The recommended daily intake of magnesium varies by age, sex, and life stage:

• Adult men generally need about 400 to 420 milligrams per day.
• Adult women require about 310 to 320 milligrams per day.
• Pregnant women need slightly more, around 350 to 360 milligrams per day.
• Breastfeeding women require about 310 to 320 milligrams per day.
• Children and adolescents have lower requirements that increase with age, for example, 80 mg/day for ages 1-3 and up to 410 mg/day for males aged 14-18

Health authorities typically set the upper intake level for magnesium supplements at 350 milligrams per day for adults, to avoid toxicity, although magnesium from food sources is safe even at higher amounts

. Some experts suggest that actual magnesium needs may be higher than official recommendations, potentially between 500 and 700 mg per day for adults, depending on body weight and conditions such as stress, illness, pregnancy, or physical activity

. In summary, a typical adult should aim for about 310-420 mg of magnesium daily from food, with supplement intake not exceeding 350 mg per day unless advised by a healthcare professional.