Magnesium Oxide 400 by Foster Regal — Ingredients, Evidence & Safety

Product Label

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Safety Alerts

⚠️ elemental Magnesium: 482.6mg is 1.4× the Tolerable Upper Intake Level (350mg)

This product received a low score because the amount of magnesium it contains exceeds the recommended maximum daily limit.

Label Data

2 Tablet(s) Serving Size

60 Servings

Mineral Product Type

100% Evidence Coverage

Supplement Facts — Evidence Check

elemental Magnesium

482.6 mg (121% DV)

⚠️ Exceeds Tolerable Upper Intake Level by 1.4× (UL: 350 mg) 📚 310 studies (Tier A: 8, B: 159)

RDA 420mg This product: 482.6mg UL 350mg

Other Ingredients

Vegetable Cellulose Vegetable Stearic Acid Vegetable Magnesium Stearate Silica

Label Claims — Verification

❓ All Other

❓ Structure/Function

All Other (100% of products) Structure/Function (78% of products) Nutrient (46% of products)

Target Groups

Adult (18 - 50 Years) Kosher Gluten Free

Product Information

📋 Directions for Use

Directions: As a dietary supplement, take 2 tablets daily with food or as directed by a physician.

⚠️ Warnings & Precautions

Tamper evident: Do not use this product if imprinted foil seal under cap is broken or missing.

Keep out of reach of children.

Caution: If you are pregnant, nursing, have kidney disease or are taking any prescription medication, consult your physician before taking this product.

🧪 Formulation Notes

Mfg. in a Ko Kosher Certified, FDA Registered Facility, using Good Manufacturing Practices (GMPs)

Conforms to USP <2091> for weight. Meets USP <2040> disintegration for maximum bioavailability.

Pharmaceutical grade Promotes bone mineralization and cardiovascular health

Gluten free

Made in USA

Additional Information

Keep tightly closed. Store at room temperature: 59 degrees - 86 degrees F (15 degrees - 30 degrees C).

Now coated, easier to swallow Compare to active ingredient of MAG-OX 400

Product Details

DSLD Entry Date 2022-04-11

Product Type Mineral

Form Tablet or Pill

Brand Foster Regal

DSLD ID 260266

Data Updated 2026-04-11

Research Evidence

7 Research Sources

45 Avg Quality Score

6 Rct

1 Meta Analysis

C Effectiveness and safety of polyethylene-glycol-4000 versus sodium picosulphate plus magnesium oxide and citric acid for bowel cleansing before colonoscopy in children: A systematic review with meta-analysis

Meta Analysis Journal of pediatric gastroenterology and nutrition 2025

PubMed DOI

C A randomized controlled study of effects of dietary magnesium oxide supplementation on bone mineral content in healthy girls

Rct The Journal of clinical endocrinology and metabolism 2006

PubMed

C Senna Versus Magnesium Oxide for the Treatment of Chronic Constipation: A Randomized, Placebo-Controlled Trial

Rct The American journal of gastroenterology 2021

PubMed DOI

C The efficacy of magnesium oxide and sodium valproate in prevention of migraine headache: a randomized, controlled, double-blind, crossover study.

Rct Acta neurologica Belgica

PubMed DOI

C A randomized, double-blind, placebo-controlled, multicenter study assessing the efficacy of magnesium oxide monohydrate in the treatment of nocturnal leg cramps.

Rct Nutrition journal

PubMed DOI

C Comparative study between manitol and sodium picosulfate with magnesium oxide solutions in the preparation for colonoscopy.

Rct Revista do Colegio Brasileiro de Cirurgioes

PubMed DOI

C Effect of magnesium oxide or citrate supplements on metabolic risk factors in kidney stone formers with idiopathic hyperoxaluria: a randomized clinical trial.

Rct Magnesium research

PubMed DOI

View all evidence for Magnesium Oxide →