Major interaction on record — check this product against your medications before combining. Based on 2 of 4 ingredients. Check your meds →
Dietary supplement

Soy Isoflavones Ingredients & Drug Interactions

by The Vitamin Shoppe

Soy Isoflavones label
See full label image
Tablet Or Pill Category: Other Combinations
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Soy Isoflavones against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Major

Soy Isoflavones is a dietary supplement by The Vitamin Shoppe with 4 active ingredients. Its ingredients are commonly taken for bone health and osteoporosis prevention, dietary calcium deficiency, heartburn relief (calcium carbonate antacids).Based on those ingredients, 664 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Soy Bean Extract, Calcium. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Soy Isoflavones by The Vitamin Shoppe

Ask about any prescription or over-the-counter medication and we check it for interactions with Soy Isoflavones by The Vitamin Shoppe — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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HelloPharmacist Scorecard of Soy Isoflavones by The Vitamin Shoppe

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

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 11, 2026

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 4 of its 4 active ingredients.
  • No proprietary blends here — you can verify the dose of every single component.

This product has four active ingredients: soy protein isolate, calcium, phosphorus, and soy bean extract. Calcium and phosphorus are minerals your body needs for bone strength and other vital functions.

Soy bean extract supplies isoflavones, plant compounds found naturally in soybeans. The inactive ingredients — microcrystalline cellulose, stearic acid, croscarmellose sodium, magnesium stearate, silicon dioxide, and aqueous coating — are fillers and binders that hold the tablet together.

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 health and menopausal symptom support.
  • We looked for evidence on: Osteoporosis, Corticosteroid-induced osteoporosis, Fractures, Fall prevention, Osteoarthritis, Menopausal symptoms — and 4 related terms.
  • The strongest evidence on file: Calcium is rated "Likely Effective" for Corticosteroid-induced osteoporosis (Natural Medicines).
  • Also on file: Calcium is rated "Likely Effective" for Osteoporosis.
  • Also on file: Soy is rated "Possibly Effective" for Osteoporosis, Menopausal symptoms.

Calcium is effective for preventing and treating low calcium levels (hypocalcemia), supporting bone strength in osteoporosis, and managing high potassium levels (hyperkalemia) and indigestion (dyspepsia). It's also effective for kidney failure.

Soy bean extract shows possibly effective evidence for blood sugar control in diabetes, cholesterol management (hyperlipidemia), bone health in osteoporosis, blood pressure in hypertension, and diarrhea relief. The evidence for soy is not as strong as for calcium — it points to modest benefits in specific conditions — but it has been studied in these areas.

The evidence, ingredient by ingredient Calcium Soy

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 2 of the 2 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 2 of 2.
  • General safety write-ups exist for 2 of 2.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Calcium is generally well tolerated at recommended doses, though high amounts can cause problems. Common side effects from oral calcium include belching, constipation, diarrhea, bloating, and stomach upset.

Rare serious concerns include kidney stones and calciphylaxis (a serious condition involving calcium deposits in soft tissue). Some research suggests very high calcium intake — over 1500 to 2000 mg daily — may be linked to increased prostate cancer risk and possibly heart disease, though this remains debated.

Soy is well tolerated when eaten as food, but concentrated isoflavone supplements warrant more caution. Common side effects include bloating, constipation, diarrhea, and nausea.

Some people have allergic reactions to soy protein — rash, itching, or other allergic symptoms. Inhaled soy dust can trigger asthma or allergy symptoms.

During pregnancy, calcium is important and safe at recommended amounts. For soy, no safety data is on file for pregnancy or breastfeeding with concentrated supplements; soy foods eaten as part of a normal diet are commonly consumed while breastfeeding, but high-dose isoflavone supplements have not been well studied.

Side effects, ingredient by ingredient Calcium Soy

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 2 of the 2 matched ingredients can interact with medications — Calcium, Soy.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; diabetes medications; heart-rhythm medications; lithium.
  • For scale: 664 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.

Before you take this product, check with your pharmacist if you use dolutegravir, elvitegravir, or ceftriaxone (Major interactions with calcium). Also double-check if you take levothyroxine, sotalol, diltiazem, raltegravir, calcipotriene, antihypertensive drugs, estrogen therapy, diabetes medications, diuretics, warfarin, caffeine regularly, or monoamine oxidase inhibitors (Moderate interactions with either calcium or soy).

