Major interaction on record — check this product against your medications before combining. Check your meds →
Dietary supplement

Heart Guard Ingredients & Drug Interactions

by KaraMD

Heart Guard label
See full label image
Capsule Category: Other Combinations
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 23, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Heart Guard 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

Heart Guard is a dietary supplement by KaraMD with 4 active ingredients. Its ingredients are commonly taken for preventing or treating magnesium deficiency, constipation, muscle cramps.Based on those ingredients, 1,148 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Grapeseed extract, Magnesium, Nattokinase. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Heart Guard by KaraMD

Ask about any prescription or over-the-counter medication and we check it for interactions with Heart Guard by KaraMD — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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HelloPharmacist Scorecard of Heart Guard by KaraMD

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 Aug 6, 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.

Heart Guard contains four active ingredients. Magnesium is an essential mineral used here to support heart and bone health.

Grapeseed extract comes from grape seeds and is studied for circulatory support. Nattokinase is an enzyme derived from fermented soybeans with potential effects on blood flow.

Hawthorn extract, made from the hawthorn plant, has a long history in heart health formulations. The capsule itself is made from vegetable cellulose, a plant-based material.

Does it work?

Moderate 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
Moderate

Some clinical evidence supports this product's ingredients for its stated purpose, but it isn't conclusive.

Why this rating?
  • The label markets this product for: Heart and cardiovascular health support.
  • We looked for evidence on: Angina, Arrhythmia, Atherosclerosis, Cardiovascular disease (CVD), Chronic venous insufficiency (CVI), Congestive heart failure (CHF) — and 4 related terms.
  • The strongest evidence on file: Grape is rated "Possibly Effective" for Chronic venous insufficiency (CVI) (Natural Medicines).
  • Also on file: Magnesium is rated "Possibly Effective" for Vasospastic angina, Arrhythmia, Hypercholesterolemia.
  • Also on file: Grape is rated "Insufficient Reliable Evidence To Rate" for Atherosclerosis, Cardiovascular disease (CVD), Hypercholesterolemia.

The evidence for these ingredients varies. Magnesium is effective for indigestion and constipation, and appears effective for low magnesium levels and pre-eclampsia in pregnancy when used under medical supervision.

Grapeseed extract shows only possibly effective evidence for chronic venous insufficiency (a circulation condition), and possibly ineffective evidence for nausea from chemotherapy, hay fever, and weight loss. Nattokinase and hawthorn extract both carry insufficient evidence to rate their effectiveness for the conditions studied, including heart disease and angina.

Because the evidence for most of these ingredients as a heart support product is limited or not established, talk with your doctor about whether this product makes sense for your specific goals.

The evidence, ingredient by ingredient Magnesium Grape Nattokinase Hawthorn

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 4 of the 4 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 4 of 4.
  • General safety write-ups exist for 4 of 4.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Magnesium is generally well tolerated at recommended doses, though it can cause diarrhea, nausea, vomiting, or upset stomach in some people. Grapeseed extract also appears well tolerated and is safe as whole grapes in food.

Nattokinase has been generally tolerated in short-term use but carries a risk of bleeding due to its blood-thinning effects; it is not enough data to use in pregnancy or while breastfeeding. Hawthorn extract is generally well tolerated in studies, though it requires medical supervision if you have a heart condition; it is also not recommended in pregnancy or while breastfeeding due to lack of safety data.

Magnesium is needed during pregnancy but supplements should only be used under your doctor's guidance. There is not enough information on concentrated grape supplements, nattokinase, or hawthorn during breastfeeding.

Side effects, ingredient by ingredient Magnesium Grape Nattokinase Hawthorn

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?
  • 4 of the 4 matched ingredients can interact with medications — Grape, Hawthorn, Magnesium, Nattokinase.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; immunosuppressants / transplant drugs; diabetes medications; heart-rhythm medications; Parkinson's medications.
  • For scale: 1,149 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 taking this product, check with your doctor or pharmacist if you take nitrates or phosphodiesterase-5 inhibitors (like sildenafil), as hawthorn may cause a dangerous drop in blood pressure. You should also verify any blood pressure medications, blood thinners or antiplatelet drugs (including aspirin), Parkinson's medication (levodopa/carbidopa), skeletal muscle relaxants, diabetes drugs, antibiotics (especially quinolone antibiotics), bone-strengthening drugs, or any other medications your liver processes—each of the four ingredients can affect different drug types.

