I just bought Starbucks cold brew last night to try it. It comes already prepared in a bottle or a box. I drank a cup before bed and no headache during the night. I'm almost afraid to say it out loud in case of jinxing it. Will try it again tonight. Going away next weekend. Driving from Northern California to Oregon and if this works it will be a miracle. Thank you so much for the suggestion. Stomach not hurting either.