Vitamin D2 vs. vitamin D3

An interesting question came up on the Track Your Plaque Member Forum about vitamin D2 vs. vitamin D3. This often comes up among our patients, as well.

Vitamin D is measured in the blood as 25-OH-vitamin D and is distinct from 1,25-diOH-vitamin D, a kidney measure, a test you do not need unless you have kidney failure.

The human form of vitamin D is cholecalciferol and is usually obtained via activation of a precursor molecule in the skin on activation by the sun. You can also take cholecalciferol and it increases blood levels of 25-hydroxy vitamin D reliably.

However, there is a cheap, plant-sourced, alternative to vitamin D3, called vitamin D2, or ergocalciferol. D2 has far less effect in the body. Taking D2 or ergocalciferol orally is an extremely inefficient way to get D. Unfortunately, it's the form often used in milk and many supplements, even the prescription form of D. About half the multivitamins and calcium supplements I've looked at contain ergocalciferol rather than cholecalciferol.

Taking vitamin D2 yields very little conversion to the effective D3. This particular issues is maddening, as the USDA requires dairy farmers to add 100 units of vitamin D to milk, and D2 is often used. In other words, the D in many dairy products barely works at all. There are many children who rely on D from dairy products who are at risk for rickets and are not getting the D they need from dairy products because of this cost-saving switch. Do not rely on milk for vitamin D for your children.

D2 or ergocalciferol is often included in the blood measures of vitamin D along with vitamin D3. The only reason it's checked with blood work is to ensure "compliance,", i.e., see whether or not you're taking a prescribed ergocalciferol. Beyond this, it has no usefulness.

25-OH-vitamin D3, or cholecalciferol, is both the blood measure and the supplement you need. This is the one that packs all the punch. Keep in mind also that it is the oil-based gelcap you want, with more consistent and efficient absorption. Tablets usually barely work at all, even if it contains cholecalciferol. Most people who take calcium tablets with D, or multivitamin with D, not only are getting a powdered form of D, but also in trivial doses. It's the pure vitamin D3, cholecalciferol, in gelcap form you want if you desire all the spectacular benefits of vitamin D.

Comments (21) -

  • Jim Wint

    4/26/2007 1:35:00 PM |

    It's good that you explained how vitamin D3 is better than vitamin D2.

    Your readers should also know that, depending on their skin type, just one or two sessions in a tanning bed will produce all the healthy vitamin D3 a human body can use.

    Moderate tanning is healthy behavior.  Don't sunburn.

  • Anonymous

    4/26/2007 3:36:00 PM |

    Dr. Davis, your blogs on vitamin D are terrific.  I am a colleague of Dr. John Cannell, and am presently coauthoring a book with him.  It will deal with the effect of vitamin D supplementation on athletic performance.  He has also endorsed my current book on the health benefits of sunlight and vitamin D.  If you would like a free copy of that book--Solar Power for Optimal Health--please contact me at or call me at 435-628-3102.  

    Keep up the good work!

    Marc Sorenson, EdD

  • Darwin

    5/3/2007 9:40:00 PM |

    Re vitamin D consumption, do you have any thoughts re this study?  I'd like to recommend to my parents that they take an oil-based Vit. D supplement (they're in their 70s), but that study gave me pause.

  • Dr. Davis

    5/4/2007 1:09:00 AM |

    Unfortunately, the study was only in abstract form, meaning none of the full details were available.

    Nonetheless, several uncertainties:

    What was the calcium intake? What was the vitamin D intake and what blood level of 25-OH-vitamin D3 was obtained?

    I suspect that few of the participants had even normal vitamin D blood levels. The majority of vitamin D preparations in calcium tablets barely work at all due to poor absorption.

    However, I do worry that, with appropriate D supplementation, the doses of calcium many people take is excessive. The true need for calcium is likely far less when D is fully replenished.

    I would not make any firm judgments based on this preliminary report. Interesting issue, however.

  • Dave Lull

    3/27/2008 3:45:00 AM |

    Hi Dr Davis,

    I'd been persuaded, like you, that D3 is the form of Vitamin D to use for maximum effect.  Now comes this study:

    "Vitamin d2 is as effective as vitamin d3 in maintaining circulating concentrations of 25-hydroxyvitamin d"

    Holick MF, Biancuzzo RM, Chen TC, Klein EK, Young A, Bibuld D, Reitz R, Salameh W, Ameri A, Tannenbaum AD.

