Magnesium in perimenopause.
Which form to take, whether the spray does anything, and why this is the one supplement I raise with almost every woman in the transition.
Magnesium is the supplement I discuss most often, and the one most often bought wrongly. It runs several hundred enzyme reactions, including the ones that govern muscle relaxation, blood sugar handling and the nervous system's brakes. Perimenopause leans on all three at once, which is why a mineral that sat quietly in the background for forty years suddenly becomes worth paying attention to.
The transition drains it from both ends. Falling estrogen reduces how well you absorb and hold magnesium, and the raised cortisol that comes with broken sleep spends it faster. Add the ordinary modern subtractions, coffee, alcohol, stress, soil that holds less of it than it used to, and a lot of women arrive at 45 running low without ever having done anything wrong.
Now the part that decides whether you waste your money: the form. Magnesium is always bound to something else, and that something else determines where it goes and what it does. Magnesium oxide is the cheapest and the most common on a supermarket shelf, and it is poorly absorbed. It will loosen your bowels efficiently and do very little else. If a bottle does not name its form, it is usually oxide.
“If the bottle will not tell you which form it is, that is the answer to whether it is a good one.”
The forms worth your money in this decade: glycinate, bound to the amino acid glycine, which is calming in its own right and is the one I reach for first for sleep and for the 3am wake. Citrate, well absorbed and gently laxative, useful if constipation is part of the picture. Malate, which some women prefer for daytime muscle aches and fatigue. Threonate has the most interesting research for brain and cognition and the highest price, and I would not start there.
On dose, the general adult intake sits around 320mg a day of elemental magnesium from all sources, and supplements typically add 200 to 400mg. Read the label carefully, because the number on the front is often the weight of the whole compound rather than the elemental magnesium inside it, and those are very different numbers. Take it in the evening if sleep is the target. Loose stools mean you have gone too high, so step back rather than push on.
The topical question, since we sell a spray and you are entitled to a straight answer. The evidence that magnesium crosses intact skin in meaningful amounts is genuinely thin, and I will not tell you otherwise. What is better supported is the local effect: magnesium on the skin over a cramping calf, or in a footbath at the end of a day, eases that muscle and settles the body before bed. That is worth something, and it sidesteps the digestive limit that caps how much you can swallow. Use it as a companion to an oral form, not a replacement for one, and expect a tingle on the first few applications, which fades as skin adjusts.
What it will not do. Magnesium is not a hormone and it does not replace one, so it will not stop a flush or restore a cycle. It supports sleep, muscle relaxation and the nervous system, and in the transition that is a meaningful amount of ground. Give it three to four weeks before you judge it, alongside the rest of the basics.
One caution worth stating plainly: if you have kidney disease, magnesium supplementation needs medical supervision, because impaired kidneys cannot clear an excess. It also interacts with some antibiotics, bisphosphonates and thyroid medication, all of which want a few hours' separation from your dose. Take that conversation to your prescriber rather than to a label.
Davina Hearne, Naturopath (Diploma, NZ) · Founder, Valentia
Educational only. Always speak to your healthcare provider about your symptoms and before starting a new supplement.
