Magnesium glycinate with zinc is a popular supplement combination in the UK, bringing together two essential minerals that support numerous bodily functions. Magnesium glycinate pairs the mineral magnesium with the amino acid glycine, whilst zinc is a vital trace element for immune health and cellular processes. Whilst both minerals are crucial for wellbeing, most people can obtain adequate amounts through a balanced diet. Supplementation may benefit those at risk of deficiency, but it's important to understand appropriate dosing, potential interactions, and when professional guidance is needed before starting any supplement regimen.

What Are Magnesium Glycinate and Zinc?

Magnesium glycinate is a form of magnesium bound to the amino acid glycine. Magnesium itself is an essential mineral involved in over 300 enzymatic reactions in the body, including energy production, protein synthesis, muscle and nerve function, and bone health. Some studies suggest the glycinate form may be gentler on the digestive system compared to certain other magnesium forms, though individual responses vary.

Zinc is an essential trace element crucial for immune function, wound healing, DNA synthesis, and cell division. It plays a vital role in supporting the body's natural defence mechanisms and is required for the proper function of numerous enzymes. Zinc is also important for growth and development during pregnancy, childhood, and adolescence, and contributes to normal cognitive function and the maintenance of healthy skin, hair, and nails.

Both minerals are obtained through diet, with magnesium found in green leafy vegetables, nuts, seeds, and whole grains, whilst zinc is abundant in meat, shellfish, legumes, and dairy products. However, dietary intake may be insufficient for some individuals due to poor absorption, restrictive diets, or increased physiological demands. When taken as supplements, doses are expressed as elemental magnesium or zinc (the actual mineral content).

It's important to note that while these minerals can be taken together, there is no established evidence for synergistic benefits beyond meeting individual requirements for each nutrient. In the UK, vitamin and mineral supplements are primarily regulated as foods by the Food Standards Agency (FSA) and local authorities, with the Medicines and Healthcare products Regulatory Agency (MHRA) involved only if products make medicinal claims.

Benefits of Taking Magnesium Glycinate with Zinc

The combination of magnesium glycinate with zinc may support several aspects of health, though it's important to understand the evidence varies in quality and strength across different applications.

Immune system support: Zinc contributes to the normal function of the immune system, as recognised in the Great Britain Nutrition and Health Claims Register. Zinc deficiency can affect immune cell development and function. Magnesium also plays a role in immune regulation, though the evidence for supplementation specifically enhancing immunity is less established.

Sleep quality and relaxation: Some people take magnesium supplements to support sleep, as magnesium contributes to normal nervous system function. Glycine (in magnesium glycinate) has relaxing properties in some studies. However, evidence that supplementation improves sleep quality is limited and mixed, and supplements are not recommended treatments for insomnia by NICE. The role of zinc in sleep regulation has been studied but remains inconclusive.

Mood and mental wellbeing: Magnesium contributes to normal psychological function, as recognised in authorised health claims. It is involved in neurotransmitter regulation, with some research suggesting potential benefits for mood in those with inadequate intake. Zinc also plays a role in brain function, though evidence for mood effects from supplementation is preliminary.

Both minerals contribute to bone health and metabolic function. Magnesium contributes to the maintenance of normal bones and works alongside calcium and vitamin D. Zinc contributes to the maintenance of normal bones and normal protein synthesis.

It's worth noting that while maintaining adequate levels of both minerals is important for overall health, most people can achieve this through a balanced diet. There is currently no robust evidence that taking these minerals in combination provides additional benefits beyond addressing individual deficiencies.

Recommended Dosage and How to Take Them Together

The Reference Nutrient Intake (RNI) in the UK for magnesium is 300 mg per day for men and 270 mg per day for women. For zinc, the RNI is 9.5 mg per day for men and 7 mg per day for women. When considering supplementation, it's important to account for dietary intake and avoid exceeding safe upper limits.

The safe upper limit for elemental magnesium from supplements is 400 mg per day for adults, as higher doses may cause gastrointestinal effects such as diarrhoea. For zinc, the upper safe limit is 25 mg per day from supplements, with prolonged intake above this level potentially interfering with copper absorption and immune function. Many combination supplements contain doses within these ranges, typically providing 100–200 mg of elemental magnesium (as magnesium glycinate) and 10–15 mg of zinc.

Timing and administration can influence absorption and tolerability. Magnesium glycinate is generally well-tolerated at any time of day, though many individuals prefer taking it in the evening. Zinc is best absorbed on an empty stomach but may cause nausea in some people, so taking it with food is often recommended. When combining these minerals, taking them with a meal can help minimise gastrointestinal discomfort.

