Nutricost Magnesium Citrate 420 mg Review
#9 of 10 · Citrate in Capsules✓ Label verified · Supplement Facts read Oct 18, 2026Real retailer photo, cut out. Label unedited.
Consider it. A fair buy if you want citrate in capsules and a full 420 mg serving from a short label. The magnesium is real and clearly printed, but it takes four capsules, the testing claim names no lab, and NOW's citrate costs about half as much per milligram.
$11.99 / 30 servings~$0.40 / 420 mg serving (about 9.5 cents per 100 mg)
Why It Scores 7.3 — And The Label Line Behind Each Number
Form bioavailability
30% of scoreMagnesium citrate, printed as such on the panel. In Walker 2003, citrate raised blood magnesium more than oxide and an amino acid chelate. It also keeps some magnesium in the gut, where it draws water in, which is why citrate suits regularity and why glycinate is the gentler pick for sleep. Same band as Pure Encapsulations Magnesium (Citrate), NOW and Calm (all 6.5).
- Form
- Magnesium citrate, capsule (hypromellose, vegetarian)
Elemental Mg per serving
25% of score420 mg of magnesium per 4 capsules, printed as 100% DV, so it is the elemental figure and not the weight of the compound. At 105 mg a capsule you can step the dose up or down. That is level with NOW's 400 mg per two tablets (8.0) and above Pure Encapsulations' 150 mg capsule, which is a single small step (7.5). The full serving sits above the 350 mg upper limit for supplemental magnesium and needs four capsules, so it is a large single dose for a citrate.
- Per serving
- 420 mg magnesium (as magnesium citrate), 100% DV, per 4 capsules
- Per capsule
- 105 mg magnesium (420 mg divided by 4 capsules)
- Suggested use
- 4 capsules daily with 8-12 oz of water, or as directed by a healthcare professional (back label)
Lab transparency
20% of scoreThe back label prints Third Party Tested and the gallery shows a GMP Compliant Facility seal. No lab is named, the product page links no certificate of analysis, and neither NSF Certified for Sport nor NSF/ANSI 173 lists a Nutricost product (searched October 18, 2026). That is a plausible claim with no paper trail. It scores below NOW and Pure Encapsulations (8.5 each), whose testing is described as an in-house program, and below Calm (7.5), which is described as batch-tested.
- Testing
- Third Party Tested printed on the back label; no lab named; no certificate of analysis on the product page; no Nutricost product in the NSF Certified for Sport or NSF/ANSI 173 listings (checked October 18, 2026)
- Certifications
- None verified. Printed seals: Vegan, GMP Compliant Facility, Non-GMO, Gluten-Free, Nutricost Quality Guaranteed. No NSF, USP or Informed mark.
Cost per active mg
15% of score$11.99 for 120 capsules on Oct 18, 2026: $0.40 a serving, 10 cents a capsule, about 9.5 cents per 100 mg of magnesium. That is cheaper than Pure Encapsulations (about 13 cents per 100 mg, 7.0) and Calm ($0.37 for 325 mg, about 11 cents, 7.5), and about twice NOW's roughly 4 cents (9.0).
- Price
- $11.99 for 120 capsules = $0.40 per 4-capsule serving ($0.10 per capsule) (Amazon US, October 18, 2026)
- Cost per 100 mg
- About 9.5 cents per 100 mg of magnesium
Real-world response
10% of scoreThe label asks for four capsules in one go with 8-12 oz of water. Citrate pulls water into the bowel, and a full serving is above the 350 mg supplemental limit, so loose stool is the likely first complaint. We have no bottle-specific tolerance data. NOW's two-tablet serving, which we scored 7.5, is easier to dose; Pure Encapsulations (8.0) is easier still with one small capsule.
- Other ingredients
- Hypromellose (cellulose) capsule, rice extract blend (rice extract, rice hulls, gum arabic, sunflower oil), stearic acid (vegetable source), magnesium stearate (vegetable source)
- More Specs
- Servings
- 120 capsules · 30 servings of 4 capsules (the Amazon title claims twice that; the panel says 30)
- Manufacturer
- Nutricost, Vineyard, UT; made and quality tested in the USA with globally sourced ingredients
Label verified. Every figure read from the Supplement Facts photo, Oct 18, 2026.
