Warning: Your pharmacist may be hazardous to your health

Pharmacists can be very helpful resources when it comes to questions about prescription drugs.

The operant word here is drugs.

What they are most definitely not expert on are nutritional supplements. In fact, a day doesn't pass by without having to dispell one falsehood or another conveyed to a patient about a nutritional supplement by a pharmacist.

Among the more common falsehoods told to patients by pharmacists:

"You have to take Niaspan. Sloniacin doesn't work."

Patent nonsense. A few years back, I was the largest prescriber of Niaspan in Wisconsin. Although I am embarassed to admit it, I also spoke for the company, educating fellow physicians on the value of niacin for correction of lipid disorders.

Then I shifted to Sloniacin due to cost--it costs 1/20th the cost of prescription Niaspan. I examined the pharmacokinetic data (pattern of release in the body), the published literature (e.g., the famous HATS Trial), and have used Sloniacin over 1000 times in patients. In my experience, there is no difference: no difference in efficacy, no difference in safety, no difference in side-effects. There is a BIG difference in price.

Unfortunately, most pharmacists get their information on niacin from the Niaspan representative.

"You shouldn't be taking vitamin D supplements. I have prescription vitamin D here."

What the pharmacist means is that you should replace your vitamin D3, or cholecalciferol--the form recognized as vitamin D by the human body--with the plant form of vitamin D, vitamin D2 or ergocalciferol.

Since when is a plant form of a hormone (vitamin D is a potent hormone, not a vitamin; it was misnamed) better than the human form?

I've previously talked about this issue in a blog post called Vitamin D for the pharmaceutically challenged.

The notion that D2 is somehow superior to the real thing, D3, is absurd. I use D3 only in my practice and have checked blood levels thousands of times. As long as the D3 comes as a gelcap, drops, or powder in a capsule, it works great, yielding predictable and substantial increases in blood levels of 25-hydroxy vitamin D. If it comes as prescription D2 (or over-the-counter D2), I have seen many failures: no increase in blood levels of vitamin D or meager increases.

Prescription status is no guarantee of effectiveness.

"Why do you need iodine? You already get enough from food."

The NHANES data over the last 25 years argue otherwise: Iodine deficiency is growing, particularly as people are avoiding iodized salt and the iodine content of processed foods is diminishing. The explosion in goiters in my office also suggest this is no longer a settled issue.

On the positive side, it is exceptionally easy to remedy with an inexpensive iodine supplement. That is, until the pharmacist intervenes and injects his bit of nutritional mis-information.

I'm not bashing pharmacists. In fact, Track Your Plaque's own Dr. BG has a pharmacy background, and she is an absolute genius with nutritonal supplements. But she is a rare exception to the rule: Most pharmacists know virtually nothing about nutritional supplements. You might as well ask your hairdresser.

Comments (24) -

  • Jenny

    6/11/2009 10:55:25 PM |

    Dr. Davis,

    Excuse me if I missed it, but what dose would you suggest supplementing iodine at?

    I've been taking a kelp pill with 150 mc since reading your blog posts about it. I seem to feel perkier, but that might be placebo effect, or spring.

  • Anonymous

    6/12/2009 2:47:45 AM |

    Actually your hairdresser might know a lot more than your pharmacist.Hairdressers do have to study nutrition you know!.

  • Helena

    6/12/2009 2:50:41 AM |

    You are saying what I have been saying for years! I am so glad I found your blog! I take at least 5000 IU of Vitamin D3 every day.
    More often I meet Doctors and other people whitin the prescription drug industry that questions my motive on taking natural nutrition, and all I do is shake my head and wonder why they are allowed to call themselves doctors. I thought that the most important thing was "First do no harm"...

  • Anna

    6/12/2009 3:06:43 AM |

    I would add that the vitamin & supp store clerk's advice needs to be taken with a grain of salt, too, at least until you have learned which clerks to trust.  

    At the local stores where I buy my supplements, there are some clerks whose judgement I trust quite a bit when choosing a new supplement or brand, because they have given sound, credible advice in the past, and I know from discussions they have a sound understanding of human nutrition and physiology.  

    But there are a few clerks I know to avoid like the plague, because they have too often "dispensed" patently untrue, biased, and  uninformed nutrition and biochemistry advice.   One of them (the one with the huge divots in his cheeks from protein deficiencies) tried to sell me "whole food plant-sourced" Vitamin D, with the argument that whole food sources are always superior (I already knew to take the fish liver D3, not the D2 from rradiated yeast or plant sterols).

    I'm glad you keep reminding everyone about choosing the right form of Vitamin D - D3.

  • Anonymous

    6/12/2009 4:03:45 AM |

    "Most pharmacists know virtually nothing about nutritional supplements".... got that right.  I asked about vitamin k2 supplements and why there was a 120mcu restriction in canada.  The pharmacist said he knew only about Vitamin K as injections used for babies....

  • Peter

    6/12/2009 10:38:11 AM |

    I don't think you should bash hairdressers as ignorant about nutrition.  Mine has lost around 60 pounds eating low carb and looks great.  I'd take anything he says about nutrition seriously.

