The Better Bones Blog

by Dr. Susan Brown, PhD.

What is the difference between vitamin D2 and vitamin D3?

Vitamin D3, also known as cholecalciferol, is the natural form of vitamin D for humans. Vitamin D3 is produced in the skin with sunlight exposure. Vitamin D2, known as ergocalciferol, is a compound produced by irradiating yeast with ultraviolet light.

A substantial body of research documents that vitamin D3 is the preferable form and researchers clearly recommend its use. Vitamin D3 has been found to be at least three times as potent as vitamin D2, and is more stable, safe, and useful in the body.

The less desirable vitamin D2 has been generally used in prescription vitamin preparations and in food fortification, while the nutritional and health food industries generally use the superior, natural vitamin D form, D3. Dr. John Cannell, vitamin D advocate and founder of the nonprofit Vitamin D Council, speaks of vitamin D3 in the following manner:

“If you take ergocalciferol, or “vegetarian” vitamin D, be warned. Ergocalciferol is not vitamin D, but a vitamin D-like patent drug whose patent has expired. It does not normally occur in the human body and is probably a weak agonist at the receptor site, meaning it may actually partially block vitamin D actions. Ergocalciferol is the villain in most of the reported cases of toxicity in the world’s literature. All bets are off in terms of measuring blood levels if you take ergocalciferol. Some of the labs can pick it up, and some can’t. Don’t take ergocalciferol; it is not vitamin D.” For more details, see Dr. Alan Gaby’s summary of the research comparing vitamin D2 and D3.



Interview with Dr. Cannell in the Townsend Letter for Doctors and Patients, November 2006, page 96.

Gaby AR. Vitamin D3 more potent than vitamin D2. Townsend Letter for Doctors and Patients, October 2005.


A look at osteopenia treatment

Osteopenia is the condition in which bone density is somewhat less than a “standard” young person of the same sex. It is not a true diagnosis, nor is it a disease; it is simply a state of relatively low bone mass.

The causes are not always related to bone loss; if you never developed a high peak bone mass during your youth, you could have lifelong osteopenia. Similarly, if you are not a young person, you will not be likely to have the same bone mass as somebody who is young.

Low bone density is one risk factor for osteoporotic fracture; however, having osteopenia doesn’t mean you will have a fracture. In fact, studies suggest that well over half of those who suffer a low-trauma “osteoporotic” fracture do not have an osteoporotic bone density; rather they have “osteopenia” or even normal bone density.  There is much more involved in the equation.

While childhood and adolescence are the best times to build strong bones, there are ways to halt and even somewhat reverse bone loss in adulthood. Contrary to what you might have heard, calcium is not a panacea. There are many other nutrients that play a role in bone health and, in fact, the societies with the highest calcium intakes also have the highest rates of osteoporosis.




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