What Happens If You Accidentally Take 800 mg of Magnesium?
                                
                                
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                                    4 min read                                
                            
                                The Tolerable Upper Intake Level for supplemental magnesium in adults is 350 mg, meaning a single 800 mg dose is significantly over this limit. If you accidentally take 800 mg of magnesium, it can trigger a range of adverse effects, from mild gastrointestinal upset to more severe complications.