  • Kismet

    6/12/2009 11:22:06 AM |

    Personally, I've yet to meet a good pharmacist in Austria. Most of them are even worse than our mediocre doctors; it's really a shame...

    I think I know what you're up to with the sleeping poll! ;.)
    Is it?

    JAMA. 2008 Dec 24;300(24):2859-66.
    Short sleep duration and incident coronary artery calcification.
    King CR, Knutson KL, Rathouz PJ, Sidney S, Liu K, Lauderdale DS.

    I'd love to see the study results discussed.

  • Mark K. Sprengel

    6/12/2009 12:11:19 PM |

    Interesting, my fiance's father was recently give Niaspan by his doctor and at a pretty high dose. He had a severe reactions, jitters, heart sped up etc. and quit taking it. The Dr. said that couldn't have been caused by the Niaspan but the pharmacist said it was as he had the same reaction when he was on it.

  • Anonymous

    6/12/2009 3:15:08 PM |

    Great Post, Thanks.

    I am a bit curious though as to the difference between Niaspan and Sloniacin. From what I've been told, and correct me if I've been given false information, is that Naispan has a substantially quicker release time than Slonaicin, therefore being easier on the liver, especially at higher doses?


  • H

    6/12/2009 5:48:27 PM |

    I have a pretty specific question about the Vitamin D issue....

    I have a Vit D deficiency -- first noticed by the endocrinologist that I see for hypothyroidism. She prescribed a supplement over one year ago; and I get it tested every few months. So far, I still have a deficiency - I don't know the exact numbers, but I got the impression it hasn't moved much at all. I usually take a gelcap weekly for about six weeks after the blood test, and then drop back to taking it monthly (per her instructions).

    After reading the post you referred to above, I looked into it a bit more and confirmed that she has me on D2 (50k units, I think). So I asked her about this, told her about what I'd read on your website and others, and whether it would be better to switch to D3. She was emphatic that it would not...partly (or entirely?? I can't remember if she had other reasons too) because I already take SO MANY medications that finding a schedule that works for taking them where they all work effectively is already a huge challenge. (Some have to be taken alone, like Synthroid, etc. And I'm on warfarin, which just makes *everything* difficult.)

    She insists that she can get Vit D stabilized "eventually" with D2, and that sometimes it just takes awhile. She is an endocrinologist with -- as far as I can tell -- a good reputation locally; so she SHOULD know what she's talking about. But I just don't know; and the ongoing deficiency concerns me a little bit.

    What is your opinion? Should I be looking for another endocrinologist? Thanks in advance for any thoughts or guidance.

  • Dr. William Davis

    6/12/2009 7:32:26 PM |

    Hi, Jenny--

    After an exhaustive search, I have come to the conclusion that nobody knows the ideal dose of iodine for human health.

    However, 500 mcg per day has been working well for us.

  • Dr. William Davis

    6/12/2009 7:34:04 PM |


    Your doctor's attitude is, sadly, representative of the knuckleheaded bias of my colleagues: Prescription = good, non-prescription = bad.

    Yet there is no rational reason for this distinction when it comes to D2 vs. D3. D3 = human; D2 = non-human. Which are you?

  • Anonymous

    6/12/2009 7:49:57 PM |


    I believe they BOTH release over a 6-8 hour period of time. If Niaspan was released faster, my guess is that it would cause more flushing and that less people would be able to tolerate it.

    I myself take Endur-acin which is also released over a 6-8 hour period of time.

  • kris

    6/12/2009 8:50:41 PM |

    i usually order mine from IHERB. the reason being is that the feed backs from the users helps to make a collective decision. the feed backs are exclusive to the actual purchasers through email invitations. still better to study my self along with the feed backs. good price, fast shipping, best customer service and large collection.
    As to the iodine Dose, Dr davis, you are absolutely right about the iodine dose that no body knows. we have 5 people in our family. our doses are from lugol's 20mg a day to 650mcg from kelp to one person can only take 150mcg every second day. mostly it is the rapid heart beat and light pain behind the neck is the indication of over dose for me. when i first started taking iodine i have taken up to 50MG a day and it was lugol's. i felt great. but soon after few days i  had to reduce my doze. now i am taking kelp tablets with 650 mcg iodine in it. i am taking these with L-tyrosine 500mg along with vitamins B's. i feel that kelp contains bromine, therefore it helps to balance if it is over dose. i also do not take any vitamins or iodine etc. 2 days in a week, so that the body can not get lazy on this extra supply of vitamins. Iodine also helps to cleanup the body from mercury, bromine, fluoride etc. so it may develop little rash or other signs like too much sweating. i also felt that Norwegian kelp feels better than any other kelp for some reason.
    the other thing that i noticed that when starting iodine or thyroid hormones, one may notice loose gum and pain around the hard working side teeth. because iodine and thyroid hormones get rid of extra water from the body. bones become smaller and stronger. to get rid of the temporary discomfort to the teeth and gum, we have used turmeric powder as a mouth wash successfully. leave it in the mouth for a minute or so and it will help big time.

