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Information on the latest vitamin D news and research.

Find out more information on deficiency, supplementation, sun exposure, and how vitamin D relates to your health.

New vitamin D drug set to hit market in near future

Readers need to be aware of a new vitamin D drug, Rayaldy, currently in phase III trials, which will possibly hit the market in a few years. In its current phase III trials, it is seeking an indication for the treatment of secondary hyperparathyroidism in vitamin D deficient chronic renal failure patients.

It passed phase II trials easily:


It recently surpassed 50% enrollment in the second of its two Phase III trials.


So what is exactly is Rayaldy? Rayaldy is a modified release form of the 25(OH)D molecule.


It is not an analog, it is the 25(OH)D molecule. That means the body will metabolize it to activated vitamin D and it will generate the same steroid signal as does activated vitamin D3.

25(OH)D used to be available as a drug in this country but it was discontinued about 15 years ago. For those who used it, such as Professor Robert Heaney at Creighton, 25(OH)D was useful, as it was more potent and got 25(OH)D levels up quicker than plain vitamin D3.

The current phase III trial is using 30 ug/day of Rayaldy. If you do the calculation, using a conversion factor of 5 for the relative potency of D3 vs. 25(OH)D, 30 ug/day of Rayaldy is equivalent to 7,000 IU/day of D3.

If Rayaldy passes phase III trials, and I predict it will, it may make a big impact on medical care. I wish that vitamin D3 would do that, but it may not, at least in the USA. When Rayaldy is available, it will be a prescription for a more potent and quicker acting D3 compound. Doctors can and will prescribe it off label. That means once it is available, doctors can legally use it for more than just treating secondary hyperparathyroidism. They can prescribe it for whatever they want, for things like multiple sclerosis, lupus, heart failure and more.

When a person goes to the doctor, neither the patient nor the doctor is usually satisfied if the doctor simply says go get some vitamin D at the pharmacy. It is not the way the doctor-patient transaction works in the United States. The patient wants a prescription and the doctor wants to write one.

That’s why I predict Rayaldy will make a big impact on modern medical care. Seven thousand IU/day of D3 will treat a lot of disease. Doctors may finally put a vitamin D compound to use if there is a prescription drug that has indications beyond just treating vitamin D deficiency. If the makers of Rayaldy choose to seek further treatment indications, doctors may end up prescribing 25(OH)D for a variety of diseases.

  About: John Cannell, MD

Dr. John Cannell is founder of the Vitamin D Council. He has written many peer-reviewed papers on vitamin D and speaks frequently across the United States on the subject. Dr. Cannell holds an M.D. and has served the medical field as a general practitioner, emergency physician, and psychiatrist.
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5 Responses to New vitamin D drug set to hit market in near future

  1. Ian says:

    This does sound promising indeed. I have found many General Practitioners to be averse to “complementary medicines” whatever they are and whatever the evidence for their efficacy.

    I hope it does not lead to any further restrictions on the availability OTC of vitamin D3. Call me paranoid!

  2. Rita and Misty says:

    Hi Ian,

    At least here in the US, I don’t think Rayaldy will lead to any problems regarding OTC D3.

    For example, we have prescription-strength Ibuprofen OTC Ibuprofen….

    I would save being “paranoid” for other life events.


    Be well,

  3. allometric24 says:

    If you live in one of the many countries like I do, which limits permitted daily D3 to 1000 IU : there is a simple alternative to developing multi-pill indigestion. Buy liquid drops where each drop delivers 1000 IU.
    Sadly as I age my hand seems to tremble and before I know it I have dispensed at least seven drops into the spoon!! I have inadvertently given myself a prescription medication.

  4. @allometric24: Sorry to hear about the palsy 😉 , but perhaps the D will someday (but not too soon!) help with that!

  5. josukuopio@btinternet.com says:

    So we shall begin to walk the talk of remedying vitamin D deficiency if this drug becomes available. The beauty of medical ethics will be restored. It is not only in the US that physicians tell patients to go and buy Vitamin D from the pharmacy. Also in the UK it is a common practice. Doctor patient relationship must be maintained. It is bonding. The doctor wants to write the prescription and the patient wants to take the prescription. So double wants.