Women over 40 need about 320mg of magnesium a day from food and supplements combined, and many don't get there from food alone. Magnesium glycinate is a form that's usually easy on the stomach, and it supports normal muscle and nerve function, bone and a calmer evening routine. A common approach is 200mg of elemental magnesium in the evening on top of magnesium-rich foods, staying under the 350mg daily upper limit for supplements.
In this article
I built our magnesium the way I read every label: slowly, fine print first. Here's what magnesium can and can't do for women in their 40s and beyond, and how to take it.
How much magnesium does a woman need?
According to the NIH Office of Dietary Supplements, the Recommended Dietary Allowance for women is 310mg a day from ages 19 to 30 and 320mg a day from 31 on. That's your total from food, drinks and supplements together. In pregnancy it goes up to 350 to 360mg.
Separately, the NIH sets a Tolerable Upper Intake Level of 350mg a day for magnesium from supplements and medicines. That limit doesn't include the magnesium in food, which doesn't cause problems for healthy people. So a woman could get 200mg from food and 200mg from a supplement and be right where she should be.
| Women, by age | Daily need (food + supplements) | Upper limit from supplements |
|---|---|---|
| 19 to 30 | 310mg | 350mg |
| 31 and older | 320mg | 350mg |
| Pregnant, 31 to 50 | 360mg | 350mg |
Why women over 40 look at magnesium
The same three reasons come up over and over.
- A lot of people fall short. An analysis of national survey data found that 48 percent of Americans get less magnesium from food and drinks than they need, according to the NIH.
- Needs and absorption shift with age. The NIH notes that older adults tend to eat less magnesium, absorb less of it from the gut and lose more through the kidneys.
- Magnesium does a lot of background work. It's involved in more than 300 enzyme systems, including protein synthesis, muscle and nerve function and energy production. About half to 60 percent of the magnesium in your body is stored in your bones.
Magnesium-rich foods to eat first
A supplement fills a gap. It shouldn't be the whole plan. These foods from the NIH's list are some of the richest sources.
| Food | Magnesium |
|---|---|
| Pumpkin seeds, roasted, 1 oz | 156mg |
| Chia seeds, 1 oz | 111mg |
| Almonds, dry roasted, 1 oz | 80mg |
| Spinach, boiled, 1/2 cup | 78mg |
| Cashews, dry roasted, 1 oz | 74mg |
| Black beans, cooked, 1/2 cup | 60mg |
A handful of pumpkin seeds on your yogurt and a side of beans at dinner can cover a good share of your day.
Magnesium glycinate and sleep
Sleep is the reason most women ask me about magnesium, so I'll start there. A 2023 systematic review found that magnesium status is linked to sleep quality in observational studies, but trials of supplements are mixed and more research is needed (Arab and colleagues, 2023). One trial in older adults with trouble sleeping found better sleep measures after 8 weeks, but it used 500mg a day (Abbasi and colleagues, 2012). That's more than our serving and above the supplement upper limit, so it isn't something to copy at home.
What I tell friends is that magnesium may support a calmer wind-down as part of good sleep habits. It's not a sleeping pill. Glycinate is a popular evening choice because it tends to be gentle on the stomach, and its partner, glycine, is an amino acid with a small body of sleep research of its own. Our guide on when to take magnesium glycinate covers timing.
Magnesium in perimenopause and menopause
I want to be careful here, because the internet isn't. Magnesium isn't a treatment for menopause symptoms, and nobody should promise you it'll stop hot flashes. It supports normal functions that matter more in midlife: muscles and nerves, energy metabolism, and bone, where most of your magnesium lives. The NIH notes that a small number of studies suggest higher magnesium intakes from food or supplements may support bone mineral density in postmenopausal women, and that more research is needed.
If you're also thinking about protein, which matters just as much for holding on to muscle in these years, read how much protein you need in perimenopause.