Regarding mineral interactions, high doses of minerals may compete for absorption pathways, though at typical supplemental doses this is generally not a significant concern. More importantly, these minerals can interact with certain medications:

• Tetracycline and quinolone antibiotics: separate by 2-4 hours

• Levothyroxine (thyroid medication): separate by at least 4 hours

• Bisphosphonates (for osteoporosis): follow specific timing instructions in the patient information leaflet

• Diuretics may affect magnesium levels

Before starting any supplement regimen, individuals should consult their GP or a registered dietitian, particularly if they have existing health conditions or take regular medications.

Potential Side Effects and Safety Considerations

Whilst magnesium glycinate and zinc are generally well-tolerated when taken at appropriate doses, potential side effects and safety considerations should be understood.

Common side effects of magnesium supplementation, even with the glycinate form, may include:

• Mild gastrointestinal symptoms such as loose stools or diarrhoea, particularly at higher doses

• Nausea or abdominal discomfort

• In rare cases, excessive magnesium intake can lead to hypermagnesaemia, characterised by nausea, low blood pressure, confusion, and irregular heartbeat

Zinc supplementation may cause:

• Nausea and gastrointestinal upset, especially when taken on an empty stomach

• Metallic taste in the mouth

• Headaches

• Reduced copper absorption with long-term high-dose use, potentially leading to copper deficiency and associated anaemia or neurological problems

Contraindications and cautions include individuals with kidney disease, who should avoid magnesium supplements unless under medical supervision, as impaired renal function reduces the body's ability to excrete excess magnesium. Those with myasthenia gravis should use magnesium cautiously as it may worsen muscle weakness.

Drug interactions are an important consideration. Both minerals can reduce the absorption of certain antibiotics (tetracyclines, quinolones), levothyroxine, and bisphosphonates. Zinc specifically interacts with penicillamine. Diuretics may affect magnesium levels, whilst certain blood pressure medications may interact with these minerals.

When to seek medical advice: Contact your GP if you experience persistent gastrointestinal symptoms, signs of deficiency despite supplementation, or any unusual symptoms after starting supplements. Seek immediate medical attention if you experience severe weakness, fainting, very slow or irregular heartbeat, or signs of allergic reaction. Pregnant or breastfeeding women should consult their healthcare provider before taking these supplements.

Suspected adverse reactions to supplements can be reported through the MHRA Yellow Card Scheme. Purchase supplements from reputable UK retailers to help ensure quality and accurate labelling.

Who Should Consider This Supplement Combination?

Certain groups may benefit from magnesium glycinate and zinc supplementation, though individual assessment is essential before starting any supplement regimen.

Individuals at risk of deficiency represent the primary group who may benefit. This includes:

• People with gastrointestinal disorders such as Crohn's disease, coeliac disease, or chronic diarrhoea, which impair mineral absorption

• Older adults, who may have reduced dietary intake and absorption efficiency

• Those following restrictive diets, including strict vegetarians or vegans, who may have limited dietary sources of zinc

• People with type 2 diabetes, who may have increased mineral losses and lower magnesium levels

• Individuals with alcohol dependence, as alcohol interferes with mineral absorption and increases excretion

People experiencing specific symptoms that may suggest inadequate intake could also consider supplementation under medical guidance. These symptoms include persistent fatigue, poor wound healing, frequent infections, muscle cramps, or sleep disturbances. However, these symptoms are non-specific and require proper medical evaluation to determine the underlying cause.

Athletes and physically active individuals may have increased requirements due to losses through sweat and increased metabolic demands, though a balanced diet typically meets these needs. Some research suggests that periods of physical or psychological stress may affect magnesium status, though evidence for routine supplementation in these circumstances is limited.

Who should avoid or use caution includes individuals with kidney disease, those taking multiple medications with potential interactions, and anyone with diagnosed mineral imbalances. Children and pregnant women should not take high-dose supplements without professional advice.

The NHS advises that most people should be able to get all the minerals they need from a balanced diet. The most appropriate approach is to consult a healthcare professional who can assess individual needs through clinical evaluation. It's worth noting that blood tests for magnesium and zinc are imperfect markers of body stores and are not routinely indicated unless deficiency is suspected. Self-prescribing high-dose supplements without professional advice may lead to imbalances or mask underlying health conditions requiring medical attention.

Frequently Asked Questions