Magnesium glycinate and magnesium citrate are two popular forms of magnesium found in food supplements. Both provide magnesium, but they are combined with different substances and may suit different routines.
Magnesium glycinate is magnesium combined with glycine, while magnesium citrate is magnesium combined with citric acid. Glycinate is commonly chosen for evening routines, whereas citrate is often selected as a general-purpose magnesium supplement and may have a more noticeable effect on digestion.
Neither form is automatically best for everyone. The most suitable option depends on digestive tolerance, the amount of elemental magnesium provided, the number of capsules required and your reason for taking a supplement.
What is magnesium?
Magnesium is an essential mineral found naturally in foods such as spinach, nuts and wholemeal bread. Most people should be able to obtain the magnesium they need from a varied and balanced diet.
In Great Britain, authorised health claims state that magnesium contributes to:
- Normal muscle function
- Normal functioning of the nervous system
- Normal psychological function
- Normal energy-yielding metabolism
- A reduction in tiredness and fatigue
- The maintenance of normal bones and teeth
- Electrolyte balance
- Normal protein synthesis
These claims may only be used when a product contains enough magnesium to meet the required conditions. They do not mean that a magnesium supplement can prevent, treat or cure a medical condition.
Why are there different types of magnesium?
Pure magnesium is not normally used by itself in supplements. Instead, it is combined with another substance to create compounds such as magnesium citrate, magnesium glycinate, magnesium oxide and magnesium malate.
The substance attached to magnesium can affect:
- How the product dissolves
- How much elemental magnesium it contains
- The number of capsules required
- Digestive tolerance
- The cost of the supplement
- How the product is marketed
Research comparing commercial magnesium products has found considerable variation in dissolution and absorption between different formulations. This means the magnesium form is important, but the overall quality and composition of the finished product matter too.
What is magnesium glycinate?
Magnesium glycinate is magnesium combined with glycine, an amino acid. It may also be described as magnesium bisglycinate or magnesium diglycinate.
The term “bisglycinate” indicates that magnesium is bonded with two glycine molecules. In everyday supplement marketing, magnesium glycinate and magnesium bisglycinate are often used to describe the same general form.
Magnesium glycinate is frequently included in products designed for evening, relaxation or recovery routines. However, these descriptions should not be interpreted as proof that it treats insomnia or guarantees better sleep.
Magnesium glycinate may suit people who:
- Want a chelated form of magnesium
- Prefer to include magnesium in an evening routine
- Have previously found citrate unsuitable
- Do not specifically want a laxative effect
- Are comfortable taking the required number of capsules
The available research does not establish that glycinate is universally better than citrate. Evidence involving magnesium diglycinate suggests it can be absorbed, but some research has involved people with specific digestive or intestinal conditions and should not automatically be applied to all supplement users.
What is magnesium citrate?
Magnesium citrate is magnesium combined with citric acid.
It is one of the most widely available forms of magnesium and is found in both single-form supplements and multi-magnesium complexes.
The US National Institutes of Health lists magnesium citrate among the forms that are generally more readily absorbed than magnesium oxide. Human studies have also found citrate to have better bioavailability than oxide and certain other forms tested. These findings do not prove that citrate is superior to every form of magnesium or that it will provide greater health benefits for every person.
Magnesium citrate may suit people who:
- Want a widely available magnesium form
- Prefer a general daily magnesium supplement
- Have previously used citrate without digestive discomfort
- Want an alternative to magnesium oxide
- Do not mind that it may loosen stools
Magnesium citrate can have a laxative effect, particularly when taken in larger quantities. Always follow the serving stated on the product label.
Magnesium glycinate vs citrate: quick comparison
| Feature | Magnesium glycinate | Magnesium citrate |
|---|---|---|
| Combined with | Glycine | Citric acid |
| Also called | Bisglycinate or diglycinate | Magnesium citrate |
| Commonly used for | Evening and general wellness routines | General magnesium supplementation |
| Digestive effect | Often selected when avoiding citrate’s laxative effect | May loosen stools |
| Availability | Widely available | Very widely available |
| Price | Often more expensive | Often moderately priced |
| Evidence on absorption | Evidence exists, but direct comparisons are limited | Better studied than several inorganic forms |
| Guaranteed to improve sleep? | No | No |
| Best choice for everyone? | No | No |
Which form is absorbed better?
