorb most of it back into the body. Jardiance blocks that reabsorption, causing excess sugar to leave through your urine. This mechanism operates independently of insulin, which is one reason the two drugs are sometimes prescribed together.
Approved Uses
Both drugs are approved for managing blood sugar in type 2 diabetes, but Jardiance has a significantly broader range of FDA-approved indications. It is also approved to reduce the risk of cardiovascular death and hospitalization in adults with heart failure, and to slow kidney disease progression in adults with chronic kidney disease at risk of getting worse. These approvals apply regardless of whether the patient has diabetes.
Januvia does not carry these additional heart or kidney indications. Its approved use is limited to improving blood sugar control in type 2 diabetes.
Effects on Body Weight
This is one of the most noticeable practical differences between the two. Because Jardiance causes your body to flush out sugar through urine, it also flushes out the calories those sugars carry. In a 90-week clinical trial, patients taking Jardiance lost between 2.2 and 4.0 kilograms (roughly 5 to 9 pounds), while those on Januvia lost only 0.4 kilograms, essentially staying weight-neutral.
A separate 12-week trial found similar results: patients on empagliflozin (Jardiance’s active ingredient) dropped from an average of 78.2 kg to 74.1 kg, a statistically significant decrease. Patients on sitagliptin (Januvia) showed no meaningful change. If weight management is a priority alongside blood sugar control, this distinction matters.
Side Effects
The side effect profiles reflect how differently these drugs work in the body.
Jardiance’s mechanism of pushing sugar into the urine creates a warm, glucose-rich environment in the urinary tract. That raises the risk of yeast infections and urinary tract infections. It can also cause increased urination and, in some people, dehydration or drops in blood pressure. Older adults and people already taking blood pressure medications are more susceptible to these volume-related effects. A rare but serious risk is diabetic ketoacidosis, a condition where the body produces dangerously high levels of acids called ketones.
Januvia is generally considered well tolerated with fewer common side effects. Rare risks include joint pain, skin reactions, and pancreatitis (inflammation of the pancreas). Allergic reactions, though uncommon, have also been reported.
Dosing Differences
Jardiance is taken as a 10 mg tablet once daily in the morning, with or without food. The dose can be increased to 25 mg if more blood sugar control is needed. It is not recommended for blood sugar management when kidney function drops below a certain threshold, and it is contraindicated for people on dialysis.
Januvia comes in 25 mg, 50 mg, and 100 mg tablets. The standard dose is 100 mg once daily, but the dose is reduced for people with moderate or severe kidney impairment. Unlike Jardiance, Januvia can still be used at lower doses in people with significantly reduced kidney function.
Who Should Avoid Each Drug
Neither drug is appropriate for type 1 diabetes. Jardiance carries specific contraindications for people with severe kidney impairment (estimated kidney filtration rate below 30), people on dialysis, and anyone with a history of serious allergic reaction to empagliflozin. It is also not recommended during the second and third trimesters of pregnancy. People with a history of pancreatic disorders, pancreatitis, or alcohol abuse face a higher risk of ketoacidosis on Jardiance and need careful monitoring.
Januvia should be avoided by anyone with a known hypersensitivity to sitagliptin. Because it is processed through the kidneys, the dose needs adjustment in kidney disease, but it is not as strictly limited by kidney function as Jardiance is for blood sugar management.
Can You Take Both Together?
Yes. Because Januvia and Jardiance work through entirely separate pathways, they can be prescribed together. Studies in healthy volunteers showed no meaningful drug interactions between the two, and no dose adjustments are needed when combining them. The combination is considered attractive specifically because each drug complements the other: Jardiance removes excess sugar through the kidneys, while Januvia boosts insulin release and reduces sugar output from the liver.
Together, the two classes also carry a low risk of causing dangerously low blood sugar, which is a common concern when stacking diabetes medications. That said, if either drug is combined with insulin or certain older diabetes drugs that directly stimulate insulin secretion, the risk of low blood sugar does increase. Both drug classes have also shown potential to reduce a marker of kidney damage called urinary albumin excretion, suggesting possible complementary kidney benefits when used together.
Which One Is Prescribed and Why
The choice between Januvia and Jardiance depends on what your doctor is trying to address beyond blood sugar. For someone with heart failure or chronic kidney disease, Jardiance offers proven benefits that Januvia does not. For someone who would benefit from weight loss alongside blood sugar control, Jardiance again has a clear edge. Januvia may be a better fit for people who are prone to urinary or yeast infections, those with lower blood pressure, or older adults at risk of dehydration. Cost, insurance coverage, and how well you tolerate each drug also factor into the decision.
They are not interchangeable, and switching from one to the other changes both how your body manages blood sugar and what additional health benefits or risks you’re exposed to.