NOW Foods Magnesium Oxide 8 oz.

What it is

NOW Foods Magnesium Oxide Pure Powder is a single-ingredient magnesium powder in an 8 oz. (227 g) bottle, providing 290 mg of elemental magnesium from 500 mg of magnesium oxide in a 1/4 level teaspoon serving. The label lists its Other Ingredients as "None" — there is no filler, no flow agent, no flavoring and no capsule shell, just the mineral compound itself. The front of the bottle marks it as a dietary supplement and as Vegetarian/Vegan, and the pack carries the Non-GMO Project Verified seal. It sits in NOW's Minerals line, alongside the rest of our minerals range.

Because the powder is loose rather than pressed or encapsulated, the serving is measured rather than counted. The bottle holds about 454 servings of a 1/4 level teaspoon, and the label notes that the product is sold by weight, not volume.

What's inside

There is exactly one ingredient in this bottle: magnesium oxide. Magnesium oxide is a compound of magnesium and oxygen, and it is one of the more concentrated forms used in supplement manufacturing, which is why a serving this small can carry 290 mg of elemental magnesium. Note the distinction the panel draws between the two numbers: 500 mg is the weight of the magnesium oxide compound, and 290 mg is the weight of the magnesium itself within it. Labels for different magnesium forms are not directly comparable unless you read the elemental figure, which is the one that maps onto the Daily Value.

At 290 mg, a serving supplies 69% of the Daily Value for magnesium used on US nutrition labels. Magnesium is an essential dietary mineral, meaning the body does not make it and it has to come from food or supplementation; the NIH Office of Dietary Supplements fact sheet on magnesium gives general background on the mineral, dietary sources and intake levels, independent of any particular product. If you want to compare how different brands declare a mineral on the panel, the NIH's Dietary Supplement Label Database indexes the label text itself.

What is not in it is equally straightforward, because the panel states it outright. No binder, no anti-caking agent, no sweetener, no color. The allergen statement on the bottle reads that it is not manufactured with wheat, gluten, soy, milk, egg, fish, shellfish, tree nut or sesame ingredients, and that it is produced in a GMP facility which processes other ingredients containing those allergens.

Supplement Facts

Transcribed from the Supplement Facts panel on the bottle. Net weight 8 oz. (227 g).

How to use it

The label's Suggested Usage is to mix 1/4 level teaspoon of powder into at least 6 oz. of cold water or clear liquid, and to take it once daily with a meal. That 6 oz. minimum is not a suggestion about taste. The bottle explains that pure magnesium oxide powder can raise the temperature of a liquid on contact, so the recommended serving must be mixed into at least 6 oz. of cold liquid to neutralize that reaction before it is swallowed.

Two further handling notes are printed on the pack. The powder should not be breathed in, and contact with skin, eyes and clothing should be avoided — sensible with any fine loose powder, and stated explicitly here. After opening, store the bottle in a cool, dry place. The label also mentions that natural color variation may occur in this product, so a batch that looks slightly different from the last one is within what the manufacturer describes.

A level measure matters more with a powder than with a tablet, since a heaped quarter-teaspoon is not the serving the panel describes. Use a proper measuring spoon rather than a kitchen teaspoon, and level it off.

Who it's for

This is a bulk, unflavored format aimed at adults who already know they want magnesium and would rather buy it by weight than by the capsule. The appeal is arithmetic: one ingredient, a stated elemental figure, about 454 servings in a bottle you can keep in a cupboard, and the freedom to measure into water, juice or any cold clear drink rather than swallowing a pill. If you dislike tablets, or you are simply tired of buying small bottles, the powder format answers both.

It is equally clearly not for everyone. There is no flavoring, so it tastes of what it is. It has to be measured and mixed every time, and it has to go into cold liquid, which rules out stirring it into a hot drink. Anyone who would rather have a fixed, pre-measured serving they can carry will be better served by a capsule or tablet from our wider supplements selection. The product is labeled for adults only.

Good to know

The bottle's own caution panel is short and is worth reading in full before the first serving: this product must be dissolved into at least 6 oz. of cold water or clear liquid before consuming; do not breathe the powder and avoid contact with skin, eyes and clothing; for adults only; consult a physician if pregnant or nursing, taking medication, or if you have a medical condition; keep out of reach of children. General guidance on using supplements sensibly alongside a normal diet is published by the NIH Office of Dietary Supplements and by the US Food and Drug Administration.

On provenance, the panel reads "Packaged by NOW FOODS, 395 S. Glen Ellyn Rd., Bloomingdale, IL 60108, USA" and adds that the product is packaged and quality tested in the USA. The pack carries a GMP Quality Assured seal, a Non-GMO Project Verified seal and a kosher mark, and the back panel notes that NOW has been family owned since 1968. The bottle itself is made from 100% PCR — post-consumer recycled — resin. You can browse related items in health and wellness.

Frequently Asked Questions

How much magnesium does one serving actually contain?

One serving contains 290 mg of elemental magnesium, which is 69% of the Daily Value. That comes from 500 mg of magnesium oxide, and a serving is 1/4 of a level teaspoon of powder. The 290 mg figure is the one to compare against other magnesium labels, because it measures the mineral rather than the compound carrying it.

Why does the label insist the powder goes into cold liquid?

Because pure magnesium oxide powder can raise the temperature of a liquid when it makes contact with it. The bottle states that the recommended serving must be mixed into at least 6 oz. of cold water or clear liquid to neutralize that reaction before ingestion, which is why the minimum volume and the temperature are both specified rather than left to preference.

Does this powder contain anything besides magnesium oxide?

No — the Supplement Facts panel lists Other Ingredients as "None". There is no filler, binder, flow agent, sweetener, flavoring or capsule shell. The front of the bottle is marked Vegetarian/Vegan and carries the Non-GMO Project Verified seal, and the allergen line states the product is not manufactured with wheat, gluten, soy, milk, egg, fish, shellfish, tree nut or sesame ingredients.

How many servings are in the 8 oz. bottle?

About 454, at the labeled serving of 1/4 level teaspoon. The net weight is 8 oz. (227 g), and the label notes the product is sold by weight rather than by volume.

How will my order be packaged?

Your order ships in plain outer packaging with no product imagery and nothing on the outside describing the contents. It will not show the Gear Isle name. The sealed bottle travels inside that outer parcel.

Product information compiled and reviewed by the Gear Isle product team. We transcribe supplement facts directly from manufacturer packaging. Found an error? Tell us.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Dietary supplement for adults 18 and over. Consult a licensed healthcare professional before use, especially if you have a medical condition, heart concerns, or take prescription medication (including nitrates). Keep out of reach of children.