Short answer: Modestly. In label trials, Jardiance (empagliflozin) and Farxiga (dapagliflozin) lowered body weight by about 2 to 3 kg, or 2 to 3%, more than placebo or compared with weight gain on some other diabetes pills. The reason is that both make the kidneys pass sugar into the urine, roughly 64 to 78 grams a day. Neither is approved for weight loss.
Both are SGLT2 inhibitors. SGLT2 is the kidney transporter that pulls filtered sugar back into the blood. Blocking it sends sugar out in the urine. The Jardiance label (section 12.2) says urine glucose rose to about 64 grams a day on 10 mg and 78 grams a day on 25 mg after 4 weeks. The Farxiga label says about 70 grams a day at week 12 on 5 or 10 mg.
That sugar carries calories out of the body. The sugar also pulls water with it: in a 5-day study, urine volume rose by 341 mL on day 1 and 135 mL on day 5 on Jardiance 25 mg. Some of the early drop on the scale may be water.
| Trial | Medicine | Comparison |
|---|---|---|
| Jardiance alone, 24 weeks (start 78 kg) | -2.8% (10 mg), -3.2% (25 mg) | -0.4% on placebo |
| Jardiance added to metformin, 24 weeks (start 82 kg) | -2.5% (10 mg), -2.9% (25 mg) | -0.5% on placebo |
| Jardiance 25 mg vs glimepiride, 104 weeks | -3.1 kg | +1.3 kg on glimepiride |
| Jardiance with insulin, 52 weeks | -1.95 kg (10 mg), -2.04 kg (25 mg) | Greater loss than placebo |
| Farxiga added to metformin, 24 weeks (start 86 kg) | -2.9 kg (10 mg), -3.0 kg (5 mg) | -0.9 kg on placebo |
The Farxiga label reports a weight drop vs placebo when added to metformin, glimepiride, pioglitazone, sitagliptin or insulin, and a drop vs a gain on glipizide over 52 weeks. Both labels also report systolic blood pressure falling by a few points.
Neither label lists weight loss as a use. Jardiance and Farxiga are approved to lower blood sugar in type 2 diabetes alongside diet and exercise, and each also has approvals for adults with heart failure or chronic kidney disease that are not limited to people with diabetes. The weight change is a side effect seen in diabetes trials, much smaller than with GLP-1 medicines.
The same sugar loss explains the common side effects: genital yeast infections and more urination. In the Jardiance pooled trials, increased urination was reported by 3.4% (10 mg) and 3.2% (25 mg) vs 1.0% on placebo. See genital yeast infections on SGLT2 medicines.
Both labels list eating fewer calories and a ketogenic diet among triggers for ketoacidosis, which can happen with normal-looking blood sugar; see SGLT2 medicines and keto diets. They also warn about dehydration and low blood pressure, especially in older adults, people with kidney problems and people on water pills.
If weight is part of the plan, raise it with your prescriber rather than changing the dose. Logging weight alongside your doses helps show what changes over months; Dose Track keeps both together.
Read more on Dose Track: Jardiance side effects · Farxiga side effects · Jardiance vs Farxiga · Metformin vs Jardiance · Weight loss: what the evidence shows