Can Magnesium Glycinate and Vitamin D Be Taken Together?
Published Updated Ben Law
Reviewed by Sarah Law, Naturopathic Nutritionist
Yes, magnesium glycinate and vitamin D can be safely taken together, and they are often paired on purpose: magnesium is a cofactor for the enzymes that convert vitamin D into its active forms. There is no known interaction between them, so you can take them at the same time, ideally with a meal that contains some fat to help vitamin D absorption.
- Yes, you can take magnesium glycinate and vitamin D3 together, in the same meal, every day. They do not compete for absorption.
- Magnesium is needed to activate vitamin D: the liver and kidney enzymes that convert vitamin D are magnesium dependent [1].
- Trial evidence with glycinate: in a 12-week randomised trial, adults taking magnesium glycinate plus vitamin D3 had a larger rise in blood vitamin D than those taking vitamin D3 alone [2].
- UK guidance: 10 micrograms (400 IU) of vitamin D a day in autumn and winter, no more than 100 micrograms (4,000 IU) a day; magnesium 300 mg a day for men and 270 mg for women [3][4].
- US guidance (NIH): vitamin D RDA 15 mcg (600 IU) a day for adults up to 70 and 20 mcg (800 IU) over 70, upper limit 100 mcg (4,000 IU); magnesium RDA 400 to 420 mg (men) and 310 to 320 mg (women), upper limit 350 mg a day from supplements [11][7].
- Vitamin D3 with K2 is fine too: magnesium glycinate, D3 and K2 can all be taken together. Our Vitamin D3 + K2 pairs the two in one capsule.
For reference, a 4-capsule serving of Love Life Supplements Magnesium Glycinate provides 303 mg of elemental magnesium from fully reacted bisglycinate (240 capsules, 60 days, batch tested by Eurofins), and one capsule of our Vitamin D3 + K2 provides 75 micrograms (3,000 IU) of vitamin D3 with 100 micrograms of K2Vital® vitamin K2.
Can I Take Magnesium Glycinate and Vitamin D3 Together?
Yes. You can take magnesium glycinate and vitamin D3 together at the same time, and many people do because magnesium supports vitamin D metabolism. Magnesium glycinate with vitamin D needs no spacing: unlike calcium, iron or zinc taken in large doses, the two do not compete for absorption in the gut.
The same answer applies whichever way round you ask it: can you take vitamin D and magnesium glycinate together, can you take magnesium glycinate with vitamin D, or vitamin D3 with magnesium glycinate? Yes to all of them, whether you take vitamin D and magnesium glycinate together, vitamin D3 with magnesium glycinate, or magnesium bisglycinate and vitamin D (bisglycinate is simply the full chemical name of the same form). Vitamin D3 (cholecalciferol) is the form most supplements use, including ours, and it is the form studied in the magnesium glycinate trial below [2].
The only practical tip is to take them with food. Vitamin D is fat soluble, so a meal containing some fat helps it absorb, and food also makes magnesium gentler on the stomach. If you take medicines that need spacing from magnesium, such as certain antibiotics or osteoporosis drugs, follow the timing in the interactions section below.
Why Are Magnesium and Vitamin D Often Paired?
Magnesium and vitamin D are paired because the body needs magnesium to convert vitamin D into the forms it can use. Vitamin D is not biologically active in the form you swallow or make in your skin; it goes through two conversion steps, first in the liver and then in the kidneys, and the enzymes for both steps depend on magnesium [1].
Researchers have suggested that low magnesium status may limit how well the body uses vitamin D, which is one reason some people see smaller rises in vitamin D levels than expected from supplements [1]. Magnesium is also involved in the vitamin D binding protein that carries vitamin D in the blood [1].
Intake matters here. In the US, an analysis of national survey data found that 79% of adults do not meet the recommended dietary allowance for magnesium [5]. Pairing a magnesium supplement with vitamin D covers both sides of the partnership.
What Do Magnesium and Vitamin D Do for the Body?