Marketing Claims Vs. Reality
420 mg of magnesium per serving.
The panel lists Magnesium (as magnesium citrate) 420 mg, 100% DV, per serving. A serving is 4 capsules, so it is 105 mg per capsule. The Nutricost product page calls it 420 mg of elemental magnesium.
120 capsules, 60 servings (Amazon title).
The capsule count is right. The panel and the front label both say 30 servings, which is 120 capsules at 4 per serving. The title's 60 servings does not match a 4-capsule serving. Trust the panel.
Third Party Tested.
Printed on the back label, and Nutricost's product page says an independent, accredited lab tests its products. No lab is named, no certificate is linked, and we found no Nutricost product in the NSF Certified for Sport brand list or the NSF/ANSI 173 listings (searched October 18, 2026).
Gluten-free and Non-GMO.
Both are printed on the back label and in the gallery, but no certifier mark (such as the Non-GMO Project) is shown. Magnesium citrate itself contains no gluten, so the claim is plausible.
Vegan, made in a GMP Compliant Facility.
Both seals appear on the bottle frame. The capsule is hypromellose and the stearates are marked as vegetable source, which fits the vegan seal. We did not check a GMP audit or an FDA registration; for a US supplement it is a baseline, not a quality signal on its own.
What Our Test Actually Found
One active ingredient, easy to read
The panel has a single line: magnesium (as magnesium citrate), 420 mg. There is no blend and no proprietary total to decode. The 100% DV printed next to it is the check that the number is magnesium itself, not the compound. The other ingredients are the capsule and flow agents: rice extract blend, stearic acid and magnesium stearate.
Four capsules is a large single dose for a citrate
A serving is four capsules with a full glass of water, and 420 mg is above the 350 mg upper limit for supplemental magnesium. At 105 mg a capsule you can take less, and for a bowel effect that is probably how to start. If you only want the magnesium and not the laxative pull, glycinate is the form to look at instead.
Testing: printed, not proven
Third Party Tested appears on the back label and on the product page, but neither names a lab or links a certificate. We searched NSF Certified for Sport and NSF/ANSI 173 on October 18, 2026 and found no Nutricost product. Absence from a list is not proof of failed testing; it means there is nothing for us to check. If it matters to you, ask Nutricost for the certificate of analysis for your lot.
Priced between NOW and Pure Encapsulations
At $0.40 a serving, about 9.5 cents per 100 mg, Nutricost costs less than Pure Encapsulations and Calm per milligram, and roughly twice what NOW's citrate tablets cost. The difference over NOW buys you a capsule instead of a tablet, not a stronger effect.
Same brand, a different product from the glycinate
Nutricost's magnesium glycinate is a separate bottle with a different form, dose and label. If you were weighing the two, citrate is the one with the bowel effect, and glycinate is the one to pick for sleep and calm.
Full analysis: all pros & cons (9), buy if / skip if
- One active ingredient: 420 mg magnesium (as citrate) per serving
- The 100% DV printed on the panel confirms the elemental number
- About 9.5 cents per 100 mg of magnesium, $11.99 for 30 days
- 105 mg capsules let you start low and step up
- Short label, no dyes or sweeteners
- Third Party Tested names no lab and has no NSF listing
- Four capsules per serving, above the 350 mg supplemental limit
- About twice NOW's citrate tablets per milligram
- Amazon title doubles the serving count; the bottle is 30
- You want citrate in capsules rather than tablets or a powder drink
- You want a plain label: one active line and a short list of flow agents
- You want a 30-day bottle for about $12
- You want the cheapest citrate: NOW's tablets cost about half as much per milligram
- You want magnesium for sleep without the bowel effect: glycinate is gentler
- You want a named lab or an NSF seal behind the testing claim; this bottle has neither
- You have kidney disease: talk to your doctor first
420 mg of magnesium per 4-capsule serving, $0.40 a day, nothing else active in the capsule. Citrate absorbs better than oxide (Walker 2003) and keeps some magnesium in the gut, so it works on the bowel as well. The label is easy to read and the price is fair. What holds the score at 7.3 is the testing paper trail (no lab named, no NSF listing) and the fact that NOW's citrate tablets give you the same form for about half the cost per milligram.
