Sodium-glucose co-transporter 2 (SGLT2) inhibitors have recently been recommended as a foundational therapy for patients with heart failure (HF) and reduced ejection fraction (HFrEF) because of their favourable effects on mortality, clinical events and quality of life. While clinical practice guidelines have recommended dapagliflozin or empagliflozin in all patients with HFrEF, or sotagliflozin in those with HFrEF and concomitant diabetes, the timing and practical integration of these drugs in clinical practice is less well defined. We propose that these drugs are candidates for early, upfront administration to patients with newly diagnosed HFrEF and for patients hospitalized with HF. Growing evidence has established early benefits, with clinically meaningful reductions in clinical events that reach statistical significance within days to weeks, following dapagliflozin, empagliflozin or, in diabetic patients, sotagliflozin initiation. Secondly, although major clinical trials have tested these drugs in patients already receiving background HF therapy, secondary analyses showed that their efficacy is independent of that. Third, SGLT2 inhibitors are generally safe and well tolerated, with clinical trial data reporting minimal effects on blood pressure, glycaemia-related adverse events, and no excess in acute kidney injury. Rather, they exert renal protective effects and reduce risk of hyperkalaemia, properties that favour initiation, tolerance and persistence of renin-angiotensin system inhibitors and mineralocorticoid receptor antagonists. This review supports the early initiation of dapagliflozin and empagliflozin (or sotagliflozin limited to patients with diabetes) to rapidly improve clinical outcome and quality of life of HFrEF patients.