Guide
Supplements and Heart Medicines: Arginine and Citrulline Interactions
Supplements can interact with heart medicines, and arginine is a clear example. Mayo Clinic warns it may drop blood pressure too low with blood pressure drugs, nitrates or sildenafil, may raise bleeding risk with blood thinners and may lower blood sugar with diabetes drugs. It is not recommended after a recent heart attack. Ask your doctor or pharmacist before you start.
Written by the Melonex label deskUpdated
The basics01
Can supplements interact with heart medicines?
Yes, supplements can interact with heart medicines. Some add to a drug's effect, some weaken it, and some raise bleeding risk. NIH gives the example of vitamin K, which can reduce the effect of the blood thinner warfarin (NIH ODS, What You Need to Know).
Supplements need no FDA approval before sale (NIH ODS, What You Need to Know), and "natural" does not always mean safe (NCCIH, Supplements Wisely).
Melonex capsules hold L-citrulline and two forms of L-arginine, which feed the body's nitric oxide system. That system relaxes blood vessels, so the capsules deserve a check against heart medicines.
Keep a written list of every medicine and supplement you take, with doses, and show it to each doctor and pharmacist you see (NIH ODS, What You Need to Know).
Interactions table02
Which heart medicines interact with arginine and citrulline?
The heart medicines that interact with arginine are blood pressure drugs, nitrates, PDE5 drugs such as sildenafil, blood thinners, potassium-sparing diuretics and diabetes drugs. Mayo Clinic lists each of these, plus isoproterenol (Mayo Clinic, L-arginine).
Citrulline is turned into arginine in the body, so the same blood pressure cautions apply to it (Aguayo 2021, L-citrulline review). A Brigham and Women's health library entry goes further and says to avoid arginine with nitrates, diuretics, diabetes medicine, blood pressure medicine or anticoagulants (Health Library, Arginine).
| Medicine group | Examples named in sources | What may happen | Source |
|---|---|---|---|
| Blood pressure drugs | Any medicine for high blood pressure | Blood pressure may drop too low | (Mayo Clinic, L-arginine) (Health Library, Arginine) |
| Nitrates | Nitroglycerin, isosorbide dinitrate, isosorbide mononitrate | Blood pressure may drop too low | (Mayo Clinic, L-arginine) (MedlinePlus, sildenafil) |
| PDE5 (erectile-dysfunction) drugs | Sildenafil, tadalafil | Blood pressure may drop too low | (Mayo Clinic, L-arginine) |
| Anticoagulants and antiplatelets | Blood thinners | Bleeding risk may rise | (Mayo Clinic, L-arginine) |
| Potassium-sparing diuretics | Water pills that hold on to potassium | Potassium may climb too high; do not combine | (Mayo Clinic, L-arginine) (Health Library, Arginine) |
| Diabetes drugs | Insulin and blood sugar pills | Blood sugar may fall too far | (Mayo Clinic, L-arginine) |
Melonex holds 0.5 to 1 g of blend a day, far below trial doses. Nobody has tested the capsules with these drugs, so the cautions still apply.
Nitrates and PDE5 drugs03
Why are nitrates and sildenafil a risky pair?
Nitrates and sildenafil are a risky pair because both lower blood pressure, and together the drop can be severe. MedlinePlus says sildenafil must not be taken with nitrate chest-pain medicines such as nitroglycerin, or with nitrate street drugs called poppers (MedlinePlus, sildenafil).
Arginine may add a third push in the same direction (Mayo Clinic, L-arginine). On a nitrate, ask your cardiologist first.
There is a hidden risk, too. FDA found undeclared sildenafil in a product sold for sexual enhancement, and warned it could lower blood pressure dangerously with nitrates (FDA, hidden drug notice). Products sold for sexual enhancement, weight loss or bodybuilding are the most likely to hide drugs (NCCIH, Supplements Wisely).
After a heart attack04
Is arginine safe after a heart attack?
No, arginine is not recommended after a recent heart attack. Mayo Clinic says it might increase the risk of death in that group (Mayo Clinic, L-arginine).
The warning comes from the VINTAGE MI trial. It gave 153 people arginine (target 9 g a day) or placebo for 6 months after a first heart attack. Six people on arginine died (8.6%) and none on placebo did, so enrollment was stopped early (VINTAGE MI trial, JAMA 2006).
Do not start Melonex or any arginine product without your cardiologist's yes. The who it's for checklist covers the other red flags.
Warning signs05
Which warning signs mean you should call 911?
Call 911 for chest discomfort that lasts more than a few minutes or comes back, pain that spreads to the arm, back, neck, jaw or stomach, or shortness of breath. Cold sweat, nausea or light-headedness can come with them (AHA, warning signs).
Stroke signs follow B.E. F.A.S.T.: balance loss, eye or vision changes, face drooping, arm weakness, speech trouble, time to call 911. Call even if the signs go away (AHA, warning signs).
- Chest discomfortPressure, squeezing or pain that lasts or comes back
- Pain that spreadsArm, back, neck, jaw or stomach
- Short of breathWith or without chest discomfort
- Face droopingOne side of the face droops or feels numb
- Arm weaknessOne arm drifts down when both are raised
- Speech troubleSlurred speech or hard to understand
Call 911Any of these signs, even if they go away. Note the time they started. Do not drive yourself to the hospital.
Low?Dizzy, light-headed, blurry vision or fainting, especially on standing, can mean blood pressure fell too low. Sit or lie down and call your doctor.
Warning signs from the American Heart Association (AHA, warning signs); low blood pressure signs from NHLBI (NHLBI, low blood pressure). Arginine and citrulline can lower blood pressure, more so with nitrates or erectile-dysfunction drugs (Mayo Clinic, L-arginine).
