Perimenopause · Nutrition
"Your Oestrogen Isn't The Only Thing Running Low"
One in four British women don't get enough magnesium — right at the age when bones, muscles and energy need it most.
By: Erika Taylor, May 2026 · Updated 10 August 2026 · 6 min read
Before you read on: we make one of the products mentioned here. Arloo sells Magnesium XXL. We're saying it up front because a guide that quietly ranks its own product first isn't a guide. Everything below is a check you can run yourself, on any tub — including ours.
When perimenopause arrives, one word explains everything
The ache in your hips getting out of bed. The three o'clock stare at the ceiling. The flat dread that turns up around six for no reason you can name. The exhaustion that sleep doesn't touch.
All of it goes in the same box, and the lid says hormones.
And a lot of it is. But here's what almost nobody mentions in the same conversation.
This is also the decade when your body comes under the most pressure it will ever face from a mineral most British women don't get enough of.
Bone density starts falling. Muscle mass starts falling. Energy metabolism changes. Magnesium sits underneath all three — it's officially recognised as contributing to the maintenance of normal bones, to normal muscle function, and to the reduction of tiredness and fatigue.
Which is why it comes up in every single thread
Spend ten minutes in any perimenopause forum and you'll see the same mineral recommended over and over — not by brands, by women who found it themselves and came back to tell everyone.
"Magnesium glycinate fixed my overall pain too. 10/10 best supplement ever."
r/Perimenopause"I've been blaming it on menopause, but the magnesium turned it right around within a week."
r/Perimenopause, on lower body painAnd then, in the same threads, the other half of the conversation.
"All the different kinds haven't done anything for me."
r/Perimenopause"I've taken that brand and others. It did nothing."
r/Perimenopause"Been on it a month now, still waiting for it to work."
r/PerimenopauseBoth groups bought something with the word magnesium on the front.
They did not buy the same thing. And the difference is printed on the back of the tub.
Three numbers, and the third one explains the rest
Sources: National Diet and Nutrition Survey Years 9–11 · UK Nutrient Reference Value · Holland & Barrett published panel, checked 10 August 2026
Three reasons it did nothing when you tried it
1. Three quarters of what you paid for wasn't magnesium
"375mg Magnesium Bisglycinate" is the weight of the whole compound — the mineral plus whatever it's bonded to. The part your body actually uses is a fraction of it. Holland & Barrett's own published panel shows 85mg of elemental magnesium in a capsule sold as 375mg. Less than a quarter. The other 290mg is the packaging the mineral arrived in.
2. You bought the form that's in there because it's cheap
Magnesium oxide is the least absorbed of the common forms and roughly 60% magnesium by weight — so it puts a big number on the front of a pack for pennies. It's in the tub because of what it costs, not because of what it does.
3. One form was being asked to do every job
Different forms are absorbed by different routes and are chosen for different things — muscle function, energy metabolism, tolerability. Most tubs contain one, and it's covering one base while the rest goes uncovered.
So we checked all four you can buy on a British high street
ASDA, Boots, Vitabiotics and Holland & Barrett — the ones you can physically pick up in a shop. Every figure below is copied straight off their own published panels.
Swipe the table sideways →
| Arloo Magnesium XXL£28.40 / 120 |
ASDA Wellbeing Magnesium 375mg£2.25 / 30 |
Boots Magnesium 375mg£6.50 / 60 |
Vitabiotics Ultra Magnesium£4.79 / 30 |
H&B Bisglycinate 375mg£19.29 / 90 |
|
|---|---|---|---|---|---|
| Elemental magnesium | ~298mg per serving | 375mg | 375mg | 375mg | 85mg per capsule |
| Cost per 100mg elemental | £0.32 · £0.16 on the 6-pack | £0.02 | £0.06 | £0.09 | £0.25 |
| Elemental figure on the front | Yes | Yes | Yes | Yes | No — compound weight |
| Free from oxide / hydroxide | Yes | No | No | No | No — oxide 95mg |
| Real chelated bisglycinate | 550mg | No | No | No | 375mg |
| Magnesium L-Threonate | 2,000mg | No | No | No | No |
| Magnesium malate | 300mg | No | No | No | No |
| Magnesium taurate | 100mg | No | No | No | No |
| Active B6 (P-5-P) | Yes | No | No | No | No |
| Morning / evening split | Yes | No | No | No | No |
| Other ingredients of note | — | Mag. stearate | Talc, mag. stearate | — | — |
| 90-day guarantee | Yes | No | No | No | No |
Figures taken from each manufacturer's own published product page, checked 10 August 2026. Cost per 100mg elemental calculated from pack price and stated daily dose. Prices vary by retailer. Brand names are the property of their respective owners and appear for identification only.