Magnesium supports muscle, nerve and energy metabolism and helps maintain normal bones; vitamin D helps the body absorb and use calcium and supports bones, muscles and the immune system. These are authorised health claims in Great Britain [6].
| Nutrient | Authorised GB health claims (selected) |
|---|---|
| Magnesium | Contributes to normal muscle function; normal functioning of the nervous system; normal psychological function; normal energy-yielding metabolism; the reduction of tiredness and fatigue; electrolyte balance; the maintenance of normal bones and teeth |
| Vitamin D | Contributes to normal absorption and utilisation of calcium and phosphorus; normal blood calcium levels; the maintenance of normal bones, teeth and muscle function; the normal function of the immune system |
| Vitamin K | Contributes to the maintenance of normal bones; normal blood clotting |
Source: Great Britain nutrition and health claims register. Claims apply to products providing a significant amount of the nutrient.
Magnesium is an essential mineral involved in more than 300 enzyme reactions [7]. Vitamin D's main job is calcium handling: it helps the gut absorb calcium and keeps blood calcium and phosphate in the normal range for bone mineralisation. In the UK, most people make enough vitamin D from sunlight between late March and September, which is why the NHS advises everyone to consider a daily vitamin D supplement in autumn and winter [3].
Taken together, both nutrients contribute to the maintenance of normal bones, and magnesium supports the conversion steps vitamin D relies on. That overlap, rather than any single dramatic effect, is the reason for combining them.
"Magnesium is a non-negotiable cofactor for vitamin D activation. Without sufficient magnesium, vitamin D can't be properly metabolised, meaning you might not be getting the full benefits from your supplements. It's a foundational partnership for bone health and beyond."
Sarah Law, Naturopathic Nutritionist | Optimised Female
How Does Magnesium Glycinate Support Vitamin D Metabolism?
Magnesium glycinate supplies well-absorbed magnesium, and magnesium is the cofactor for the enzymes that turn vitamin D into 25-hydroxyvitamin D and then into active calcitriol. It does not increase how much vitamin D you absorb from a capsule; it supports what happens to vitamin D after absorption [1].
The first step happens in the liver, where vitamin D3 (cholecalciferol) is converted to 25-hydroxyvitamin D (calcidiol), the form measured in a blood test. The second happens mainly in the kidneys, where calcidiol becomes 1,25-dihydroxyvitamin D (calcitriol), the active hormone. Both conversion enzymes are magnesium dependent [1].
Two randomised trials have tested this in people:
- Magnesium glycinate plus vitamin D3 (2022): 95 adults with overweight or obesity were randomised to magnesium glycinate plus vitamin D3, vitamin D3 alone, or placebo for 12 weeks. The combined group had the largest rise in blood 25-hydroxyvitamin D, an average of 6.3 ng/mL [2].
- Magnesium and vitamin D status (2018): in 180 adults aged 40 to 85, magnesium supplementation raised 25-hydroxyvitamin D3 when starting levels were around 30 ng/mL and lowered it when starting levels were higher (about 30 to 50 ng/mL). The authors concluded that optimal magnesium status may be important for optimising vitamin D status [5].
So does magnesium glycinate help with vitamin D absorption? Strictly, no: it helps with vitamin D metabolism, which is the step that matters once vitamin D is in your body.
Comparison of Magnesium Forms for Vitamin D Support
Any form that raises your magnesium status supports vitamin D metabolism, so the best form is the one you absorb well and tolerate daily; glycinate scores well on both. Exact absorption percentages vary between studies and people, so the table uses relative ratings rather than single figures.
| Magnesium form | Elemental magnesium | Relative absorption | For vitamin D support | Potential side effects |
|---|---|---|---|---|
| Magnesium glycinate | Up to 14.1% (11% on our label) | High [8] | The form used in the 2022 combined trial [2]; gentle on digestion | Minimal; mild stomach upset in sensitive people |
| Magnesium citrate | ~16% | Moderate to high [9] | Supports overall magnesium status | Laxative effect at higher doses |
| Magnesium oxide | ~60% | Low [9] | Less useful for raising status because little is absorbed | Marked laxative effect |
| Magnesium malate | ~11 to 15% | Moderate | Supports overall magnesium status | Generally well tolerated |
Are There Any Benefits to Taking Them Together?
