High-Potency 2:1 Mineral Ratio for Bone Density, Muscular Relaxation, and Daily Cardiovascular Balance
If you are looking to protect your bone strength, ease nighttime leg tension, or keep your daily electrolyte levels balanced, the balance between calcium and magnesium matters just as much as the dose itself. NOW Foods CAL-MAG 500/250 mg (SKU: N1272) provides a physician-preferred 2:1 ratio of bioavailable elemental calcium (1,000 mg per full 2-tablet daily serving) to elemental magnesium (500 mg per serving).
Quick Takeaway: Each single tablet supplies 500 mg of elemental calcium and 250 mg of elemental magnesium. Taking 1 tablet twice daily with food keeps intestinal absorption high, prevents stomach upset, and ensures your skeleton and nervous system get a continuous supply of vital minerals.
✓ Synergistic 2:1 Ratio: Formulated to match the body’s physiological requirements for bone turnover and cellular mineral balance.
✓ Tri-Source Mineral Matrix: Combines carbonate, citrate, and ascorbate forms for sustained bioavailability across different digestive pH levels.
✓ Economical 125-Day Supply: The generous 250-tablet bottle gives you over four full months of nutritional support.
✓ Risk-Free Purchase: Protected by VitaNet’s unconditional 100% money-back guarantee, covering return shipping even if opened[cite: 1].
The Importance of Calcium & Magnesium: Why the 2:1 Ratio Matters
Calcium and magnesium are biological partners. In bone tissue, calcium forms the rigid mineral framework known as hydroxyapatite crystals, while magnesium controls bone mineral density and helps regulate osteoclast and osteoblast activity. Taking large doses of calcium alone can suppress magnesium levels, leading to muscle stiffness and calcification in soft tissues.
Magnesium is also required to activate Vitamin D in the liver and kidneys. Without adequate magnesium, your body cannot convert stored Vitamin D into calcitriol (its active hormonal form), which reduces your ability to absorb calcium from your food. By delivering calcium and magnesium in a calibrated 2:1 proportion, this supplement supports steady skeletal renewal without exhausting your body’s magnesium reserves (National Institutes of Health Office of Dietary Supplements; Journal of the American College of Nutrition).
The Push-Pull Muscle & Nerve Mechanism
At the neuromuscular level, calcium acts as the "contractor" and magnesium acts as the "relaxer." When a motor nerve fires, calcium floods into muscle fibers to trigger contraction. Magnesium then rushes in as a natural physiological calcium blocker, pumping calcium back into the cells so the muscle fiber can rest. Maintaining this balance helps prevent occasional leg spasms, eye twitches, and physical tension.
The Multi-Form Mineral Complex: Carbonate, Citrate, and Ascorbate
Many standard drugstore supplements rely entirely on basic calcium carbonate and magnesium oxide because they are inexpensive. NOW Foods utilizes a tri-blend complex to provide both high elemental concentration and smooth digestive comfort:
Mineral Form
Elemental Concentration
Digestion Characteristic
Clinical Benefit
Calcium Carbonate
High (~40%)
Requires gastric acid (best with meals)
Delivers dense calcium volume in smaller tablet sizes.
Calcium Citrate
Moderate (~21%)
Acid-independent absorption
Easily absorbed by older adults and those taking antacids or PPIs.
Calcium Ascorbate
Variable (~10%)
Non-acidic buffered Vitamin C salt
Gentle on the stomach lining while delivering antioxidant ascorbate.
Magnesium Complex (Oxide, Citrate, Ascorbate)
Balanced (~54% avg)
Dual-speed intestinal uptake
Combines compact mineral volume with gentle digestive tolerance.
By combining these sources, NOW provides 1,000 mg of elemental calcium and 500 mg of elemental magnesium without requiring massive, difficult-to-swallow horse pills or causing common digestive upset.
NOW Foods Quality Testing: Heavy Metal & Contaminant Verification
Because mined minerals can naturally carry environmental heavy metals from soil and rock formations, supplement purity comes down to lab verification. NOW Foods runs one of the most advanced private analytical facilities in North America, testing every batch before it is packaged.
✓ ISO/IEC 17025:2017 Accredited Labs
Accredited by the American Association for Laboratory Accreditation (A2LA) for both microbiological and chemical analysis, ensuring testing protocols match independent scientific standards.
✓ ICP-MS Heavy Metal Screening
Inductively Coupled Plasma Mass Spectrometry monitors incoming mineral lots for lead, arsenic, cadmium, and mercury down to parts-per-billion (ppb) detection limits.
✓ Strict Contaminant Thresholds
All batches adhere to rigid specifications that meet or exceed California Proposition 65 limits, U.S. Pharmacopeia (USP) guidelines, and FDA Good Manufacturing Practices (cGMP).
✓ 31,000+ Quality Tests Per Month
Raw materials and finished goods are screened for microbials (E. coli, Salmonella) and identity-verified with Fourier-Transform Infrared (FTIR) spectroscopy.