All four are built on oxide or hydroxide. One of them sells it under the word "bisglycinate".
Chelated forms sit at roughly 10–14% magnesium by weight. To reach a comparable elemental dose from bisglycinate alone you need somewhere around two to three grams of powder — four to five times the raw material, at many times the price per kilo.
That's the whole difference. You are not paying for a better number on the front. You are paying for the number on the front to be made of something else.
Every tub in that table contains one magnesium. Ours contains four.
Each one listed at its own dose, because a blend that hides the split is hiding something. ~298mg elemental magnesium across the day — and not one milligram of it from oxide.
So here's where you are
You now know the three checks: find the elemental figure, read the ingredients in order, divide the price by the milligrams.
Two sensible things to do with that.
Seriously — do it before you buy anything else. If it states an elemental figure and oxide isn't in the ingredients, you may already have a decent one. We'd rather you found that out than bought ours by mistake.
Four forms, ~298mg elemental printed on the tub, no oxide. £28.40 for thirty days, free UK delivery, and ninety days to send it back if you decide it isn't doing anything.
✅ Opened tubs accepted. One email, no forms.
What's in Arloo Magnesium XXL
- Magnesium L-Threonate — 2,000mg. Authorised in Great Britain from August 2026. On no UK high-street shelf.
- Magnesium Bisglycinate Chelate — 550mg. A real chelate, with no oxide behind it.
- Magnesium Malate — 300mg. Bonded to malic acid.
- Magnesium Taurate — 100mg. The gentlest of the four on digestion.
- Vitamin B6 as P-5-P — 10mg. The active form, not plain pyridoxine.
- ~298mg elemental magnesium — printed on the tub. Split morning and evening, both with food.
Magnesium contributes to the maintenance of normal bones and teeth, to normal muscle function, to the reduction of tiredness and fatigue, to normal energy-yielding metabolism, to the normal functioning of the nervous system, to normal psychological function, to normal protein synthesis, and to electrolyte balance. Vitamin B6 contributes to normal psychological function, to the reduction of tiredness and fatigue and to the regulation of hormonal activity.
What customers say
Magnesium XXL is the UK version of a formula we've been selling in the United States. Same forms, same doses. These reviews are from those customers.
“I've been taking this magnesium for about a month and it has really helped my sleep. I used to wake up around 3 AM every night, but I'm finally sleeping through the night.”
“I didn't expect much at first, but my nights feel much calmer now. I fall asleep with less overthinking and wake up feeling more refreshed.”
“I've been sleeping much better since I started taking this magnesium. Sleep has been a big concern for me, so I'm very grateful that it has helped.”
Reviews relate to the same formula sold in the United States. Individual experiences vary and are not a guaranteed outcome.
Choose your supply
1 tub
30-day supply · £0.95 a day · free UK delivery
3 tubs
£18.93 each · £0.63 a day · three for the price of two
6 tubs
£14.20 each · £0.47 a day · six for the price of three
At six tubs you're paying £0.16 per 100mg of magnesium — less per milligram than the Holland & Barrett tub in the table above.
One genuine caveat on supply. Magnesium L-Threonate was only authorised for sale in Great Britain in August 2026, and there are very few compliant suppliers of it. That's a real constraint, not a marketing one — it has put this formula out of stock before and will again. The £28.40 price is held until 30 August 2026.