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. Major medication interactions have been identified, and safety information is well characterized.

This product is worth considering if you need calcium and are interested in soy isoflavones for bone health or blood pressure, but you must check your medications first — calcium and soy interact with many common drugs. If you take any HIV medication, thyroid replacement, blood pressure drugs, diabetes medication, warfarin, or an older antidepressant, talk to your pharmacist before you start.

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

Assessment coverage: 2 of 4 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Jan 25, 2016.

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 Soy Isoflavones, straight from the product label.

Brand The Vitamin Shoppe
Barcode (UPC) 766536010981
Net contents 120 Tablet(s)
Market status On market
Date entered into DSLD Jan 25, 2016
DSLD ID 55266
Product type Other Combinations
Supplement form Tablet Or Pill
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years), Gluten Free, Dairy Free, Sugar 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 Soy Isoflavones by The Vitamin Shoppe, 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:
4 Tablet(s)
Maximum serving Sizes:
4 Tablet(s)
Servings per container
30
UPC/BARCODE
766536010981
IngredientAmount% DV
Soy Protein isolate400 mg--
Calcium300 mg30%
Phosphorus232 mg23%
Soy Bean Extract2334 mg--

Other ingredients: Microcrystalline Cellulose, Stearic Acid, Croscarmellose Sodium, Magnesium Stearate, Silicon Dioxide, Aqueous Coating

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.
General Statements

bone

specialty

{tablet} actual size

Visit www.vitaminshoppe.com or call 1-800-223-1216 for more information and to reorder.

{QRC} learn more at vsquality.net

FDA Statement of Identity

dietary supplement

Formulation

gluten free dairy free nut free

Does not contain: Yeast, Corn, Wheat, Gluten, Sugar, Salt, Starch, Dairy, Citrus, Fish, Animal Derivatives, Preservatives, Artificial Colors or Flavors.

Seals/Symbols

V Suitable for most Vegetarians

Formula

Contains: Soy.

Precautions

Contains: Soy.

Warning: Consult your healthcare provider prior to use if you are pregnant, nursing, taking any medication or have any medical conditions.

Keep out of reach of children.

Tamper Evident Do not use if outer seal is broken or missing.

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.

Suggested/Recommended/Usage/Directions

Directions: As a dietary supplement, take four (4) tablets daily, preferably with meals.

Brand IP Statement(s)

The Vitamin Shoppe Isoflavones are derived from the germ of soybeans, a naturally rich source of isoflavones such as genistein, daidzein and glycitein. Isoflavones are classified as phytoestrogens.

Soylife is a registered trademark of Schouten USA Inc.

Storage

Store in a cool, dry place.

General

Item No. VS-1098 1037612 DO 1

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Soy Isoflavones by The Vitamin Shoppe label

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

Soy Isoflavones label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Soy Isoflavones by The Vitamin Shoppe

These are the 4 active ingredients this product is made of. Select any to open its full monograph.

Serving size4 Tablet(s) Dosage formTablet Or Pill Servings per container30 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

Soy Protein isolate

400 mg per serving

Calcium

Interacts with
168 drugs
300 mg per serving Form: Dicalcium Phosphate

Calcium is an essential mineral your body needs for strong bones, nerve signaling, and muscle function, and supplements can help fill gaps when diet f...

Calcium monograph & interactions

Phosphorus

232 mg per serving Form: Dicalcium Phosphate

Soy Bean Extract

Interacts with
611 drugs
2334 mg per serving Form: Isoflavones, Soylife

Soy is a nutritious bean that is a staple food and a popular source of plant protein and isoflavones. Eating soy foods as part of a balanced diet is g...

Soy Bean Extract monograph & interactions

Other (inactive) ingredients: Microcrystalline Cellulose, Stearic Acid, Croscarmellose Sodium, Magnesium Stearate, Silicon Dioxide, Aqueous Coating. These complete the product’s ingredient list but are not active constituents.

Interaction report

Soy Isoflavones by The Vitamin Shoppe Drug Interactions

Want to check YOUR meds against Soy Isoflavones?

