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Dietary supplement

High Potency Vitamin D-3 1,000 IU Ingredients & Drug Interactions

by NOW

Softgel Capsule Category: Vitamin
Most serious interaction: Moderate
The interaction bottom line Most serious interaction: Moderate

High Potency Vitamin D-3 1,000 IU is a dietary supplement by NOW with 1 active ingredient. Its ingredients are commonly taken for bone health and osteoporosis, correcting vitamin d deficiency, immune system support.Based on those ingredients, 715 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Vitamin D. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

HelloPharmacist Scorecard of High Potency Vitamin D-3 1,000 IU by NOW

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains one active ingredient: vitamin D, which your body uses to absorb calcium, support bone health, and regulate immune function. The softgel capsule also contains inactive ingredients — extra virgin olive oil, bovine gelatin, glycerin, water, and safflower oil — to deliver the vitamin.

Does it work?

Strong evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Strong

Clinical evidence supports at least one of this product's ingredients for its stated purpose.

Why this rating?
  • The label markets this product for: Bone and immune health; supports healthy teeth.
  • We looked for evidence on: Dental caries, Fall prevention, Fractures, Muscle strength, Physical performance, Child growth — and 4 related terms.
  • The strongest evidence on file: Vitamin D is rated "Effective" for Osteomalacia (Natural Medicines).
  • Also on file: Vitamin D is rated "Likely Effective" for Corticosteroid-induced osteoporosis.
  • Also on file: Vitamin D is rated "Possibly Effective" for Dental caries, Hyperparathyroidism-related bone loss.

Vitamin D at this dose is effective for treating certain bone and mineral disorders: rickets, osteomalacia (soft bones), familial hypophosphatemia (a genetic calcium disorder), renal osteodystrophy (bone disease from kidney failure), and hypoparathyroidism (low parathyroid hormone). The evidence we hold covers these specific conditions; effectiveness for other uses — like general bone health or immune support — isn't established in our data.

The evidence, ingredient by ingredient Vitamin D

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Vitamin D is generally well tolerated at recommended doses. Very high doses taken over time can cause vitamin D toxicity, with symptoms of high blood calcium (hypercalcemia), kidney problems (azotemia), and anemia.

Rare side effects from excessive doses also include eye inflammation and sensitivity to light, and slower growth in children. This product's 1,000 IU dose is conservative and within safe daily ranges for adults.

Side effects, ingredient by ingredient Vitamin D

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Vitamin D.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: heart-rhythm medications.
  • For scale: 716 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

If you take any heart rhythm medications (especially digoxin), thiazide water pills, calcium channel blockers (verapamil, diltiazem), atorvastatin, calcipotriene cream, or aluminum-containing products, double-check with your pharmacist first — vitamin D can raise blood calcium and interfere with these drugs. Additionally, if you take medications broken down by your liver via the CYP3A4 enzyme, vitamin D may reduce their levels.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with clinical evidence supporting its stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

This product is for people who need vitamin D to treat rickets, osteomalacia, or parathyroid or kidney-related bone disease. If you take heart rhythm medications, water pills, cholesterol drugs, or psoriasis creams, talk to your pharmacist before starting — vitamin D can affect how some of these work.

At this dose, it's generally well tolerated, but doses well above recommended amounts can cause toxicity over time.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Jul 24, 2025.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about High Potency Vitamin D-3 1,000 IU, straight from the product label.

Brand NOW
Barcode (UPC) 733739003751
Net contents 360 Softgel(s)
Market status On market
Date entered into DSLD Jul 24, 2025
DSLD ID 335246
Product type Vitamin
Supplement form Softgel Capsule
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Kosher, Halal, Gluten Free, Dairy Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for High Potency Vitamin D-3 1,000 IU by NOW, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Softgel(s)
Maximum serving Sizes:
1 Softgel(s)
Servings per container
360
UPC/BARCODE
733739003751
IngredientAmount% DV
Vitamin D25 mcg125%

Other ingredients: Extra Virgin Olive Oil, Bovine Gelatin, Glycerin, Water, Safflower Oil

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Suggested/Recommended/Usage/Directions

Suggested Usage: Take 1 softgel daily with a meal.

Formula

NOW Vitamin D-3 softgels supply this key vitamin in a highly absorbable liquid softgel form. Vitamin D is normally obtained from the diet or produced by the skin from the ultraviolet energy of the sun. However, it is not abundant in food. As more people avoid sun exposure, Vitamin D supplementation becomes even more necessary to ensure that your body receives an adequate supply.

Triangle K (Kosher) Contains gelatin

Triangle K (Kosher) Contains gelatin

Crescent H (Halal)

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Precautions

Caution: For adults only. Keep out of reach of children.

