Is it okay to drink Monster after coffee? Understanding the Health Risks
                                
                                
                                •
                                
                                
                        
                                    
                                    3 min read                                
                            
                                According to the FDA, most healthy adults can safely consume up to 400 milligrams of caffeine a day. Stacking caffeine from a cup of coffee and a Monster energy drink can push your intake well beyond that limit, triggering potentially harmful effects.