The main benefit of taking magnesium glycinate and vitamin D together is that magnesium supports the conversion of vitamin D, and both contribute to the maintenance of normal bones and normal muscle function [6]. In the 2022 trial, the combination raised blood vitamin D more than vitamin D3 alone [2].
Vitamin D helps the body absorb and use calcium, and magnesium is needed for the parathyroid hormone system that regulates calcium and phosphate levels [7]. Vitamin D also contributes to the normal function of the immune system, while magnesium contributes to normal muscle function and the reduction of tiredness and fatigue [6].
Those are the realistic magnesium glycinate and vitamin D3 benefits. It is worth keeping expectations realistic. Not every outcome improves: a 2023 randomised trial found that combined vitamin D and magnesium did not change markers of bone turnover or blood glucose control over the study period [10]. The clearest evidence is for vitamin D status itself.
Can I Take Magnesium Glycinate and Vitamin D3 K2 Together?
Yes. You can take magnesium glycinate and vitamin D3 with K2 together; there is no known interaction between the three. Vitamin K2 is often added to vitamin D3 supplements because vitamin K contributes to the maintenance of normal bones [6], and all three can go with the same meal.
One caution applies to vitamin K, not magnesium: if you take warfarin or another vitamin K antagonist blood thinner, do not start a K2 supplement without speaking to your GP or anticoagulation clinic, because vitamin K affects how those medicines work.
If you want both in one order, our Magnesium Glycinate + Vitamin D3/K2 bundle pairs one tub of each, a 2-month supply at £54.81 against £60.90 bought separately (storefront prices, 13 October 2026).
What is the Optimal Dosage for Magnesium Glycinate and Vitamin D?
For most UK adults, a sensible daily combination is 200 to 400 mg of elemental magnesium from magnesium glycinate plus 10 to 25 micrograms (400 to 1,000 IU) of vitamin D, staying under 100 micrograms (4,000 IU) of vitamin D and 400 mg of supplemental magnesium. The NHS recommends 10 micrograms of vitamin D a day in autumn and winter and says not to exceed 100 micrograms a day [3], and says 400 mg or less of magnesium a day from supplements is unlikely to cause harm [4]. In the US the equivalent combination is 200 to 350 mg of elemental magnesium plus 15 to 25 mcg (600 to 1,000 IU) of vitamin D, because the US upper limit for supplemental magnesium is 350 mg a day and the vitamin D RDA is 600 IU (800 IU over 70) [11][7].
There is no fixed ratio between magnesium and vitamin D; claims that you need a set number of milligrams of magnesium per IU of vitamin D are not based on trials. What matters is that both intakes are adequate. If you take a higher-dose vitamin D, it is a good reason to make sure your magnesium intake is adequate too. A blood test for 25-hydroxyvitamin D, through your GP, is the most accurate way to judge your own vitamin D needs.
UK daily amounts and what our products provide
| Nutrient | UK recommendation (adults) | UK upper guidance | Love Life Supplements daily serving | Cost per day |
|---|---|---|---|---|
| Magnesium | 300 mg men / 270 mg women (total diet) [4] | 400 mg or less a day from supplements unlikely to cause harm [4] | Magnesium Glycinate, 4 capsules: 303 mg elemental (2 capsules: 152 mg) | 63p (57p on subscription) |
| Vitamin D | 10 micrograms (400 IU) a day, autumn and winter [3] | No more than 100 micrograms (4,000 IU) a day [3] | Vitamin D3 + K2, 1 capsule: 75 micrograms (3,000 IU) D3 | 38p (34p on subscription) |
| Vitamin K2 | No separate UK figure for K2 | Not set | Vitamin D3 + K2, 1 capsule: 100 micrograms K2Vital® | Included above |
| Both together | Within UK upper guidance for magnesium and vitamin D | Bundle, 2-month supply | 91p (£54.81 / 60 days) | |
Storefront prices on 3 November 2026: Magnesium Glycinate £37.95 (240 capsules) or £34.16 first Subscribe & Save order; Vitamin D3 + K2 £22.95 (60 capsules) or £20.66. Our 3,000 IU dose is above the NHS's 400 IU baseline and below its 4,000 IU limit; if you already take another vitamin D product, add the amounts together. Every order carries our 60-day money-back guarantee.
