Written by Dr Ilma Imtiaz

Quick answer: Magnesium glycinate is commonly paired with ingredients such as melatonin, L-theanine, ashwagandha, vitamin D3 and vitamin B6. Each has a different nutritional or physiological role, from supporting normal sleep and relaxation to muscle, bone, immune and nervous-system function.

Why take magnesium glycinate?

Magnesium glycinate, also called magnesium bisglycinate, combines magnesium with the amino acid glycine. It is generally well tolerated and provides magnesium, an essential mineral involved in hundreds of enzymatic reactions throughout the body [1].

Its role extends well beyond relaxation. Magnesium contributes to normal energy production, muscle and nerve function, glucose metabolism, bone health and normal psychological function. More recently, magnesium bisglycinate has also been studied specifically for sleep. In a 2025 randomized controlled trial of 155 adults reporting poor sleep, 250 mg of elemental magnesium per day produced a modest improvement in insomnia severity compared with placebo after four weeks [2]. 

So, why combine magnesium with anything else? Usually because another ingredient addresses a different physiological pathway or nutritional need, rather than because magnesium itself needs a “stack.”

1. Melatonin: sleep timing

Melatonin is a hormone naturally produced by the body that helps regulate the sleep-wake cycle. Supplemental melatonin has been studied most consistently for sleep timing and sleep onset, with meta-analyses reporting modest reductions in the time it takes to fall asleep [3].

There is also some research outside sleep. In a small 12-month randomized trial in postmenopausal women with osteopenia, melatonin was studied alongside calcium and vitamin D, with changes reported in femoral-neck bone mineral density [4]. While this is an emerging area of research, it suggests melatonin may have roles beyond sleep that are still being explored.

Where it may fit: For someone who finds it difficult to wind down in the evening or keep a consistent sleep schedule, the two ingredients offer different types of support: magnesium supports relaxation and normal nervous-system function, while melatonin helps regulate sleep timing.

2. L-theanine: relaxation and calm focus

L-theanine is an amino acid naturally found in tea (Camellia sinensis) with research on relaxation, attention and responses to everyday stress. In a randomized controlled trial, four weeks of L-theanine was associated with improvements in several stress-related and cognitive measures in healthy adults [5]. Other research has investigated L-theanine in relation to sleep.

Where it may fit: For someone who wants to feel calmer while staying mentally alert, such as during a busy workday or when winding down in the evening, L-theanine may offer relaxation support without being primarily sedating.

3. Ashwagandha: stress and sleep support

Ashwagandha (Withania somnifera) is an adaptogenic herb traditionally used in Ayurvedic medicine. Modern clinical research generally uses standardized extracts rather than generic ashwagandha preparations.

Randomized controlled trials of standardized ashwagandha extracts have reported lower perceived stress and improvements in aspects of sleep, energy, mood and cognitive function in adults [7,8], supporting its use as an ingredient for everyday stress and well-being.

Where it may fit: For someone looking for broader support during periods of everyday stress, particularly when stress also affects sleep, energy or well-being.

4. Vitamin D3: bone, muscle and immune support

Vitamin D has established physiological roles in calcium absorption, bone mineralization, muscle function and immune function. Magnesium and vitamin D are also biologically connected because magnesium-dependent enzymes participate in vitamin D metabolism [10].

This does not necessarily mean everyone taking vitamin D needs additional magnesium, or vice versa. Individual dietary intake, sun exposure and vitamin D status still matter.

Where it may fit: This pairing may be particularly relevant for someone looking to support bone and muscle health, especially when dietary magnesium intake, sun exposure or vitamin D status may be less than optimal.

5. Vitamin B6: nervous-system and energy metabolism

Vitamin B6 is a coenzyme involved in amino acid metabolism, energy metabolism, neurotransmitter synthesis and normal nervous-system function.

Magnesium and vitamin B6 have also been studied together. In an eight-week randomized trial of adults with low magnesium status and stress, both magnesium alone and magnesium plus vitamin B6 were associated with improvements in perceived stress. An additional benefit from B6 was observed in a subgroup with severe baseline stress [12].

Where it may fit: For someone going through a particularly stressful period, magnesium and vitamin B6 offer complementary nutritional support for normal nervous-system function and the body’s response to everyday stress

Have these ingredients actually been studied together?

While magnesium, melatonin, L-theanine, ashwagandha, vitamin D3 and vitamin B6 have each been studied individually, researchers have also explored several of these ingredients in combination, giving us some insight into how they may work together.

Magnesium + vitamin B6: In an 8-week randomized trial, adults experiencing stress who also had low magnesium levels received either 300 mg of magnesium alone or 300 mg of magnesium plus 30 mg of vitamin B6 daily. Stress scores improved in both groups, with the magnesium-plus-B6 group showing a greater improvement among participants who began the study with severe or extremely severe stress [12].

Magnesium + vitamin D: Magnesium plays a role in the enzymes involved in vitamin D activation and metabolism [10]. This relationship has also been explored in population research. An analysis of 12,257 US adults found that higher magnesium intake was associated with a lower likelihood of vitamin D deficiency or insufficiency, supporting the biological connection between the two nutrients [13].

Melatonin + calcium + vitamin D: In a 12-month randomized controlled trial, postmenopausal women with osteopenia received melatonin alongside calcium and vitamin D3. Researchers found improvements in femoral-neck bone mineral density, along with changes in markers of bone turnover [4].

Magnesium + L-theanine: A 2022 study investigated a magnesium-L-theanine complex and found improvements in sleep latency and duration alongside changes in sleep-related brain-wave activity and neurotransmitter-receptor expression [6]. However, this was an animal study, so it provides early mechanistic evidence rather than evidence of the same effects in humans.

