Can Magnesium Supplements Cause Weight Gain or Loss?
Are you constantly hitting a roadblock in your weight loss journey? Have you considered magnesium supplements for weight loss, but you’re hesitant because you’ve heard they might cause weight gain?
Fear not, my friends! With so much conflicting information out there, it’s hard to know what to believe. In this blog post, we’ll dive into the science behind magnesium and weight, and separate fact from fiction.
So let’s jump in!
Short on time? Scroll to the bottom for health hacks you can implement TODAY.
Magnesium: The Magnificent Mineral
Think of magnesium as a conductor in an orchestra. Just as a conductor directs the musicians to play in harmony, magnesium directs numerous processes in the body to work in sync to maintain optimal health.
Magnesium is an important mineral that is involved in over 300 different chemical reactions in the body.
It helps maintain normal nerve and muscle function, supports a healthy immune system, regulates heart rhythm, and contributes to strong bones.
Magnesium also helps regulate blood sugar levels, supports the production of energy, and is crucial for muscle and tissue repair.
Additionally, magnesium has a calming effect on the nervous system, making it beneficial for managing stress, promoting relaxation, and helping you get enough sleep.
Health Benefits of Magnesium

Common Signs of Magnesium Deficiency
Looking for More Magnesium? Try These Foods!
Could you be deficient in magnesium? About half (48%) of Americans consume too little magnesium in their diet (7). Check out this list to see how you compare.

Top Sources of Magnesium
Dark leafy greens. Spinach, Swiss chard, kale, broccoli sprouts, and collard greens are all excellent sources of magnesium.
Nuts and seeds. Almonds, cashews, pumpkin seeds, and sunflower seeds are all rich in magnesium.
Whole grains. Brown rice, quinoa, and whole wheat are good sources of magnesium.
Legumes. Black beans, kidney beans, and lentils are all high in magnesium.
Avocado. This delicious fruit is a good source of magnesium, as well as healthy fats and fiber.
Fatty fish. Salmon and mackerel are not only high in magnesium, but also omega-3 fatty acids, which are important for heart health.
Dark chocolate. In addition to being a tasty treat, dark chocolate is a good source of magnesium.
Seaweed. This nutrient-dense and sustainable superfood not only adds a unique umami flavor to dishes but also provides a substantial amount of magnesium.
Keep in mind that there are many other foods that contain magnesium.
However, the amount of magnesium in these foods can vary based on factors such as soil quality and farming practices.
Why You Should Consider a Magnesium Supplement (even if you think you don’t need to)
Are you wondering whether to take a magnesium supplement?
Consuming a magnesium-rich diet can be challenging due to modern agricultural practices, soil depletion, and other factors.
Even if you think you get enough magnesium, taking a supplement may prevent deficiencies and support optimal health.
Why You Might Not be Getting Enough Magnesium
Soil depletion. It’s not your fault that it’s hard to get enough magnesium from food. Our soil has been depleted of magnesium over time due to farming practices, which means that the crops we eat have lower magnesium content than they used to.
Processing. Many of the processed foods we love, like sugary snacks and refined grains, are low in magnesium.
Low intake of magnesium-rich foods. Many of us simply don’t consume enough magnesium-rich foods, such as leafy greens, nuts, and seeds, on a regular basis.
Medications. Certain medications, such as diuretics and antibiotics, can deplete magnesium levels in the body.
Health conditions. Gastrointestinal disorders may impair the body’s ability to absorb magnesium from food.
Lifestyle factors. Excessive alcohol consumption and chronic stress can also contribute to magnesium depletion. It’s not just what you eat, but also how you live your life that affects your magnesium levels.
Poor gut health. An unhealthy gut microbiome can impair magnesium absorption and lead to a deficiency.
Types of Magnesium Supplements
Maybe you’re concerned you don’t get enough magnesium in your diet. Or perhaps you struggle with some of the magnesium deficiency symptoms and hope a supplement will help.
If this describes you, then you’ve come to the right place! Read on to determine the best source of magnesium for you.

