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Magnesium is an essential dietary mineral that is involved in energy production, nervous system function, blood pressure regulation, and blood glucose control. A lack of magnesium in the diet — which is common in modern societies — is associated with an increased risk of diabetes, cardiovascular disease, and other health conditions.
Magnesium is most often used for
Last Updated:April 11, 2023
Magnesium is an essential dietary nutrient and is one of the most abundant minerals in the body. Magnesium acts as an electrolyte and is a cofactor for more than 300 enzymes. Magnesium is required for energy (ATP) production, glucose metabolism, DNA and protein synthesis, nerve conduction, bone health, and cardiovascular regulation, among other functions. It also plays a crucial role in the synthesis and activation of vitamin D.
Dietary sources of magnesium include dark green leafy vegetables, nuts and seeds, legumes, whole grains, and meat/fish such as salmon, chicken, and beef.[4] Many foods such as breakfast cereals and bread are fortified with magnesium. It appears that approximately 20%–40% of the dietary magnesium that enters the body becomes bioavailable.[5][6][7]
More than half of adults may not meet the recommended daily intake of magnesium,[4] likely because Western diets tend to be very low in magnesium-rich foods and high in processed foods and refined grains, which are magnesium-poor. As such, magnesium deficiency — which elevates the risk of obesity, diabetes, cardiovascular disease, metabolic syndrome, and osteoporosis — is a major public health concern, especially for older adults.[8][9]
Low magnesium levels are associated with a higher risk of diabetes, and supplementation with magnesium has been shown to reduce blood glucose and improve insulin sensitivity,[10][11][12] especially in people who are insulin resistant and/or magnesium deficient[13][14][15][16] and/or in women with gestational diabetes.[12][17]
Supplemental magnesium also appears to lower blood pressure in people who are deficient in magnesium[18][19] and in those who have elevated blood pressure (hypertension).[20][21][22] The average reduction in blood pressure after magnesium supplementation is 2–4 mmHg for systolic blood pressure and 2 mmHg for diastolic blood pressure,[23][24] though the reductions may be greater for individuals with type 2 diabetes (6–8 mmHg and 2–3 mmHg for systolic and diastolic blood pressure, respectively).[25][26]
There is some indication that magnesium supplementation may normalize age-related changes in sleep patterns or improve sleep in people who have insomnia or who are magnesium deficient,[27][28][29] reduce the frequency and intensity of migraine headache,[30][31][32] and attenuate premenstrual symptoms in women.[33][34][35]
Magnesium supplementation that is not excessive is well tolerated and probably won’t cause side effects, and it’s difficult to ingest too much magnesium from food sources alone. Excess magnesium in the body is eliminated by the kidneys, so the risk of magnesium toxicity from food is quite low for healthy people.[36]
Supplementing with high doses and certain magnesium salts (i.e., magnesium carbonate, magnesium chloride, magnesium gluconate, magnesium hydroxide, and magnesium oxide) can have a laxative effect — though some people choose to take certain forms of magnesium for this reason.[2][4] Unabsorbed magnesium salts have an osmotic effect in the intestinal tract and can increase gastric motility. In one study, 12% of participants experienced diarrhea with a 1,000 mg dose of magnesium oxide,[37] but this form of magnesium is poorly absorbed, and the dose is well above the tolerable upper limit (UL) for magnesium of 350 mg for healthy adults.[38] Nausea, diarrhea, and abdominal cramping are also occasional side effects reported from supplemental magnesium.
Magnesium supplements can also interfere with the absorption of certain medications, including bisphosphonates (used for treating osteoporosis) and antibiotics — to avoid these interactions, individuals who are taking these types of medications should talk to their healthcare provider about how to space out and time their supplemental magnesium.[4]
Many observations related to magnesium’s effect on reducing disease risk are likely due to correction of a deficiency. In other words, it may not be the case that supplemental magnesium is beneficial per se; instead, magnesium deficiency may lead to several health problems, many of which may be related to chronic low-grade inflammation.[39] There is also the possibility of reverse causation because many modern diseases (i.e., obesity and diabetes) may lead to a magnesium deficiency.
