Jardiance (empagliflozin) lowers blood sugar by blocking the kidney’s ability to reclaim glucose from urine, so excess glucose leaves the body every time you urinate instead of cycling back into the bloodstream. This makes it fundamentally different from most diabetes drugs, which work by increasing insulin or making cells more sensitive to it. Jardiance sidesteps insulin entirely, and that single distinction ripples into a surprising number of secondary effects on weight, blood pressure, heart health, and even how the body fuels itself.
How the Kidney Normally Handles Glucose
Your kidneys filter roughly 180 grams of glucose out of your blood every day. Under normal circumstances, almost all of it gets reabsorbed before reaching the bladder. The heavy lifting happens in a stretch of tubing called the proximal tubule, where a transporter protein called SGLT2 pulls glucose and sodium back into the bloodstream together. A second transporter, SGLT1, picks up whatever SGLT2 misses. Between the two, healthy kidneys send virtually zero glucose into the urine.
When SGLT2 is blocked, the kidney’s total glucose-reclaiming capacity drops to about 80 grams per day, which is roughly what SGLT1 alone can handle.1PubMed Central. Targeting renal glucose reabsorption to treat hyperglycaemia: the pleiotropic effects of SGLT2 inhibition That means any filtered glucose above 80 grams spills into the urine. In someone with type 2 diabetes whose blood sugar runs high, the amount of glucose being filtered is well above that threshold, so a meaningful quantity ends up being excreted. This is the core mechanism behind Jardiance’s glucose-lowering effect: the drug does not change how much insulin you make or how well your cells respond to it. It simply lowers the bar for how much glucose your kidneys hold onto.
Why Empagliflozin Is Particularly Selective
Several drugs in the SGLT2 inhibitor class are on the market, including dapagliflozin (Farxiga) and canagliflozin (Invokana). Empagliflozin stands out for having the highest selectivity for SGLT2 over SGLT1 among clinically used options.2PubMed. A complete review of empagliflozin: Most specific and potent SGLT2 inhibitor used for the treatment of type 2 diabetes mellitus That selectivity matters because SGLT1 does important work elsewhere in the body, especially in the gut, where it helps absorb glucose from food. A drug that also blocked SGLT1 at meaningful levels could cause gastrointestinal side effects like diarrhea. By targeting SGLT2 with high precision, Jardiance achieves its glucose-lowering effect in the kidney while leaving gut absorption largely undisturbed.
The Insulin-Independent Advantage
Most type 2 diabetes medications either push the pancreas to release more insulin (sulfonylureas), make cells more sensitive to insulin (metformin, thiazolidinediones), or supply insulin directly (injectable insulin). All of these approaches depend on insulin working, which becomes increasingly difficult as the disease progresses and the pancreas wears down. Jardiance works regardless of how much insulin you produce or how resistant your cells are to it, because the drug acts on the kidney, not on insulin signaling.
This independence from insulin has an interesting secondary benefit. By lowering blood glucose without requiring the pancreas to work harder, Jardiance reduces what researchers call glucotoxicity, the damaging effect that chronically high blood sugar has on the insulin-producing beta cells of the pancreas. Studies in people with type 2 diabetes have shown that empagliflozin treatment is associated with improved beta-cell function, likely because once blood glucose drops, the beta cells recover some of their ability to secrete insulin on their own.3PubMed Central. Empagliflozin Treatment Is Associated With Improved β-Cell Function in Type 2 Diabetes Mellitus The drug does not directly repair the pancreas, but by relieving the toxic glucose environment, it gives beta cells a better chance to function.
The Glucagon Paradox
If the mechanism sounds straightforward so far, here is where it gets complicated. SGLT2 inhibitors cause a paradoxical rise in glucagon, the hormone that tells the liver to release stored glucose into the bloodstream. Studies have found that empagliflozin can trigger a 7.5% to 24% increase in post-meal glucagon levels, accompanied by an 8.8% to nearly 21% rise in the liver’s own glucose production.4Canadian Journal of Diabetes. Can the Combination of Incretin Agents and Sodium-Glucose Cotransporter 2 (SGLT2) Inhibitors Reconcile the Yin and Yang of Glucagon? That is working against the drug’s glucose-lowering purpose.
The explanation appears to involve the alpha cells of the pancreas, the cells that produce glucagon. Researchers have discovered that alpha cells actually carry their own SGLT2 transporters. When empagliflozin blocks those transporters, the alpha cells sense less glucose coming in and respond by releasing more glucagon. This partially offsets the glucose being lost through the urine and helps explain why SGLT2 inhibitors, while effective, do not lower blood sugar as dramatically as their urinary glucose losses alone would predict. The body partially compensates, which is also part of why SGLT2 inhibitors rarely cause dangerously low blood sugar on their own.