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
664Drugs
16 Major 423 Moderate 225 Minor

Ingredients driving the most interactions

Soy Bean Extract 611
Calcium 168

Individual Drug Interactions

The ingredients in Soy Isoflavones interact with 664 drugs. Click any drug to see the details.

2 of the 4 ingredients in Soy Isoflavones interact with drugs. Each result below shows which ingredient is responsible. Soy Bean Extract Calcium

Each ingredient & the kinds of drugs it affects

For each ingredient in Soy Isoflavones with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.

Soy Bean Extract12 drug types · 611 drugs

Monoamine Oxidase Inhibitors (Maois)

Taking soy products containing high amounts of tyramine along with MAOIs can increase the risk of hypertensive crisis.
Fermented soy products such as tofu and soy sauce contain tyramine, a naturally occurring chemical that affects blood pressure regulation. The metabolism of tyramine is decreased by MAOIs. Consuming more than 6 mg of tyramine while taking an MAOI can increase the risk of hypertensive crisis. The amount of tyramine in fermented soy products is usually less than 0.6 mg per serving; however, there can be significant variation depending on the specific product used, storage conditions, and length of storage. Storing one brand of tofu for a week can increase tyramine content from 0.23 mg to 4.8 mg per serving. Advise patients taking MAOIs to avoid fermented soy products that contain high amounts of tyramine.

Likelihood Likely Evidence C
Antidiabetes Drugs

Soy can lower blood glucose and have additive effects with antidiabetes drugs.
Clinical research shows that whole soy diets and soy-based meals reduce fasting glucose levels in diabetic and non-diabetic individuals. Also, individuals following a soy-based meal replacement plan seem to require lower doses of sulfonylureas and metformin to manage blood glucose levels when compared with individuals following a diet plan recommended by the American Diabetes Association.

Likelihood Possible Evidence A
Antihypertensive Drugs

Theoretically soy protein may have additive effects with antihypertensive drugs and increase the risk of hypotension.
Although some contradictory research exists, most clinical evidence suggests that consuming soy protein modestly reduces systolic and diastolic blood pressure in individuals with prehypertension or hypertension.

Likelihood Possible Evidence A
Caffeine

Theoretically, soy might reduce the clearance of caffeine.
Soy contains genistein. Taking genistein 1 gram daily for 14 days seems to inhibit caffeine clearance and metabolism in healthy females. This effect has been attributed to inhibition of the cytochrome P450 1A2 (CYP1A2) enzyme, which is involved in caffeine metabolism. It is unclear if this effect occurs with the lower amounts of genistein found in soy.

Likelihood Possible Evidence D
Diuretic Drugs

Theoretically, soy might have additive effects when used with diuretic drugs.
Animal research suggests that genistein, a soy isoflavone, increases diuresis within 6 hours of subcutaneous administration in rats. The effects seem to be similar to those of furosemide. This effect has not been reported in humans.

Likelihood Possible Evidence D
Estrogens

Theoretically, soy might competitively inhibit the effects of estrogen replacement therapy.
Soy contains phytoestrogens and has been shown to have estrogenic activity in some patients. Although this has not been demonstrated in humans, theoretically, concomitant use of soy with estrogen replacement therapy might reduce the effects of the estrogen replacement therapy.

Likelihood Possible Evidence D
Levothyroxine (Synthroid, Others)

Soy products might reduce the absorption of levothyroxine in some patients.
Preliminary clinical research and a case report suggest that soy-based formulas inhibit the absorption of levothyroxine in infants with congenital hypothyroidism. A levothyroxine dosage increase may be needed for infants with congenital hypothyroidism while using soy-based formulas, and the dose may need to be reduced when soy-based formulas are no longer administered. However, in postmenopausal adults, clinical research shows that taking a single dose of soy extract containing isoflavones 60 mg along with levothyroxine does not affect the oral bioavailability of levothyroxine.

Likelihood Possible Evidence B
Progesterone

Theoretically, combining soy isoflavones with transdermal progesterone may worsen bone density.
Clinical research suggests that significant bone loss may occur in females with osteoporosis who receive a combination of transdermal progesterone with soy milk containing isoflavones when compared with placebo, soy milk alone, or progesterone alone.

