Use these timing tips to get the most out of your collagen supplement. Reviewed by Dietitian Sarah Pflugradt, Ph.D., RDN, ...

Iron supplements may work better if taken on an empty stomach. Some experts suggest 30 minutes before eating or two hours after eating for best absorption. Taking iron pills with vitamin C may improve ...

Taking magnesium supplements with calcium, iron, or zinc may lead to decreased absorption or increased excretion. Other factors include age and diet.