Is creatine safe to use as a supplement in patients with heart failure?

Creatine Supplementation in Heart Failure

Creatine supplementation appears safe and may improve skeletal muscle performance in heart failure patients, though it does not improve cardiac ejection fraction or overall functional capacity based on the most recent high-quality evidence.

Safety Profile

• Creatine supplementation is generally safe in heart failure patients and does not adversely affect cardiac function or ejection fraction 1, 2.
• No significant safety concerns or adverse cardiac effects have been reported in clinical trials of heart failure patients receiving creatine supplementation 3, 2.
• The standard supplementation dose used in heart failure studies is 5-20 g daily of creatine monohydrate 3, 2.

Effects on Cardiac Function

• Creatine supplementation does not improve left ventricular ejection fraction at rest or during exercise in heart failure patients 3, 2.
• Despite the theoretical rationale that creatine could benefit the failing heart (where creatine and phosphocreatine levels are decreased due to reduced creatine transporter expression), supplementation has not demonstrated improvements in primary cardiac outcomes 1, 4.
• The degree of myocardial phosphocreatine/ATP ratio reduction correlates with disease severity and is a predictor of mortality, but correcting this deficit through oral supplementation has shown controversial findings 4.

Effects on Skeletal Muscle and Exercise Capacity

The evidence on functional capacity is mixed, with older studies showing benefit but the most recent trial showing no improvement:

• The most recent 2012 randomized controlled trial found no significant improvement in peak VO₂, anaerobic threshold, oxygen pulse, or 6-minute walk distance after 6 months of creatine supplementation (5 g/day) in heart failure patients 3.

• However, earlier studies from 1995-1998 demonstrated that creatine supplementation increased skeletal muscle phosphocreatine levels by 12% and total creatine by 17%, with corresponding improvements in muscle strength (5% increase in peak torque) and endurance (21% increase in one-legged performance, 10% in two-legged performance) 2, 5.

• Creatine supplementation attenuated abnormal skeletal muscle metabolic responses to exercise, reducing ammonia production per contraction and lactate accumulation 5.

Clinical Rationale and Mechanism

• In heart failure, creatine and phosphocreatine decrease due to reduced creatine transporter expression, leading to decreased contractility reserve 1.
• Creatine functions as an energy shuttle between mitochondria and cytosol through the creatine kinase system, which is a major component of cardiac metabolic machinery 4.
• Phosphocreatine degradation occurs to prevent ATP exhaustion in the failing heart 1.
• Creatine may also provide pleiotropic antioxidant properties that could be beneficial 1.

Practical Recommendations

Given the safety profile and potential skeletal muscle benefits, creatine supplementation may be considered in heart failure patients primarily for improving muscle strength and exercise tolerance, not cardiac function:

• Dosing: Use 5-20 g daily of creatine monohydrate, with most studies using either 5 g/day for 6 months or 20 g/day for 5-10 days 3, 2.
• Patient selection: May be most beneficial for heart failure patients with significant skeletal muscle weakness or exercise intolerance 2, 5.
• Monitoring: No specific cardiac monitoring is required beyond standard heart failure management, as creatine does not affect ejection fraction or cardiac function 3, 2.
• Expectations: Counsel patients that benefits, if any, will be related to skeletal muscle performance rather than cardiac function improvement 3, 2.

Important Caveats

• The most recent and longest-duration trial (6 months) showed no functional benefit, which should temper enthusiasm despite positive findings in earlier shorter-term studies 3.
• Creatine supplementation increases skeletal muscle creatine content only in patients with baseline total creatine <140 mmol/kg dry weight 2.
• This is not a guideline-recommended therapy for heart failure—no major heart failure guidelines (European Society of Cardiology, American Heart Association) include creatine supplementation in their recommendations 6.
• Standard heart failure therapies (ACE inhibitors, beta-blockers, aldosterone antagonists, diuretics) remain the cornerstone of treatment and should be optimized first 6.