US daily amounts: NIH RDA and upper limits
For readers in the US, the reference values come from the NIH Office of Dietary Supplements, and they differ from the UK figures above: the vitamin D RDA applies all year rather than just in autumn and winter, and the magnesium upper limit for supplements is lower [11][7].
| Nutrient | US RDA (adults) | US upper limit (UL) | Love Life Supplements in the US |
|---|---|---|---|
| Magnesium | 400 to 420 mg men / 310 to 320 mg women (total diet) | 350 mg a day from supplements | Magnesium Glycinate, 4 capsules: 303 mg elemental, $43.23 per 240-capsule tub on our US store (about 72 cents a day) |
| Vitamin D | 15 mcg (600 IU) to age 70; 20 mcg (800 IU) over 70 | 100 mcg (4,000 IU) a day | Our Vitamin D3 + K2 is not currently sold on our US store |
US magnesium RDA rises from 400 to 420 mg (men) and 310 to 320 mg (women) at age 31. The magnesium UL covers supplements and medicines only, not food. US Supplement Facts labels show % Daily Value, based on 420 mg for magnesium and 20 mcg (800 IU) for vitamin D.
How much vitamin D3 should I take with magnesium glycinate?
Taking magnesium glycinate does not change how much vitamin D3 you need. Use the NHS baseline of 10 micrograms (400 IU) a day in autumn and winter, or the amount your GP suggests after a blood test, and keep the total under 100 micrograms (4,000 IU) a day [3]. In the US, the NIH RDA is 15 mcg (600 IU) a day up to age 70 and 20 mcg (800 IU) over 70, with the same 4,000 IU upper limit [11].
When to Take Magnesium Glycinate and Vitamin D3
Take magnesium glycinate and vitamin D3 together with your main meal, or take vitamin D with a meal and the magnesium glycinate in the evening; both approaches work. Vitamin D absorbs best with some dietary fat, and the timing of magnesium glycinate is flexible.
Can you take magnesium glycinate and vitamin D3 together at night? Yes, if that is when you eat your main meal or when you remember. Many people take magnesium glycinate in the evening because glycine has been studied for sleep quality; our guide on whether to take magnesium glycinate in the morning or at night covers the detail. Some people prefer vitamin D earlier in the day, but no firm evidence says vitamin D must be taken in the morning.
Can I take magnesium glycinate with calcium and vitamin D? Yes, though large doses of calcium and magnesium taken at exactly the same moment may compete for absorption, so some people take a calcium supplement at a different meal. For the full picture on dose, see how much magnesium glycinate per day.
Are There Any Side Effects or Interactions?
Magnesium glycinate and vitamin D do not interact with each other, and both are well tolerated within UK and US guidance; side effects come from taking too much of either. Too much magnesium causes diarrhoea: the NHS says more than 400 mg a day for a short time can cause it [4], and the US upper limit of 350 mg a day from supplements is set to avoid diarrhea (diarrhoea), the main side effect of too much supplemental magnesium [7]. Magnesium glycinate is one of the gentler forms on the gut.
Too much vitamin D over a long period can cause too much calcium to build up in the body (hypercalcaemia), which can weaken bones and damage the kidneys and heart. That is why the NHS says not to take more than 100 micrograms (4,000 IU) a day unless a doctor advises it [3].
Regarding medicines, magnesium can reduce the absorption of tetracycline and quinolone antibiotics and oral bisphosphonates; take those antibiotics at least 2 hours before or 4 to 6 hours after magnesium, and bisphosphonates at least 2 hours apart [7]. Some diuretics and long-term proton pump inhibitors can lower magnesium levels [7]. Vitamin D can interact with some medicines too, including certain anti-seizure drugs and steroids, and vitamin K2 matters if you take warfarin. People with kidney disease should not take magnesium supplements unless their doctor recommends them. Our guide on who should not take magnesium covers this in more depth.
"When considering any new supplement, especially a combination like magnesium and vitamin D, always consult your GP or a qualified healthcare professional. They can assess your individual needs, check for potential interactions with medications, and help determine the most appropriate dosage to ensure safety and efficacy."
