Vitamin K-2 100 mcg
NOW
Vitamin K-2 100 mcg
4.8
★ ★ ★ ★ ★
(13261 ratings)
Vitamin K 100 mcg
Score 88.0
A cost-effective and well-regarded Vitamin K2 (MK-4) supplement, highly effective for bone and cardiovascular health, offering great value despite MK-4's shorter half-life.
Quantity: 250 Capsule(s)Servings size: 1 Veg Capsule(s) (250 servings)
Selected goals:
Other goals:
Bone Health
Heart Health
Cardiovascular Support
General Health
leaderboard Score 88.0
A cost-effective and well-regarded Vitamin K2 (MK-4) supplement, highly effective for bone and cardiovascular health, offering great value despite MK-4's shorter half-life.
insights Analysis
NOW's Vitamin K-2 100 mcg (MK-4) is a highly regarded supplement. MK-4 is an effective form of K2, known for its role in bone metabolism and arterial health by directing calcium. While it requires a higher dose or more frequent intake compared to MK-7 due to its shorter half-life, the generous 250-serving count makes it incredibly cost-effective. The sheer volume of positive reviews online (over 12,000) underscores its popularity and perceived efficacy among consumers. Nutritionists acknowledge MK-4's benefits, though often recommend MK-7 for its convenience due to longer systemic presence.
- Excellent price per serving for a Vitamin K2 supplement.
- Contains Menaquinone-4 (MK-4), an effective form of K2 for bone and cardiovascular health.
- High number of servings provides long-term supply.
- Extremely high review count indicates broad customer satisfaction.
- Menaquinone-4 (MK-4) has a shorter half-life compared to Menaquinone-7 (MK-7), potentially requiring more frequent dosing for sustained levels.
- Does not include other synergistic vitamins like D3, which are often recommended alongside K2 for optimal calcium utilization.
$18.59($0.07 per serving)
 Vitacost | $ 18.59 | |
 Walmart | $ 20.00 | |
 Daily Vita | $ 20.30 | |
 iHerb | $ 21.42 |
bolt Effectiveness for goals
Vitamin K is essential for proper blood clotting and plays a significant role in bone metabolism. It helps the body produce proteins necessary for these vital bodily functions.
Vitamin K activates proteins such as osteocalcin, which are crucial for incorporating calcium into the bone matrix. This mechanism supports bone mineralization and helps maintain bone density.
Vitamin K1 (phylloquinone) is primarily effective for blood coagulation and is abundant in green leafy vegetables. Vitamin K2 (menaquinones) is more involved in bone and cardiovascular health, found in fermented foods and animal products, and has different bioavailabilities.
Emerging research suggests that Vitamin K, particularly K2, may help prevent arterial calcification by activating matrix Gla protein. This protein helps inhibit calcium deposition in soft tissues, supporting arterial flexibility.
Vitamin K works synergistically with calcium by helping to direct calcium to the bones and away from soft tissues like arteries. It activates proteins like osteocalcin for bone binding and matrix Gla protein to inhibit soft tissue calcification.
schedule Dosage, timing & forms
Recommended dosages for Vitamin K vary by age and form (K1 vs K2). For adults, the Adequate Intake (AI) for Vitamin K is 120 mcg per day for men and 90 mcg per day for women. Specific supplemental dosages may differ depending on individual needs and health goals.
Yes, dosages can differ between Vitamin K1 and K2 due to their varying potencies and half-lives. While K1 is measured in micrograms (mcg) for general intake, K2 (especially MK-7) may be effective at lower microgram doses due to its longer half-life. It's important to check the specific form and dosage on the supplement label.
Yes, Vitamin K is a fat-soluble vitamin, meaning it is best absorbed when taken with a meal containing some dietary fat. This helps facilitate its absorption into the body.
The two main forms of Vitamin K found in supplements are Vitamin K1 (phylloquinone) and Vitamin K2 (menaquinone). Vitamin K2 further has various subtypes, with MK-4 and MK-7 being the most common in supplements. Each form may have distinct roles and bioavailability.
There is no established Upper Limit (UL) for Vitamin K from food or supplements, as toxicity is rare. However, high doses of synthetic Vitamin K (menadione, K3) can be toxic, though this form is not typically found in supplements. Always adhere to recommended dosages and consult a healthcare provider if you have concerns.
health_and_safety Safety & interactions
Vitamin K plays a crucial role in blood clotting, which is the opposite effect of anticoagulant medications such as warfarin. Consuming inconsistent amounts of Vitamin K can alter warfarin's effectiveness, potentially making the blood thinner less effective or increasing bleeding risk. Individuals taking warfarin should maintain a consistent intake of Vitamin K and consult their healthcare provider.
Individuals taking anticoagulant medications like warfarin should consult their doctor before taking Vitamin K supplements due to potential interactions. People with certain liver conditions or those with a G6PD deficiency should also seek medical advice before supplementation. Always discuss new supplements with a healthcare provider.
Vitamin K supplements are generally considered safe for most healthy individuals when taken at recommended dosages. Side effects are uncommon but can include upset stomach, diarrhea, or allergic reactions in sensitive individuals. High doses of synthetic Vitamin K (menadione, K3) can be toxic, but this form is rarely used in supplements.
Vitamin K is essential during pregnancy and breastfeeding, and adequate intake is important for both mother and child. However, supplementation during these periods should only be undertaken under the guidance of a healthcare professional. High doses are generally not recommended without specific medical advice.