  • Jessica

    6/12/2009 11:25:02 PM |


    "So far, I still have a deficiency - I don't know the exact numbers, but I got the impression it hasn't moved much at all."

    Not at all surprising. D2 is only 1/3 as effective as D3. Taking 50,000 IU of D2 is equivalent to roughly 2,000 IU of D3.

    I started with a Vit D 25(OH) level of 26 ng/mL and it took nearly 9 months of 10,000 IU/daily of D3 to get an optimal level (70-90 ng/mL).

    If you have any of the NUMEROUS medical conditions that need Vitamin D, then you likely will require more D than the average person...if you're carrying extra weight you'll likely need more than the average person...if you're dark skinned, you'll likely need more than the average person...if you live north of Atlanta, GA, you'll likely require more D than the average person...

    With all of these factors, its not at all surprising that you haven't yet achieved a good Vit D level since you've only been taking D2.

    Taking D2 instead of D3 is like giving a thirty man in a desert a thimble of water to quench his thirst. He's getting water, right? But, it's not enough to do any good, so whats the point?

    Take D3 and take enough to get a good blood level.

  • Becki

    6/12/2009 11:51:17 PM |

    D3 is best in power or gelcap form?  Does that mean I'm wasting my money on the tablets I purchased?

  • Anonymous

    6/13/2009 12:59:06 AM |

    Hey Kent,

    My primary care physician sent me to a cardiologist at Ottawa heart institute.  I had already started using the "Now" brand Niacin after reading a study from Baylor's lipids online.  I asked about Niaspan as I assumed it was a pharmaceutical grade and more accurately controlled.
    The Cardiologist's comment was that the blood work indicated what I was taking was just fine but she had no issues providing a prescription for Niaspan.  My insurance at the time covered the cost.  I changed jobs, the new insurance company would not. I take 2grms at bedtime.  I sometimes get a flush and tingling, which I did with Niaspan too; but who the hell cares, my tg numbers speak to the value of this minor inconvenience
    Sups= Niacin/K2/D3/fish oil

  • gkwellness

    6/13/2009 8:07:48 AM |

    About 9 weeks back, my 25-Hydroxy Vitamin D levels were found to be dangerously low at 12.2 ng/ml! My situation led me to research, begin a self-directed treatment and create a blog www.gkwellness.wordpress.com to benefit others. I have taken a re-test of Vitamin D and expect the new results soon. Considering that my 6th week supplementation went up to 604,000 IU, it would be most interesting to know my new levels which I shall promptly post on my blog.

  • Helena

    6/13/2009 11:30:44 PM |


    "D3 is best in power or gelcap form? Does that mean I'm wasting my money on the tablets I purchased?"

    To answer you I would say that liquid is always the best. The body can absorb up to 98% when taken by liquid, but it can be as low as 20% when taking by pill. With powder you should always wait until it is compleatley dissolved (20 minutes) or you will loose some vital IU's.

    However I would not throw away your pills, but take them until you have no more. Until then I would look for a better alternative.

    I take my Vitamin D3 by liquid and I love it.

    Good luck!

  • Trinkwasser

    6/17/2009 1:26:50 PM |

    IME pharmacists have a competence range at least as great as doctors

    "If you needed a glucometer one would have been prescribed for you"

    "Sounds like you may be diabetic, I'll sell you a meter and you can take the test results to your doctor"

    two different pharmacists. I've found much the same with respect to knowledge both of drugs and other supplements. A good one can be an excellent source of useful information, if you can find one.

  • AustralianPharma

    12/15/2009 3:10:49 AM |

    I'd like to second a previous comment to put into perspective that a range of expertise exists across all members of a particular field, whether that be pharmacy or medicine. I've had plenty of disturbing queries from doctors to my pharmacy, one that comes to mind is from a doctor (over fifty years of age) that needed to know the name of any antibiotic that comes in a cream. You would think that over the course of a career, and access to printed and electronic resources within their practice, they could figure it out on their own. However, does that mean most GPs are woefully out of touch and lacking the continuing education necessary to practice or let along know where to find drug info without resorting to the phonebook for the nearest pharmacy? Of course not, branding an entire profession due to personal bad experiences is the same as saying a treatment is fantastic and bound to work because of hearsay evidence, or that it worked for your friend's friend.

    Most doctors I deal with are knowledgeable and I am glad to assist with queries, most pharmacists I find the same. If you are asking a 'shop clerk' for help, that is different from asking a pharmacist. It is like asking the receptionist at your  GP's clinic to check your rash and makes a diagnosis.


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  • rhett daniels,m.sc.

    5/2/2011 10:23:31 AM |

    hello -

    there IS a difference between Slo-Niacin and Niapsan.  It has to do with the difference btw Ph-dependent release and non Ph-dependent release.  the Niaspan product has a bile containing element that achieves optimum absorption at targeted GI areas.

    also, there are two forms of pharmaceutical grade D2/D3:  brand names drisdol and rocaltral.

    any Non-Rx you get on the shelf is not regulated.  take at your own risk.