Consult physician if pregnant/nursing, taking medication, or have a medical condition.

Not manufactured with yeast, wheat, gluten, soy, corn, milk, egg, fish, shellfish or sesame ingredients. Produced in a GMP facility that processes other ingredients containing these allergens.

General Statements

This bottle is made from 100% PCR (post-consumer recycled) resin.

Larger count

Vitamins Family owned since 1968.

Formulation

Bone & immune health Supports healthy teeth Promotes muscle health

Non-GMO

Packaged and quality tested in the USA.

Not manufactured with yeast, wheat, gluten, soy, corn, milk, egg, fish, shellfish or sesame ingredients.

Natural color variation may occur in this product.

FDA Statement of Identity

A Dietary Supplement

Seals/Symbols

Triangle K (Kosher) Contains gelatin

Crescent H (Halal) GMP Quality Assured

Storage

Store in a cool, dry place after opening.

See for yourself

High Potency Vitamin D-3 1,000 IU by NOW label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

What’s inside

The Ingredients in High Potency Vitamin D-3 1,000 IU by NOW

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size1 Softgel(s) Dosage formSoftgel Capsule Servings per container360 Amounts shown are per serving.

Vitamin D

Interacts with
715 drugs
25 mcg per serving Form: Vitamin D3

Vitamin D is a fat-soluble vitamin that helps your body absorb calcium and is important for healthy bones, muscles, and immune function. Many people,...

Vitamin D monograph & interactions

Other (inactive) ingredients: Extra Virgin Olive Oil, Bovine Gelatin, Glycerin, Water, Safflower Oil. These complete the product’s ingredient list but are not active constituents.

Interaction report

High Potency Vitamin D-3 1,000 IU by NOW Drug Interactions

Want to check YOUR meds against High Potency Vitamin D-3 1,000 IU?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

Go to the checker
715Drugs
80 Moderate 635 Minor

Ingredients driving the most interactions

Vitamin D 715

Each ingredient & the kinds of drugs it affects

For each ingredient in High Potency Vitamin D-3 1,000 IU with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

Vitamin D8 drug types · 715 drugs

Aluminum

Vitamin D might increase aluminum absorption and toxicity, but this has only been reported in people with renal failure.
The protein that transports calcium across the intestinal wall can also bind and transport aluminum. This protein is stimulated by vitamin D, which may therefore increase aluminum absorption. This mechanism may contribute to increased aluminum levels and toxicity in people with renal failure, when they take vitamin D and aluminum-containing phosphate binders chronically.

Likelihood Probable Evidence B
Atorvastatin (Lipitor)

Vitamin D might reduce absorption of atorvastatin.
A small, low-quality clinical study shows that taking vitamin D reduces levels of atorvastatin and its active metabolites by up to 55%. However, while atorvastatin levels decreased, total cholesterol, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol levels did not substantially change. Atorvastatin is metabolized in the gut by CYP3A4 enzymes, and researchers theorized that vitamin D might induce CYP3A4, causing reduced levels of atorvastatin. However, this proposed mechanism was not specifically studied.

Likelihood Probable Evidence B
Calcipotriene (Dovonex)

Taking calcipotriene with vitamin D increases the risk for hypercalcemia.
Calcipotriene is a vitamin D analog used topically for psoriasis. It can be absorbed in sufficient amounts to cause systemic effects, including hypercalcemia. Theoretically, combining calcipotriene with vitamin D supplements might increase the risk of hypercalcemia.

Likelihood Probable Evidence D
Digoxin (Lanoxin)

Theoretically, hypercalcemia induced by high-dose vitamin D can increase the risk of arrhythmia from digoxin.
High doses of vitamin D can cause hypercalcemia. Hypercalcemia increases the risk of fatal cardiac arrhythmias with digoxin. Avoid vitamin D doses above the tolerable upper intake level (4000 IU daily for adults) and monitor serum calcium levels in people taking vitamin D and digoxin concurrently.

Likelihood Possible Evidence D
Diltiazem (Cardizem, Others)

Theoretically, hypercalcemia induced by high-dose vitamin D can reduce the therapeutic effects of diltiazem for arrhythmia.
High doses of vitamin D can cause hypercalcemia. Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation. Theoretically this could also occur with diltiazem. Avoid vitamin D doses above the tolerable upper intake level (4000 IU daily for adults) and monitor serum calcium levels in people taking vitamin D and diltiazem concurrently.

Likelihood Probable Evidence B
Thiazide Diuretics

Theoretically, taking thiazide diuretics and high-dose vitamin D can increase the risk of hypercalcemia.
Thiazide diuretics decrease urinary calcium excretion, which could lead to hypercalcemia if vitamin D supplements are taken concurrently. This has been reported in people being treated with vitamin D for hypoparathyroidism, and also in elderly people with normal parathyroid function who were taking a thiazide, vitamin D, and calcium-containing antacids daily.