Likelihood Possible Evidence A
Tamoxifen (Nolvadex)

Theoretically, estrogenic soy isoflavones might alter the effects of tamoxifen.
Laboratory research suggests that genistein and daidzen, isoflavones from soy, can antagonize the antitumor effects of tamoxifen under some circumstances; however, soy isoflavones might have different effects when used at different doses. A relatively low in vitro concentration of soy isoflavones such as 1 microM/L seems to interfere with tamoxifen, whereas high in vitro concentrations such as those >10 microM/L might actually enhance tamoxifen effects. People on a high-soy diet have soy isoflavones levels ranging from 0.1-6 microM/L. Until more is known, advise patients taking tamoxifen to avoid therapeutic use of soy products.

Likelihood Possible Evidence B
Warfarin (Coumadin)

Theoretically, soy might interfere with the effects of warfarin.
Soy milk has been reported to decrease the international normalized ratio (INR) in a patient taking warfarin. The mechanism of this interaction is not known. However, animal and in vitro research suggests that soy may also inhibit platelet aggregation. Dosing adjustments for warfarin may be necessary.

Likelihood Possible Evidence D
Antibiotic Drugs

Theoretically, antibiotics may decrease the activity of soy isoflavones.
Intestinal bacteria are responsible in part for converting soy isoflavones into their active forms. Antibiotics may decrease the amount of intestinal bacteria and decrease its ability to convert isoflavones.

Likelihood Possible Evidence D
Cytochrome P450 2C9 (Cyp2C9) Substrates

Soy might modestly induce CYP2C9 enzymes. However, this effect does not seem to be clinically significant.
In vitro research suggests that an unhydrolyzed soy extract might induce CYP2C9. However, the significance of this interaction is likely minimal. In healthy females taking a specific extract of soy (Genistein Soy Complex, Source Naturals), blood levels of losartan, a CYP2C9 substrate, were not significantly affected.

Likelihood Unlikely Evidence D
Soy Bean Extract full monograph & interactions

Calcium18 drug types · 168 drugs

Ceftriaxone (Rocephin)

Co-administration of intravenous calcium and ceftriaxone can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys.
Avoid administering intravenous calcium in any form, such as parenteral nutrition or Lactated Ringers, within 48 hours of intravenous ceftriaxone. Case reports in neonates show that administering intravenous ceftriaxone and calcium can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys. In several cases, neonates have died as a result of this interaction. So far there are no reports in adults; however, there is still concern that this interaction might occur in adults.

Likelihood Probable Evidence D
Dolutegravir (Tivicay)

Calcium seems to reduce levels of dolutegravir.
Advise patients to take dolutegravir either 2 hours before or 6 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium carbonate 1200 mg concomitantly with dolutegravir 50 mg reduces plasma levels of dolutegravir by almost 40%. Calcium appears to decrease levels of dolutegravir through chelation.

Likelihood Probable Evidence B
Elvitegravir (Vitekta)

Calcium seems to reduce levels of elvitegravir.
Advise patients to take elvitegravir either 2 hours before or 2 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium along with elvitegravir can reduce blood levels of elvitegravir through chelation.

Likelihood Probable Evidence B
Aluminum

Calcium citrate might increase aluminum absorption and toxicity. Other types of calcium do not increase aluminum absorption.
Calcium citrate can increase the absorption of aluminum when taken with aluminum hydroxide. The increase in aluminum levels may become toxic, particularly in individuals with kidney disease. However, the effect of calcium citrate on aluminum absorption is due to the citrate anion rather than calcium cation. Calcium acetate does not appear to increase aluminum absorption.

Likelihood Possible Evidence B
Bictegravir/Emtricitabine/Tenofovir Alafenamide (Biktarvy)

Calcium might decrease levels of bictegravir/emtricitabine/tenofovir alafenamide by reducing its absorption when taken in a fasting state.
Advise patients that bictegravir/emtricitabine/tenofovir alafenamide and calcium can be taken together if taken with food. However, if taken on an empty stomach, bictegravir/emtricitabine/tenofovir alafenamide should not be taken with, or 2 hours after, calcium containing products.

