Magnesium 250 mg
21st Century
Magnesium 250 mg
4.7
★ ★ ★ ★ ★
(63969 ratings)
Magnesium 250 mg
Score 58.0
A very cheap and popular magnesium supplement, but its use of poorly absorbed Magnesium Oxide and inclusion of Calcium Carbonate make it inefficient for systemic magnesium benefits.
Quantity: 110 Tablet(s)Servings size: 1 Tablet(s) (110 servings)
Selected goals:
Other goals:
General Health
Energy
Stress Relief
Heart Health
Bone Health
leaderboard Score 58.0
A very cheap and popular magnesium supplement, but its use of poorly absorbed Magnesium Oxide and inclusion of Calcium Carbonate make it inefficient for systemic magnesium benefits.
insights Analysis
21st Century provides a very budget-friendly magnesium supplement, which accounts for its widespread use and high review count. However, the core issue is the form: magnesium oxide is largely unabsorbed by the body, meaning that for goals like energy, stress relief, or heart health, its effectiveness is minimal. Many online reviews might praise it for its laxative effect rather than its systemic health benefits. The addition of Calcium Carbonate, another low-bioavailability form of calcium, can also interfere with magnesium absorption if both compete for the same absorption pathways. For those truly seeking to increase their magnesium levels for systemic health, this product is generally not recommended by nutritionists.
- Extremely low price per serving.
- Very high review count, indicating popularity.
- Can serve as a mild laxative.
- Uses Magnesium Oxide, which has poor systemic bioavailability.
- Includes Calcium Carbonate, which can compete with magnesium absorption.
- Not ideal for achieving broader health benefits beyond laxative effect.
- May cause digestive upset (diarrhea) due to laxative effect.
- Poor absorption for systemic benefits.
- Calcium inclusion might not be ideal for dedicated magnesium supplementation.
$4.99($0.04 per serving)
 iHerb | $ 4.99 |
bolt Effectiveness for goals
The effectiveness of magnesium can vary by its specific form due to differences in bioavailability and targeted uses. For instance, magnesium L-threonate is researched for cognitive support due to its ability to cross the blood-brain barrier. Magnesium citrate is often chosen for digestive regularity, while magnesium glycinate is frequently used for relaxation benefits and high absorption.
Magnesium contributes to the regulation of neurotransmitters and hormones involved in the sleep cycle. Studies indicate that magnesium supplementation may help improve sleep quality, especially in older adults or those with restless leg syndrome. It is often sought for its calming properties that can support relaxation.
Magnesium plays a role in regulating neurotransmitters that promote relaxation and sleep. Some studies indicate that magnesium supplementation may improve sleep quality, especially in older adults or those with insomnia symptoms, by helping to calm the nervous system. More research is needed to fully understand its effects across different populations.
Magnesium contributes to the relaxation of blood vessels and may help regulate blood pressure. Some studies have shown a modest reduction in blood pressure, especially in individuals with hypertension or at risk for it, with magnesium supplementation. The effect can vary based on individual health status and existing conditions.
Magnesium plays a vital role in muscle contraction and relaxation. Some research suggests that magnesium supplementation may help reduce the frequency and intensity of muscle cramps, particularly in individuals experiencing magnesium deficiency. It is a commonly explored option for this purpose.
schedule Dosage, timing & forms
The recommended daily allowance (RDA) for magnesium varies by age and sex, generally ranging from 310-420 mg for adult men and 310-320 mg for adult women. These recommendations are for dietary intake from food and supplements combined. It is important to consult current health guidelines for specific age and life stages.
The Recommended Dietary Allowance (RDA) for adult men is 400-420 mg per day, and for adult women, it is 310-320 mg per day. These recommendations can vary slightly based on age and life stage. It's important to consult with a healthcare professional for personalized guidance.
Common forms include magnesium citrate, oxide, glycinate, and L-threonate. Magnesium citrate is often used for bowel regularity, while magnesium oxide has lower bioavailability but is a common, inexpensive form. Magnesium glycinate is typically well-absorbed and gentle on the stomach, and magnesium L-threonate is studied for its potential to cross the blood-brain barrier.
Excessive intake of magnesium from supplements, but not from food, can lead to side effects like diarrhea, nausea, and abdominal cramping. In very high doses, it can cause more serious issues such as low blood pressure, muscle weakness, and irregular heartbeat. The tolerable upper intake level for supplemental magnesium is 350 mg per day for adults.
For healthy adults, the Tolerable Upper Intake Level (UL) for supplemental magnesium is 350 mg per day. This UL specifically applies to magnesium from supplements and medications, not from food or water. Exceeding this limit regularly may lead to adverse effects like diarrhea, nausea, and abdominal cramping.
health_and_safety Safety & interactions
Yes, magnesium supplements can interact with several types of medications. These include certain antibiotics (tetracyclines and quinolones), diuretics, proton pump inhibitors, and bisphosphonates. It's advisable to consult a healthcare professional about potential interactions when taking medications.
Common side effects often involve the digestive system, such as diarrhea, nausea, and abdominal cramping. These effects are typically mild and more likely with higher doses or certain forms like magnesium citrate. Starting with a lower dose and gradually increasing can help mitigate these symptoms.
Common side effects, especially with higher doses, can include diarrhea, nausea, and abdominal cramping. These effects are often dose-dependent and may be mitigated by reducing the amount taken. Different forms of magnesium can also influence gastrointestinal tolerance.