Start On Magnesium XXLFree UK delivery · 90-day guarantee✅ 90 days to change your mind, opened tubs included
Your purchase is protected for 90 days
Nutrient intake works over weeks, not days. Give it a proper run. If you don't think it's doing anything, send it back within 90 days — opened tub included — and we'll refund you.
One email. We don't ask you to justify it and we don't make you post anything back at your own cost.
This guarantee sits on top of your rights under UK consumer law, which are not affected by it.
The forms, for reference
If you want to check any other tub against this, here's what each form is and what it's generally chosen for.
Swipe sideways →
| Form | Absorption | Typically chosen for | Watch out |
|---|---|---|---|
| Bisglycinate | High | Everyday use, muscle function | — |
| L-Threonate | High | The most researched newer form | Only legal in GB since Aug 2026 |
| Malate | High | Energy metabolism, tiredness | — |
| Taurate | High | Gentlest on digestion | Expensive, rare in UK |
| Citrate | Moderate | Digestive regularity | Laxative at higher doses |
| Oxide | Poor | Bulking out a cheap tub | Big number, little delivery |
| Hydroxide | Poor | — | Active ingredient in milk of magnesia |
Absorption ratings reflect the general position in the published literature on comparative bioavailability of magnesium salts.
Questions
I've tried magnesium before and felt nothing. Why would this be different?
Two things worth checking on the tub you tried: whether it stated an elemental figure, and whether oxide was in the ingredients. If the answer is no and yes, you were taking a small amount of a poorly absorbed compound. That's the most common version of "magnesium didn't work for me". It may not be your answer — but it's worth ruling out before you give up on the mineral.
Is it safe to take every day?
Magnesium supplements are intended for daily use. Ours is third-party tested for purity, potency and heavy metals and made in a GMP-certified facility. Do not exceed the stated dose. If you're pregnant, breastfeeding, taking medication or under medical supervision, speak to your GP or pharmacist before starting any supplement.
Can I take it alongside HRT?
Many women do, but we're not able to advise on your medication. Magnesium can affect the absorption of some medicines, so speak to your GP or pharmacist about timing and about anything you're already taking.
ASDA sells 375mg for £2.25. Why is yours £28.40?
Because of what it's made of. Magnesium oxide is about 60% magnesium by weight, so a big number fits into one small tablet for pennies — and it's the form the body absorbs worst. Chelated forms are roughly 10–14% magnesium by weight, which means several times the raw material for the same elemental dose, at many times the cost. If price is your binding constraint, the ASDA tub is a rational purchase.
Is Magnesium L-Threonate legal in the UK?
In Great Britain, yes — authorised as a novel food in August 2026. Northern Ireland follows separate rules and we don't ship there.
How long before I know whether it's doing anything?
Nutrient intake works on the timescale of weeks, not days. Give it a full month before you judge it. That's why the guarantee runs 90 days rather than 30 — so you can take it long enough to have an opinion, and still send it back.
What if it does nothing for me?
Send it back within 90 days for a refund, opened tub included. In addition to your statutory rights under UK consumer law, which are not affected.
Before you buy another tub
Turn over whatever is in your cupboard right now.
Find the word elemental. Read the ingredients in order. Divide the price by the milligrams.
Those three checks take ninety seconds and they'll tell you more than any page will — including this one. We printed our numbers above precisely so you can run them on us too.
Start On Magnesium XXL£28.40 · free UK delivery · 90-day guarantee✅ Opened tubs accepted. One email, no forms.
About this page. This is an advertisement published by Arloo, which sells Magnesium XXL. It is not an independent review and does not claim to be. Competitor figures are drawn from each manufacturer's own published information on the date shown. Quotations from public forum discussions refer to magnesium generally and are not reviews of any product sold by Arloo.
Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. Do not exceed the stated dose. Keep out of reach of children. If you are pregnant, breastfeeding, taking medication or under medical supervision, consult your GP or pharmacist before use. This product is not intended to diagnose, treat, cure or prevent any disease. Individual results may vary.
We ship to Great Britain only. Northern Ireland is excluded as it follows separate rules on novel foods.
© 2026 Arloo.