Which to choose?
Metformin: first line in type 2 diabetes without comorbidity. Empagliflozin (or adding it to metformin): type 2 diabetes with heart failure, CKD, obesity or established cardiovascular disease. Current guidance prioritises SGLT2 inhibitors for cardiac and renal protection, REGARDLESS of glycaemic control.
Point-by-point comparison
Brands: Glucophage
Brands: Jardiance
| Metformin | Empagliflozin | |
|---|---|---|
| Mechanism | Reduces hepatic glucose production and increases insulin sensitivity. | Inhibits the renal SGLT2 cotransporter, causing glycosuria and lowering blood glucose. |
| Indications | Type 2 diabetes (first line). | Type 2 diabetes (including with heart failure or CKD). Heart failure with or without diabetes. |
| Adult dose | 500-2550 mg/day in 2-3 doses. | 10-25 mg/day. |
| Onset of effect | HbA1c falls at 4-8 weeks. | HbA1c falls at 4-8 weeks. Cardiovascular and renal benefit over months to years. |
| Duration of effect | While treatment continues. | While treatment continues. |
| Pregnancy | Compatible. Useful in gestational diabetes and PCOS. | CONTRAINDICATED in the second and third trimesters. |
| Breastfeeding | Compatible. | Not recommended. |
| Paediatric use | From 10 years. | Not indicated. |
| Advantages | First line on cost and efficacy. No hypoglycaemia. Slight weight loss. | Proven cardiovascular and renal benefit. Weight loss. Lowers blood pressure. No hypoglycaemia as monotherapy. |
| Disadvantages | GI intolerance (diarrhoea, nausea). Contraindicated if eGFR <30. B12 deficiency with long-term use. | Genital infection (thrush), UTI, euglycaemic ketoacidosis (rare). Prescribing restrictions vary by country. |
Source: BNF, NICE NG28, ADA Standards 2026
Frequently asked questions
Which is better, metformin or empagliflozin?
Metformin: first line in type 2 diabetes without comorbidity. Empagliflozin (or adding it to metformin): type 2 diabetes with heart failure, CKD, obesity or established cardiovascular disease. Current guidance prioritises SGLT2 inhibitors for cardiac and renal protection, REGARDLESS of glycaemic control.
Can metformin or empagliflozin be taken in pregnancy?
Metformin: Compatible. Useful in gestational diabetes and PCOS. Empagliflozin: CONTRAINDICATED in the second and third trimesters. Always ask a doctor or pharmacist before taking a medicine in pregnancy.
And while breastfeeding?
Metformin: Compatible. Empagliflozin: Not recommended.