    Boston University School of Medicine, 715 Albany Street, M-1013, Boston, Massachusetts 02118.

    J Clin Endocrinol Metab. 2008 Mar;93(3):677-81. Epub 2007 Dec 18.

    Dr Holick uses Vitamin d2 in treating his patients.

    He was recently interviewed on the radio program the People's Pharmacy; the interview is available as a podcast.


  • Anonymous

    6/24/2008 4:31:00 AM |

    where can I buy vitamin D3 in Gel Caps?  Are they readily available?

  • Anonymous

    7/4/2008 9:36:00 PM |

    Google "vitamin d2 tablets".  Loog for softgels, or gelcaps.

  • Anonymous

    7/25/2008 4:45:00 PM |

    Buy Vitamin D3 in softgels (oil based form from

  • Anonymous

    9/21/2008 12:06:00 AM |

    So, if I am buying a supplement that is labeled as Vitamin-D (not D3), but the label says it is 1000 IU of Cholecalciferol, the supplement is really Vitamin D3?

  • Anonymous

    11/18/2008 8:16:00 PM |

    I'm curious why you have no comment on the above story that refutes your entire theory.

  • Anonymous

    12/12/2008 11:56:00 PM |

    Actually your post is very confusing because you say vitamin d3 is 25-oh-d3, actually it's a metabolite of d3, also you say ergocalciferol is inneficient because yields little conversion to 25-oh-d3, but d2 converts ONLY to 25-oh-d2 and very efficiently, and has similar activity to the d3 form(about 2/3 of the potency), the bad about d2 is also that has faster metabolism than d3.
    All in all, d2 is efficient, not like d3, but it's not useless like you say, and d2 has metabolites with potent anticancer activity, similarly to tamoxifen in breast cancer, so d2 has it's own benefits over d3.

  • Alphonzen

    3/19/2009 1:42:00 PM |

    Vitamin D2 Is As Effective As Vitamin D3 In Maintaining Concentrations Of 25-hydroxyvitamin D, Study Suggests

    Sorry blogger, but you have been proven wrong.

  • Anonymous

    9/24/2009 11:21:46 PM |

    The difference as I've understood - there are actually 5 forms of Vitamin D (D1-D5). Vitamin D2 must be converted to be used, Vitamin D3 is used directly. Vitamin D2 is "relatively ineffective" because it is the  stored form and it's stored in the body's fat- which is why it has certain properties that D3 doesn't possess for fatty tissue health. Eventually D2 effectiveness would equal D3 because the body eventually converts what it needs. However, it has requirements for the conversion, and if taken for anti-inflammatory, anti-cytokine storm, immune modulation, then D3 is the much better form since it can be used immediately. When healthy I take D2 and D3 - D2 fills the body's stores while D3 is consumed. When the immune system is being challenged Vitamin D3 is the better form and will keep the D2 levels in the fat unaffected.

    As far as calcium supplementation - I think it's ludicrous - I can't imagine anyone, other than people that cannot tolerate milk products, not getting enough dietary calcium. I think that's one of the biggest myths propagated today. Hypercalcemia, and even just excessive calcium intake, has been shown to cause brain lesions in elderly, and calcium creates issues when Vitamin D is supplemented.   Magnesium supplementation is MUCH more important for everything from healthful bones, heart rhythm and heart attack protection, to smooth muscle relaxation, and mental acuity. We need a MINIMUM of 400mg and should be taking more.  With everyone drinking bottled water that has next to no magnesium content, we are all susceptible to dangerously low "sudden heart attack" levels of magnesium.

  • Anonymous

    11/16/2009 7:21:58 AM |

    Have you studied people who have had gastric bypass / weight loss surgery? They have completely different calcium citrate and vitamin D requirements than a regular person. Please see the web site  There are many professionals on this site with articles on supplementation.

    I buy my supplements from

  • Anonymous

    12/2/2009 6:11:36 PM |

    For vegetarians (where killing of an animal is prohibited) -
    D3 made from lanlolin (sheeps wool) is the only choice, there is no pure plant based D3?

