Key points
In short: Magnesium L-threonate is a form of magnesium bound to L-threonate, a compound the body produces when it metabolises vitamin C. Like every form of magnesium, it contributes to normal psychological function and to the normal functioning of the nervous system. What distinguishes it is its structure, which was developed to carry magnesium across the blood-brain barrier. In GB it is a regulated novel food, and Magtein is the only authorised source.
- What it is: magnesium bound to L-threonate, a compound the body already produces when it metabolises vitamin C. The pairing was developed by researchers at the Massachusetts Institute of Technology and published in Neuron in 2010.
- Authorised claims: like all magnesium, it contributes to normal psychological function and to the normal functioning of the nervous system.
- How the form differs: it was designed to travel using a transport route the brain keeps open, a route ordinary magnesium does not take easily. The distinction is delivery, not dose.
- Regulatory status in GB: magnesium L-threonate is classed as a novel food and requires specific authorisation. One branded source currently holds it, and that source is Magtein.
- Evidence base: four published, controlled human trials between 2016 and 2026, run by different teams in different countries, all using Magtein as the study material.
- Alongside everyday magnesium: it is made to sit with a daily form such as bisglycinate rather than to replace it. Consider your total daily magnesium intake before combining forms.
- Dose used in the research: published human trials have typically used between 1g and 2g of Magtein a day, usually split between morning and evening.
- Who it is for: adults. It is not suitable during pregnancy or breastfeeding, and anyone taking medication or managing a health condition should speak to their GP or practitioner first.
What is magnesium L-threonate?
If you already take a magnesium supplement, or recommend one, this is a launch worth knowing about. Magnesium L-threonate is the newest addition to our magnesium range, and one of the most deliberately engineered forms of any nutrient we have worked with.
Magnesium is one of the minerals many of us fall short on, and it does a great deal of quiet work. Magnesium contributes to normal muscle function, to normal energy-yielding metabolism, to the reduction of tiredness and fatigue, to normal psychological function, and to the normal functioning of the nervous system. Most forms of magnesium do that job well. What sets L-threonate apart is not that it does more. It is where it was designed to go.
What makes this form different
Your brain sits behind the blood-brain barrier, a highly selective filter that decides what is allowed through. It is very good at its job, and ordinary magnesium is not on its list of easy entries. That is not a flaw in everyday magnesium. For muscles, energy and the nervous system generally, the magnesium already in your routine is well placed to help.
Magnesium L-threonate takes a different route. In 2010, researchers at the Massachusetts Institute of Technology paired magnesium with L-threonate (Slutsky et al., Neuron, 2010). That pairing lets the magnesium travel using a transport route the brain keeps open, something ordinary magnesium cannot do simply by being taken in larger amounts. The distinction is not the dose. It is the delivery.
The most researched magnesium of its kind
What drew us to this form is the evidence behind it. For a single supplement ingredient, the research base is unusually developed. Magnesium L-threonate has been examined in four published, controlled human trials between 2016 and 2026, carried out by different teams in different countries. We would rather point you to that research than paraphrase it, so each study is linked in full at the end of this article, for you or your practitioner to read directly.
It remains the only form of magnesium studied in this way, which is part of why we think it has earned a place in the range.
Magnesium L-threonate and magnesium bisglycinate: how the two forms compare
This is the question we are asked most often, so it is worth setting out plainly. If you already take our Magnesium Bisglycinate, you do not need to swap.
| Magnesium bisglycinate | Magtein Magnesium L-threonate | |
|---|---|---|
| What it is | Magnesium bound to the amino acid glycine | Magnesium bound to L-threonate, a vitamin C metabolite |
| Authorised claims | Contributes to normal muscle function, normal energy-yielding metabolism, the reduction of tiredness and fatigue, normal psychological function and the normal functioning of the nervous system | The same authorised magnesium claims apply |
| What is distinctive | A well-absorbed, gentle everyday form | Developed to cross the blood-brain barrier using a transport route ordinary magnesium does not use |
| Regulatory status in GB | Established food supplement ingredient | Novel food, requiring specific authorisation. Magtein is the only authorised source |
| Typical role | The daily foundation | Taken for its distinct delivery, alongside a daily form |
Neither form is better or worse than the other. They are different, and many people will find a role for both: bisglycinate as the daily foundation, L-threonate for its distinct delivery. As ever, choose the form, or the forms, that suit you.