Likelihood Probable Evidence D
Verapamil (Calan, Others)

Hypercalcemia induced by high-dose vitamin D can reduce the therapeutic effects of verapamil for arrhythmia.
Hypercalcemia due to high doses of vitamin D can reduce the effectiveness of verapamil in atrial fibrillation. Avoid vitamin D doses above the tolerable upper intake level (4000 IU daily for adults) and monitor serum calcium levels in people taking vitamin D and verapamil concurrently.

Likelihood Probable Evidence B
Cytochrome P450 3A4 (Cyp3A4) Substrates

Vitamin D might induce CYP3A4 enzymes and reduce the bioavailability of CYP3A4 substrates.
There is some concern that vitamin D might induce CYP3A4. In vitro research suggests that vitamin D induces CYP3A4 transcription. Additionally, observational research has found that increased UV light exposure and serum vitamin D levels are associated with decreased serum levels of CYP3A4 substrates such as tacrolimus and sirolimus, while no association between UV light exposure or vitamin D levels and levels of mycophenolic acid, a non-CYP3A4 substrate, was found. A small, low-quality clinical study shows that taking vitamin D reduces levels of the CYP3A4 substrate atorvastatin and its active metabolites by up to 55%; however, the clinical effects of atorvastatin were not reduced. While researchers theorized that vitamin D might induce CYP3A4, this proposed mechanism was not specifically studied.

Likelihood Possible Evidence D
The maker

Brand information

Manufacturer and brand details for High Potency Vitamin D-3 1,000 IU, from the product label.

NOW

See all NOW products
Name
NOW FOODS
Street Address
395 S. Glen Ellyn Rd.
City
Bloomingdale
State
IL
ZipCode
60108
Web Address
nowfoods.com
Pharmacist Counseling Corner

High Potency Vitamin D-3 1,000 IU by NOW: Common Questions

Does High Potency Vitamin D-3 1,000 IU by NOW interact with any medications?
Yes. Based on its ingredients, High Potency Vitamin D-3 1,000 IU has a known interaction with 715 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
High Potency Vitamin D-3 1,000 IU contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Is 1,000 IU of vitamin D safe to take every day?
Yes, 1,000 IU is well below the safe upper limit of 4,000 IU daily for adults. At this dose, vitamin D is generally well tolerated. However, very high doses taken over time can cause toxicity, so stick to the dose on the label and don't combine it with other vitamin D supplements.
Can I take this if I'm pregnant or breastfeeding?
The safety data on file doesn't cover pregnancy or breastfeeding for this product. Vitamin D is often used during pregnancy at recommended doses, but you should use it only under your doctor's guidance if you're pregnant or nursing — talk with your doctor or pharmacist for personalized advice.
What does vitamin D actually do in my body?
Vitamin D helps your body absorb calcium and supports bone health and immune function. At therapeutic doses, it's effective for treating specific bone and mineral disorders like rickets and osteomalacia.
What are the side effects of this product?
At recommended doses, vitamin D is well tolerated. Serious side effects are rare and occur only with excessive doses over time — they include high blood calcium, kidney problems, and symptoms like eye inflammation and light sensitivity.
Will this interact with my cholesterol or blood pressure medications?
Possibly. Vitamin D interacts Moderately with atorvastatin (a cholesterol drug) and may reduce its absorption, and it can interact with certain blood pressure medications like calcium channel blockers. Check your exact medications with the tool on this page before you start.
Can I take this with calcium supplements?
That data isn't on file for this product. Talk with your pharmacist — they can assess your total calcium intake and vitamin D dose together to make sure you're in a safe range.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

High Potency Vitamin D-3 1,000 IU label
Go deeper

The Full Monographs Behind High Potency Vitamin D-3 1,000 IU’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Sources