Nutricost Magnesium Citrate is one ingredient in a capsule. The Supplement Facts panel lists a single line: magnesium (as magnesium citrate), 420 mg per serving, which is 100% of the Daily Value, and a serving is four capsules. That makes each capsule 105 mg and the 120-capsule bottle 30 servings. The Amazon offer we checked on October 18, 2026 was $11.99, or $0.40 a serving and about 9.5 cents per 100 mg of magnesium. The back label prints Third Party Tested, but it names no lab, and we found no Nutricost product in the NSF Certified for Sport or NSF/ANSI 173 listings. The magnesium is what the front says it is. The things to weigh are the four-capsule serving, which sits above the 350 mg upper limit for supplemental magnesium, and a cheaper citrate from NOW.
A fair citrate capsule, but NOW does the same job for less.
Nutricost Magnesium Citrate gives you what the front says: 420 mg of magnesium as citrate, one active ingredient, and a plain label. At about $0.40 a serving it is a sensible price, cheaper per milligram than Pure Encapsulations and Calm. If you want citrate in capsules and like being able to take two or four, it does the job. What holds the score at 7.3 is what the label cannot show and what the dose asks of you. Third Party Tested names no lab, and we could not find the product at NSF. A full serving is four capsules and above the 350 mg supplemental limit, so most people should start with fewer. And NOW's citrate tablets, which we scored 7.8, cost about half as much per milligram. Pick Nutricost for the capsule format, not for a better magnesium. If sleep rather than regularity is the goal, buy a glycinate instead.
If This Doesn’t Fit — Try These
NOW Magnesium Citrate 200 mg Tablets
Same form, about half the price per milligram: 400 mg per two-tablet serving, about 4 cents per 100 mg, with NOW's own testing and the GMP Quality Assured seal.
Natural Vitality Calm Magnesium Citrate
Citrate as a flavored hot drink: 325 mg per serving.
Pure Encapsulations Magnesium (Citrate)
150 mg capsules with two other ingredients, easy to step the dose up slowly.
Quick Answers
How much magnesium is in a Nutricost Magnesium Citrate capsule?
The Supplement Facts panel lists 420 mg of magnesium (as magnesium citrate) per serving, and a serving is 4 capsules, so each capsule holds 105 mg. The 420 mg is the magnesium itself, not the weight of the citrate compound: it is printed as 100% of the Daily Value. The bottle holds 120 capsules, which is 30 servings. The Amazon title claims twice as many servings as the panel prints.
Do I have to take all four capsules at once?
The back label says to take 4 capsules daily with 8-12 oz of water. A full serving is above the 350 mg upper limit for supplemental magnesium. Citrate also draws water into the bowel, so some people start with half a serving and add capsules until the stool is where they want it. The maker's label gives no split-dose directions.
Is Nutricost Magnesium Citrate third-party tested?
The back label prints Third Party Tested, and the Nutricost product page says an independent, accredited lab tests its products. Neither names the lab, and the page links no certificate of analysis. We searched the NSF Certified for Sport brand list and the NSF/ANSI 173 listings on October 18, 2026 and found no Nutricost product in either. So the claim is plausible, but we could not verify it at any certifier.
Citrate or glycinate: which one is this for?
Citrate is the form to pick when you also want the bowel effect, because part of it stays in the gut and draws water in. Glycinate is the gentler choice for sleep and calm. Nutricost sells both; this is the citrate. The glycinate is a different product with a different label and its own review.
What else is in the capsule?
Per the panel: a hypromellose capsule, a rice extract blend (rice extract, rice hulls, gum arabic, sunflower oil), stearic acid and magnesium stearate, both from a vegetable source. They are flow agents, not active ingredients. The label shows no dyes or sweeteners.
Sources & Further Reading
1 peer-reviewed source, each linked to PubMed
- [1] Walker 2003 PMID 14596323 — Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. 46 healthy adults took 300 mg of magnesium a day as citrate, amino acid chelate or oxide for 60 days. Citrate gave the highest blood magnesium after a single dose and after 60 days; oxide did not differ from placebo.
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