Flush-free niacin kills

Here, I re-post a conversation I've posted before, that of the scam product, "no-flush" niacin, also known as "flush-free" niacin.

I find this issue particularly bothersome, since I have a patient or two each and every week who forgets the explicit advice I gave them to avoid these scam products altogether. Despite costing more than conventional niacin, they exert no effect, beneficial or otherwise. Niacin--the real thing--exerts real and substantial beneficial effects. No-flush or flush-free does nothing except drain your wallet. I continue to marvel at the fact that supplement manufacturers persist in selling this product. Ironically, it commands a significant premium over other niacin forms.

They are outright scams that should be avoided altogether.

My former post, No-flush niacin kills:

Gwen was miserable and defeated.

No wonder. After a bypass operation failed just 12 months earlier with closure of 3 out of 4 bypass grafts, she has since undergone 9 heart catheterization procedures and received umpteen stents. She presented to me for an opinion on why she had such aggressive coronary disease (despite Lipitor).

No surprise, several new causes of heart disease were identified, including a very severe small LDL pattern: 100% of LDL particles were small.

Given her stormy procedural history, I urged Gwen to immediately drop all processed carbohydrates from her diet, including any food made from wheat or corn starch. (She and her husband were shocked by this, by the way, since she'd been urged repeatedly to increase her whole grains by the hospital dietitians.) I also urged her to begin to lose the 30 lbs of weight that she'd gained following the hospital dietitians' advice. She also added fish oil at a higher-than-usual dose.

I asked her to add niacin, among our most effective agents for reduction of small LDL particles, not to mention reduction of the likelihood of future cardiovascular events.

Although I instructed Gwen on where and how to obtain niacin, she went to a health food store and bought "no-flush niacin," or inositol hexaniacinate. She was curious why she experienced none of the hot flush I told her about.

When she came back to the office some weeks later to review her treatment program, she told me that chest pains had returned. On questioning her about what she had changed specifically, the problem became clear: She'd been taking no-flush niacin, rather than the Slo-Niacin I had recommended.

What is no-flush niacin? It is inositol hexaniacinate, a molecule that indeed carries six niacin molecules attached to an inositol backbone. Unfortunately, it exerts virtually no effect in humans. It is a scam. Though I love nutritional supplements in general, it pains me to know that supplement distributors and health food stores persist in selling this outright scam product that not only fails to exert any of the benefits of real niacin, it also puts people like Gwen in real danger because of its failure to provide the effects she needed.

So, if niacin saves lives, no-flush niacin in effect could kill you. Avoid this scam like the plague.

No-flush niacin does not work. Period.

Disclosure: I have no financial or other relationship with Upsher Smith, the manufacturer of Slo-Niacin.

Copyright 2008 William Davis, MD

Comments (12) -

  • JPB

    11/29/2008 4:15:00 PM |

    What is your opinion of "Nia-Span"?  My former doctor insisted that this "by prescription only" drug was the only way to take niacin.  The cost per month was virtually the same as for a statin.  (BTW, I declined this product and continued with regular niacin.)

  • Anna

    11/29/2008 4:31:00 PM |

    FYI: the Slo-Niacin link isn't working.

  • Zbig

    11/29/2008 11:02:00 PM |

    RDA for niacin is 18 mg/day - what is your opinion on that, sir?
    BTW, do you guys in the States just go to a pharmacy and buy niacin and D3 without a prescription?

  • Anonymous

    11/30/2008 6:37:00 AM |

    "Slo-Niacin" uses a "polygel" to delay release of the nicotinic acid.  I've been taking Carlson's "Niacin-Time" (also nicotinic acid) which uses brazil wax to delay release.

    The Carlson's product is about a third the price of the Slo-Niacin.

  • IggyDalrymple

    12/1/2008 1:13:00 AM |

    I've been taking regular (not no-flush) niacin for a few months.  Dr Davis recommends "Slo-Niacin" but I got sick from taking timed-release niacin back in the 80s and "Slo-Niacin" sounds suspiciously like "Timed-Release".  I should know in January when I have bloodwork, if the regular niacin helps.

