Magnesium oxide and hip bone growth in young girls
What it found
Girls aged 8 to 14 who took magnesium oxide for a year gained about 3% more bone mineral at the hip than those taking a placebo.
The effect was seen across different stages of puberty.
What they found
Studies in people
Hip bone mineral content
Over the year, girls taking magnesium oxide gained about 3% more bone mineral at the hip compared with the placebo group. This trend held true for girls in early puberty and those further along.
Spine bone changes
The spine also showed slightly more bone mineral gain in the magnesium group. However, this difference was small and could have happened by chance.
Blood and urine markers
Levels of minerals, bone hormones, and other blood markers stayed about the same in both groups over the year.
Side effects and compliance
Only two girls reported loose bowel movements when starting the supplement, which cleared up when the dose was briefly halved. Pill counts showed the girls took about 73% of their capsules overall.
What the authors conclude
- They conclude that daily magnesium oxide capsules were well tolerated by the girls in the study.
- They report a positive effect of the supplement on hip bone mineral buildup in this small group.
- They suggest larger studies are needed to confirm these findings.
How it was done
Scientists know that building strong bones during childhood matters for preventing weak bones later in life. Many young American girls get less magnesium from food than recommended, so the authors wanted to see if extra magnesium would help them build more bone.
The authors recruited 50 healthy Caucasian girls aged 8 to 14 whose diets provided less than 220 mg of magnesium per day. For 12 months, half took capsules containing 300 mg of elemental magnesium as magnesium oxide each day, and half took identical placebo capsules. Bone scans were done at the start, at 6 months, and at 12 months.
What it can’t tell you
- Because only Caucasian girls with low dietary magnesium were studied, the results may not apply to boys, other ethnic groups, or people who already get enough magnesium from food.
- This was a small pilot study, so the authors caution against reading too much into the exact size of the bone gains.
Who paid
- Funding
- Funded by NICHD NIH HHS; NIDDK NIH HHS; NIA NIH HHS; PHS HHS (from the PubMed record).
- Authors work at
- Yale University School of Medicine, USA
The paper
- Title
- A randomized controlled study of effects of dietary magnesium oxide supplementation on bone mineral content in healthy girls
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Carpenter TO, DeLucia MC, Zhang JH, et al (2006). A randomized controlled study of effects of dietary magnesium oxide supplementation on bone mineral content in healthy girls. The Journal of clinical endocrinology and metabolism. doi:10.1210/jc.2006-1391Free full textPubMed 17018656DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error