It is difficult to say that one form is always absorbed better because studies differ in their doses, products, participants and methods of measuring magnesium status.
Magnesium citrate has reasonably established evidence showing better absorption than magnesium oxide. However, there is much less high-quality research directly comparing magnesium citrate with magnesium glycinate in typical healthy adults.
Claims that glycinate is always the most absorbable form or that citrate is always superior are therefore too definite.
Absorption may also be affected by:
- The amount taken
- The full product formulation
- Whether it is taken with food
- The individual’s magnesium status
- Digestive health
- Other medicines or supplements
- How the study measures absorption
The most absorbable product on paper is not necessarily the most practical choice. A supplement is unlikely to be useful when its serving is difficult to maintain or it causes digestive discomfort.
Which is gentler on the stomach?
Magnesium glycinate is often chosen by people trying to avoid the stool-loosening effect associated with citrate. However, individual tolerance varies, and glycinate can still cause digestive symptoms in some people.
Magnesium citrate draws water into the bowel and may loosen stools. This does not mean everyone taking it will experience diarrhoea, but the effect may become more noticeable with higher amounts.
When trying a new magnesium supplement:
- Follow the recommended serving
- Do not take extra to obtain faster results
- Consider taking it with food when permitted by the directions
- Stop taking it and seek advice if symptoms are persistent or severe
Is magnesium glycinate better for sleep?
Magnesium glycinate is commonly marketed for sleep and evening relaxation because it contains glycine and is often considered suitable for nighttime routines.
However, magnesium is not a sleeping medicine, and there is not enough evidence to say that magnesium glycinate will improve sleep for everyone.
Magnesium contributes to normal muscle function, normal nervous-system function and normal psychological function. These are authorised nutritional functions, but they should not be turned into claims that magnesium treats insomnia or causes sleep.
Someone primarily looking for an evening magnesium supplement may decide to try glycinate. Someone who already tolerates citrate and is satisfied with it may have no reason to change.
Persistent sleep problems should be discussed with a GP rather than managed solely with supplements.
Is magnesium citrate better for digestion?
Magnesium citrate can affect bowel movements and is also used in some medicinal laxative products. However, a food supplement should not be presented as a treatment for constipation unless it is specifically authorised and licensed for that purpose.
Some people may view citrate’s digestive effect as useful, while others may find it inconvenient. The effect depends on the amount taken, the product and individual tolerance.
Someone who regularly experiences loose stools may prefer to avoid citrate or seek professional advice before using it.
What is elemental magnesium?
Elemental magnesium is the amount of actual magnesium supplied by the supplement.
A label might state that a product contains a large quantity of magnesium glycinate or magnesium citrate. That figure includes the complete compound, not only the magnesium within it.
For example, a large quantity of magnesium bisglycinate powder may provide a much smaller amount of elemental magnesium.
When comparing products, look for the nutritional information that states:
Magnesium: 200mg
This is more useful than relying on wording such as:
Magnesium glycinate complex: 1,000mg
The second figure may refer to the entire ingredient rather than the amount of magnesium it contributes.
How to compare magnesium labels
When comparing magnesium glycinate and citrate supplements, check the following information.
Elemental magnesium per daily serving
Use the amount labelled simply as magnesium. Make sure you know whether this is listed per capsule or per complete daily serving.
Number of capsules
One product may provide its daily amount in one capsule, while another may require two, three or four.
A lower price per bottle may not represent better value when the bottle requires a larger daily serving.
Percentage nutrient reference value
The nutrient reference value can help place the amount of magnesium into context. It should be considered alongside your diet and other supplements.
Additional magnesium forms
Some products promoted as glycinate or citrate may also contain magnesium oxide. Read the complete ingredient list rather than relying solely on the front label.
Other active ingredients
Magnesium supplements may also contain vitamin B6, zinc, calcium, herbal extracts or other nutrients.
Check products you already use to avoid accidentally duplicating ingredients.
Capsule suitability
Look for confirmation of whether the product is suitable for vegetarians or vegans. Magnesium itself is a mineral, but capsule shells and other ingredients can vary.
