Magnesium Dosage for Children

Cashews are a great source of magnesium.
Image Credit: Rermrat Kaewpukdee / EyeEm/EyeEm/GettyImages

Magnesium is important to the growth of your child's body and brain. If your youngster cannot get a sufficient amount of this mineral from food to meet his needs for proper development, a pediatric supplemental dose of magnesium for toddlers or young children may be beneficial.


Benefits of Magnesium for Children

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Magnesium is required for the metabolism of over 300 enzymes in your child's young body. With 50 to 60 percent of the body's total magnesium found in the bones, it's important to maintain adequate levels to help maintain growing bones. Magnesium is necessary for energy production and to regulate nerve and muscle function, including brain function. In addition, magnesium plays a role in helping balance blood sugar and blood pressure levels.

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Persistently low levels of magnesium can increase the risk of illness over time in young children. Although a deficiency does not cause hyperactivity in children, evidence suggests that children with autism often have a lower level of magnesium than non-autistic kids. Magnesium supplementation, along with vitamin B6, can have a calming effect on some children with attention-deficit hyperactivity disorder, or ADHD, according to Autism Canada.

A systematic review and meta-analysis published in ‌Psychiatry Research‌ in April 2019 supports the relationship between magnesium deficiency and ADHD and suggest that magnesium supplementation may be beneficial to treat the disorder.


How Much Do Children Need?

The Food and Nutrition Board (FNB) has established recommended intakes of magnesium dosage by weight and age of children. These include:

  • Recommended amount of magnesium for infants from birth to 6 months: 30 milligrams; ages 7 to 12 months: 75 milligrams
  • Recommended amount of magnesium for toddlers ages 1 to 3 years: 80 milligrams
  • Recommended amount of magnesium dosage for kids ages 4 to 8 years: 130 milligrams; ages 9 to 13 years: 240 milligrams


Many healthy foods from both plant and animal sources are prolific in magnesium. Generally, foods containing fiber are a good source of magnesium, including green leafy vegetables, legumes, nuts, seeds and whole grains. Many foods are fortified with magnesium, such as breakfast cereals, which makes it easier to fulfill your child's requirements. In addition, water can be a good source of magnesium, including tap, mineral and bottled water.

About 30 to 40 percent of dietary magnesium from food is typically absorbed by the body. Some good natural food sources of magnesium are:


  • Almonds, dry roasted, per ounce
  • Spinach, boiled, per half cup
  • Cashews, dry roasted, per ounce
  • Peanuts, oil roasted, per quarter cup
  • Soy milk, plain or vanilla, per cup
  • Black beans, cooked, per half cup
  • Peanut butter, smooth, per 2 tablespoons
  • Avocado, cubed, per cup
  • Rice, brown, cooked, per half cup
  • Yogurt, plain, low fat, per 8 ounces


Signs of a Deficiency

Symptoms of a magnesium deficiency may go unnoticed because the kidneys limit urinary excretion of the mineral. Your child may have a magnesium deficiency for a variety of reasons that can cause her body to lose magnesium quicker than she can replenish it. Some of these include:


  • Poor or restricted diet, or food intolerance
  • Certain health conditions that inhibit absorption of minerals, such as celiac or Crohn's disease
  • Use of certain medications that interact with magnesium
  • Autism

If you think your child is at risk of a magnesium deficiency, watch for these signs and symptoms that may indicate low levels in your children:

  • Loss of appetite
  • Nausea and vomiting
  • Fatigue and weakness
  • Numbness, tingling, muscle contractions and cramps
  • Seizures
  • Personality changes
  • Abnormal heart rhythms and coronary spasms


Severe magnesium deficiency can lead to hypocalcemia (low calcium levels) or hypokalemia (low potassium levels) because mineral equilibrium is disrupted.

About Magnesium Supplements

The majority of people, including children, are deficient in magnesium, says the National Institutes of Health. In addition to treating a low-magnesium level, children are often prescribed magnesium for alleviating hyperactivity, asthma or autism.


Before giving magnesium supplements to your child, talk with your doctor or pharmacist if your child has:

  • An allergy to magnesium salts
  • Kidney disease
  • Heart disease
  • Intestinal or bowel disease
  • Been taking any medications or herbal supplements

Magnesium supplements are made by combining different types of salts, and they vary in the amount of actual elemental magnesium they contain. Some forms are absorbed better than others. Magnesium supplements are available in tablet, capsule, extended release, powder, chewable and liquid forms, both by prescription or over-the-counter.


Dietary supplements come in various forms, including:

  • Magnesium citrate
  • Magnesium lactate
  • Magnesium aspartate
  • Magnesium chloride
  • Magnesium oxide
  • Magnesium sulfate
  • Magnesium malate
  • Magnesium taurate

According to the National Institutes of Health, magnesium in the citrate, lactate, aspartate and chloride forms is absorbed more completely and is more bioavailable than what's in magnesium oxide and magnesium sulfate.

How to Take Magnesium Supplements

Some magnesium tablets have a bitter taste, so you might want to give these to your child crushed and mixed with a spoonful of applesauce. Never mix magnesium in dairy products such as pudding or yogurt, because calcium and phosphorous can reduce the amount of magnesium absorbed by the body.

The Mayo Clinic notes that magnesium supplements should be taken with meals to prevent diarrhea. Since magnesium supplements can interfere with how your child's body absorbs certain minerals, they should be taken two hours before or after milk and dairy products, antacids, or calcium, phosphorus or iron supplements.

Magnesium citrate is used as a laxative on an ‌as-needed basis‌. It comes in an easily absorbable liquid form. For children under 6 years of age, the magnesium dosage by weight for constipation is 0.5 milliliters per kilogram to a maximum of 200 milliliters, repeated every four to six hours. For children ages 6 to 12 years, the pediatric dosage is 100 to 150 milliliters orally, one time.

Magnesium Supplement Dosage

Talk to your pediatrician to determine the proper amount of supplement, because the magnesium dosage for a child varies, depending on the reason for the treatment and the strength of the pills.


The FNB has set Tolerable Upper Intake Levels as a guideline to the ‌maximum amount‌ for daily magnesium ‌supplement dosage‌ for a child. These are:

  • Magnesium for toddlers ages 1 to 3: 65 milligrams
  • Magnesium dosage for children ages 4 to 8: 110 milligrams
  • Magnesium dosage for children ages 9 to 18: 350 milligrams

Magnesium supplements can cause some mild side effects that will usually go away during treatment as your child's body adjusts to the medicine. These include:

  • Diarrhea
  • Nausea
  • Abdominal cramping

If your child ingests an excessive amount of magnesium, or if you notice a reaction to the supplement or any of the following symptoms, you should notify your doctor right away.

  • Dizziness or fainting
  • Flushing or reddening of skin
  • Muscle paralysis
  • Troubled breathing

Rarely, in children with normal kidney function, some other symptoms may occur such as:

  • Blurred or double vision
  • Severe drowsiness
  • Increased or decreased urination
  • Slow heartbeat
  • Coma




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