Nonetheless, there are well-documented mechanisms that explain why magnesium may benefit health.
For one, magnesium plays a role in beta-cell activity in the pancreas, influencing insulin secretion and, therefore, our ability to regulate blood glucose. Magnesium deficiency can lead to impaired insulin secretion, impaired glucose utilization, and insulin resistance — all of which contribute to the development of type 2 diabetes.[40]
In the cardiovascular system, magnesium regulates calcium concentrations, which enhances vascular relaxation and inhibits vasoconstriction, leading to healthy vascular tone and protecting against high blood pressure (hypertension). Magnesium also improves endothelial function by directly stimulating the release of nitric oxide(NO).[41]
In the brain, magnesium binds to and blocks the actions of NMDA receptors, thereby preventing glutamate-dependent transmission of cortical spreading depression — one mechanism involved in the pathogenesis of migraine headache. Magnesium is also a GABA agonist. Magnesium affects the function of serotonin receptors, influences platelet aggregation, and regulates the synthesis and release of several neurotransmitters. These mechanisms explain magnesium’s benefit for migraine, as well as the potential for magnesium to improve sleep and other aspects of neurological health.[42][43]
The recommended dietary allowance (RDA) for magnesium for adults is 410–420 mg/day for men and 320–360 mg/day for women. This includes magnesium from all sources such as food, beverages, supplements, and medications. The upper intake level (UL) for magnesium for adults is 350 mg; this value only includes magnesium obtained from dietary supplements and medications.
Which forms of magnesium are best for people who are looking to increase their magnesium levels for general purposes or to correct a deficiency? Magnesium citrate appears to have the highest bioavailability of all forms of magnesium[1], followed by magnesium lactate. Magnesium chloride, magnesium gluconate, and magnesium glycinate also appear to have good bioavailability.[2] On the other hand, magnesium oxide and magnesium carbonate have extremely poor absorption and aren’t recommended for the purpose of increasing magnesium levels in the body.
Magnesium citrate — especially potassium magnesium citrate — and magnesium lactate also appear to carry a lower risk for gastrointestinal side effects and diarrhea compared to other formulations.[2] More frequent reporting of side effects seems to be related to supplementing with magnesium carbonate and magnesium oxide, though gastrointestinal-related issues can occur with any type of magnesium supplement if too high of a dose is taken.
Although magnesium sulfate (Epsom salt) is often used in bath preparations to soothe achy and sore muscles, there’s a lack of evidence to support the transdermal (through the skin) absorption of magnesium.[3] A warm soak might be relaxing, but it’s not due to the magnesium.
When it comes to increasing your testosterone, quality sleep, physical activity, and weight management come first. A few supplements can help sustain healthy testosterone levels, but most supplements marketed as testosterone boosters don't work, though some can make you believe they do by boosting your libido.
Testosterone is an androgen, a male sex hormone, though women need it too. In men, low testosterone has been associated with low libido[63] and poor health outcomes, such as the development of metabolic syndrome.[64] In men and women, low testosterone has been associated with depression.[65][66]
Middle-aged[67] and older[68] men see their testosterone levels decrease by 0.4% to 1.6% per year, and many are the men who experience lower-than-average levels even in their 30s.[69] Fortunately, quality sleep, physical activity, weight management, magnesium, zinc, and vitamin D can all help sustain healthy testosterone levels.
To optimize your testosterone levels, you don’t only need the proper amounts of vitamins and minerals; you also need to sleep well, exercise, and keep a healthy weight.
Lack of sleep causes numerous health issues. Notably, it decreases testosterone production[70][71][72][73][74] and facilitates fat gain[75] (and we’ll see that fat gain itself can impair testosterone production). Getting enough quality sleep is so important that we will be publishing an article on that soon.
