Magnesium is essential for joint and bone health and there is plenty of evidence to suggest that people with joint problems can benefit from a magnesium supplement, although most of this is in relation to those who are currently below the recommended daily intake. For example low magnesium has been shown to increase joint pain in people with osteoarthritis   .
Magnesium deficiency rates are also relatively common with sub clinical deficiencies (minor but not immediately detrimental) being up to 48% in the US, although most studies suggest it to be closer to 20% . And with clinical deficiency is more around the 2% mark. It should also be noted that magnesium deficiency is more prevalent in the elderly population who are more likely to suffer with joint pain. And even a relatively mild deficiency increases the risk of elevated CRP (a plasma that causes inflammation, by 50%).
It isn’t just about arthritis though, and magnesium deficiencies can cause pain in those that are otherwise healthy.
That said magnesium supplementation is one of the more awkward supplements in that there are a lot of magnesium compounds available and unfortunately the ones with the higher dose of magnesium tend to produce laxative effects. That means that just because a supplement that is labelled as magnesium and claims to be 300mg that doesn’t mean you’re getting 300mg of magnesium, in fact some types such as the commonly used magnesium glycinate is only 14% magnesium. Which if you’re looking for 300-350mg per day would require you to have 3 large capsules full as each large supplement capsule usually contains enough space for 1000mg.
Dosage of Magnesium For Joints
The dosage for adults with joint issues (arthritis for example) is usually around 350-420mg day,  this also tends to apply out to those who are looking to look after their joints after strenuous exercise and there are many studies which suggest that magnesium could improve performance beyond joint protection as it’s been a common muscle building supplement for some time.  Although most studies showed that it was only effective in people who were deficient in magnesium, the mineral is quite a common deficiency meaning there’s a good chance people on restrictive diets could benefit. It should also be mentioned that improved muscularity, if achieved with careful exercise can improve overall joint health and stability, meaning activity and exercise are important for joints and in helping overcome joint pain adding to magnesium benefits.
Magnesium for Arthritis
Magnesium does seem to be quite useful for treating some types of arthritis pain, and even people who were less than 12% under the RDI for magnesium were shown to be more than 1.5X as likely to have elevated CRP (a plasma that causes inflammation) . As both osteoarthritis and rheumatoid arthritis benefit from a reduction in inflammation this would suggest that magnesium is good for arthritis.
Types Of Magnesium Supplements
The main types of magnesium supplements for joints and the percentage of magnesium by type are:
- magnesium glycinate (14% magnesium)
- magnesium aspartate (7% magnesium)
- magnesium citrate (16% magnesium)
- magnesium gluconate (5-20% magnesium)
- magnesium chloride (26% magnesium) can be used topically and absorbed through the skin and is usually found in creams
The types that won’t benefit joints are
- magnesium oxide (40% magnesium)
- magnesium hydroxide (41% magnesium)
Both of these would have a laxative effect if dosed high enough to be effective.
Other Benefits Of Magnesium
- Magnesium Oxide can be used as a laxative in doses over 300mg
- Magnesium can aid sleep in doses over 600mg (this should come from a none laxative source)
- Magnesium has been shown to aid depression
- Magnesium can help regulate blood sugar
- Magnesium can help with muscle cramps and PMS
Conclusion: Is Magnesium Good For Joints?
In short if you’re deficient in magnesium it can exacerbate existing issues around joint pain quite significantly and thus yes, magnesium is good for joint pain for a lot of people, but shouldn't be the go to for everyone. You do however need to be careful about which magnesium supplement you select as there is a variety of types and not all with be beneficial for joints.
1 - https://pubmed.ncbi.nlm.nih.gov/29454594/
2 - https://pubmed.ncbi.nlm.nih.gov/34023805/
3 - https://bmjopen.bmj.com/content/10/11/e039640
4 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5786912/
5 - https://www.arthritis.org/health-wellness/treatment/complementary-therapies/supplements-and-vitamins/vitamin-and-mineral-guide-for-arthritis
6 - https://www.ncbi.nlm.nih.gov/pubmed/24015935
7 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3685774