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!

The two kinds of small LDL

The two kinds of small LDL

You won't find this in any publication nor description (at least ones that I've come across) about the ubiquitous small LDL particles. It's an observation I've made having obtained thousands of advanced lipoprotein panels of the sort that break lipoproteins down by size. I've discussed this issue previously here. But small LDL is so ubiquitous, not addressed by conventional strategies like statin drugs or fat restriction (it is made worse, in fact, by reducing fat in the diet), that it is worth keeping at the top of everyone's consciousness.

(Because most of the lipoprotein analyses performed in my office are done via NMR, I will discuss in terms relevant to NMR. This does not necessarily mean that similar observations cannot be made with centrifugation, i.e, VAP from Atherotech, or gel electropheresis from Berkeley, Boston Heart Lab, Spectracell, and others).

There are two basic varieties of small LDL particles:

1) Genetically-programmed--e.g., via cholesteryl-ester transfer protein (CETP) activity
2) Acquired--via carbohydrate consumption

It means that people with acquired small LDL from carbohydrate consumption can reduce small LDL to zero with reduction of carbohydrates, especially the most small LDL-provoking foods of all: wheat, cornstarch, and sucrose.

It also means that people who have small LDL for genetically-determined reasons can only minimize, not eliminate, small LDL. By NMR, we struggle to keep small LDL in the 300-600 nmol/L range when genetically-determined. (People typically start with 1400-3000 nmol/L small LDL particles prior to diet changes and other efforts.) We can only presumptively identify genetically-determined small LDL when all the appropriate efforts have been made, including reduction in weight to ideal, yet small LDL persists.

Here is where we need better tools: when you've done everything possible, yet small LDL persists.

While we break LDL particles (NOT LDL cholesterol, the crude and misleading way of viewing atherosclerosis causation) down by size, it's really about all the undesirable characteristics that accompany small size:

--Distortion of Apo B conformation--i.e., the primary protein that directs LDL particle fate is distorted, making it less likely to be cleared by the liver but more likely to be taken up by inflammatory (macrophages) in the artery wall, creating plaque. It means that small LDL particles linger for a longer time than larger particles.

--Small LDLs are more oxidation-prone. Oxidized LDL are more avidly taken up by inflammatory macrophages.

--Small LDLs are more glycation-prone.

--Small LDLs are more adherent to structural tissues, e.g., glycosaminoglycans, that reside in the artery wall.

You and I cannot measure such phenomena, so we resort to distinguishing LDL particles by size.

The drug industry believes it may have a solution to small LDL in the form of CETP-inhibiting drugs, like anacetrapib. In the way of nutritional solutions beyond carbohydrate reduction, weight loss/exercise, niacin, vitamin D normalization, and omega-3 fatty acid supplementation, there are exciting but very preliminary data surrounding the possibility that anthocyanins may inhibit CETP activity. Having toyed with this concept for the past 6 months, I remain uncertain how meaningful the effect truly is, but it is harmless, since we obtain anthocyanins from foods colored purple or purplish, such as blackberries, blueberries, cherries, red leaf lettuce, red cabbage, etc.

I welcome any unique observations on this issue.

Comments (17) -

  • Tommy

    12/27/2010 3:37:38 PM |

    "But small LDL is so ubiquitous, not addressed by conventional strategies like statin drugs or fat restriction (it is made worse, in fact, but reducing fat in the diet)"

    Just to be clear about the above quote. You say "it is made worse, in fact, but reducing fat." Did you mean "by" reducing fat?

    Also, if that is the case, is that because of the fat itself or because less fat means replacing it with carbs?

  • Jonathan Byron

    12/27/2010 4:50:45 PM |

    In addition to CETP inhibition, some other benefits of red/blue/purple foods (that also include polyphenols other than the anthocyanins - elligitanins, etc) include:

    1) inhibition of amylase - less of a blood sugar spike after eating starchy foods, less aberrant glycation and AGEs.

    2) Estrogenic activity - anthocyanin stimulates the beta-estrogen receptors in blood vessels and bone, not much activity in the alpha receptors in breast, uterus.

    3) Phosphodiesterase inhibition!

  • Peter

    12/27/2010 5:09:05 PM |

    I was surprised that Ron Krauss, who did a lot of research on small particle LDL and recently published a mega-study supposedly showing saturated fat is unrelated to heart disease, made these comments in a recent interview:

    People should limit saturated fat to 10% of their diet, though some can get away with more.