Check your own medication Run your meds through the checker above

The bottom line

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

Heart Guard combines four ingredients with varying evidence and real interaction risks, especially if you take blood pressure medications, blood thinners, or heart drugs. Because the product's effectiveness for heart health is not well established and the interaction list is long, this is not a take-it-and-see situation.

Talk with your doctor or pharmacist before starting, especially if you have a heart condition or take any prescription medications.

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

Assessment coverage: 4 of 4 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Feb 25, 2021.

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 Heart Guard, straight from the product label.

Brand KaraMD
Barcode (UPC) X002ED18CB
Net contents 60 Veggie Capsule(s)
Market status On market
Date entered into DSLD Feb 25, 2021
DSLD ID 243872
Product type Other Combinations
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years)
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 Heart Guard by KaraMD, 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:
2 Veggie Capsule(s)
Maximum serving Sizes:
2 Veggie Capsule(s)
Servings per container
30
UPC/BARCODE
X002ED18CB
IngredientAmount% DV
Magnesium200 mg--
Grapeseed extract150 mg--
Nattokinase50 mg--
Hawthorne extract400 mg--

Other ingredients: Vegetable Cellulose

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.
Brand IP Statement(s)

Copyright 2019

Suggested/Recommended/Usage/Directions

Suggested Use: Take 2 Heart Guard veggie capsules once a day with 8 fl oz of water.

Formulation

Heart Guard is made in the USA in our FDA Registered Facility using natural ingredients.

Helps protect essential heart functions

Non GMO

Vegan

Precautions

Consult your physician if you have any medical condition, you're pregnant/lactating or under 18, or if you're taking any medications.

Consult your physician if you have any medical condition, you're pregnant/lactating or under 18, or if you're taking any medications.

Do not use if safety seal is damaged or missing.

Keep out of reach of children.

Storage

Store in a cool, dry place

FDA Disclaimer Statement

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.

FDA Statement of Identity

Heart Health Supplement

Seals/Symbols

Made in the USA

General Statements

90 Day Money Back Guarantee

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

See for yourself

Heart Guard by KaraMD label

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

Heart Guard 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 Heart Guard by KaraMD

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

Serving size2 Veggie Capsule(s) Dosage formCapsule 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.

Magnesium

Interacts with
295 drugs
200 mg per serving

Magnesium is an essential mineral your body needs for muscles, nerves, blood pressure, and many other functions, and supplements are useful for preven...

Magnesium monograph & interactions

Grapeseed extract

Interacts with
910 drugs
150 mg per serving

Grapes and grape products like grape seed extract contain antioxidant compounds such as resveratrol and proanthocyanidins that may support heart and b...

Grapeseed extract monograph & interactions

Nattokinase

Interacts with
289 drugs
50 mg per serving

Nattokinase is an enzyme from the fermented soybean food natto that may have mild blood-thinning and blood-flow effects. Some small studies hint at be...

Nattokinase monograph & interactions

Hawthorne extract

Interacts with
191 drugs
400 mg per serving

Hawthorn is a plant traditionally used for heart-related complaints, and some studies suggest it may modestly help symptoms of mild heart failure when...

Hawthorne extract monograph & interactions

Other (inactive) ingredients: Vegetable Cellulose. These complete the product’s ingredient list but are not active constituents.

Interaction report

Heart Guard by KaraMD Drug Interactions

Want to check YOUR meds against Heart Guard?

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
1,148Drugs
20 Major 1,099 Moderate 29 Minor

Ingredients driving the most interactions

Grapeseed extract 910
Magnesium 295
Nattokinase 289
Hawthorne extract 191

Individual Drug Interactions

The ingredients in Heart Guard interact with 1,148 drugs. Click any drug to see the details.

4 of the 4 ingredients in Heart Guard interact with drugs. Each result below shows which ingredient is responsible. Grapeseed extract Magnesium Nattokinase Hawthorne extract

Each ingredient & the kinds of drugs it affects

For each ingredient in Heart Guard 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.

Grapeseed extract9 drug types · 910 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, grape extracts may have antiplatelet effects and may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
In vitro evidence suggests that grape extracts might decrease platelet aggregation.