Magnesium Citrate
This is a popular form of magnesium supplement that’s well-absorbed by the body. It’s best used to support digestive health and relieve constipation. However, it can have a laxative effect and may not be suitable for everyone.
Pro-tip: If you choose magnesium citrate, start at a half dose and increase every 3-4 days until you reach the desired level. If you find it has a laxative effect, you can back off or choose another type of magnesium.
Magnesium Glycinate
This highly absorbable form of magnesium supports sleep and relaxation. It’s less likely to cause digestive issues or diarrhea than other forms.
Pro-tip: Magnesium glycinate and threonate (see below) are preferred when anxiety is a concern.
Magnesium Oxide
This form of magnesium is less expensive than other forms, but it’s also not well absorbed. It can be used to support heart health or as a mild laxative. However, it may cause gastrointestinal side effects like diarrhea and stomach upset.
Magnesium Carbonate
This form is also less expensive and less readily absorbed. Because it acts like an antacid, it may be a good choice for those with indigestion or acid reflux. However, if you have low stomach acid it’s best to choose another type of magnesium.
Magnesium Chloride
This form of magnesium is often used topically, in the form of lotions or oils, to support muscle and joint health.
Magnesium Threonate
This form of magnesium is the only form of magnesium able to cross the blood-brain barrier. This makes it beneficial for brain health and cognitive function.
However, it’s rather expensive and may not provide the relaxation benefits found in magnesium glycinate or the stool-loosening benefits found in magnesium citrate.
Pro-tip: If you struggle with falling asleep or staying asleep, taking magnesium glycinate before bed may help!

Finding the Right Magnesium Dose: Balancing Benefits and Risks
What’s the best way for you to meet your magnesium needs? Adequate magnesium intake can be achieved through a balanced diet or supplementation.
It’s not likely that you will consume too much magnesium from food alone. Fortunately, the body is able to regulate the absorption of magnesium from food sources.
However, excessive magnesium from supplements can cause magnesium overload (hypermagnesemia). High doses of magnesium citrate or magnesium oxide are more likely to cause hypermagnesemia than other forms.
Symptoms of Magnesium Overload (Hypermagnesemia)
In severe cases, it can even lead to cardiac arrest and death.
To avoid potential complications, it’s important to follow the recommended daily allowance (RDA) for magnesium. Recommendations are 400-420 mg for men and 310-320 mg for women.
Pro-tip: Occasionally the recommended amount on a label will be substantially less than the RDA, so be sure to look at % RDA and aim for close to 100%.
If you’re considering taking a magnesium supplement, talk to your healthcare provider first to determine whether it’s necessary and safe for you.