Resistance training can raise testosterone levels for 15–30 minutes post-exercise.[76][77] More importantly, it can benefit testosterone production in the long run by improving body composition and reducing insulin resistance.[76]
Overtraining, however, is counterproductive. Prolonged endurance exercise especially can cause your testosterone to drop.[78][79] Ensuring adequate recovery time will help you receive the full benefits of physical activity.
Weight gain and the associated chronic diseases, such as cardiovascular disease and type 2 diabetes,[80][81][82] are strongly linked to decreases in testosterone, particularly in middle-aged and older men.
If you gain weight (as fat), your testosterone production drops. Fortunately, if you lose weight, your testosterone production can climb back up.
Adapted from Grossmann and Matsumoto. J Clin Endocrinol Metab. 2017.[83]
As this figure shows, observational studies have seen consistent results: in people who are overweight or obese, the greater the weight loss, the greater the testosterone increase.[80]
These results have been echoed in clinical trials. A meta-analysis of 24 RCTs looked at weight loss caused by diet or bariatric surgery:[84] In the diet studies, the average 9.8% weight loss was linked to a testosterone increase of 2.9 nmol/L (84 ng/dL). In the bariatric-surgery studies, the average 32% weight loss was linked to a testosterone increase of 8.7 nmol/L (251 ng/dL).
You need not lose huge amounts of weight to see a bump in testosterone levels, either: a 5% loss in weight can increase total testosterone by 2 nmol/L (58 ng/dL).[85]
Quality sleep, physical activity, and weight management support healthy testosterone levels, and they’re synergistic: If you lack sleep, you find it harder to exercise and easier to gain fat. If you exercise, you find it easier to sleep and to keep a healthy weight. If your weight is healthy, you find it easier to exercise and easier to sleep.
If you want to know more about the lifestyle-testosterone connection, check out our infographic and article here.
Only a few supplements have been shown to benefit testosterone production. Among those, the evidence mostly supports vitamin D and zinc, followed by magnesium. Two caveats should be kept in mind, however:
Supplementing with a vitamin or mineral is likely to help you only if you suffer from a deficiency or an insufficiency in this vitamin or mineral.
Correcting a deficiency or an insufficiency is more likely to raise your testosterone levels if they are low.
Vitamin D helps regulate testosterone levels.[86][87] Ideally, you would produce all the vitamin D you need through sunlight exposure, but if you live far from the equator, have dark skin, or simply spend most of your time inside, you may need to complement your own production with the help of foods or supplements.
In Canada and the United States, the Recommended Daily Allowance (RDA) for vitamin D falls between 400 and 800 IU (International Units).[88] These amounts, which have been criticized as too low by some,[89][90] are attainable from only a few food sources, which is why vitamin D has become a popular supplement.
AGE | MALE | FEMALE | PREGNANT | LACTATING |
---|---|---|---|---|
0–12 months | 400** | 400** | — | — |
1–13 years | 600 | 600 | — | — |
14–18 years | 600 | 600 | 600 | 600 |
19–50 years | 600 | 600 | 600 | 600 |
51–70 years | 600 | 600 | — | — |
>70 years | 800 | 800 | — | — |
* 40 IU = 1 mcg | ** Adequate intake (AI)
Reference: Institute of Medicine. Dietary Reference Intakes for Adequacy: Calcium and Vitamin D (chapter 5 in Dietary Reference Intakes for Calcium and Vitamin D. The National Academies Press. 2011. DOI:10.17226/13050)
Zinc deficiency can hinder testosterone production.[91][92] Like magnesium, zinc is lost through sweat,[93] so athletes and other people who sweat a lot are more likely to be deficient. Although dietary zinc is mostly found in animal products, zinc-rich foods include some grains and nuts.