What Happens to Body Weight
When you excrete glucose through urine, you are literally flushing calories down the toilet. Each gram of glucose carries about four calories, so losing 60 to 80 grams of glucose per day translates to roughly 240 to 320 calories lost daily. Over time, this contributes to weight loss. Mouse studies have shown that empagliflozin reduces body mass primarily by shrinking fat deposits, including the deep abdominal fat around internal organs, rather than by losing muscle or other lean tissue.5BMJ Open Diabetes Research & Care. Empagliflozin reverses obesity and insulin resistance through fat browning and alternative macrophage activation in mice fed a high-fat diet
In clinical practice, the weight loss people experience on Jardiance is modest, typically a few pounds over the first several months. Part of the reason the weight loss is not larger is the glucagon-driven compensation described above: the liver ramps up its own glucose production, partially replacing calories that were lost. Some people also eat more to make up for the energy deficit. Still, even modest weight loss helps improve insulin sensitivity and other metabolic markers, making the weight effect a meaningful bonus rather than the primary reason most people take the drug.
Effects on Blood Pressure and Fluid Balance
Because SGLT2 moves sodium along with glucose, blocking it also increases sodium excretion in the urine. This natriuresis, combined with the osmotic pull of all that extra glucose dragging water into the urine, produces a mild diuretic effect. The result is a modest reduction in blood volume and blood pressure, typically around 4 to 6 mmHg for systolic blood pressure.6Anesthesia & Analgesia. Perioperative Considerations for the Use of Sodium-Glucose Cotransporter-2 Inhibitors in Patients With Type 2 Diabetes That might sound small, but population-level data suggest that even reductions of a few points in systolic pressure meaningfully lower cardiovascular risk over time.
The extra sodium delivery to a downstream part of the kidney also reactivates a feedback loop called tubuloglomerular feedback, which reduces the pressure inside the filtering units of the kidney (glomeruli).7PubMed Central. Kidney-Protective Effects of SGLT2 Inhibitors In people with diabetes, these filtering units are often under abnormally high pressure, a condition called hyperfiltration that gradually damages the kidney. By dialing down that pressure, Jardiance provides a kidney-protective effect that goes beyond simple glucose control. This hemodynamic relief, along with the reduction in plasma volume and blood pressure, also helps explain why SGLT2 inhibitors have been approved for heart failure, even in people without diabetes.8PubMed. Mechanistic insights and clinical horizons of SGLT2 inhibitors in heart failure management
The Metabolic Fuel Shift
When you lose a significant amount of glucose through the kidneys every day, the body needs to find alternative fuels. One response is increased fat breakdown, which generates fatty acids and eventually ketone bodies, molecules the heart, brain, and muscles can burn for energy. Empagliflozin has been shown to promote a shift in cardiac metabolism away from glucose and toward ketone utilization.9Cardiovascular Research. Empagliflozin improves cardiac energetics during ischaemia/reperfusion by directly increasing cardiac ketone utilization Some researchers believe this fuel shift is one reason the drug protects the heart: ketones are a more oxygen-efficient fuel for cardiac muscle, and the heart in people with diabetes or heart failure often struggles with its usual energy supply.
Animal studies have found that empagliflozin increases both the synthesis and utilization of ketone bodies in heart tissue, improving mitochondrial function and ATP production while reducing oxidative stress.10PubMed Central. Empagliflozin improves mitochondrial dysfunction in diabetic cardiomyopathy by modulating ketone body metabolism and oxidative stress In addition, empagliflozin appears to directly inhibit a protein called the sodium-hydrogen exchanger (NHE1) in heart muscle cells. Blocking NHE1 reduces sodium and calcium overload inside cardiac cells, which protects them from injury and death.11PubMed Central. Unraveling the Molecular Mechanism of Action of Empagliflozin in Heart Failure With Reduced Ejection Fraction With or Without Diabetes Studies in isolated human atrial heart cells have confirmed that empagliflozin nearly abolishes NHE activity at clinically relevant concentrations.12ESC Heart Failure. Empagliflozin Inhibits Na+/H+ Exchanger Activity in Human Atrial Cardiomyocytes Whether NHE1 inhibition or the ketone fuel shift contributes more to Jardiance’s cardiac benefits is still debated, and the honest answer is that both probably matter.
Why Kidney Function Affects How Well It Works
Because Jardiance depends on the kidneys filtering glucose, the drug’s glucose-lowering power declines as kidney function decreases. With less blood being filtered, there is less glucose available to be excreted, so the drug has less raw material to work with. Pooled analyses of clinical trials have confirmed that the HbA1c reduction from empagliflozin shrinks as baseline kidney function drops.13PubMed. Pooled analysis of Phase III trials indicate contrasting influences of renal function on blood pressure, body weight, and HbA1c reductions with empagliflozin The same analyses found that blood pressure and weight reductions are generally preserved even in people with chronic kidney disease, since those effects depend more on fluid shifts and calorie loss than on the absolute volume of glucose excreted.14PubMed. Empagliflozin and Clinical Outcomes in Patients With Type 2 Diabetes Mellitus, Established Cardiovascular Disease, and Chronic Kidney Disease
This has practical implications. If your doctor prescribes Jardiance primarily to lower blood sugar and your kidneys are significantly impaired, the glucose-lowering benefit will be smaller. But if the prescription is partly for heart or kidney protection, the drug’s hemodynamic and metabolic effects still offer meaningful benefits even with reduced kidney function, which is why prescribing guidelines have gradually expanded to include patients with lower kidney filtration rates.
