Side effect MK-7

I would like to know if anyone else has experience breast tenderness when taking MK- 7. I have been taking it every other day and still get the reaction. I know it is from the MK-7 since when I do not take it my breasts are not tender. I am in my sixities. I also wanted to know if there was another MK-7 that was not from soy that would be just as good since I feel it is the soy that is the problem.

Report post

12 replies. Join the discussion

This is an unusual result. You could try changing to the MK4 from of Vitamin K2 which is also produced by the human body, just not enough as we get older. Other option is to go to a different provider of MK7 and see if your symptoms change.
Give us a report in case others are experiencing this.

Report post

You could try th Mk4 which you would have to take 3 times daily. A bit more exppenive, but I prefer it over the mk7. Pure formulas has it (complementary prescriptions).

Report post

On Dr Sue Brown's 'Better Bones Blog' she mentions Dr Cees Vermeer's three year European study using natural Vitamin K 2 MK-7 which was found to increase BMD in both the hips and spines of postmenopausal women. Does MK - 4 do the same?
I have been trying to avoid heavy duty traditional drugs and was so pleased to read this study, but unfortunately I have found that Vitamin K 2 MK-7 or MK4 is impossible to get hold of due to the rulings of the TGA here in Aussie! So will have to stock up on Japanese natto!!!
Unbelievable really, of course they are happy for you to have traditional drug treatment!! Need to move to your neck of the woods!

Report post

I have never taken K2 and so cannot comment on the side effects. I am not surprised at the effects Petluv had because it is Soya; I'm guessing a much higher concentration than we would get from tofu or S milk. I personally don't like to take soya albeit fermented.
However I have read a lot and watched the interview with Dr Vermeer and Dr Mercola re K2.
I noticed ( and you have to be attentive not to miss it) that he said the trials were done using K2 MK4 but they are promoting K2 MK7 because it stays longer in the body.
I'm inclined to agree with the comments here that suggest MK4.
I m not having success in finding it in Europe, anyone know of a reputable brand availabe please?

Report post

Hi Dormouse,
Thorne's vitamin K2 MK-4 liquid, 1 drop=1mg, is what I use and I've bought it from the company MandiMart.
I've ordered it from them twice with no problem delivering to France.

Report post

Hi Lela, Thank you for this, I had not heard of Mini mart, will be having a good look at that later.

I must say the Thornes drops are very expensive, it must be difficult to make perhaps, is it synthetic do you think?

Can you tell us how you like it, do you feel any effects from it, like smoother teeth or anything?

Report post

Hi Dormouse & Petluv

According to vitamin K2 MK-4 is synthetic, vitamin K2 MK-7 is natural, from natto, but there are also new synthetic forms of MK-7, synthesized from flower extract such as geraniol and famisol.
Member Tango02 has explained that the synthetic vitamin K2 MK-4 is identical to the MK-4 produced by the human body.
I did a quick search on Google for synthetic MK-7 and these links came up: c-vitamin-K-mass-market -agreement-on-vitamin-k2-mk-7/

Petluv, in the 3rd link dated Mar 29 2012, they say "This new unique form of vitamin K2 (synthetic MK-7/Lela) has been developed by Kappa Bioscience in Norway. In 2011 DuPont entered an agreement with Kappa to cooperate on expanding sales to global markets, and the new vitamin was launched in selected markets already last year." - so if you want a synthetic MK-7 maybe you can contact them and ask where you can buy it?

Unfortunately vitamin K2 MK-7 gave me heart palpation. I've had no such side effect with MK-4 and yes I feel a difference on my teeth. Many talk about that it clear up their sinuses, and that is something that I feel too. Smother skin is also mentioned but I've never had any problems with dry skin (Yeah, got to be thankful for non-problem areas!) but yes, I think I need even less lotion nowadays.

There have been MANY discussions on Inspire about vitamin K2, the different forms and side effects - for instants this and this.
But I don't remember ever reading about your side effect Petluv.

I like what I've read about MK-4. The advice to take MK-4 3 times a day is nevertheless something that I've had a hard time following so today I take mine twice daily, after/at the end of my breakfast and dinner meals (I've read somewhere, but can't find the reference, that if you take it (directly) after your meal it will be much better absorbed). In this study, they only took a low dose MK-4 ONCE daily, after breakfast, and got a good results.

There is also research pointing to the fact that MK-4 can do something that MK-7 can't ! - I find that interesting. "MK-4 can modulate/upregulate certain genes; growth differentiation factor 15 (GDF15) and stanniocalcin 2 (STC2) in human Osteoblastic cells" - you can read about that in the article Are the MK-4 and MK-7 Forms of Vitamin K2 Equivalent?

Dormouse, on the topic of vitamin K2 - what do you think about The French Paradox ...?

