Jardiance (empagliflozin) lowers blood sugar by blocking your kidneys from reabsorbing glucose back into your bloodstream. Instead of recycling that sugar, your body flushes it out through urine. This mechanism is fundamentally different from most other diabetes medications, which work by increasing insulin production or improving how your cells respond to insulin. Jardiance sidesteps insulin entirely.
How Jardiance Works in the Kidneys
Your kidneys filter about 180 grams of glucose from your blood every day. Normally, a protein called SGLT2, located in the early portion of the kidney’s filtering tubes, captures nearly all of that glucose and sends it back into the bloodstream. Jardiance blocks this protein. With SGLT2 disabled, a significant portion of filtered glucose stays in the urine and leaves your body when you urinate.
This process also changes how sodium moves through the kidney. When more sodium reaches a sensor point deeper in the kidney (called the macula densa), it triggers a pressure-lowering response inside the kidney’s tiny filtering units. That reduced pressure protects the kidney from the long-term damage that high blood sugar and high blood pressure cause over years. It’s one reason Jardiance has benefits beyond glucose control alone.
How Much It Lowers Blood Sugar
In clinical trials reviewed by the FDA, Jardiance lowered HbA1c (the measure of average blood sugar over about three months) by roughly 0.5% to 1.2% more than a placebo over 26 weeks. The effect varies depending on the dose and what other medications a person is already taking, but most patients see a meaningful drop. For context, a 1% reduction in HbA1c is clinically significant and associated with meaningfully lower risks of diabetes complications.
Because the drug works through the kidneys rather than through insulin, its blood sugar lowering effect depends on how well your kidneys are functioning. If your kidney filtration rate (eGFR) drops below 45, Jardiance becomes less effective at lowering glucose, and it should not be started in patients below that threshold. For patients already taking it, the drug is discontinued if kidney function stays persistently below that level.
Weight Loss and Blood Pressure Effects
When your body dumps glucose into urine, those are calories leaving your body instead of being stored. In 24-week clinical studies, patients on the 10 mg dose lost an average of 2.8% of their body weight, while those on 25 mg lost about 3.2%. People taking a placebo lost only 0.4%. The pattern held when Jardiance was combined with metformin or other medications. For someone weighing 200 pounds, that translates to roughly 5.5 to 6.5 pounds over six months.
Jardiance also modestly lowers systolic blood pressure (the top number). In trials, the 10 mg dose reduced it by about 2.6 mmHg compared to placebo, and the 25 mg dose by about 3.4 mmHg. That’s a small but meaningful shift, particularly for people who already have cardiovascular risk factors stacked alongside their diabetes.
Heart and Kidney Protection
The landmark EMPA-REG OUTCOME trial found that Jardiance reduced the risk of cardiovascular death by 38% in people with type 2 diabetes and established heart disease. Among patients who also had kidney disease at the start of the study, it cut hospitalizations for heart failure by 39%. These results changed how doctors think about diabetes treatment: Jardiance became not just a glucose drug, but a cardiovascular and kidney drug that also happens to lower blood sugar.
Current guidelines from the American Diabetes Association (2025) reflect this shift. For adults with type 2 diabetes who have heart failure, chronic kidney disease, or established cardiovascular disease, an SGLT2 inhibitor like Jardiance is now recommended regardless of how well their blood sugar is already controlled. In other words, even if your HbA1c is at goal, your doctor may still prescribe Jardiance specifically for heart or kidney protection.
Common Side Effects
The most distinctive side effect is genital yeast infections, a direct consequence of sugar-rich urine passing through the urinary tract. In clinical trials, about 5.4% to 6.4% of women on Jardiance developed genital yeast infections, compared to 1.5% on placebo. For men, the rates were 1.6% to 3.1%, compared to 0.4% on placebo. These infections are typically mild and treatable, but they’re common enough that you should know to expect the possibility.
Urinary tract infections and increased urination are also reported more frequently. Because the drug pulls extra fluid through the kidneys along with the glucose, some people experience dehydration symptoms, especially early on. Drinking enough water matters more than usual while taking Jardiance.
Hypoglycemia Risk With Other Medications
Jardiance on its own carries a low risk of causing dangerously low blood sugar, precisely because it doesn’t stimulate insulin production. However, if you take it alongside insulin or a sulfonylurea (medications that do increase insulin), the combined effect can push blood sugar too low. In clinical trials, hypoglycemia was a very common side effect in patients using these combinations. Your doctor will often lower the dose of insulin or the sulfonylurea when adding Jardiance to prevent this.
Ketoacidosis: A Rare but Serious Risk
Jardiance carries a warning for a condition called euglycemic ketoacidosis, where the body builds up dangerous levels of acid even though blood sugar readings look normal or only slightly elevated. This is rare, but it’s tricky because the normal blood sugar reading can be falsely reassuring. Symptoms include nausea, vomiting, abdominal pain, excessive thirst, shortness of breath, and confusion. If you experience these symptoms while taking Jardiance, they warrant immediate medical attention regardless of what your glucose meter says.
How to Take It
Jardiance is taken once daily, with or without food, at whatever time of day works for you. The key is consistency: pick a time and stick with it. It comes in 10 mg and 25 mg tablets. Many doctors start at 10 mg and increase to 25 mg if more glucose lowering is needed and the lower dose is well tolerated.