A simple way to cover both is protein in the morning and magnesium at night: a mug of Bone Broth Protein Mix with breakfast, then your capsules 30 to 60 minutes before bed. There's no proven synergy between them, just two gaps many women have. I explain the routine, and how to space magnesium from medicines, in can you take magnesium with protein?
Magnesium for PMS and cramps
A small 1991 trial in women with premenstrual symptoms found that magnesium was associated with improvements in premenstrual mood changes (Facchinetti and colleagues, 1991). It had 32 women and used a different form at a much higher dose, so I'd call it interesting, not proof. Magnesium supports normal muscle function, which is why many women keep it in their routine all month. If cramps or mood changes are severe, bring that to your clinician.
Magnesium glycinate for women: dosage and how to take it
- Start with the label. Look for the elemental magnesium amount, not the weight of the whole compound. Our three capsules supply 200mg of elemental magnesium from about 1,700mg of magnesium bisglycinate.
- Stay under 350mg from supplements. Count any other magnesium you take, including multivitamins and antacids.
- Take it at the same time every day. Most women pick the evening, with dinner or 30 to 60 minutes before bed.
- Check the form. Some "glycinate" products are buffered with magnesium oxide, which the body absorbs poorly. In one study, only about 4 percent of the oxide was absorbed (Firoz and Graber, 2001). Our guide to buffered vs non-buffered magnesium glycinate shows how to spot it.
“Magnesium is an important nutrient for women, and I wanted NO. 04 to provide it in a highly absorbable, well-tolerated form. We chose pure, non-buffered magnesium glycinate so women can get 200mg of magnesium without a bunch of unnecessary ingredients.”
Skotie Rae, RN, founder
Talk to your clinician first if you have kidney disease, are pregnant or breastfeeding, or take antibiotics, osteoporosis medicines, diuretics or acid reducers, since magnesium can affect how some of them work. For what's normal and what isn't, see magnesium glycinate side effects.
What's in NO. 04
NO. 04 Magnesium Glycinate is three capsules of Chelamax non-buffered magnesium bisglycinate, 200mg of elemental magnesium, with tapioca starch in a vegetable (HPMC) capsule. That's the whole list: three ingredients and no oxide. Each bottle holds 90 capsules, a 30-day supply, and every lot is third-party tested, with results on our Certificate of Analysis page. It's $36 a bottle, or $30 with a subscription. Every product fact lives on Rae Basics at a glance.
Quick answers
How much magnesium should a woman over 40 take?
Women 31 and older need 320mg a day in total from food and supplements. Keep supplemental magnesium at or below 350mg a day unless your clinician tells you otherwise.
Is magnesium glycinate good for women?
It's a popular form because it tends to be gentle on the stomach. It supports normal muscle and nerve function and fits easily into an evening routine.
Can magnesium help with menopause?
It supports normal muscle, nerve and bone function, which matter in midlife. It isn't a treatment for menopause symptoms.
Should women take magnesium at night?
Many do, because it fits a wind-down routine. Taking it consistently matters more than the exact time.
Can I take magnesium glycinate every day?
For most healthy adults, yes, within the 350mg supplement limit. Ask your clinician first if you have kidney disease or take prescription medicines.
Sources
- NIH Office of Dietary Supplements. Magnesium: Fact Sheet for Health Professionals.
- NIH Office of Dietary Supplements. Magnesium: Fact Sheet for Consumers.
- Arab A, Rafie N, Amani R, Shirani F. The role of magnesium in sleep health: a systematic review of available literature. Biol Trace Elem Res. 2023;201(1):121-128.
- Abbasi B, Kimiagar M, Sadeghniiat K, et al. The effect of magnesium supplementation on primary insomnia in elderly: a double-blind placebo-controlled clinical trial. J Res Med Sci. 2012;17(12):1161-1169.
- Facchinetti F, Borella P, Sances G, et al. Oral magnesium successfully relieves premenstrual mood changes. Obstet Gynecol. 1991;78(2):177-181.
- Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnes Res. 2001;14(4):257-262.