Can Magnesium Supplements Cause Weight Gain?
Are you concerned that magnesium may cause you to gain weight?
Magnesium plays a crucial role in muscle contraction, nerve function, blood sugar control, and energy production. As a result, it has been the subject of many studies exploring its potential impact on weight management.
As a dietitian, I am often asked whether magnesium supplements can cause weight gain.
While there is limited research specifically investigating weight gain, available studies suggest that taking magnesium supplements is very unlikely to cause weight gain (9).
However, there is a catch! While magnesium is known to have a mild diuretic effect, meaning it can help the body get rid of excess water, it can also cause temporary fluid retention. Say what?
It’s true! The very thing that can flush out excess water from the body can also cause it to hold onto water. But why?
Magnesium in the form of magnesium citrate, oxide, or carbonate works as a laxative by drawing water into the intestines.
This increase in fluids induces a bowel movement and helps soften your stool, making it easier to pass. Think of it like a gentle massage for your digestive system, helping to stimulate the muscles and move things along.
And while it’s true that magnesium can cause water retention in the short term, especially if you are very constipated, it’s unlikely to cause actual fat gain.
Plus, the water-retention effects are short-lived and once you have a bowel movement the effect is gone.
Which begs the question…
Can Magnesium Supplements Cause Weight Loss?
Now that you understand the role of magnesium, you may be wondering if it can help you lose weight.
Whether magnesium supplements promote weight loss is not straightforward. Multiple factors contribute to weight loss, and magnesium is just one piece of the puzzle.
But there is good news! For those with low levels of magnesium, a diet or supplement that supports adequate magnesium levels may promote healthy body mass index and weight loss (3).
How Magnesium Can Support Weight Loss Efforts
Regulates blood sugar and insulin levels. Magnesium plays a significant role in regulating blood sugar and insulin levels, which is important for people with insulin resistance, a condition that leads to excess abdominal fat.
Improves insulin sensitivity. By improving insulin sensitivity, magnesium can help the body use glucose (sugar) more effectively, potentially reducing the risk of weight gain and diabetes (4).
Supports metabolism. Magnesium plays a vital role in metabolism, particularly in the breakdown of carbohydrates and fats. Studies have found that magnesium deficiency can impair metabolism, leading to weight gain and other metabolic disorders (5).
Boosts healthy muscle function. Magnesium promotes healthy muscle tissue (7), which supports healthy weight because muscles burn more calories than fat, even at rest.
Reduces inflammation. Magnesium supplements can reduce inflammation and improve metabolic health, which supports weight loss. Chronic inflammation interferes with normal hormonal regulation of metabolism and leads to insulin resistance.
Relaxation and sleep. Magnesium promotes relaxation and calmness, which can lead to better sleep. Good sleep, in turn, can help regulate appetite and metabolism, which may contribute to weight loss efforts.

But don’t think of magnesium as a magic weight loss pill! I hate to break it to you, but magic pills do not exist. 😔
Sustainable weight loss requires a combination of a healthy diet, regular exercise, and lifestyle changes.
That being said, if you’re magnesium deficient, a supplement might help.
Before you start taking magnesium supplements for weight loss, though, it’s important to talk to your doctor or a registered dietitian. They can help determine if you’re deficient in magnesium and whether a supplement is right for you.
Plus, they can provide guidance on how to incorporate magnesium-rich foods into your diet to support your overall health and well-being.
So, Can Magnesium Supplements Cause Weight Gain or Loss?
Though magnesium will not directly cause you to lose weight, it does promote weight loss by supporting healthy muscles, metabolism, blood sugar levels, and better sleep. And it is very unlikely that it will cause weight gain.
Unfortunately, there’s no one-size-fits-all solution when it comes to weight loss.
However, incorporating magnesium-rich foods and potentially a supplement may help reduce body weight and waist circumference.
But remember, magnesium supplements are not a quick fix! Talk to your doctor or a registered dietitian to determine if a magnesium supplement is right for you and how it fits into your overall health and weight loss goals.

Health Hacks
Want to take immediate action? These easy changes can have big payoffs!
For the Nutrition Newbie
Add 2 tablespoons of pumpkin seeds to your smoothie, cereal, or trail mix to increase magnesium intake by a whopping 168 mg (about half of the RDA)!
Choose whole grains like brown rice, quinoa, and whole wheat bread instead of refined grains for higher magnesium content.
For the Health Enthusiast
Optimize magnesium absorption by pairing magnesium-rich foods with foods that are high in vitamin D (8). Foods that are high in vitamin D include fatty fish like salmon, mushrooms, and fortified milk.
Consider taking a magnesium supplement under the guidance of a qualified healthcare professional. Choose the form of magnesium that best addresses your symptoms and needs (see list above).
For the Wellness Guru
Incorporate seaweed and sea vegetables like nori, kelp, and dulse into your diet. These are excellent natural sources of magnesium.
Take an epsom salt bath or apply a magnesium oil after you shower to increase magnesium levels through skin absorption.

Pam is a Registered Dietitian Nutritionist with a Master’s of Public Health and a Certificate in Integrative and Functional Nutrition. Passionate about the science of health and nutrition, she loves to share her knowledge to help others live healthy, vibrant lives. When not working, Pam can be found hiking, traveling, and enjoying great-tasting, nutritious food.