Thera-D 4000


Our high-quality, independently tested and certified vitamin D3 supplement, available in three programs—Rapid Repletion (Thera-D 4000 followed by Thera-D 2000), Thera-D 2000, Thera-D 4000, or Thera-D 6000.

Thera-D includes automatic refills timed to arrive just before you run out. The auto-refill program includes free delivery.

Program A:
Rapid Repletion Program
($21.00 when using a
Provider Referral Code)
Program B:
Thera-D 2000
6-month supply
($21.00 when using a
Provider Referral Code)
Program C:
Thera-D 4000
3-month supply
($21.00 when using a
Provider Referral Code)
Program D:
Thera-D 6000
3-month supply
($23.00 when using a
Provider Referral Code)

* This statement has not been evaluated by the Food and Drug Administration.
This product is not intended to diagnose, treat, cure or prevent any disease.

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More About this Product

Frequently Asked Questions

Q. What is Thera-D?

A. Thera-D is a high quality vitamin D3 supplement that has been independently tested and certified by NSF International for content accuracy, purity, and freedom from contaminants. Because vitamin D needs vary and are dependent on several factors, Thera-D is available with two different amounts of vitamin D. Thera-D 2000 contains 2000 IU vitamin D3, Thera-D 4000 contains 4000 IU vitamin D3, and Thera-D 6000 contains 6000 IU vitamin D3. Your doctor or other healthcare provider will advise you on which Thera-D you need.

Q. What is the difference between the Thera-D programs?

A. The Rapid Repletion Program is designed to quickly restore (replete) your vitamin D level, and then maintain that level within the desired range.* This program begins with an initial three-month supply of Thera-D 4000 for repletion, followed by Thera-D 2000 for maintenance.

The Thera-D 2000 Program is designed for adults whose vitamin D level is currently normal or has been restored to normal. This program provides a maintenance dose of 2000 IU per day.

The Thera-D 4000 Program is designed for adults who have persistently low vitamin D levels, or whose doctor has recommended they maintain a higher vitamin D level. This program provides an ongoing daily dose of 4000 IU.

The Thera-D 6000 Program is designed for adults who are deficient in vitamin D, and whose doctor has recommended a higher level of vitamin D supplementation. This program provides an ongoing daily dose of 6000 IU.

Q. What is the difference between vitamin D2 and vitamin D3?

A. There are two different types of vitamin D: D2 (ergocalciferol) and D3 (cholecalciferol). Vitamin D2 is the plant form of vitamin D. When produced commercially, it is made from yeast. Prescription vitamin D products are made with vitamin D2.

Vitamin D3 is the type of vitamin D produced in our skin after exposure to sunlight. It is also the type of vitamin D found in fatty fish such as salmon and herring. Most supplements, including Thera-D, source their vitamin D3 from lanolin.

Our bodies metabolize vitamin D3 more effectively than vitamin D2, and vitamin D3 supplementation is less likely to result in toxicity. Recent studies have shown that daily vitamin D3 is 2 to 3 times more efficient than high-dose weekly or monthly vitamin D2. For these and other reasons, vitamin D3 is considered to be the superior supplemental form of vitamin D.

Q. How are blood levels of vitamin D measured?

A. Blood levels of vitamin D are measured as 25(OH)D. Your doctor may order a vitamin D blood test to determine your level. The amount of vitamin D you need to take each day will depend on the results of this test, as well as your sun exposure, geographic location, and health status.

Although The Institute of Medicine recently proposed that a vitamin D level of 20-50 ng/mL is sufficient for the general public, vitamin D experts recommend maintaining a level of at least 30 ng/mL, with 30-80 ng/mL considered vitamin D sufficiency, 20-30 ng/mL considered insufficiency, and below 20 ng/ml considered vitamin D deficiency.

Q. How should I take Thera-D?

A. It is best to take Thera-D with a meal that contains some fat. Because vitamin D is a fat-soluble vitamin, studies suggest that vitamin D may be better absorbed with a larger meal or with a meal containing a decent amount of fat (Example: salmon and a salad with dressing contains a decent amount of healthy fat).