There is currently no established Tolerable Upper Intake Level (UL) for Vitamin K from food or supplements due to its low potential for toxicity. However, excessive intake, especially of synthetic forms, could potentially have adverse effects. It is always best to adhere to recommended dosages on supplement labels or as advised by a healthcare professional.
Ingredients
| Ingredient | Amount per serving |
|---|---|
Vitamin K2 | 100 mcg |
Alfalfa powder | 250 mg |
Categories
Vitamin K 88.0
As a Vitamin K supplement, it provides the K2 (MK-4) form, which is superior to K1 for targeted bone and cardiovascular benefits. Its excellent value makes it a strong contender in the Vitamin K category.
Goals
Bone Health 90.0
MK-4 is highly effective for bone health, playing a crucial role in activating osteocalcin, a protein that integrates calcium into the bone matrix. This makes it a strong choice for supporting bone density and strength.
General Health 90.0
As an essential vitamin, K2 (MK-4) contributes significantly to overall well-being by supporting not just bone and heart health, but also other vital bodily functions where Vitamin K is involved, making it a valuable addition to a general health regimen.
Heart Health 85.0
Vitamin K2, including MK-4, is vital for heart health as it helps activate matrix Gla protein, which prevents calcium from depositing in arterial walls, thus supporting cardiovascular elasticity and function.
Recommended Alternatives
85 Value 
Vitamin K-2 100 mcg
NOW
4.8
★★★★★
(13824 ratings)
This alternative from NOW also offers K2 MK-4 at a competitive price (9 cents per serving), providing comparable benefits and excellent value within the K2 MK-4 category.
90 Value 
Vitamins D and K with Sea-lodine
Life Extension
4.8
★★★★★
(20811 ratings)
This alternative offers a very high dose of Vitamin K combined with Vitamin D, a synergistic duo for bone and heart health, providing a strong value proposition for comprehensive benefits for a slightly higher price per serving.
80 Value 
Prenatal Blend
Super Nutrition
4.5
★★★★★
(1930 ratings)
Although the price per serving for K alone is higher, this is a comprehensive prenatal multivitamin that includes K2, offering excellent overall nutritional value beyond just Vitamin K for specific life stages.
98 Performance 
ADK Vitamins
Codeage
4.8
★★★★★
(1294 ratings)
This alternative is superior because it provides a much higher dose of the superior K2 (MK-7) form with a longer half-life, and includes synergistic Vitamins A and D3 for comprehensive bone, heart, and immune support.
95 Performance 
Vitamin D3 & K2 Peach Apricot Flavor
Advanced Nutrition by Zahler
4.8
★★★★★
(463 ratings)
This product is better as it contains the more bioavailable K2 (MK-7) form and is combined with D3, a critical pairing that synergistically optimizes calcium regulation for bone and arterial health more effectively than MK-4 alone.
80 Performance 
Vitamin K2 Advantage 2200 mcg
Source Naturals
4.8
★★★★★
(356 ratings)
While more expensive, this alternative offers a higher dose of the superior K2 (MK-7) form (MenaQ7), which provides better bioavailability and a longer half-life compared to MK-4, making it potentially more effective for targeted benefits.
70 Budget 
Sentry Adults
21st Century
4.7
★★★★★
(23601 ratings)
This product offers a Vitamin K supplement (K1) at a significantly lower price per serving (4 cents), making it a more budget-friendly option for basic K supplementation, though it's not K2.
65 Budget 
Therapeutic-M
21st Century
4.7
★★★★★
(587 ratings)
Providing Vitamin K1 at 5 cents per serving, this is another very economical choice for those seeking fundamental K intake, at a lower cost than the K2 product.
65 Budget 
Vitamin K-1 100 mcg
Swanson Premium Brand
4.7
★★★★★
(459 ratings)
This K1 product offers a similar dose to the original but at 5 cents per serving, making it a cheaper option for general Vitamin K although it lacks the specific K2 benefits.
85 Value
Vitamin K-2 100 mcg
NOW
4.8
★★★★★
(13824 ratings)
This alternative from NOW also offers K2 MK-4 at a competitive price (9 cents per serving), providing comparable benefits and excellent value within the K2 MK-4 category.
90 Value
Vitamins D and K with Sea-lodine
Life Extension
4.8
★★★★★
(20811 ratings)
This alternative offers a very high dose of Vitamin K combined with Vitamin D, a synergistic duo for bone and heart health, providing a strong value proposition for comprehensive benefits for a slightly higher price per serving.
80 Value
Prenatal Blend
Super Nutrition
4.5
★★★★★
(1930 ratings)
Although the price per serving for K alone is higher, this is a comprehensive prenatal multivitamin that includes K2, offering excellent overall nutritional value beyond just Vitamin K for specific life stages.
98 Performance
ADK Vitamins
Codeage
4.8
★★★★★
(1294 ratings)
This alternative is superior because it provides a much higher dose of the superior K2 (MK-7) form with a longer half-life, and includes synergistic Vitamins A and D3 for comprehensive bone, heart, and immune support.
95 Performance
Vitamin D3 & K2 Peach Apricot Flavor
Advanced Nutrition by Zahler
4.8
★★★★★
(463 ratings)
This product is better as it contains the more bioavailable K2 (MK-7) form and is combined with D3, a critical pairing that synergistically optimizes calcium regulation for bone and arterial health more effectively than MK-4 alone.
80 Performance
Vitamin K2 Advantage 2200 mcg
Source Naturals
4.8
★★★★★
(356 ratings)
While more expensive, this alternative offers a higher dose of the superior K2 (MK-7) form (MenaQ7), which provides better bioavailability and a longer half-life compared to MK-4, making it potentially more effective for targeted benefits.