    For Vegans (has to be plant based only)
    Looks like D2 made from yeast is the only choice.
    If any one know best form of D3/D2 suitable for vegetarians/vegans, please post where one can get (Please note, gel capsules are made from animal sources, they would not be suitable). Thank you

  • Steve D'Sa

    2/16/2010 4:27:48 AM |

    I'm taking a vegan calcium supplement, with vitamin D3. Its branded Vitamin Code, RAW CALCIUM, from Garden of Life, its fortified with Magnesium and other things. Its vegan, and RAW. I think the D3 source is algae.

  • Anonymous

    9/8/2010 5:49:49 AM |

    Sorry Steve. The code RAW vitamins you're talking about aren't vegan. They get their D3 "primarily from lanolin" (=occasionally fish?). According to them, since they remove the traces of lanolin during processing, they felt that it was vegan.

    After listening to them go on and on with their justifications of it and why it was vegan, it just felt like a giant marketing scheme. Needless to say, I'm now quite wary of all Garden of Life products.

    Regardless, they're still in the process of changing labels, but in the meantime, nope, not vegan. Frown

  • edegra online

    9/23/2010 6:40:36 AM |

    Thanks for providing the comparison
    between Vitamin D2 and Vitamin D3.

    Best Regards
    Smith Alan

  • buy jeans

    11/3/2010 8:32:37 PM |

    D2 or ergocalciferol is often included in the blood measures of vitamin D along with vitamin D3. The only reason it's checked with blood work is to ensure "compliance,", i.e., see whether or not you're taking a prescribed ergocalciferol. Beyond this, it has no usefulness.

  • Dr Brad

    6/13/2011 5:48:35 AM |

    Case study:  lab result shows Total Vit D, 25-OH 36; D3=6, D2=30.  Person supposedly taking 2000 IU D3 daily.   What is the significance of the D3=6 measurement.  I typically look at total and make recommendation from there but have been told that perhaps I should look at sub-classes. thoughts?

  • Annika Brixner

    5/19/2014 4:34:26 AM |

    Wonderful site. Plenty of useful information here. I am sending it to a few pals ans additionally sharing in delicious. And of course, thank you on your effort!

Lies, damned lies, and statistics

Lies, damned lies, and statistics

In the last Heart Scan Blog post, I discussed the question of whether statin drugs provide incremental benefit when excellent lipid values are already achieved without drugs.

But I admit that I was guilty of oversimplification.

One peculiar phenomenon is that, when plaque-causing small LDL particles are reduced or eliminated and leave relatively benign large LDL particles in their place, conventional calculated LDL overestimates true LDL.

In other words, eliminate wheat from your diet, lose 25 lbs. Small LDL is reduced as a result, leaving large LDL. Now the LDL cholesterol from your doctor's office overestimates the true value.

Anne raised this issue in her comment on the discussion:

I eliminated wheat - and all grains - from my diet nearly three years ago (I eat low carb Paleo). My fish oils give me a total of 1680 mg EPA and DHA per day, and my vitamin D levels since last year have varied between 50 ng/ml and 80 ng/ml. However, my lipid profile is not like either John's or Sam's:

LDL cholesterol 154 mg/dl
HDL cholesterol 93 mg/dl
Triglycerides 36 mg/dl
Total cholesterol 255 mg/dl

My cardiologist and endocrinologist are happy with my profile because they say the ratios are good, no one is asking me to take a statin. My calcium score is 0.

However, if we were to measure LDL, not just calculate it from the miserably inaccurate Friedewald equation, we would likely discover that her true LDL is far lower, certainly <100 mg/dl. (My preferred method is the bull's eye accurate NMR LDL particle number; alternatives include apoprotein B, the main apoprotein on LDL.)

So Anne, don't despair. You are yet another victim of the misleading inaccuracy of standard LDL cholesterol determination, a number that I believe should no longer be used at all, but eliminated. Unfortunately, it would further confuse your poor primary care doctor or cardiologist, who--still believe in the sanctity of LDL cholesterol.