Q. What are the benefits of vitamin D?

A. Vitamin D is a fat-soluble vitamin that plays several important roles in our bodies. It is an essential factor for the regulation of calcium balance. It helps us absorb calcium, thus promoting the development and maintenance of strong bones.*

Research over the last decade has revealed that vitamin D is not only important for bone health, but it plays a vital role throughout our bodies. Vitamin D deficiency has been associated with an increased risk of various health conditions.*

Vitamin D is also important for neuromuscular function, and studies have shown that supplementing with vitamin D may help decrease the risk of falls in the elderly.*

Q. Aside from supplements, what are some other sources of vitamin D?

A. Vitamin D is produced in the skin in response to exposure to sunlight. The amount of vitamin D produced in the skin varies greatly depending on age, location or latitude, smog, time of day, and use of sunscreen. At least 1/3 of Americans have insufficient vitamin D levels due to lack of sunlight exposure, increased sunscreen use, less efficient vitamin D production and metabolism with age, increased obesity rates, and decreased intake of vitamin D from foods.

It is difficult for most people to acquire enough vitamin D from foods alone because significant levels of vitamin D occur naturally only in wild-caught fatty fish (salmon, mackerel, and sardines). Milk, which does not naturally contain vitamin D, is fortified with only 100 IU per cup. For most adults, supplementation is necessary to achieve adequate levels.

Q. Are there any side effects from Thera-D?

A. There are no expected side effects from Thera-D.

Q. Does Thera-D interact with prescription medications?

A. Please refer to the medication interactions information page to check whether your medication may interact with the nutrients in this product.

Q. Can I take Thera-D along with my multivitamin or other supplements?

A. Most multivitamin and mineral supplements contain only 400 IU vitamin D, although the amounts can vary. Theralogix Companion multivitamin contains no vitamin D and was formulated to be taken along with Thera-D. Most other supplements are safe to take with Thera-D. If you have questions about taking Thera-D with other supplements, please call toll-free (888)899-3899, x4 or email our Nutrition Department.

Q. I already take a calcium and vitamin D supplement. Do I need Thera-D?

A. If you take TheraCal, our bone health supplement containing calcium citrate with either 2000 or 4000 IU vitamin D3 along with other vitamins and minerals for bone health, you are receiving the vitamin D3 you need and do not need an additional vitamin D supplement. TheraCal can be taken in place of an existing calcium and vitamin D supplement.

If you take any other calcium supplement with D, you are likely getting only 400-800 IU vitamin D per daily dose. Therefore, many adults may need to supplement with extra vitamin D when taking a typical calcium and vitamin D or bone health supplement. Thera-D can be taken along with these supplements to increase your vitamin D intake.

Q. What are the current vitamin D recommendations? How much vitamin D is too much?

A. There is not complete agreement on the optimal daily dose of vitamin D. The current Recommended Dietary Allowance (RDA) set by the Institute of Medicine's Food and Nutrition Board is 600-800 IU per day depending on age, and the upper limit for daily intake is set at 4000 IU. Vitamin D experts consider the RDA doses to be conservative, and generally recommend higher intakes for most adults, particularly those who have low or deficient vitamin D levels. Vitamin D needs also vary from person to person, and are dependent on several factors. Speak to your doctor to determine how much vitamin D you need.

Q. Is this product gluten-free and artificial dye-free?

A. Yes, all Theralogix products are gluten-free and contain no artificial dyes. Each Theralogix product is tested by NSF International® for content accuracy, purity, and freedom from contaminants. During this testing process, each product is also tested to confirm that there is no gluten present.

Q. What does the date printed on my Theralogix product mean?

A. Theralogix products list an EXP (expiration) date. To ensure best potency, keep your nutritional supplements in a cool dry place, away from heat and moisture and use before this date.

If you have any questions about the shelf life of your product, feel free to contact our Nutrition Department by email or call us toll-free at (888)899-3899 ext. 4.

* This statement has not been evaluated by the Food and Drug Administration.
This product is not intended to diagnose, treat, cure or prevent any disease.