While rare from food sources alone, excessive intake from supplements can lead to hypermagnesemia, particularly in individuals with impaired kidney function. Symptoms may include low blood pressure, lethargy, muscle weakness, and an irregular heartbeat. In severe cases, it can be life-threatening.
Individuals with impaired kidney function should exercise caution and consult a healthcare professional before taking magnesium supplements. Kidneys are responsible for excreting excess magnesium, and compromised function can lead to an accumulation of magnesium in the body. This accumulation can result in hypermagnesemia, which is potentially dangerous.
Ingredients
| Ingredient | Amount per serving |
|---|---|
| Calcium (Calcium Carbonate) | 65 mg |
| Magnesium (Magnesium Oxide) | 250 mg |
Categories
Magnesium 58.0
Its very low price and high review count are appealing, but the exclusive use of poorly absorbed magnesium oxide significantly limits its effectiveness for systemic magnesium benefits, making it primarily a laxative.
Goals
General Health 45.0
Very limited systemic absorption due to magnesium oxide and potential interference from calcium carbonate make it largely ineffective for general health benefits.
Bone Health 40.0
While both minerals are for bones, their forms are poorly absorbed, and they may compete, limiting true benefit.
Energy 35.0
Poor absorption renders it ineffective for supporting cellular energy production.
Recommended Alternatives
100 Value 
Magnesium Caps 500 mg
Life Extension
4.8
★★★★★
(71620 ratings)
Exceptional value, combining a premium, highly bioavailable multi-magnesium blend with an excellent price per serving (0.08), offering a superior product for a reasonable cost increase.
95 Value 
Triple Magnesium Complex 400 mg
Swanson Premium Brand
4.8
★★★★★
(15546 ratings)
Provides a balanced blend of magnesium forms (Oxide, Citrate, Aspartate) at a very competitive price per serving (0.11), offering better overall efficacy than pure oxide for a slightly higher cost.
90 Value 
Calcium Magnesium Zinc
Nature's Bounty
4.8
★★★★★
(59702 ratings)
Combines magnesium with essential calcium and zinc at an incredibly low price per serving (0.05), providing broad mineral support and good value.
100 Performance
Magnesium Caps 500 mg
Life Extension
4.8
★★★★★
(71620 ratings)
Features a premium blend including highly bioavailable TRAACS Lysyl Glycinate Chelate, offering vastly superior absorption and efficacy for systemic benefits over magnesium oxide.
98 Performance 
Chelated Magnesium 133 mg
Swanson
4.8
★★★★★
(5354 ratings)
Contains TRAACS Magnesium Bisglycinate Chelate, a highly absorbed and gentle form of magnesium, ideal for addressing deficiencies effectively, unlike oxide.
95 Performance 
Magnesium & Calcium
NOW
4.8
★★★★★
(16706 ratings)
Offers a comprehensive blend of well-absorbed magnesium forms including Glycinate and Citrate, providing significantly better bioavailability than magnesium oxide.
98 Budget 
Magnesium 500 mg
Nature's Bounty
4.7
★★★★★
(95059 ratings)
Offers an even lower price per serving (0.03) for magnesium oxide, making it the most budget-friendly alternative for this basic form.
95 Budget 
Magnesium 250 mg
Nature Made
4.7
★★★★★
(4316 ratings)
Provides a very low price per serving (0.04) for magnesium oxide, offering a similarly cheap option for basic magnesium.
90 Budget 
Magnesium 200 mg
Swanson Premium Brand
4.7
★★★★★
(927 ratings)
A highly affordable magnesium oxide option with a low price per serving (0.04), providing a direct cost-effective alternative.
100 Value
Magnesium Caps 500 mg
Life Extension
4.8
★★★★★
(71620 ratings)
Exceptional value, combining a premium, highly bioavailable multi-magnesium blend with an excellent price per serving (0.08), offering a superior product for a reasonable cost increase.
95 Value
Triple Magnesium Complex 400 mg
Swanson Premium Brand
4.8
★★★★★
(15546 ratings)
Provides a balanced blend of magnesium forms (Oxide, Citrate, Aspartate) at a very competitive price per serving (0.11), offering better overall efficacy than pure oxide for a slightly higher cost.
90 Value
Calcium Magnesium Zinc
Nature's Bounty
4.8
★★★★★
(59702 ratings)
Combines magnesium with essential calcium and zinc at an incredibly low price per serving (0.05), providing broad mineral support and good value.
100 Performance
Magnesium Caps 500 mg
Life Extension
4.8
★★★★★
(71620 ratings)
Features a premium blend including highly bioavailable TRAACS Lysyl Glycinate Chelate, offering vastly superior absorption and efficacy for systemic benefits over magnesium oxide.
98 Performance
Chelated Magnesium 133 mg
Swanson
4.8
★★★★★
(5354 ratings)
Contains TRAACS Magnesium Bisglycinate Chelate, a highly absorbed and gentle form of magnesium, ideal for addressing deficiencies effectively, unlike oxide.
95 Performance
Magnesium & Calcium
NOW
4.8
★★★★★
(16706 ratings)
Offers a comprehensive blend of well-absorbed magnesium forms including Glycinate and Citrate, providing significantly better bioavailability than magnesium oxide.