Melonex: from $49 a bottle60 capsules · 2, 3 or 6 bottles · free US shipping on 3 or 6 · 60-day guarantee
See packsOther supplements06
Do other heart supplements interact with medicines?
Yes, several other heart supplements interact with medicines. Garlic, fish oil, CoQ10, red yeast rice, green tea and potassium each have at least one known clash, mostly with blood thinners or blood pressure drugs.
Stacking products that each raise bleeding risk is the pattern to watch.
| Supplement | Medicine | Concern | Source |
|---|---|---|---|
| Garlic | Anticoagulants, aspirin, saquinavir | Bleeding risk; may interfere with saquinavir | (NCCIH, Garlic) (NCCIH, hypertension digest) |
| Omega-3 (high dose) | Warfarin and other anticoagulants | Bleeding problems | (NIH ODS, Omega-3s) |
| CoQ10 | Warfarin, insulin | May interact with both | (NCCIH, Coenzyme Q10) |
| Red yeast rice | The same drugs that interact with statins | Statin-like muscle, kidney and liver harm | (NCCIH, Red yeast rice) |
| Green tea (high dose) | Nadolol, a beta-blocker | Weaker drug effect | (NCCIH, hypertension digest) |
| Potassium, salt substitutes | ACE inhibitors, potassium-sparing diuretics | Dangerously high potassium | (NIH ODS, Potassium) |
| Vitamin K | Warfarin | Weaker drug effect | (NIH ODS, What You Need to Know) |
Each product is compared on evidence in heart health supplements compared.
Your prescriptions07
Should you stop a prescribed medicine to try a supplement?
No. Keep taking prescribed medicine exactly as written, and never cut a dose to make room for a supplement. A blood pressure or heart drug is matched to your readings and your risk.
A supplement is not a substitute. Melonex is a dietary supplement, and its label says it is not intended to diagnose, treat, cure or prevent any disease.
If a doctor agrees you may try one, change one thing at a time so a drop or side effect has a clear cause.
Ask
Show your doctor or pharmacist the bottle before the first capsule.
Log
Take home readings for a week, same time each day, two readings a minute apart (AHA, home BP monitoring).
Report
Stop the supplement and call if you feel dizzy or unwell (NCCIH, Supplements Wisely).
At the pharmacy08
What should you ask your pharmacist about a supplement?
Ask your pharmacist whether each ingredient on the label can change how your current medicines work. A pharmacist can check the whole list at once.
Bring the bottle, not just the name.
Questions worth asking
- Could arginine or citrulline add to my blood pressure or nitrate medicine?
- Does anything I take raise bleeding risk, and would this add to it?
- Could this change my potassium or blood sugar?
- What symptoms should make me stop and call you?
- How do I report a reaction? NIH points to FDA at 800-FDA-1088 (NIH ODS, What You Need to Know).
More on reactions in Melonex side effects and on reading results in blood pressure numbers.
FAQ09
Supplement and heart medicine questions
Can I take L-arginine with my blood pressure pills?
Only with your doctor's approval. Mayo Clinic says arginine combined with blood pressure drugs might make pressure drop too low. If your doctor agrees, log home readings and watch for dizziness or fainting (Mayo Clinic, L-arginine) (NHLBI, low blood pressure).
Can L-citrulline be taken with tadalafil?
Ask your doctor first. Citrulline is converted into arginine, and arginine with erectile-dysfunction drugs may lower blood pressure too far. Never combine either of them with a nitrate such as nitroglycerin (Aguayo 2021, L-citrulline review) (Mayo Clinic, L-arginine) (MedlinePlus, sildenafil).
Does arginine raise bleeding risk with blood thinners?
It may. Mayo Clinic lists a possible rise in bleeding risk when arginine is used with anticoagulants or antiplatelet drugs. Tell whoever manages your blood thinner before you start any arginine product (Mayo Clinic, L-arginine).
Can arginine affect blood sugar on diabetes medicine?
Yes, arginine may lower blood sugar when combined with diabetes drugs, Mayo Clinic says. If you use insulin or blood sugar pills, ask your doctor whether to check your sugar more often after starting it (Mayo Clinic, L-arginine).
Is arginine safe with a water pill?
Not with potassium-sparing diuretics. Arginine may raise potassium, and together they risk dangerously high levels. The Brigham and Women's health library advises avoiding arginine with diuretics in general (Mayo Clinic, L-arginine) (Health Library, Arginine).
How long after a heart attack should arginine be avoided?
No source gives a safe waiting period. Mayo Clinic advises against arginine after a recent heart attack, and the VINTAGE MI trial was stopped early during 6 months of use. Your cardiologist is the one to ask (Mayo Clinic, L-arginine) (VINTAGE MI trial, JAMA 2006).
Can a supplement contain a hidden prescription drug?
Yes. FDA has found sildenafil and warfarin in products sold as supplements, most often ones promoted for sexual enhancement, weight loss or bodybuilding. A hidden drug can clash with your heart medicines without warning (FDA, hidden drug notice) (NCCIH, Supplements Wisely).
Who wrote this10
Written and reviewed by
Pages built from the label, the sales page and linked NIH, FDA, AHA, CDC, FTC and peer-reviewed sources.
Last updated . Read our editorial standards and how we check reviews. This website is run by a USA authorized Melonex retailer, not by the manufacturer or the distributor. We earn money when you buy through our order links.
Keep reading
More about Melonex
USA authorized Melonex retailer
Ready to try Melonex?
Check your medicines first, then pick a pack. Three or six bottles ship free in the US and cost less per bottle, and the 60-day guarantee opens after 30 days of use.
- Secure checkout
- 60-day guarantee
- Ships from the U.S.