Sarah Law, Naturopathic Nutritionist & Functional Practitioner (Optimised Female, 2023)
Frequently Asked Questions
Can I take magnesium glycinate and vitamin D3 together?
Yes. Magnesium glycinate and vitamin D3 can be taken together at the same time, ideally with a meal that contains some fat. They do not compete for absorption, and magnesium is a cofactor for the enzymes that convert vitamin D into its active forms.
Can I take magnesium glycinate and vitamin D3 K2 together?
Yes. Magnesium glycinate, vitamin D3 and vitamin K2 can all be taken together with the same meal. If you take warfarin or another vitamin K antagonist, speak to your GP before starting vitamin K2.
Should I take vitamin D with magnesium glycinate?
You do not have to, but it is a sensible pairing. Magnesium supports vitamin D metabolism, and in a 12-week trial magnesium glycinate plus vitamin D3 raised blood vitamin D more than vitamin D3 alone.
Does magnesium glycinate help with vitamin D absorption?
Not absorption as such. Magnesium supports what happens after vitamin D is absorbed: the enzymes in the liver and kidneys that convert it into 25-hydroxyvitamin D and active calcitriol depend on magnesium.
Can I take magnesium glycinate and vitamin D3 together at night?
Yes. Taking both with your evening meal works well, and many people prefer magnesium glycinate in the evening anyway. Vitamin D just needs to go with food that contains some fat.
How much vitamin D3 should I take with magnesium glycinate?
The same amount you would take on its own: the NHS advises 10 micrograms (400 IU) a day in autumn and winter and no more than 100 micrograms (4,000 IU) a day. Magnesium glycinate does not change that figure. In the US, the NIH RDA is 15 micrograms (600 IU) a day for adults up to 70 and 20 micrograms (800 IU) over 70, with the same 4,000 IU upper limit.
Can I take magnesium glycinate with calcium and vitamin D?
Yes. Magnesium glycinate, calcium and vitamin D can all be part of the same daily routine. Large doses of calcium and magnesium taken at exactly the same moment may compete for absorption, so many people take a calcium supplement with a different meal from their magnesium. Vitamin D can go with either, ideally with food that contains some fat.
References
- Uwitonze AM, Razzaque MS. Role of Magnesium in Vitamin D Activation and Function. J Am Osteopath Assoc. 2018. PubMed 29480918
- Cheung MM, Dall RD, Shewokis PA, et al. The effect of combined magnesium and vitamin D supplementation on vitamin D status, systemic inflammation, and blood pressure: a randomized double-blinded controlled trial. Nutrition. 2022. PubMed 35576873
- NHS. Vitamins and minerals: Vitamin D. nhs.uk
- NHS. Vitamins and minerals: Others (magnesium). nhs.uk
- Dai Q, Zhu X, Manson JE, et al. Magnesium status and supplementation influence vitamin D status and metabolism: results from a randomized trial. Am J Clin Nutr. 2018. PubMed 30541089
- GOV.UK. Great Britain nutrition and health claims (NHC) register. GOV.UK
- NIH Office of Dietary Supplements. Magnesium Fact Sheet for Health Professionals. NIH ODS
- Schuette SA, Lashner BA, Janghorbani M. Bioavailability of magnesium diglycinate vs magnesium oxide in patients with ileal resection. JPEN J Parenter Enteral Nutr. 1994. PubMed 7815675
- Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnes Res. 2001. PubMed 11794633
- Dall RD, Cheung MM, Shewokis PA, et al. Combined vitamin D and magnesium supplementation does not influence markers of bone turnover or glycemic control: a randomized controlled clinical trial. Nutr Res. 2023. PubMed 36640582
- NIH Office of Dietary Supplements. Vitamin D Fact Sheet for Health Professionals (RDA and tolerable upper intake levels). NIH ODS
References checked against PubMed and the source pages on 13 October 2026.
The sleep and calm specialist: Magnesium Glycinate, fully reacted bisglycinate, 303 mg elemental magnesium per serving, UK-made and third-party tested.
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