Likelihood Possible Evidence D
Cyclosporine (Neoral, Sandimmune)

Ingesting grape juice with cyclosporine can reduce cyclosporine absorption.
A small pharmacokinetic study in healthy young adults shows that intake of purple grape juice 200 mL along with cyclosporine can decrease the absorption of cyclosporine by up to 30% when compared with water. Separate doses of grape juice and cyclosporine by at least 2 hours to avoid this interaction.

Likelihood Possible Evidence B
Cytochrome P450 1A2 (Cyp1A2) Substrates

Theoretically, grape juice might reduce the levels of CYP1A2 substrates.
A small pharmacokinetic study in healthy adults shows that ingestion of 200 mL of grape juice decreases phenacetin plasma levels. This is thought to be due to induction of CYP1A2.

Likelihood Possible Evidence B
Cytochrome P450 2D6 (Cyp2D6) Substrates

Theoretically, grape seed extract may increase the levels of CYP2D6 substrates.
In vitro evidence suggests that grape seed extract might inhibit CYP2D6 enzymes. However, this interaction has not been reported in humans.

Likelihood Possible Evidence D
Cytochrome P450 2E1 (Cyp2E1) Substrates

Theoretically, grape seed extract might increase the levels of CYP2E1 substrates.
In vitro and animal research suggests that grape seed proanthocyanidin extract inhibits CYP2E1 enzymes. However, this interaction has not been reported in humans.

Likelihood Possible Evidence D
Cytochrome P450 3A4 (Cyp3A4) Substrates

It is unclear if grape seed extract inhibits or induces CYP3A4; research is conflicting.
In vitro evidence suggests that grape seed extract might inhibit CYP3A4 enzymes. However, evidence from animal research shows that grape seed extract may induce CYP3A4 in the liver. So far, these interactions have not been reported in humans.

Likelihood Possible Evidence D
Midazolam (Versed)

Theoretically, long-term intake of grape seed extract might decrease the effects of midazolam.
Animal research shows that subchronic ingestions of grape seed extract can increase the elimination of intravenous midazolam by increasing hepatic CYP3A4 activity. Single doses of grape seed extract do not appear to affect midazolam elimination.

Likelihood Possible Evidence D
Phenacetin

Grape juice might decrease phenacetin absorption.
A small pharmacokinetic study in healthy adults shows that ingestion of 200 mL of grape juice decreases phenacetin plasma levels. This is thought to be due to induction of cytochrome P450 1A2 (CYP1A2).

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

It is unclear if grape juice or grape seed extract inhibits CYP2C9; research is conflicting.
In vitro evidence shows that grape seed extract or grape juice might inhibit CYP2C9 enzymes. However, a small pharmacokinetic study in healthy adults shows that drinking 8 ounces of grape juice once does not affect the clearance of flurbiprofen, a probe-drug for CYP2C9 metabolism. The effects of continued grape juice consumption are unclear.

Likelihood Unlikely Evidence D
Grapeseed extract full monograph & interactions

Magnesium15 drug types · 295 drugs

Levodopa/Carbidopa (Sinemet)

Magnesium can reduce the bioavailability of levodopa/carbidopa.
Clinical research in healthy volunteers shows that taking magnesium oxide 1000 mg with levodopa 100 mg/carbidopa 10 mg reduces the area under the curve (AUC) of levodopa by 35% and of carbidopa by 81%. In vitro and animal research shows that magnesium produces an alkaline environment in the digestive tract, which might lead to degradation and reduced bioavailability of levodopa/carbidopa.

Likelihood Probable Evidence B
Aminoglycoside Antibiotics

Concomitant use of aminoglycoside antibiotics and magnesium can increase the risk for neuromuscular weakness.
Both aminoglycosides and magnesium reduce presynaptic acetylcholine release, which can lead to neuromuscular blockade and possible paralysis. This is most likely to occur with high doses of magnesium given intravenously.

Likelihood Possible Evidence D
Antacids

Use of acid reducers may reduce the laxative effect of magnesium oxide.
A retrospective analysis shows that, in the presence of H2 receptor antagonists (H2RAs) or proton pump inhibitors (PPIs), a higher dose of magnesium oxide is needed for a laxative effect. This may also occur with antacids. Under acidic conditions, magnesium oxide is converted to magnesium chloride and then to magnesium bicarbonate, which has an osmotic laxative effect. By reducing acidity, antacids may reduce the conversion of magnesium oxide to the active bicarbonate salt.