For magnesium + ashwagandha, the ingredients have been studied individually, but there is currently little direct research examining them together as a combination. 

Start with magnesium glycinate, then build around your goal

Magnesium glycinate can be a practical starting point because magnesium supports several areas at once, including normal muscle and nervous-system function, energy metabolism, bone health and relaxation. From there, another ingredient may make sense depending on what you want to support. Melatonin may be considered for healthy sleep timing, L-theanine for calm focus, ashwagandha for the response to everyday stress, vitamin D3 for bone, muscle and immune health, or vitamin B6 for nervous-system and energy metabolism.

Rather than adding several ingredients at once, consider what magnesium glycinate already provides and whether another supplement adds a distinct benefit that fits your goal. If you take medications, have a health condition, are pregnant or breastfeeding, or are considering higher supplemental doses, discuss your supplement routine with a healthcare professional.

Take-home message

Magnesium glycinate provides a versatile foundation for everyday supplementation, supporting normal muscle and nervous-system function, energy metabolism, bone health and relaxation.

From there, ingredients such as melatonin, L-theanine, ashwagandha, vitamin D3 or vitamin B6 can be added depending on your individual goals. The key is not to build the biggest stack, but to start with a strong foundation and add with purpose, choosing ingredients and doses supported by research.

FAQs

Can I take magnesium glycinate with melatonin?
Magnesium glycinate and melatonin are commonly used for different aspects of sleep support. Magnesium supports relaxation and normal nervous-system function, while melatonin helps support healthy sleep-wake cycles.

Does magnesium glycinate support bone health?
Yes. Magnesium is an essential mineral that supports normal bone structure and mineralization and plays a role in vitamin D metabolism. Adequate magnesium intake is an important part of maintaining bone health throughout life.

Will these supplements make me drowsy during the day?
Responses vary by ingredient and individual. Melatonin is generally used around bedtime, while L-theanine is often used for relaxation without significant drowsiness. Ashwagandha may cause drowsiness in some people.

Have these ingredients been studied together?
Some combinations have. Magnesium has been studied with vitamin B6, while melatonin has been studied alongside calcium and vitamin D. Magnesium and vitamin D also have complementary biological roles. However, the complete combination has not been studied in a clinical trial.

References 

[1] Matek Sarić M, Sorić T, Juko Kasap Ž, et al. Magnesium: Health Effects, Deficiency Burden, and Future Public Health Directions. Nutrients. 2025;17(22):3626. Published 2025 Nov 20. doi:10.3390/nu17223626

[2] 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

[3] Ferracioli-Oda E, Qawasmi A, Bloch MH. Meta-analysis: melatonin for the treatment of primary sleep disorders. PLoS One. 2013;8(5):e63773. Published 2013 May 17. doi:10.1371/journal.pone.0063773

[4] Amstrup, A.K., Sikjaer, T., Heickendorff, L., Mosekilde, L. and Rejnmark, L. (2015), Melatonin improves bone mineral density at the femoral neck in postmenopausal women with osteopenia: a randomized controlled trial. J. Pineal Res., 59: 221-229. https://doi-org.ezproxy.scu.edu.au/10.1111/jpi.12252

[5] Hidese S, Ogawa S, Ota M, et al. Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. Nutrients. 2019;11(10):2362. Published 2019 Oct 3. doi:10.3390/nu11102362

[6] Dasdelen MF, Er S, Kaplan B, et al. A Novel Theanine Complex, Mg-L-Theanine Improves Sleep Quality via Regulating Brain Electrochemical Activity. Front Nutr. 2022;9:874254. Published 2022 Apr 5. doi:10.3389/fnut.2022.874254

[7] West RE, Biswas A, Rao R, Tayade H, Ademola J. A proprietary herbal extract of ashwagandha root for stress and anxiety in healthy adults: a randomized, double-blind, three-arm, placebo-controlled efficacy and safety study. J Med Life. 2026;19(1):49-62. doi:10.25122/jml-2025-0172

[8] Kale, S., Lopresti, A., Suri, R., Garg, N., & Langade, D. (2026). Safety and Efficacy of Ashwagandha Root Extract on Cognition, Energy and Mood Problems in Adults: Prospective, Randomized, Placebo-Controlled Study. Journal of Psychoactive Drugs, 58(1), 45–57. https://doi.org/10.1080/02791072.2024.2424279

[9] Shaffer JA, Edmondson D, Wasson LT, et al. Vitamin D supplementation for depressive symptoms: a systematic review and meta-analysis of randomized controlled trials. Psychosom Med. 2014;76(3):190-196. doi:10.1097/PSY.0000000000000044

[10] Uwitonze, Anne Marie and Razzaque, Mohammed S.. "Role of Magnesium in Vitamin D Activation and Function" Journal of Osteopathic Medicine, vol. 118, no. 3, 2018, pp. 181-189. https://doi.org/10.7556/jaoa.2018.037

[11] Field DT, Cracknell R, Biagi N. High Dose Vitamin B6 Reduces Depression Symptoms. Depress Anxiety. 2026;2026:8926512. Published 2026 Aug 7. doi:10.1155/da/8926512

[12] Pouteau, E., Kabir-Ahmadi, M., Noah, L., Mazur, A., Dye, L., Hellhammer, J., ... & Dubray, C. (2018). Superiority of magnesium and vitamin B6 over magnesium alone on severe stress in healthy adults with low magnesemia: A randomized, single-blind clinical trial. PloS one, 13(12), e0208454.

[13] Deng, X., Song, Y., Manson, J.E. et al. Magnesium, vitamin D status and mortality: results from US National Health and Nutrition Examination Survey (NHANES) 2001 to 2006 and NHANES III. BMC Med 11, 187 (2013). https://doi.org/10.1186/1741-7015-11-187

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.