These strict controls ensure that the minerals listed on the bottle are pure, biologically active, and free from dangerous heavy metal impurities.
How to Take NOW Cal-Mag: The Divided Dose Advantage
Clinical nutrition research shows that the human digestive tract absorbs calcium best in single doses of 500 mg or less (Heaney et al., American Journal of Clinical Nutrition). When you swallow more than 500 mg of calcium at once, the body's active intestinal transporters saturate, and the remaining calcium passes through unabsorbed.
Practical Daily Routine
Tablet 1 (Morning or Afternoon): Take 1 tablet with a meal (such as breakfast or lunch). The natural stomach acids produced during meals break down the calcium carbonate and citrate for optimal absorption.
Tablet 2 (Evening or Before Bed): Take 1 tablet with dinner or an evening snack. Magnesium helps calm the central nervous system, eases evening muscle tension, and promotes restful sleep.
Always drink a full 8-ounce glass of water with each tablet to assist breakdown and maintain proper hydration.
Who Should Use Caution? Real Constraints & Drug Interactions
While calcium and magnesium are essential minerals, high-potency supplements must be used responsibly. Consult your healthcare provider before starting this product if you have any existing medical conditions or take prescription medications:
Pre-Existing Conditions
Individuals with chronic kidney disease, hypercalcemia (elevated blood calcium), hyperparathyroidism, or a history of calcium-oxalate kidney stones should not take high-potency calcium supplements without medical supervision.
Separating Prescriptions
Calcium and magnesium can bind to medications in the gut, preventing their absorption:
Thyroid meds (Levothyroxine): Separate by at least 4 hours.
Antibiotics (Tetracyclines/Fluoroquinolones): Separate by 2 to 4 hours.
Osteoporosis drugs (Bisphosphonates): Separate by at least 2 hours.
*Disclaimer: 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.
Allergen Information: Not manufactured with wheat, gluten, soy, milk, egg, fish, shellfish, or tree nut ingredients. Produced in a GMP facility that processes other ingredients containing these allergens.
Storage: Store in a cool, dry place after opening. Natural color variation may occur in this product.
Why Buy NOW Cal-Mag from VitaNet®?
Online marketplaces can leave you guessing about storage temperatures, expiration dates, or authentic sourcing. When you order from VitaNet, LLC, you work directly with an independent, family-owned American vitamin retailer serving wellness seekers nationwide since 1995[cite: 1].
✓ 100% Money-Back Guarantee
VitaNet offers an unconditional refund policy that even pays for return shipping, whether your bottle is opened or unopened[cite: 1].
✓ Over 31 Years of Experience
Our family-owned Ohio team brings hands-on supplement expertise to help you find the right health formulas[cite: 1].
✓ Direct Warehouse Freshness
All stock is shipped directly from our temperature-controlled facility in Hartville, Ohio, guaranteeing lot-tested freshness[cite: 1].
✓ BBB A+ Accredited Service
Have questions? Reach real product specialists directly by phone at (330) 877-8786 or toll-free at 1-800-877-8702[cite: 1].
Frequently Asked Questions (FAQ)
Why does this bottle say 500/250 mg if the serving size is 1,000 mg and 500 mg?
The front label lists the potency of a single tablet: 500 mg of elemental calcium and 250 mg of elemental magnesium. The Supplement Facts panel reflects the full recommended daily serving of 2 tablets, which yields 1,000 mg of calcium and 500 mg of magnesium.
Can I take both tablets together at the same time?
You can, but dividing them (1 tablet with breakfast and 1 tablet with dinner) is far more effective. The body absorbs calcium most efficiently in amounts of 500 mg or less per sitting. Dividing your dose doubles your absorption efficiency and reduces the risk of stomach heaviness.
Does this supplement cause constipation or loose stools?
Calcium supplements can sometimes cause constipation, while magnesium draws water into the stool and acts as a gentle laxative. In this balanced 2:1 ratio, the two minerals offset one another, producing neutral digestive comfort for most individuals.
Is this product tested for lead and heavy metals?
Yes. NOW Foods tests all incoming raw ingredients and finished tablets using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in ISO/IEC 17025:2017 accredited laboratories. They test specifically for lead, arsenic, cadmium, and mercury to ensure every lot meets strict safety standards.
Is NOW Cal-Mag suitable for vegans and those with food allergies?
Yes. These tablets use a vegetarian coating and contain no animal derivatives. They are certified Kosher, non-GMO, and formulated without wheat, gluten, soy, dairy, eggs, fish, shellfish, or tree nuts.
What is VitaNet’s return policy if this supplement doesn't agree with me?
VitaNet provides an unconditional 100% money-back guarantee[cite: 1]. If you are dissatisfied for any reason, VitaNet will refund your purchase price and pay the return shipping costs, even if the bottle has been opened[cite: 1].