Likelihood Probable Evidence D
Bisphosphonates

Calcium reduces the absorption of bisphosphonates.
Advise patients to take bisphosphonates at least 30 minutes before calcium, but preferably at a different time of day. Calcium supplements decrease absorption of bisphosphonates.

Likelihood Probable Evidence C
Calcipotriene (Dovonex)

Taking calcipotriene with calcium might increase 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 calcium supplements might increase the risk of hypercalcemia.

Likelihood Possible Evidence B
Digoxin (Lanoxin)

Using intravenous calcium with digoxin might increase the risk of fatal cardiac arrhythmias.
Hypercalcemia increases the risk of fatal cardiac arrhythmias with digoxin. However, one retrospective analysis of clinical data suggests that intravenous calcium does not increase the risk of dysrhythmias or mortality in patients receiving digoxin.

Likelihood Possible Evidence B
Diltiazem (Cardizem, Others)

Theoretically, calcium may reduce the therapeutic effects of diltiazem.
Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation. Theoretically, calcium might increase this risk of hypercalcemia and reduce the effectiveness of diltiazem.

Likelihood Probable Evidence D
Levothyroxine (Synthroid, Others)

Calcium seems to reduce the absorption and effectiveness of levothyroxine.
Advise patients to take levothyroxine and calcium supplements at least 4 hours apart. Calcium reduces levothyroxine absorption, probably by forming insoluble complexes. Calcium carbonate supplements reduce effectiveness of levothyroxine in patients with hypothyroidism.

Likelihood Probable Evidence B
Lithium

Theoretically, concomitant use of calcium and lithium may increase this risk of hypercalcemia.
Clinical research suggests that long-term use of lithium may cause hypercalcemia in 10% to 60% of patients. Theoretically, concomitant use of lithium and calcium supplements may further increase this risk.

Likelihood Possible Evidence B
Quinolone Antibiotics

Calcium seems to reduce the absorption of quinolone antibiotics.
Advise patients to take oral quinolones at least 2 hours before or 4-6 hours after calcium supplements or calcium-fortified foods. Taking calcium at the same time as oral quinolones can reduce quinolone absorption. Calcium binds to quinolones in the gut.

Likelihood Probable Evidence B
Raltegravir (Isentress)

Calcium may reduce levels of raltegravir.
Pharmacokinetic research shows that taking a single dose of calcium carbonate 3000 mg along with raltegravir 400 mg twice daily modestly decreases the mean area under the curve of raltegravir, but the decrease does not necessitate a dose adjustment of raltegravir. However, a case of elevated HIV-1 RNA levels and documented resistance to raltegravir has been reported for a patient taking calcium carbonate 1 gram three times daily plus vitamin D3 (cholecalciferol) 400 IU three times daily in combination with raltegravir 400 mg twice daily for 11 months. It is thought that calcium reduced raltegravir levels by chelation, leading to treatment failure.

Likelihood Possible Evidence B
Sotalol (Betapace)

Calcium seems to reduce the absorption of sotalol.
Advise patients to separate doses by at least 2 hours before or 4-6 hours after calcium. Calcium appears to reduce the absorption of sotalol, probably by forming insoluble complexes.

Likelihood Possible Evidence B
Tetracycline Antibiotics

Calcium seems to reduce the absorption of tetracycline antibiotics.
Advise patients to take oral tetracyclines at least 2 hours before, or 4-6 hours after calcium supplements. Taking calcium at the same time as oral tetracyclines can reduce tetracycline absorption. Calcium binds to tetracyclines in the gut.

Likelihood Probable Evidence C
Thiazide Diuretics

Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.
Thiazides reduce calcium excretion by the kidneys. Using thiazides along with moderately large amounts of calcium carbonate increases the risk of milk-alkali syndrome (hypercalcemia, metabolic alkalosis, renal failure). Patients may need to have their serum calcium levels and/or parathyroid function monitored regularly.

Likelihood Probable Evidence C
Verapamil (Calan, Others)

Theoretically, calcium may reduce the therapeutic effects of verapamil.
Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation. Theoretically, use of calcium supplements may increase this risk of hypercalcemia and reduce the effectiveness of verapamil.