By the way, the so-called "ratios" (i.e., total cholesterol to HDL and the like) are absurd notions of risk. Take weak statistical predictors, manipulate them, and try to squeeze better predictive value out of them. This is no better than suggesting that, since you've installed new brakes on your car, you no longer are at risk for a car accident. It may reduce risk, but there are too many other variables that have nothing to do with your new brakes. Likewise cholesterol ratios.

Comments (8) -

  • Jeff

    4/18/2009 12:02:00 PM |

    I am in a similar boat.  I eliminated wheat, added cod liver oil(1-1.5 TBS or so per day), and take vitamin D supplements(gel caps around 4-5K IU per day).  Here were my results:

    TOTAL: 272
    HDL: 76
    LDL(calculated): 184
    Triglycerides: 62

    I strongly suspect the LDL is BS due to large particle size.  I will only be able to tell with the NMR, which I will do sometime this year.  I am not worried so I am in no rush.

  • arnoud

    4/18/2009 1:26:00 PM |

    Dr. Davis, thank you for providing such eye-opening insights in the interpretation of lipid testing results, and for explaining the limits of the usefulness of these measurements.

    However, in the typical doctor's office, the high (calculated) LDL prompts the doctor to push for treatment (including statins).  My doctor tells me that I need not avoid statins, as he is taking those himself, and he wouldn't if he'd think they were a problem.

    I can take my NMR Liposcience LDL particle count result to my doctor, and tell him that my real LDL number is 1/10th of the LDL particle count.  This actual number looks great!  How can I show my doctor that this calculation is correct (LDL particle count divided by 10), and that the standard Framingham calculated LDL should be ignored.   Is there a reference paper I can show my doctor, which explains the science behind the "LDL particle count divided by 10" rule?

  • john elfrank

    4/18/2009 1:35:00 PM |

    I had a coronary calcium scan a  few years ago. My score was about 350 with most of the calcium in the LAD.

    My Manhattan cardiologist responded by putting me on the treadmill and doing an eco stress test. I passed it with flying colors.

    I went to my internist who said  I should be concerned about that calcium score. I said my cardio won't give me any other tests. He said to go back and tell him I have chest pains. I did, got the angiogram and a stent for the 80% blockage in my "widow-maker" LAD.

    Now my lipid profile (I have dyslipidemia) is LDL 23, HDL 23, triglycerides 350 (1000 w/o meds). I had thyroidectomy in 1991 and take synthroid 200 mg.

    My combo thereapy is:
    2000 Niaspan, 40 Simvastatin, 200 Co-enzyme Q10, 1200 fish oil. It'a about as aggressive as my body can stand. Tricor and other fibrates interfere with synthroid absorption (I bet you didn't know that).

    My questions are:
    1. Would it be better for me to take the new combo Simvastatin/Niaspan drug rather than take them separately?

    2. Just passed a nuclear stress test. Should I insist on another angiogram soon?

    3. Would another calcium scan be useful?



  • sk

    4/18/2009 3:38:00 PM |

    this is absolutely spot on!  My numbers prior to NMR showed a total cholesterol of 150, HDL of 41, and TRG of 53.  Because of family history, my internist had me take NMR study and results showed that my particle number for LDL was 1795 and all small particles.  Since eliminating wheat and being on a statin my particle number is down to 1305,but still all small. Not sure that size can be changed, probably genetic.  
    Sadly, many out there think they have a fine profile from indirect measurement, and reality is that many probably do not.

  • Kiwi

    4/18/2009 10:05:00 PM |

    What is the recommended range for the ApoB test?
    My lab gives this:

    Male reference range 0.52 - 1.09 g/L
    Female reference range 0.49 - 1.03 g/L

    Using the Immunoturbidimetric method.
    VAP and NMR tests not available here.

  • Dr. B G

    4/20/2009 9:42:00 PM |


    Those are FANTASTIC, phenomenal labs !!!

    You go GIRL!


  • Dr. B G

    4/20/2009 9:42:00 PM |


    Those are FANTASTIC, phenomenal labs !!!

    You go GIRL!


  • Ravi

    4/23/2009 9:42:00 AM |

    I strongly suspect the LDL is BS due to large particle size. I will only be able to tell with the NMR, which I will do sometime this year. I am not worried so I am in no rush.