AGE | MALE | FEMALE | PREGNANT | LACTATING |
---|---|---|---|---|
0–6 months | 2* | 2* | — | — |
7–12 months | 3 | 3 | — | — |
1–3 years | 3 | 3 | — | — |
4–8 years | 5 | 5 | — | — |
9–13 years | 8 | 8 | — | — |
14–18 years | 11 | 9 | 12 | 13 |
19+ years | 11 | 8 | 11 | 12 |
* Adequate Intake (AI) Reference: Institute of Medicine. Zinc (chapter 12 in Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. The National Academies Press. 2001. DOI:10.17226/10026)
Consuming much more than your RDA[94] can be harmful. In the short term, high doses can cause nausea[95] and vomiting.[96] In the long term, they can lead to a copper deficiency.[97][98]
In males with low magnesium levels and low testosterone levels, an increase in magnesium intake can translate into an increase in testosterone production,[99] both directly and (since one of magnesium’s functions in your body is to help convert vitamin D into its active form[100]) indirectly.
While more common in the older population,[101] magnesium deficiency isn’t unknown in younger people (notably athletes,[102] since, link zinc, magnesium is lost through sweat[93][103][104]). Yet getting your RDA should be easy: magnesium-rich foods are numerous and can fit all kinds of diets.
AGE | MALE | FEMALE | PREGNANT | LACTATING |
---|---|---|---|---|
0–6 months | 30* | 30* | — | — |
7–12 months | 75* | 75* | — | — |
1–3 years | 80 | 80 | — | — |
4–8 years | 130 | 130 | — | — |
9–13 years | 240 | 240 | — | — |
14–18 years | 410 | 360 | 400 | 360 |
19-30 years | 400 | 310 | 350 | 310 |
31–50 years | 420 | 320 | 360 | 320 |
>51 years | 420 | 320 | — | — |
* Adequate intake (AI)
Reference: Institute of Medicine. Magnesium (chapter 6 in Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. The National Academies Press. 1997. [105])
If you still feel the need to supplement, keep in mind that supplemental magnesium is more likely than dietary magnesium to cause adverse effects, which is why the FDA fixed at 350 mg the Tolerable Upper Intake Level for magnesium supplementation in adults. Also, you may want to avoid magnesium oxide: it has poor bioavailability (rats absorbed only 15% in one study,[106] and humans only 4% in another[107]) and can cause intestinal discomfort and diarrhea.
Numerous products are advertised as testosterone boosters, but the vast majority don’t work, though some can make you believe they do by boosting your libido. Maca, for instance, can enhance libido without affecting testosterone.[108][109][110][111]
Maybe the most popular “testosterone booster” is D-aspartic acid (DAA, or D-aspartate). DAA did increase testosterone levels in two studies, one that used 2.66 g/day[112] and the other 3.12 g/day,[113] but two later studies found no increase with 3 g/day,[114][115] and the latest even noted a decrease with 6 g/day.[114]
Eat a healthy, balanced diet, so as to avoid nutritional deficiencies. If your testosterone levels are low, pay attention to your intakes of vitamin D, zinc, and magnesium. Be skeptical of supplements marketed as testosterone boosters; there’s a good chance the only thing these supplements will boost is their manufacturers’ bottom lines.
The interventions discussed in this article will work best for men with low testosterone, but they can also help men with normal testosterone to sustain their levels, year after year.
Supplements can help, but they can’t replace a healthy lifestyle. In order to optimize your testosterone production, make sure you get enough quality sleep on a daily basis, incorporate some resistance training into your workout program, and monitor your weight.
Try to get enough vitamin D, zinc, and magnesium through your diet. However, if dietary changes prove insufficient, supplementation can help make up the difference.
Not all testosterone deficiencies can be fixed through lifestyle or supplement interventions. It may be prudent to speak with your doctor if the options discussed above do not yield sufficient results.
FAQs and database updated with new literature.
We added newly published studies to our FAQs and database.
The information in this section is slated for renovation — it will soon be transformed into a more usable (and readable!) form in the coming months. As such, the text in this section may be out of date and not up to Examine’s current standards for writing style.