  • Anonymous

    12/3/2008 9:26:00 PM |

    JPB: Niaspan releases over 6-8 hours and yes..it is prescription only. I substituted it for Endur-acin which is MUCH cheaper and non-prescription and also releases over 6-8 hours. No difference in my lipid profiles...just big savings in my pocket book.

    Zbig: 18mg is probably sufficient as a RDA, but in order to achieve the lipid lowering affects from Niacin, one has to take larger doses of 500mg or more from what I understand. And yes, we can buy many supplements like (high dose) niacin, vitamin D3 & even DHEA without a prescription here in the USA.

    Anonymous: I believe Carlson buys their "Niacin-Time" from Endur. I looked at the picture on the Carlson website and the tablets are the exact same shape as Endur-acin. Endur has been around since the late 1980's from what I understand. You can buy direct from Endur.

    IggyDalrmple: Here is a link to an excellent article about (time-release) Niacin written by Doctor Davis himself:


  • CindynHouston

    2/3/2009 5:15:00 AM |

    Hi, Id like to know what research supports flush free Niacin has no effect on the human body ?
    I had/have horrible heart palpitations after a heart attack, and after taking Flush Free Niacin 2 to 3 times daily, control them, while time released I tried did not .. and Im afraid to take regular Niacin being so unstable.  I take several other things as well now, but not at the beginning.  I have Late Stage Lyme which has its own set of causal factors as well as the typical ones, but if it has no effect on the human body .. it wouldnt work period.  So, I would guess ..  like all else one thing might work for some, another substance for another depending on what I wish they would narrow down to "Cause".  I still have high Blood pressure, some medications work for a week or two, then stop being effective.  Areas of the brain control heart beat .. I have no clue if this is the whats causing high blood pressure or not .. Lyme can go any where and do anything .. Ive had it since I was a child with mild symptoms until my immune system got a faulty in mid thirties when it became aggressive.  No Doctors know how to treat other than antibiotics, dont treat symptoms like really bad hypercoagulation (thick blood) caused by being exposed to bacteria etc for a long period of time and the immune system becoming over active .. 2002 I had an attack which took me out almost completely .. No heart or other doctor even tried to diagnose and gave me a "hearts fine" .. 3 yrs later I had an almost deadly heart attack.  All these yrs, almost 10 .. spent trying to find help, treating symptoms on my own, having no family and absolutely No life, except for trying to survive. (people with Lyme ramble) Though its good to know info.... Question still remains about Flush Free Niacin...

  • Anonymous

    8/25/2009 9:29:49 PM |

    "IHN is more effective than niacin in its hypocholesterolemic,
    antihypertensive and lipotropic effects"
    Welsh AL, Eade M. Inositol hexanicotinate for improved nicotinic acid therapy.
    Int Record Med 1961;174:9-15.

    "significant lipid-lowering effects of IHN at doses of 400 mg 3-4 times daily"
    Dorner V, Fischer FW. The influence of m-inositol hexanicotinate ester on the serum lipids and lipoproteins. Arzneim-Forsch 1961;11:110-113.

    Sommer H. Nicotinic acid levels in the blood and fibrinolysis under the influence of the hexanicotinic ester of m-inositol. Arzneim Forsch. 1975;15:1337

    "IHN was found to be more effective than niacin in reducing hypercholesterolemia"
    El-Enein AMA, Hafez YS, Salem H, Abdel M. The role of nicotinic acid and inositol hexaniacinate as anticholesterolemic and antilipemic agents.
    Nutr Reports Int 1983;28:899-911.

