How Long Will 120 mg of Caffeine Last? A Comprehensive Guide to Your Metabolism
                                
                                
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                                    4 min read                                
                            
                                In healthy adults, the average caffeine half-life is around 5 hours, but for a 120 mg dose, the effects can be felt for 4 to 6 hours and linger even longer, making the answer to 'How long will 120 mg of caffeine last?' surprisingly variable depending on individual factors.