Magnesium Supplements: Benefits for Sleep, Stress, & Wellness

Magnesium is a mineral found widely throughout the body and in various foods, but it's also a popular supplement. We've examined why getting enough is important for your health, signs you may be falling short, and how to navigate magnesium supplements.

Magnesium is one of the most abundant minerals on Earth, found in soil, water, and foods like dark leafy greens, legumes, whole grains, and dark chocolate. Still, many people don't get enough magnesium from diet alone.

In the body, magnesium acts as a cofactor for over 300 enzymatic reactions, including those involved in making proteins, DNA synthesis, bone formation, muscle and nerve function, and normal blood sugar and heart function.

Being a cofactor means that magnesium is essentially a "helper" molecule that allows certain enzymes to function properly and do their jobs.

Magnesium supports the activity of GABA, an inhibitory brain chemical that supports relaxation. This may help quiet the brain at night. Magnesium may also help regulate melatonin, the hormone that controls your circadian rhythm, or sleep-wake cycle.

Some people find that adding a magnesium supplement to their routine helps them sleep better, particularly magnesium glycinate.

The calming capability of magnesium is important for muscles, too, as it helps them relax after contracting. Specifically, calcium triggers contraction, and magnesium counterbalances that by signaling relaxation.

This is why getting enough magnesium often supports healthy muscle function. Adequate magnesium may also help support recovery after physical activity.

Approximately 60% of the magnesium in your body is stored in your bones, where it contributes to bone density and strength. It does this by working with calcium and vitamin D. Magnesium activates vitamin D, which is essential for calcium absorption.

Magnesium plays a role in regulating the nervous system, and its calming effect may help support a balanced stress response by influencing cortisol and other stress hormones. By supporting GABA activity, magnesium helps encourage relaxation.

Not getting enough magnesium doesn't typically produce instant or obvious symptoms, as your body tries to counteract low intake by reducing magnesium loss through urine. However, if inadequate magnesium intake is prolonged, you may eventually notice signs like:

• Nausea
• Loss of appetite
• Vomiting
• Fatigue and weakness
  

It's important to note that certain groups of people may be at a higher risk of low magnesium from inadequate intake, including those with certain dietary restraints, older individuals, and those whose lifestyle factors may affect nutrient absorption.

There are several important considerations when choosing a magnesium supplement, such as the type of magnesium, dosage, purpose, and quality.

• Magnesium glycinate: Considered the best magnesium for sleep and all-around uses because it's well-absorbed and gentle on the stomach.
• Magnesium malate: Well-absorbed and tends to be more energizing than relaxing, so it's often suggested for daytime use.
• Magnesium citrate: Has a reasonable absorption rate, making it good for general use and occasional digestive support.
• Magnesium oxide: Poorly absorbed as it works in the gut versus the bloodstream, making it best for short-term digestive support.
• Magnesium threonate: This is a newer form that studies suggest may cross the blood-brain barrier more effectively, making it best for supporting brain wellness.
• Magnesium taurate: This form is bound to taurine, which supports heart and nervous system function, making its best uses for cardiovascular wellness.
• Magnesium chloride: Available in topical form as well as an oral supplement, and often used for muscle soreness or for people who experience digestive side effects from taking it by mouth.

The RDA for adults is roughly 310–420mg per day, depending on age and sex. Most supplements come in 200–400mg doses.

Magnesium can interfere with certain prescription medications. Be sure to discuss adding a magnesium supplement with your healthcare provider.

Look for supplements that are third-party tested by organizations like USP, NSF International, or Informed Sport, which indicate the product has been independently verified for purity and accuracy of labeling.

The best time to take magnesium depends on why you're taking it. Forms like glycinate work well in the evening, about an hour before bed, due to its calming effects. On the other hand, magnesium malate has more of an energizing effect, so it's better taken in the morning or early afternoon.

It's also helpful to start with a smaller dose and increase as needed and tolerated. If you're taking other supplements like calcium or zinc, try to space them out by a couple of hours since they can compete for absorption.

Magnesium works best when taken consistently rather than occasionally, as it takes time to build up adequate levels in the body.

1. Zhang C, Hu Q, Li S, et al. A Magtein®, Magnesium L-Threonate, -Based Formula Improves Brain Cognitive Functions in Healthy Chinese Adults. Nutrients. 2022;14(24):5235. Published 2022 Dec 8. doi:10.3390/nu14245235
2. Reno AM, Green M, Killen LG, O'Neal EK, Pritchett K, Hanson Z. Effects of Magnesium Supplementation on Muscle Soreness and Performance. J Strength Cond Res. 2022;36(8):2198-2203. doi:10.1519/JSC.0000000000003827
3. Schuster J, Cycelskij I, Lopresti A, Hahn A. Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep: A Randomized, Placebo-Controlled Trial. Nat Sci Sleep. 2025;17:2027-2040. Published 2025 Aug 30. doi:10.2147/NSS.S524348
4. NIH Office of Dietary Supplements. Magnesium Fact Sheet for Consumers. https://ods.od.nih.gov/factsheets/magnesium-healthprofessional/