    "Derivatives of niacin have been examined for their ability to alter lipid levels as well as niacin. It would be advantageous if the niacin vasodilation (flush) were eliminated or removed. The main disadvantage of the niacin derivatives will be cost. Inositol hexanicotinate is an ester of inositol and niacin. In the body it is slowly hydrolyzed releasing both of these important nutrients. The ester is more effective than niacin in lowering cholesterol and triglyceride levels, Abou El-Enein, Hafez, Salem and Abdel (1983). I have used this compound, Linodil, available in Canada but not the U.S.A. (at the time this paper was written) for thirty years for patients who can not or will not tolerate the flush. It is very gentle, effective, and can be tolerated by almost every person who uses it."
    From: Niacin, Coronary Disease and Longevity by Abram Hoffer, M.D., Ph.D.

  • LynP

    11/16/2009 5:25:16 AM |

    Question:  at dinner took 500 mgm Slo-Niacin and within a few hrs had some stomach unpleasant...sensations might be the best description, then my glucose rose.  Fasting rose 25 pts (shock) and yesterday was marked with ravenous hunger and 15-20 pts higher glucose all day; today's fasting was still higher than usual.  Is this expected?  It's almost as if it is undoing the work of my 1500 mg metformin ER in reducing the production of sugar in the liver. This isn't going to wk with higher glucose.  Suggestions? Comments?
    6/25/09 labs: TRI-119, calc LDL-150, HDL-57, D-35, TSH-4.5, AIC-6.4. Taking 12.5 mg Maxzide, 4K IU D3.
    9/22/09 labs: TRI-145, calc LDL-147, HDL-60, D-41, TSH-5.5, AIC-6.5, ApoB-111. Taking 12.5 mg Maxzide, 8K IU D3.
    Doc put me on 25 mcg levothyroxine (don't think this is enough or I need Armour).

    I think my TRI is up from too much carb (eat super low, ate a bit more more berries over summer).  I think my LDL is up from my rising TSH (free T4 & T3 midrange), been rising since Sept08 when it was 2.8 (when I started taking vit D). Wt loss (obese) has been stalled until I started subbing eggs for hi-protein shake with 2-3 ozs coconut milk a month ago.  TSH was high in 2001 (4.7) with high amts of reverse T3 (doc won't test for it)& given 2 mcg Cytomel but my TC was 205 with TRI=100. Now what to do?  Try the 250 mgm SloNiacin & see what happens?  Or just concentrate on improving D levels and improving thyroid function and hoping they help normalize lipids? Just looking for suggestions, not treatment, all ideas will be run by doc. He said statins or niacin...I'm female no familiy hist of heart probs, why statins with no good studies for women? 'Cause he takes a statin *sigh*.

  • Anonymous

    8/16/2010 3:17:08 AM |

    After my heart attack from Late Stage Lyme Disease causing hypercoagulation/thick blood .. after released from the hospital, I had/have severe heart palpatations .. and IM SORRY BUT, FLUSH FREE NIACIN DOES WORK!!  I have to take 2-500mg twice daily and it stops the heart palpatations .. its no gimmick or hype.  IT Works !!  Ive heard about the severe very uncomfortable flush rush with regular Niacin which I think would scare me and make me panick, if not make me ill with the fragile state my system is in.  Purchased at any store online or otherwise .. a lot less than and w/no side effects, I also take Argnine to help open my vessels, but is not needed to stop my heart palpatations. Obviously, something is wrong though if I or anyone is having heart palpatation, so you should keep looking or asking RN/head nurse until you find a heart doctor who will actually address the issue and find out whats going on!!  Once in a while with stressful event I do need to take a beta blocker to stop palpations, but only 3-5 times a yr.  NO SIDE EFFECTS like beta blockers...

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    11/3/2010 3:18:31 PM |

    Given her stormy procedural history, I urged Gwen to immediately drop all processed carbohydrates from her diet, including any food made from wheat or corn starch. (She and her husband were shocked by this, by the way, since she'd been urged repeatedly to increase her whole grains by the hospital dietitians.) I also urged her to begin to lose the 30 lbs of weight that she'd gained following the hospital dietitians' advice. She also added fish oil at a higher-than-usual dose.

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Does fish oil cause blood thinning?

Does fish oil cause blood thinning?