Can magnesium glycinate and citrate be taken together?
Some multi-form magnesium complexes contain both glycinate and citrate.
They can therefore appear in the same supplement, but taking both does not automatically provide better results. The important figure is the total elemental magnesium supplied by the complete serving.
Before combining separate magnesium products:
- Add together their elemental magnesium amounts
- Check for overlapping ingredients
- Follow each product’s warnings
- Consider whether combining them increases digestive discomfort
- Ask a pharmacist when taking regular medication
There is usually no need to purchase multiple magnesium supplements simply to obtain a longer list of forms.
How much magnesium should you take?
The NHS states that adults should generally be able to obtain their magnesium from a varied and balanced diet. It advises that taking 400mg or less per day of magnesium from supplements is unlikely to cause harm for most people. This is a safety statement, not a recommended target or an instruction to take 400mg.
The appropriate amount depends on the product and the individual. Always follow the directions on the label rather than aiming for the highest possible dose.
Taking too much supplemental magnesium can cause:
- Diarrhoea
- Nausea
- Abdominal discomfort
- Stomach cramping
People with reduced kidney function can be at greater risk because their bodies may not remove excess magnesium effectively.
Can magnesium interact with medication?
Magnesium supplements can interact with certain medicines or affect their absorption.
Examples include:
- Some antibiotics
- Bisphosphonates used for osteoporosis
- Certain diuretics
- Some medicines used for acid reflux or indigestion
A pharmacist can advise whether magnesium needs to be taken several hours apart from a medicine. People with kidney problems, ongoing health conditions or regular prescriptions should seek advice before beginning a magnesium supplement.
Magnesium glycinate vs citrate: which should you choose?
Magnesium glycinate may be a practical choice when you:
- Want magnesium as part of an evening routine
- Prefer to avoid citrate’s potential laxative effect
- Have used a glycinate product successfully before
- Are happy with its serving size and price
Magnesium citrate may be a practical choice when you:
- Want a widely available general magnesium supplement
- Prefer a form with established evidence of absorption compared with oxide
- Already know you tolerate citrate
- Do not mind its possible effect on digestion
Neither form is guaranteed to be better. Look beyond the name on the front of the bottle and compare elemental magnesium, serving size, full ingredients, dietary suitability and directions.
Frequently asked questions
Are magnesium glycinate and bisglycinate the same?
The names are frequently used interchangeably in the supplement market. Bisglycinate more specifically describes magnesium bonded to two glycine molecules. Check the complete ingredient information because formulations can vary between manufacturers.
Is magnesium citrate stronger than glycinate?
Not necessarily. Strength should be compared using the elemental magnesium per serving rather than the total weight of the citrate or glycinate compound.
Can magnesium citrate be taken at night?
Magnesium citrate can generally be taken in the evening when this agrees with the product directions. Some people may prefer another time because citrate can affect digestion.
Can magnesium glycinate be taken during the day?
Yes. Glycinate is often marketed for nighttime use, but this does not mean it can only be taken at night. Follow the instructions supplied with the product.
Does magnesium glycinate make you sleepy?
Magnesium glycinate is not a sedative and should not be expected to make someone suddenly sleepy. It is commonly included in evening routines, but individual experiences vary.
Which is better for muscle function?
Both forms can provide magnesium. Magnesium contributes to normal muscle function when the product contains enough magnesium to qualify for the authorised health claim. One form has not been established as universally better for this purpose.
Which is better for constipation?
Magnesium citrate may have a greater stool-loosening effect. However, a food supplement should not be used as a replacement for medical advice or presented as a treatment for persistent constipation.
Can I switch from citrate to glycinate?
Most adults can change supplement forms, but check the elemental magnesium and serving size because they may differ. Seek advice first when taking medication or managing a health condition.
Final comparison
The main difference between magnesium glycinate and citrate is the substance attached to the magnesium.
Glycinate is combined with glycine and is commonly selected for evening routines or by people wishing to avoid citrate’s digestive effects. Citrate is combined with citric acid, is widely available and has evidence of better absorption than magnesium oxide.
The best choice is not necessarily the form with the strongest marketing claim. Choose a clearly labelled product that provides an appropriate amount of elemental magnesium, has a manageable serving and fits your individual routine.