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

Magnesium might decrease levels of bictegravir/emtricitabine/tenofovir alafenamide by reducing its absorption.
Advise patients that bictegravir/emtricitabine/tenofovir alafenamide should be taken at least 2 hours before or 6 hours after magnesium containing products.

Likelihood Probable Evidence D
Bisphosphonates

Magnesium can decrease absorption of bisphosphonates.
Cations, including magnesium, can decrease bisphosphonate absorption. Advise patients to separate doses of magnesium and these drugs by at least 2 hours.

Likelihood Probable Evidence B
Calcium Channel Blockers

Magnesium can have additive effects with calcium channel blockers, although evidence is conflicting.
Magnesium inhibits calcium entry into smooth muscle cells and may therefore have additive effects with calcium channel blockers. Severe hypotension and neuromuscular blockades may occur when nifedipine is used with intravenous magnesium, although some contradictory evidence suggests that concurrent use of magnesium with nifedipine does not increase the risk of neuromuscular weakness. High doses of magnesium could theoretically have additive effects with other calcium channel blockers.

Likelihood Possible Evidence D
Digoxin

Magnesium salts may reduce absorption of digoxin.
Clinical evidence suggests that treatment with oral magnesium hydroxide or magnesium trisilicate reduces absorption of digoxin from the intestines. This may reduce the blood levels of digoxin and decrease its therapeutic effects.

Likelihood Possible Evidence B
Potassium-Sparing Diuretics

Potassium-sparing diuretics decrease excretion of magnesium, possibly increasing magnesium levels.
Potassium-sparing diuretics also have magnesium-sparing properties, which can counteract the magnesium losses associated with loop and thiazide diuretics. Theoretically, increased magnesium levels could result from concomitant use of potassium-sparing diuretics and magnesium supplements.

Likelihood Probable Evidence D
Quinolone Antibiotics

Magnesium decreases absorption of quinolones.
Magnesium can form insoluble complexes with quinolones and decrease their absorption. Advise patients to take these drugs at least 2 hours before, or 4 to 6 hours after, magnesium supplements.

Likelihood Probable Evidence D
Skeletal Muscle Relaxants

Parenteral magnesium alters the pharmacokinetics of skeletal muscle relaxants, increasing their effects and accelerating the onset of effect.
Parenteral magnesium shortens the time to onset of skeletal muscle relaxants by about 1 minute and prolongs the duration of action by about 2 minutes. Magnesium potentiates the effects of skeletal muscle relaxants by decreasing calcium-mediated release of acetylcholine from presynaptic nerve terminals, reducing postsynaptic sensitivity to acetylcholine, and having a direct effect on the membrane potential of myocytes. Magnesium also has vasodilatory actions and increases cardiac output, allowing a greater amount of muscle relaxant to reach the motor end plate. A clinical study found that low-dose rocuronium (0.45 mg/kg), when given after administration of magnesium 30 mg/kg over 10 minutes, has an accelerated onset of effect, which matches the onset of effect seen with a full-dose rocuronium regimen (0.6 mg/kg). In another clinical study, onset times for rocuronium doses of 0.3, 0.6, and 1.2 mg/kg were 86, 76, and 50 seconds, respectively, when given alone, but were reduced to 66, 44, and 38 seconds, respectively, when the doses were given after a 15-minute infusion of magnesium sulfate 60 mg/kg. Giving intraoperative intravenous magnesium sulfate, 50 mg/kg loading dose followed by 15 mg/kg/hour, reduces the onset time of rocuronium, enhances its clinical effects, reduces the dose of intraoperative opiates, and prolongs the spontaneous recovery time. It does not affect the activity of subsequently administered neostigmine.

Likelihood Probable Evidence A
Sulfonylureas

Magnesium increases the systemic absorption of sulfonylureas, increasing their effects and side effects.
Clinical research shows that administration of magnesium hydroxide with glyburide increases glyburide absorption, increases maximal insulin response by 35-fold, and increases the risk of hypoglycemia, when compared with glyburide alone. A similar interaction occurs between magnesium hydroxide and glipizide. The mechanism of this effect appears to be related to the elevation of gastrointestinal pH by magnesium-based antacids, increasing solubility and enhancing absorption of sulfonylureas.