Uric Acid and Gout Risk
An underappreciated effect of Jardiance is its impact on uric acid, the molecule responsible for gout. Empagliflozin lowers serum uric acid levels, and the effect is more pronounced in people who start with higher uric acid. In the large EMPA-REG OUTCOME trial, the drug reduced uric acid by about 0.37 mg/dL overall compared to placebo at one year, and by 0.56 mg/dL in those who began with elevated levels above 7.0 mg/dL. Among patients not already taking gout medications, gout events or the need to start gout treatment occurred in 3.6% of the empagliflozin group compared to 5.2% of the placebo group, a roughly one-third lower risk.15PubMed Central. Empagliflozin and uric acid metabolism in diabetes: A post hoc analysis of the EMPA‐REG OUTCOME trial The mechanism likely involves increased uric acid excretion in the urine alongside the extra glucose, since the same tubular transport systems overlap. For people with type 2 diabetes who also have gout or borderline-high uric acid, this is a welcome side benefit.
The Risk of Euglycemic Ketoacidosis
The same fuel shift that may help the heart can, in rare circumstances, tip into dangerous territory. When the body loses large amounts of glucose through the kidneys, it mimics a state of carbohydrate starvation. The ratio of glucagon to insulin rises, fat breakdown accelerates, and ketone production ramps up. In most people, this stays within safe limits. But certain triggers, such as skipping meals, severe dehydration, illness, surgery, or excessive alcohol intake, can push ketone levels high enough to cause ketoacidosis.16PubMed Central. Empagliflozin induced euglycemic diabetic ketoacidosis
What makes this especially tricky is that blood sugar can remain near-normal during the episode, because the kidneys are still clearing glucose efficiently. Clinicians call this euglycemic diabetic ketoacidosis (euDKA), and it can be missed if providers rely on high blood sugar as a warning sign. The proposed mechanism involves multiple overlapping factors: glucose lost in the urine reduces insulin secretion, empagliflozin stimulates glucagon release from the pancreas, and the kidneys’ ability to clear the ketone bodies beta-hydroxybutyrate and acetoacetate is impaired.17Kidney Medicine. SGLT2 Inhibitor–Induced Euglycemic Diabetic Ketoacidosis: A Case Report EuDKA is rare, but it is serious enough that doctors typically advise pausing Jardiance before planned surgery and during acute illness.
Urinary Tract and Genital Infections
Spilling glucose into the urine creates an environment where bacteria and yeast can thrive. The sugar-rich urine essentially feeds the microorganisms that cause urinary tract infections and genital yeast infections, particularly in women and uncircumcised men.18Health Sciences Review. Metabolic and microbial crossroads: Sodium-glucose cotransporter-2 inhibitors and urinary tract infections in (Asian) diabetes care These infections are the most commonly reported side effect of SGLT2 inhibitors as a class. They are usually mild and treatable, but for people prone to recurrent infections, the risk-benefit balance may shift. Good hygiene, adequate hydration, and prompt treatment of early symptoms help keep this side effect manageable.
How the Drug Moves Through Your Body
Empagliflozin is taken as a once-daily oral tablet, typically at 10 mg or 25 mg. After absorption from the gut, the drug circulates and reaches the kidneys, where it binds to SGLT2 transporters on the luminal side of the proximal tubule. Its primary breakdown pathway involves glucuronidation, a process in which liver enzymes attach a sugar molecule to the drug to make it water-soluble for excretion.19PubMed Central. Pharmacokinetics and pharmacodynamics of empagliflozin in paediatric patients aged 10–17 years with type 2 diabetes mellitus Because this pathway does not rely heavily on the same liver enzymes (cytochrome P450 system) that process many other drugs, Jardiance has relatively few drug-drug interactions compared to medications that compete for those enzymes. The drug’s effects on urinary glucose excretion are dose-dependent: the 25 mg dose causes somewhat more glucose loss than the 10 mg dose, though both produce meaningful blood sugar reductions.
A Drug Born From Tree Bark
The concept behind SGLT2 inhibitors traces back to the 19th century, when scientists isolated a compound called phlorizin from the bark of apple trees. Phlorizin caused glucosuria in animals and could lower blood sugar in diabetic models, but it blocked both SGLT1 and SGLT2 indiscriminately, causing significant gut side effects that made it useless as a medicine.20PubMed Central. From the discovery of phlorizin (a Belgian story) to SGLT2 inhibitors It took over a century of chemical modification to develop selective SGLT2 inhibitors that could target the kidney transporter without wreaking havoc on the intestine. Empagliflozin emerged from that long refinement process as the most SGLT2-selective compound in clinical use, which is part of why it has a relatively clean side-effect profile compared to what phlorizin would have offered.