Likelihood Probable Evidence D
Calcium Channel Blockers

Intravenous calcium may decrease the effects of calcium channel blockers; oral calcium is unlikely to have this effect.
Intravenous calcium is used to decrease the effects of calcium channel blockers in the management of overdose. Intravenous calcium gluconate has been used before intravenous verapamil (Isoptin) to prevent or reduce the hypotensive effects without affecting the antiarrhythmic effects. But there is no evidence that dietary or supplemental calcium when taken orally interacts with calcium channel blockers.

Likelihood Unlikely Evidence D
Calcium full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Soy Isoflavones, from the product label.

The Vitamin Shoppe

See all The Vitamin Shoppe products
Name
Vitamin Shoppe, Inc.
City
Secaucus
State
NJ
ZipCode
07094
Phone Number
1-800-223-1216
Web Address
www.vitaminshoppe.com
Pharmacist Counseling Corner

Soy Isoflavones by The Vitamin Shoppe: Common Questions

Does Soy Isoflavones by The Vitamin Shoppe interact with any medications?
Yes. Based on its ingredients, Soy Isoflavones has a known interaction with 664 medications, including 16 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Soy Isoflavones contains 4 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is 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.
Does this product actually help with bone health?
Calcium is established as effective for osteoporosis and preventing low calcium levels. Soy bean extract shows possibly effective evidence for osteoporosis, meaning some clinical research supports it but the evidence is not as robust. Together they may offer complementary support, but talk to your doctor about whether this product is right for your specific bone health needs.
What are the most common side effects?
From calcium, you might experience belching, constipation, diarrhea, bloating, or stomach upset. From soy, common side effects include bloating, constipation, diarrhea, and nausea. These tend to be mild and often improve with time, but if they persist or worsen, let your pharmacist know.
Can I take this product if I'm pregnant?
Calcium at recommended doses is important during pregnancy and considered safe. However, we don't have safety data on file for concentrated soy isoflavone supplements in pregnancy — soy foods eaten as part of a normal diet are fine, but high-dose supplements haven't been well studied. Talk to your doctor or pharmacist about whether this product is appropriate for you during pregnancy.
Is it safe to take this while breastfeeding?
Calcium at recommended amounts is safe during breastfeeding and helps meet your body's needs. Soy foods are commonly eaten while breastfeeding, but concentrated isoflavone supplements like this one have not been well studied. Check with your pharmacist or doctor to decide if this product is right for you.
What's the difference between soy protein isolate and soy bean extract in this product?
Soy protein isolate is a purified form of soy protein used for its nutritional content. Soy bean extract is where the isoflavones — the active plant compounds — are concentrated. We don't have interaction data on file for soy protein isolate specifically, but soy bean extract is the ingredient responsible for the interactions listed on this page.
Will this interfere with my thyroid medication?
Yes, both calcium and soy can reduce how well your body absorbs levothyroxine and other thyroid medications. If you take thyroid replacement therapy, you'll need to space this supplement several hours away from your dose — talk to your pharmacist about the exact timing for your specific medication.

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.

Soy Isoflavones label
Go deeper

The Full Monographs Behind Soy Isoflavones’s Ingredients

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

Herb & supplement monograph

Calcium

Interacts with 168 drugs

Calcium is an essential mineral your body needs for strong bones, nerve signaling, and muscle function, and supplements can help fill gaps when diet falls short. Most people do best getting...

Read the full Calcium monograph → Herb & supplement monograph

Soy

Interacts with 611 drugs

Soy is a nutritious bean that is a staple food and a popular source of plant protein and isoflavones. Eating soy foods as part of a balanced diet is generally considered safe for most people...

Read the full Soy monograph →
Sources

Sources & How We Checked

Soy Isoflavones'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 150 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.

Calcium 62 references
  1. Shils M, Olson A, Shike M. Modern Nutrition in Health and Disease. 8th ed. Philadelphia, PA: Lea and Febiger, 1994.
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See these in context on the Calcium monograph →

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  86. Upson K, Sathyanarayana S, Scholes D, Holt VL. Early-life factors and endometriosis risk. Fertil Steril. 2015;104(4):964-971.e5. PubMed
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See these in context on the Soy 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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