Why only Magtein, and why that matters
In GB and the EU, magnesium L-threonate is classed as a novel food, which means it cannot simply be added to a capsule and sold. It requires specific regulatory authorisation, and at present one branded form holds that authorisation: Magtein.
Magtein is also the precise material used in every one of the human trials mentioned above. So when we say the research relates to what is in the capsule, we mean it literally: it is the same ingredient. Any other route would have meant a thinner evidence base and, in GB, no authorisation at all.
We have spent more than 30 years making supplements in our own facility in Wiltshire, choosing the most appropriate form of each nutrient and leaving out anything that does not need to be there. No unnecessary fillers, no shortcuts. Magnesium L-threonate, using Magtein, is that same standard applied to one of the most interesting nutrients in the range.
Common questions
Is magnesium threonate the same as magnesium L-threonate?
Yes. The two names refer to the same compound, and you will see both used. L-threonate is the precise chemical name, and Magtein is the branded, authorised source of it.
What is the difference between magnesium L-threonate and magnesium glycinate?
Both are well-absorbed forms of magnesium and both carry the same authorised claims, including contributing to normal psychological function and to the normal functioning of the nervous system. Bisglycinate is magnesium bound to the amino acid glycine and works well as a daily foundation. L-threonate is bound to a vitamin C metabolite and was developed to cross the blood-brain barrier. The difference is the delivery route, not the strength.
Can I take magnesium L-threonate with my other magnesium supplements?
If you already take another magnesium supplement, consider your total daily magnesium intake before adding L-threonate. Follow the recommended directions for use and avoid exceeding the advised daily intake. If you are unsure which magnesium product is most appropriate for you, please speak to your healthcare practitioner or contact our team for advice.
When should I take magnesium L-threonate?
Most of the published trials split the dose between morning and evening. Follow the directions for use on the label of the product you are taking.
How much magnesium L-threonate does the research use?
Published human trials have typically used between 1g and 2g of Magtein a day, usually split between morning and evening. Product servings are set by the authorised intake for the ingredient, so follow the label rather than the trial protocol.
How long does magnesium L-threonate take to work?
Magnesium is a nutrient, not a stimulant, so it works with your body over time rather than giving the immediate lift of caffeine. In the published trials, any differences tended to emerge over weeks rather than days. The sensible approach is to take it consistently and give it time to settle in. If you like understanding why supplements take time, we wrote about that here.
What happens if I stop taking it?
Nothing dramatic. Magnesium L-threonate is not habit-forming and there is no rebound to worry about. Like any nutrient, its contribution simply tapers off once you stop topping it up, so if it has become a useful part of your routine, it is worth keeping it there rather than dipping in and out.
Is magnesium L-threonate suitable for everyone?
It is intended for adults. It is not suitable during pregnancy or breastfeeding, and anyone on medication or managing a health condition should check with their GP or practitioner first. It should not be used as a substitute for a varied and balanced diet and a healthy lifestyle.
A considered addition, chosen the way we choose everything
Magnesium L-threonate is for adults who want to look after their mental and physical wellbeing, and, like everything we make, it has been chosen for a specific reason and made to a specific standard. It is not a replacement for eating well, and it is not a treatment for any medical condition. If you are pregnant or breastfeeding it is not suitable, and if you take medication or manage a health condition, please speak to your doctor or a qualified practitioner before starting anything new. If you already trust magnesium, this is the form we would most want you to know about.
References
Liu G, Weinger JG, Lu ZL, Xue F, Sadeghpour S. Efficacy and safety of MMFS-01, a synapse density enhancer, for treating cognitive impairment in older adults: a randomised, double-blind, placebo-controlled trial. Journal of Alzheimer's Disease. 2016;49(4):971-990. Read the study
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. Read the study
Hausenblas HA, Lynch T, Hooper S, Shrestha A, Rosendale D, Gu J. Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: a randomised controlled trial. Sleep Medicine: X. 2024;8:100121. Read the study
Lopresti AL, Smith SJ. The effects of magnesium L-threonate (Magtein) on cognitive performance and sleep quality in adults: a randomised, double-blind, placebo-controlled trial. Frontiers in Nutrition. 2026;12:1729164. Read the study
Slutsky I, Abumaria N, Wu LJ, et al. Enhancement of learning and memory by elevating brain magnesium. Neuron. 2010;65(2):165-177. Read the study
