Carlson - Vitamin K2, MK-4 (Menatetrenone), Vitamin K Supplement, Bone & Heart Health, K2 Vitamin, Soy-free, Vitamin K-2, K2 Vitamins, 180 Capsules

I purchased this product here and was happy with it. It seems MK-4 exists in certain mammalian tissues, with some organs having higher concentrations than others. Experiments with radio-labeled K-1 suggests that it can be converted into MK-4, but probably not at the therapeutic level individuals might seek.The source in supplements seems to be entirely synthetic for MK-4(from a tobacco product I read), because sourcing animal products for it for extraction would be out of sight expensive. The highest food source seems to be "Fois Gras" and has 369 mcg in 100 grams, etc. Geese seem to consume the type of grass and consequently K-1 that their system can convert to Mk-4.MK-9 seems exist in certain cheeses and has a very long half-life.Mk-7 might have a three day half-life it is claimed.MK-4 is said to be prescription in Japan for osteoporosis and typically given at 45 mg a day, in three 15 mg doses. Taking it with oil or fat containing meals seems to have a huge impact on absorption and consequentially utilization.I ordered two shippings of "two month supplies" at the just mentioned dosage, from a different than Amazon vendor, after ordering and partially consuming this Carlson product.I just discovered that Amazon now has vendors, including itself or Prime vendors, that carry the 15 mg/90 capsule bottles, which would be the Japanese monthly dosage for osteoporosis therapeutics. The source, brand, bottler, or whatever is called "Complementary Prescriptions" and can be located with a search on Amazon. The bulk manufacturer is probably based in China, though this isn't documented for the above product, there does seem to be MK-4 manufacturing sources in China, (...and since it isn't stated as being based elsewhere...).edit: In Japan the supplier is "Eisai" who apparently has a patent from the Ministry of Japan. MK-4 is sold in Japan and across Asia under the brand name Glakay.

Quick shipping. Very satisfied.

I'm glad they make this MK-4 version. MK-7 gives me horrible insomnia, even though other people do just fine on it.

Was having problems for MONTHS with inner ear fullness - had what felt like a lot of wax buildup. I could barely hear, I couldn't sleep, I could hear my heartbeat in my ear - it felt like pulsatile tinnitus. Absolutely unbearable. I would spend half of my nights crying because of the immense amount of distress I was in. My nutritionist and I eventually determined that it might be inner ear calcification, which would point to a K2 deficiency. So I bought this, and Solgar's K2 MK-7 supplement, and within two days my ear problems began to reverse!! I do believe my dietary changes had a lot to do with the reversal (was previously vegetarian for 15 years, then switched to mostly carnivore, with lots of raw dairy) - but this stuff skyrocketed my healing. If you have inner ear problems like I had, it might be a K2 deficiency. The inner ear inflammation seems to be *extremely* sensitive to stress/nerves, even whilst healing, so it'd be very beneficial to learn calming techniques as well, like meditation, or drink calming teas. :)

My wife and I have been taking a capsule daily for several months now.I have noticed vague differences that may only be psychological or related to something else.Nonetheless, I feel good about taking this product based on the burgeoning research that is taking place regarding Vitamin K2 (the MK4 version has had the most studies done at this point). Cause and effect points to K2 superior to our previous routine of taking calcium and Vitamin D. We have stopped taking calcium (we eat foods that have plenty of calcium) and are now taking D and K2. Do some research and one will find that K2 is superior regarding bone building/bone loss prevention along with preventing calcification of arteries, heart tissue/other organ tissues vs. the accepted, conventional calcium supplementation. There are also other suspected benefits being investigated.

Vitamin K2 plays a key role in the proper distribution of calcium; in particular, it helps to move it out of the circulatory system where it can lead to atherosclerosis and into the skeletal system leading to stronger bones. It is hard to get enough K2 from diet alone and while the body converts some vitamin K1 into K2 the conversion rate decreases with age. Vitamin K2 supplements typically come in one of two forms: MK4 or MK7. Both forms have shown some success in the treatment of osteoporosis. MK4 has a short half-life in the blood of only a few hours whereas MK7 has a much longer half life. In Japan, MK4 is used, by prescription, to treat osteoporosis at a dose of 45 mg/day typically subdivided into three smaller doses whereas MK7 is typically taken is much smaller doses of ~100 micrograms/day. The Carlson capsules contain 5 mg of MK4, so one would need to take 9 per day to match the dose prescribed in Japan (Carlson Labs only recommends taking 1 capsule per day). Even one capsule provides 6250% of the RDA for vitamin K. Presumably the very high dosages were initially explored to counteract the short serum half like of K2/MK4 and research into benefits at lower doses is not yet available. Vitamin K is typically well tolerated at very high doses (K1 does not seem to have an established dose at which it becomes toxic) so for many people greatly exceeding the RDA values won't be an issue. However, Vitamin K interferes with blood thinning medications such as Warfarin, so doses at these levels are dangerous for those taking these medications. Partly for this reason, you don't typically find vitamin K2 in multivitamins. A very strong case can be made for the benefits of supplementation of K2, but optimal dosing and the choice between MK4 and MK7 are murky issues at this time. Supplementing with both MK4 and MK7 may be the best option.