This was posted by a reader as a comment to the "MK-4 & MK-7 .. equivalent?" article. "It's interesting to note that many French people get a high intake of both -4 and -7, the former from foie gras (and other pate and liver containing charcuterie) and the latter via their cheese. ... I'll bet those factors have far more to do with explaining the "French Paradox" than red wine and resveratrol."
The following is from an Inspire discussion about vitamin K2 "Perigord, France, is the world's capital of foie gras, or fatty goose liver. Good news for the bon vivants: foie gras turns out to be the richest known source of K2 (MK-4/Lela). Perigord also has the lowest rate of cardiovascular mortality in France, a country already noted for its low CVD mortality. …" member Sylvia6789 posted that and it was a quote from this article, she has also posted this list of Foods containing vitamin K2.
I think vitamin K2 is a real factor but I think there is also a difference HOW(!) French people eat - They sit down! don't look stressed and it takes time! Often they eat a menu - appetizer, main course, cheese and dessert. The courses are not huge. Yes they drink wine but what I see at lunchtime is that most people are drinking water. This is my reflection as a foreigner who have moved to France.

Good luck with choosing your vitamin K2 supplements. I like Thorne's liquid MK-4 because it is easy to adjust the dose - yes it is expensive when you buy it but there are 1200 drops(=mg) in the bottle so it lasts a long time. Kind regards /Lela

Report post

I think the MK7 form is pushed because it is cheaper and stays in the body longer. I personally think that the MK4 form is the better way since you do replenish it on a regular basis and therefore do not have build up. Each body is different and for me pesonally the idea that i may be taking too much of something one day and not enough on another because it may store in my body differently depending on my body chemistry at that time makes me a bit uncomfortable. I liike the Pure Formulas because it is a little pill. I keep a stash in my purse and try to remember the lunch time pill. I figure that I at least get it for breakfast and dinner, and don't sweat it if I forget the lunch time. I also take a small dose of Strontium before bed. Taking the MK4 with meals as I do all my supplements seems to help me better metabolize what I am taking. I also do not get any side effects. I figure it is the most natural way to take supplements. I get my DEXA this summer and we shall see if I get a change in my numbers. It has been two years so I am keeping my fingers crossed. So glad my Gynecologist suggested this site to me. I have learned so much and gained access to information and sites to learn more. Thank you to all who share here.

Report post

Thanks everyone who posted on this thread. I have been on/off with the k2 over the past yr...probably due to the expense and also the skepticism as to ....does it really work? I just checked my bottle in the fridge and it is MK 4 from Thorne that I purchased from a naturopathic physician who seemed to know a lot about osteoporosis but not the hyperparathyroidism. I still have not had the surgery so I wasn't sure if it would really increase bone while I still had the high PTH....anyone know this?

Report post

The 5th paragraph down in your post you mention the low dose in "this study". I checked out the study and that
looks like a really low dose of only a drop of mk4 as it said 1.5 mg/day.
Maybe there was a typing error? or maybe I misunderstood something.

Report post

Thank you Lela for the incredible amount of information and links that you have given us.
I had a look at the list of foods that contain MK4 and worked out that even if you managed to concentrate on eating as much as possible with K2 MK4 in you could only get about 100 mcg and that would be hard going, probably have to eat a bit of Goose liver as well to get that much.
This is incredibly small considering the doses they are recommending. I realise that the doses are as a treatment but it is astounding. If you only take 1mg per day that is 10 times more than you can eat, if you take 45mg per day 450 times more than you can eat!
I know this has been said before and I also think Thornes drops are the way to go then you can gradually introduce it in small doses and divide it throughout the day.

Report post

Hi Greengold, No I can't imagine that it is a typing error because in the full text (pdf) of the study they state that the aim of the study was to examine the effect of supplementing a low dose of 1.5mg vitamin K2 MK-4 taken daily after breakfast for 4 weeks and measure different things, for instants various markers of bone turnover, in healthy postmenopausal Japanese women between 53-65 years of age. It states that they didn't eat natto (MK-7) for 1 week before and during the study. This graph below is from the study and shows that - quote "After 2 and 4 weeks of supplementation, ucOC (undercarboxylated Osteocalcin) in the MK-4 group was significantly lower than in the control group."

Bild 41

Note: there is no mention of the participants bone density or fracture risk ("healthy postmenopausal") - the aim of this study was not to study if this low dose reduced fractures, this was a short study that looked at varoius markers of bone turnover. For more results and info about the study please download and read the full text pdf because I couldn't copy text ftom the pdf and paste here. I hope this helped /Lela

Hi Dormouse, your welcome - glad I could help :-)

Report post

This discussion is closed to replies. We close all discussions after 90 days.

If there's something you'd like to discuss, click below to start a new discussion.

Things you can do

Support NOF

Help the National Osteoporosis Foundation reach its goals and support people like yourself by making a donation today.

Donate to the National Osteoporosis Foundation

Learn more about osteoporosis awareness and prevention

Discussion topics

Links and resources from NOF

Community leaders


The National Osteoporosis Foundation would like to remind visitors and community members that the views and opinions expressed on this site are not necessarily those of NOF. Please consult your personal healthcare provider regarding any medical information that is shared on this site.