    Optimal carbs intake: 35 to 40%.

    People used to get heart disease from high cholesterol, but now its mainly high carbs.

    The interview is here, and those ideas are toward the end:

    I would love to know if you have any comment.

  • Geoffrey Levens

    12/27/2010 5:20:51 PM |

    This is worth knowing about! Low cost (relatively) lab tests without needing a doc visit/prescription

    All tests performed by LabCorp

  • steve

    12/27/2010 9:35:35 PM |

    sometimes it comes down to our health being all about our genetics. As a result of the recomendations of this blog with regard to wheat and sugar elimination, normalizing vitamin D i have taken down my LDL from 1810, all small to 609 of which 346 are small; i can only lower my particles with statins- diet alone will not do it.  My understanding of the research is that at low levels, size does not matter. I will note that when my particles were sky high i thought i was follwoing a very healthy low fat, grain oriented diet.  Now, i eat now grains and have a fair amount of mono fats from avocado and olive oil, some sat fat from lean meats, poultry and eggs, and hope i have minimized the progression of artery plaque that shocked me when i found out i had it when i followed healthy heart diet, exercise and maintained a very lean body weight.  Gentics are tough to overcome, but the risks can be minimzed via diet and meds.

  • Might-o'chondri-AL

    12/28/2010 6:12:34 AM |

    Different segments of the same carotid artery can apparently be affected by a different gene. Each segment is itself susceptable to different pathological processes, like shear rate of the near inner arterial wall. Artherosclerosis at different arterial segments seem to predict if pathological event will be ischemic stroke or myocardial infarction.

    The North Manhattan Study tried to tweak 145 genes modulated by 702 single nucleotide polymorphisms. That study and the San Antonio, Erasmo Rucphen and Framingham have led to opinions that 30% to 60% of the thickness of the carotid artery's intima-media is geneticly inherited. Then for carotid plaque +/- 28% is passed on geneticly.

    Sex of the individual and racial ethnicity are other genetic variables. Doc Davis' clinical observation is telling us something equally important about small LDL's genetic variation.

  • Ryan

    12/28/2010 2:47:00 PM |

    Is small LDL the "VLDL" on blood results?

  • Dr. William Davis

    12/28/2010 2:55:38 PM |

    Hi, Tommy--

    Yes, indeed. Just a typo.

    Probably both.

  • Dr. William Davis

    12/28/2010 2:57:59 PM |

    Hi, Jonathan--

    Excellent! Yes, the conversation surrounding anthocyanins is becoming increasingly interesting.

    Hi, Peter--

    I don't personally know Ron Krauss, but I too have been puzzled by the fact that his public comments don't seem to reflect his research findings. If he were to echo the important findings of his research, he would indeed be a low-carb, high-fat advocate.

  • Dr. William Davis

    12/28/2010 2:59:31 PM |


    Wonderful results! The diet approach works, no doubt about it.

    Hi, Ryan--

    No, two different things.

  • Anonymous

    12/29/2010 5:50:28 AM |

    Hello Dr.Davis,
    Your comments sound very similar to Dr Ray you read his work? If not, I think you would enjoy his thoughts. His website is
    Sue in BC Canada

  • Brent

    12/29/2010 4:02:25 PM |

    Question for all you Small Particle techies out there.  Always had "Good" lipid panels, even though overweight and borderline type 2 under control with a low carb diet.

    Numbers usually average:
    Total Cholesterol 125
    LDL  65
    HDL  45
    Tri  90  

    Just got first particle size test done, results in VAP format:  

    LDL-1Innocent 3
    LDL-2Innocent 0
    LDL-3(B) 36
    LDL-4(B) 34

    I know particle size goes down as the LDL- number goes up, but how do these numbers translate to the NMR numbers Dr. Davis listed as a target for those of us genetically pre-disposed to pattern B LDL?

  • Anonymous

    12/29/2010 9:22:31 PM |

    ^I'm interested in the same thing

  • David

    12/30/2010 8:30:59 PM |


    Your small LDL makes up 96% of your total LDL particles. This is a severe pattern.

    Also, your HDL is too low and your triglycerides are a tad too high. Dr. Davis' Track Your Plaque goal of 60-60-60 is a good rule of thumb. LDL down to 60, HDL up to 60, trigs down to 60.

    If you're currently following a low-carb diet and still have all of this small LDL, your small LDL pattern is probably the genetic type that Dr. Davis talks about here.


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