Omega-3 fatty acids from fish oil have the capacity to "thin the blood." In reality, omega-3s exert a mild platelet-blocking effect (platelet activation and "clumping" are part of clot formation), while also inhibiting arachidonic acid formation and thromboxane.

But can fish oil cause excessive bleeding?

This question comes up frequently in the office, particularly when my colleagues see the doses of fish oil we use for cardiovascular protection. "Why so much fish oil? That's too much blood thinning!"

The most recent addition to the conversation comes from a Philadelphia experience reported in the American Journal of Cardiology:

Comparison of bleeding complications with omega-3 fatty acids + aspirin + clopidogrel--versus--aspirin + clopidogrel in patients with cardiovascular disease.(Watson et al; Am J Cardiol 2009 Oct 15;104(8):1052-4).

All 364 subjects in the study took aspirin and Plavix (a platelet-inhibiting drug), mostly for coronary disease. Mean dose aspirin = 161 mg/day; mean dose Plavix = 75 mg/day. 182 of the subjects were also taking fish oil, mean dose 3000 mg with unspecified omega-3 content.

During nearly 3 years of observation, there was no excess of bleeding events in the group taking fish oil. (In fact, the group not taking fish oil had more bleeding events, though the difference fell short of achieving statistical significance.) Thus, 3000 mg per day of fish oil appeared to exert no observable increase in risk for bleeding. This is consistent with several other studies, including that including Coumadin (warfarin), with no increased bleeding risk when fish oil is added.

Rather than causing blood thinning, I prefer to think that omega-3 fatty acids from fish oil restore protection from abnormal clotting. Taking omega-3 fatty acids from fish oil simply restores a normal level of omega-3 fatty acids in the blood sufficient to strike a healthy balance between blood "thinning" and healthy blood clotting.

Comments (20) -

  • Marc

    10/26/2009 9:46:32 PM |

    Long time reader, first comment.
    Thank you for so freely sharing all the information.


  • Daniel

    10/26/2009 11:02:46 PM |

    Thank you for this!  I have had this question for a long time given the number of things I take that "thin the blood."

  • Kevin

    10/26/2009 11:44:45 PM |

    As a veterinarian I've dispensed fish oil capsules for several years.  Some owners give so many that the dogs smell 'fishy' when seen for routine care.  The owner doesn't smell it since they're with the dog a lot.  The coats are gorgeous, something that doesn't often happen in Wyoming at 7000ft altitude.

  • Dr. William Davis

    10/26/2009 11:47:45 PM |

    Hi, Kevin--

    My two Boston terriers jump for their fish oil capsules, two every day!

    I'm glad to hear from a veterinarian that the coat sheen is indeed from the fish oil.

  • Rich

    10/27/2009 1:27:09 AM |

    Due to an afib episode a couple of years ago, I was taking 20 mg of warfarin per day, plus around 5000 mg of EPA+DHA, and never had bleeding issues.  

    My INR was always a stable 2.0.

    As I've not had an afib reoccurrence, I've replaced the 20mg coumadin with 325mg aspirin daily, and still take around 5000 mg EPA+DHA.  No bleeding issues with that combo either.

  • Catherine

    10/27/2009 3:55:32 AM |

    Glad this topic came up.
    Over the last 5 years, I've had to periodically eliminate my fish oil intake as I would start to bruise badly. My internist said she has seen this occasionally with fish oil and called it "capillary fragility." I bruise easily anyway, but it would really get bad with fish oil. So there must be some quality in fish oil that influences this.

    Then about 6 months ago I started a strong supplement change to help with my low bone density--already taking magnesium and calcium but added:
    Boron, K2, silica,pomegrantate juice, and BIG increase in vitamin D.
    I also increased omegas to 3,000 a day which I was not able to tolerate before.

    It has been over 4 months since I have had ANY bruise---which is just unheard of for me. I usually have 3-4 different bruises on arms/legs. So something in these supplements  strengthened my capillaries I guess, and I can now take high fish oil doses!
    Anyone else had a bruising problem with fish oil?