Likelihood Probable Evidence B
Tetracycline Antibiotics

Magnesium decreases absorption of tetracyclines.
Magnesium can form insoluble complexes with tetracyclines in the gut and decrease their absorption and antibacterial activity. Advise patients to take these drugs 1 hour before or 2 hours after magnesium supplements.

Likelihood Probable Evidence D
Anticoagulant/Antiplatelet Drugs

Theoretically, magnesium may have antiplatelet effects, but the evidence is conflicting.
In vitro evidence shows that magnesium sulfate inhibits platelet aggregation, even at low concentrations. Some preliminary clinical evidence shows that infusion of magnesium sulfate increases bleeding time by 48% and reduces platelet activity. However, other clinical research shows that magnesium does not affect platelet aggregation, although inhibition of platelet-dependent thrombosis can occur.

Likelihood Unlikely Evidence B
Gabapentin (Neurontin)

Gabapentin absorption can be decreased by magnesium.
Clinical research shows that giving magnesium oxide orally along with gabapentin decreases the maximum plasma concentration of gabapentin by 33%, time to maximum concentration by 36%, and area under the curve by 43%. Advise patients to take gabapentin at least 2 hours before, or 4 to 6 hours after, magnesium supplements.

Likelihood Unlikely Evidence B
Sevelamer (Renagel, Renvela)

Sevelamer may increase serum magnesium levels.
In patients on hemodialysis, sevelamer use was associated with a 0.28 mg/dL increase in serum magnesium. The mechanism of this interaction remains unclear.

Likelihood Possible Evidence B
Magnesium full monograph & interactions

Nattokinase2 drug types · 289 drugs

Anticoagulant/Antiplatelet Drugs

Nattokinase might increase the risk of bleeding when used with anticoagulant/antiplatelet drugs.
Nattokinase has thrombolytic and anticoagulant effects. There is a case report of intracranial hemorrhage in a patient who added nattokinase to aspirin therapy.

Likelihood Possible Evidence D
Antihypertensive Drugs

Theoretically, nattokinase might increase the risk of hypotension when used with antihypertensive drugs.
Some clinical research suggests that nattokinase may reduce systolic and diastolic blood pressure.

Likelihood Possible Evidence D
Nattokinase full monograph & interactions

Hawthorne extract6 drug types · 191 drugs

Nitrates

Theoretically, concomitant use might cause additive coronary vasodilatory effects.
Some evidence shows that hawthorn might lower blood pressure due to vasodilatory effects.

Likelihood Probable Evidence D
Phosphodiesterase-5 Inhibitors

Theoretically, concomitant use might result in additive vasodilation and hypotension.
Hawthorn might inhibit PDE-5 and cause vasodilation.

Likelihood Probable Evidence D
Anticoagulant/Antiplatelet Drugs

Theoretically, hawthorn may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
In vitro and animal research shows that hawthorn can inhibit platelet aggregation. However, its effect in humans is unclear. One observational study shows that patients taking hawthorn shortly before undergoing coronary artery bypass graft (CABG) surgery or valve replacement surgery have a 10% incidence of postoperative bleeding, compared with 1% in those who never consumed hawthorn extract. However, clinical research shows that taking a specific preparation of dried hawthorn leaves and flowers (Crataesor, Soria Natural Lab) 800 mg three times daily for 15 days does not affect platelet aggregation or levels of thromboxane B2, the metabolite of thromboxane A2, in healthy humans.

Likelihood Possible Evidence D
Beta-Blockers

Theoretically, concomitant use might cause additive effects on blood pressure and heart rate.
Some evidence shows that hawthorn might lower blood pressure and heart rate.

Likelihood Possible Evidence D
Calcium Channel Blockers

Theoretically, concomitant use might cause additive coronary vasodilation and hypotensive effects.
Some evidence shows that hawthorn might lower blood pressure due to vasodilatory effects.

