I’ve been taking Jigsaw’s Brain Boost for more than six months and I’ve bought it twice. I also can’t tell you whether it does anything.
This is the expensive corner of the magnesium shelf, roughly five times the cost of the glycinate I take at night, and it’s sold on a promise about your brain that is much harder to verify than “did I sleep better.”
The L-threonate guide covers what the research actually found. That’s the more important page. This one is just about the product and my experience of paying for it.
Some links here are affiliate links, which means I may earn a commission if you buy through one. It costs you nothing extra and doesn’t change what I write. Full detail on the affiliate disclosure page.
What’s in it
Magtein, which is the branded form of magnesium L-threonate that the published research was done on. That matters more here than with other forms: the trials people cite for threonate used Magtein specifically, so a product using it can point at that research while a generic can only point at the form.
48mg of elemental magnesium per capsule, with a labelled serving of three capsules giving 144mg. Jigsaw list a third-party verification of the label claim, which is worth having on a product this expensive.
What it costs
$59.97 for 90 capsules. At the labelled three a day that’s a 30-day bottle and about $2 a day.
For comparison, the MagPure glycinate I take at night is about 25 cents a day. These are different purchases with different reasoning behind them, and it’s worth being clear which one you’re making before you spend $60.
The dose I actually take
I take two capsules, not three.
That gives me about 96mg of elemental magnesium, which is roughly two thirds of what the trials used. It stretches the bottle to about 45 days and brings the cost to around $1.33 a day.
I’m flagging this because it cuts against my own review. The published evidence, thin as it is, tested around 144mg elemental. I’m taking less than that, so strictly speaking I’m not taking the dose the research supports. If you want to match the trials, budget for three capsules and $2 a day.
There’s no clever reason for two. Three capsules a day of anything is a habit that takes effort, and two is what I’ve managed to stick to.
What I noticed
Nothing I would put my name to. Six months in, I can’t point at anything and reasonably say the threonate did it. My sleep is decent, but I take glycinate at night as well, so I have no way to separate the two.
I’m not saying it does nothing. Cognitive and age-related brain effects would be slow and invisible from the inside, so six months of paying attention to how I feel was never going to settle it either way. That’s the trouble with this kind of claim: my experience can’t confirm it and can’t rule it out.
It has never upset my stomach and the capsules are unremarkable to swallow.
The honest limitation
The limitation is that I cannot tell you it works, and neither, yet, can the research.
The evidence is an interesting rat study from 2010, one decent 2024 human sleep trial using objective wearable data, and a scattering of small cognitive studies, several of them funded by the company that makes the ingredient. That’s enough to make it worth watching and nowhere near enough to make it worth relying on.
So this is a considered bet on early science. If your budget stretches to one magnesium product, this should not be it. Get your overall intake right with a cheaper form first, and eat the leafy greens.
Who it suits
It suits people who find the cognitive angle interesting, who understand the evidence is early, and for whom $2 a day is not a meaningful amount of money.
Disclosure: the links below are affiliate links. If you buy through one I may earn a small commission, at no extra cost to you. It never changes what I recommend.
Cognitive goals
Jigsaw Health
Brain Boost
Uses Magtein, the branded L-threonate the research was done on. The form I've recently started taking myself. It is the expensive option, so go in knowing the evidence is early.
- Elemental magnesium144 mg per 3-capsule serving
- Third-party testedThird-party label claim verified
- Price$59.97 for 30 servings (about $2 a day)
I’ll keep buying it for the long-game reasons, not because of anything I’ve felt, and there’s something odd about spending $60 every six or seven weeks on a bet I have no way of settling. Ask me in another six months.
Buying something you can’t evaluate is an unsatisfying end to a product review. It’s also where I actually am, and inventing a confidence I don’t have would make the rest of this site harder to believe.
Sources: Slutsky et al., Enhancement of learning and memory by elevating brain magnesium, Neuron, 2010 (https://pubmed.ncbi.nlm.nih.gov/20152124/); Hausenblas et al., Magnesium-L-threonate improves sleep quality and daytime functioning in adults with self-reported sleep problems: a randomized controlled trial, Sleep Medicine: X, 2024 (https://pmc.ncbi.nlm.nih.gov/articles/PMC11381753/); NIH Office of Dietary Supplements: Magnesium Fact Sheet (https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/)
This article describes one person’s experience and is general information, not medical advice. Talk to a doctor or pharmacist before starting a supplement, especially if you have kidney problems or take other medication.