Sources & How We Checked

High Potency Vitamin D-3 1,000 IU's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 26 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Vitamin D 26 references
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Tatro DS, ed. Drug Interactions Facts. Facts and Comparisons Inc., St. Louis, MO. 1999.
  3. Koutkia P, Chen TC, Holick MF. Vitamin D intoxication associated with an over-the-counter supplement. N Engl J Med 2001;345:66-7. PubMed
  4. Bar-Or D, Yoel G. Calcium and calciferol antagonize effect of verapamil in atrial fibrillation. Br Med J 1981;282:1585-6.
  5. Demontis R, Leflon A, Fournier A, et al. 1 alpha(OH) vitamin D3 increases plasma aluminum in hemodialyzed patients taking AI(OH)3. Clin Nephrol 1986;26:146-9.
  6. Crowe M, Wollner L, Griffiths RA. Hypercalcemia following vitamin D and thiazide therapy in the elderly. Practitioner 1984;228:312-3.
  7. Parfitt AM. Thiazide-induced hypercalcemia in vitamin D-treated hypoparathyroidism. Ann Intern Med 1972;77:557-63. PubMed
  8. Thiazide diuretics and the risk of osteoporosis. Pharmacist's Letter/Prescriber's Letter 2003;19(11):191105.
  9. Moon J. The role of vitamin D in toxic metal absorption. J Am Coll Nutr 1994;13:559-64.
  10. Demontis R, Reissi D, Noel C, et al. Indirect clinical evidence that 1alphaOH vitamin D<SUB>3</SUB> increases the intestinal absorption of aluminum. Clin Nephrol 1989;31:123-7.
  11. Adler AJ, Berlyne GM. Duodenal aluminum absorption in the rat: effect of vitamin D. Am J Physiol 1985;249:G209-13. PubMed
  12. Schwartz JB. Effects of vitamin D supplementation in atorvastatin-treated patients: A new drug interaction with an unexpected consequence. Clin Pharmacol Ther 2009;85:198-203. PubMed
  13. Dietary reference intakes for calcium and vitamin D. Institute of Medicine, November 30, 2010. Available at: http://www.iom.edu/~/media/Files/Report%20Files/2010/Dietary-Reference-Intakes-for-Calcium-and-Vitamin-D/Vitamin%20D%20and%20Calcium%202010%20Repo
  14. Cox KA, Dunn MA. Aluminum toxicity alters the regulation of calbindin-D28k protein and mRNA expression in chick intestine. J Nutr 2001;131:2007-13. PubMed
  15. Escribano, J., Balaguer, A., Pagone, F., Feliu, A., and Roque, I. Figuls. Pharmacological interventions for preventing complications in idiopathic hypercalciuria. Cochrane.Database.Syst.Rev. 2009;(1):CD004754. PubMed
  16. Carlton, S., Clopton, D., and Cappuzzo, K. A. Vitamin D deficiency: appropriate replenishment therapies and the effects of vitamin D toxicity. Consult Pharm 2010;25(3):171-177. PubMed
  17. Wang, H., Xia, N., Yang, Y., and Peng, D. Q. Influence of vitamin D supplementation on plasma lipid profiles: a meta-analysis of randomized controlled trials. Lipids Health Dis. 2012;11:42. PubMed
  18. Turner AN, Carr Reese P, Fields KS, Anderson J, Ervin M, Davis JA, Fichorova RN, Roberts MW, Klebanoff MA, Jackson RD. A blinded, randomized controlled trial of high-dose vitamin D supplementation to reduce recurrence of bacterial vaginosis. Am J Obstet G PubMed
  19. Weiner M, Epstein FH. Signs and symptoms of electrolyte disorders. Yale J Biol Med. 1970;43(2):76-109.
  20. Lappe J, Watson P, Travers-Gustafson D, Recker R, Garland C, Gorham E, Baggerly K, McDonnell SL. Effect of Vitamin D and Calcium Supplementation on Cancer Incidence in Older Women: A Randomized Clinical Trial. JAMA. 2017 Mar 28;317(12):1234-1243. PubMed
  21. Roth DE, Leung M, Mesfin E, Qamar H, Watterworth J, Papp E. Vitamin D supplementation during pregnancy: state of the evidence from a systematic review of randomised trials. BMJ. 2017;359:j5237. PubMed
  22. Murai IH, Fernandes AL, Sales LP, et al. Effect of a single high dose of vitamin D3 on hospital length of stay in patients with moderate to severe COVID-19: A randomized clinical trial. JAMA. 2021.
  23. Wang Z, Schuetz EG, Xu Y, Thummel KE. Interplay between vitamin D and the drug metabolizing enzyme CYP3A4. J Steroid Biochem Mol Biol 2013;136:54-8. PubMed
  24. Doyle D, Browne U, Brickley A, Murphy D. Vitamin D-induced hypercalcaemia and acute kidney injury in sarcoidosis. BMJ Case Rep 2023;16(1):e250580. PubMed
  25. Williamson A, Martineau AR, Sheikh A, Jolliffe D, Griffiths CJ. Vitamin D for the management of asthma. Cochrane Database Syst Rev 2023;2(2):CD011511. PubMed
  26. Kinesya E, Santoso D, Gde Arya N, et al. Vitamin D as adjuvant therapy for diabetic foot ulcers: Systematic review and meta-analysis approach. Clin Nutr ESPEN 2023;54:137-143. PubMed

See these in context on the Vitamin D monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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