Likelihood Possible Evidence D
Digoxin (Lanoxin)

Theoretically, hawthorn might potentiate the effects and adverse effects of digoxin.
Hawthorn appears to improve cardiac output; however, hawthorn does not appear to affect digoxin pharmacokinetics. Case reports suggest that at least one species of hawthorn root extract (Crataegus mexicana) may produce adverse effects similar to digoxin and can cross-react with digoxin assays, leading to falsely elevated plasma digoxin levels.

Likelihood Possible Evidence D
Hawthorne extract full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Heart Guard, from the product label.

KaraMD

See all KaraMD products
Name
KaraMD, Inc
Street Address
3100 East 45th Street Suite 234 #109
City
Cleveland
State
OH
ZipCode
44127
Phone Number
(800) 991-4518
Web Address
KaraMD.com
Pharmacist Counseling Corner

Heart Guard by KaraMD: Common Questions

Does Heart Guard by KaraMD interact with any medications?
Yes. Based on its ingredients, Heart Guard has a known interaction with 1,148 medications, including 20 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Heart Guard 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 work for heart health?
That's the tricky part—the evidence is mixed or lacking. Magnesium is proven for indigestion and constipation, and hawthorn, nattokinase, and grapeseed extract are studied for circulation and heart conditions, but the research on them for heart support is not strong enough to rate. Your doctor can help you decide if it's the right choice for your situation.
What are the side effects I should watch for?
Magnesium commonly causes diarrhea, nausea, or upset stomach. Grapeseed extract can cause abdominal pain, headache, or joint pain. Nattokinase carries a rare risk of bleeding. Hawthorn is generally well tolerated but can cause heart palpitations in some people. Stop and call your doctor if you experience bleeding, severe dizziness, or chest symptoms.
Can I take this while pregnant or breastfeeding?
Magnesium is needed in pregnancy but only as a supplement under your doctor's supervision. For grapeseed extract, hawthorn, and nattokinase, there is not enough safety information to recommend them during pregnancy or breastfeeding—talk with your doctor or pharmacist about what's right for you.
What is nattokinase and why is it in this product?
Nattokinase is an enzyme from fermented soybeans that has blood-thinning and clot-dissolving properties. It's included because some research suggests it may support circulation, but the evidence is not established, and it does carry a real risk of bleeding, especially when combined with blood thinners.
Does magnesium in this product help lower blood pressure?
Magnesium is not in this formula for blood pressure control—it's an essential mineral needed for general health and has proven benefits for indigestion and constipation. If blood pressure management is your goal, check with your doctor first, because this product also contains hawthorn and nattokinase, both of which can lower blood pressure and may not be safe for you.

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.

Heart Guard label
Go deeper

The Full Monographs Behind Heart Guard’s Ingredients

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

Herb & supplement monograph

Magnesium

Interacts with 295 drugs

Magnesium is an essential mineral your body needs for muscles, nerves, blood pressure, and many other functions, and supplements are useful for preventing or correcting deficiency. Some othe...

Read the full Magnesium monograph → Herb & supplement monograph

Grape

Interacts with 910 drugs

Grapes and grape products like grape seed extract contain antioxidant compounds such as resveratrol and proanthocyanidins that may support heart and blood vessel health. While the food is he...

Read the full Grape monograph → Herb & supplement monograph

Nattokinase

Interacts with 289 drugs

Nattokinase is an enzyme from the fermented soybean food natto that may have mild blood-thinning and blood-flow effects. Some small studies hint at benefits for blood pressure and circulatio...

Read the full Nattokinase monograph → Herb & supplement monograph

Hawthorn

Interacts with 191 drugs

Hawthorn is a plant traditionally used for heart-related complaints, and some studies suggest it may modestly help symptoms of mild heart failure when added to standard care. However, the ev...

Read the full Hawthorn monograph →
Sources

Sources & How We Checked

Heart Guard'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.

Magnesium 82 references
  1. Rodin SM, Johnson BF. Pharmacokinetic interactions with digoxin. Clin Pharmacokinet 1988;15:227-44.
  2. Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
  3. Dahle LO, Berg G, Hammar M, et al. The effect of oral magnesium substitution on pregnancy-induced leg cramps. Am J Obstet Gynecol 1995;173:175-80. PubMed
  4. Hansten PD, Horn JR. Drug Interactions Analysis and Management. Vancouver, WA: Applied Therapeutics Inc., 1997 and updates.
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See these in context on the Hawthorn monograph →

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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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