  • Dr. William Davis

    10/27/2009 11:04:59 AM |

    Hi, Catherine--

    Fascinating observation!

    I'll bet it has something to do with the vitamin D, more than anything else. Vitamin D seems to strengthen structural tissues in bones, muscle, heart valves, and perhaps capillaries and other small blood vessels.

  • trix

    10/27/2009 11:59:37 AM |

    Several years ago I bruised easily for a while and attributed it to taking garlic supplements daily.  I started taking Vit C and the bruising stopped.  I don't think it had to do with fish oil (in my case); I don't think I was taking fish oil at the time.

  • Daniel

    10/27/2009 9:37:33 PM |

    I too achieve rapid blood thinning when taking 2400mg of EPA/DHA per day. That's only 4 pharmaceutical grade capsules. Even after my vitamin d levels were normalized I still got bruising.

    I now take Vitamin K2 (MK-7 natto extract) twice a week and it's allowed me to bump my EPA/DHA up to 3600mg with no ill effects or bruising.

    It was either supplement or eat a lot of aged cheese, they both seemed to do the trick in my particular case.

  • Healthy Oil Guy

    10/27/2009 9:53:51 PM |

    Thank you for sharing this study with us.  It helps clarify whether there is a risk for blood thinning from taking fish oils.  This information may help individuals who are taking blood thinning medications and considering adding fish oils to their daily diet.

  • Dave

    10/28/2009 2:22:01 AM |


    Without a doubt, your cessation of bruising was due to vitamin k2. I routinely take nattokinase, large doses of fish oil, curcumin, and other blood thinning agents, and if I don't take vitamin K2, I will begin bruising. (I also take high doses of Vitamin D). When I take K2, I have absolutely no bruising.

    Vitamin K2 has many clinical trials showing that it helps endothelium  integrity and elasticity.

    Also, grapeseed extract and pine bark extract (specifically oligomeric proanthcyanins) has the same beneficial effect.

  • Catherine

    10/28/2009 4:41:41 PM |


    That's really interesting! There is a lot of research on K2's effect on strengthening weak bones. Bone fractures go down considerably when high doses of K2 are used (Japan is using K2 as osteoporosis treatment) BUT studies show it needs to be in conjunction with adequate calcium and Vitamin D---they work synergistically for bone strength.  So it makes sense that K2 and D could do the same with strengthening fragile capillaries. I am also taking the M7 natto form.

  • Catherine

    10/29/2009 12:01:36 AM |


    Thanks for sharing your experience with this, you've really confirmed it now for me.  I can't believe I have suffered with this for most of my life with no answers (tried high dose Vit C, grape seed, etc) and now within months on K2, there's no bruising and I can tolerate fish oil. Hope my bones are responding this well!
    This blog is so helpful....

  • Mina

    10/29/2009 12:21:31 PM |

    Thanks for posting this. The question recently came up in our office. I like your assertion that omega-3s restore the blood to normal and remove abnormal clotting. And to comment on a post above, our dog has a beautifully shiny coat and takes 2 pure EPA capsules each day!

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    I have enjoyed reading That During nearly 3 years of observation, there was no excess of bleeding events in the group taking fish oil. (In fact, the group not taking fish oil had more bleeding events, though the difference fell short of achieving statistical significance.

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    I've been drinking fish oil for many year and I don't have any chance in my body people use to said me that but I think it is just a rumor.

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  • moseley2010

    12/7/2010 2:37:16 AM |

    I haven't heard of this problem
    fish oil supplements. But now we know what to tell them when this sort of concern comes up. Fish oil or Omega-3 is really beneficial to health. It's just important that it comes from clean waters.

  • Jack

    3/12/2013 7:03:38 PM |

    What is an appropriate dose of fish oil for someone taking coumadin?

  • dorange

    6/15/2014 3:53:03 PM |

    Dr. Davis, when  person is taking Tamoxifen...
    (1) is it safe to take vitamin k2 or K1?
    (2) will fish oil have a role in preventing blood clots?