Salt Substitutes and ACE Inhibitors or ARBs: The Hidden Potassium Danger

Most people think switching to a salt substitute is a simple, healthy choice-especially if they’re trying to lower their blood pressure. But for millions of Americans taking ACE inhibitors or ARBs, that swap could be life-threatening. It’s not about the salt. It’s about what replaces it: potassium chloride.

What’s in those salt substitutes?

Many salt substitutes, like LoSalt or NoSalt, don’t just reduce sodium-they replace it with potassium chloride. A typical "lite" salt is half sodium chloride, half potassium chloride. Pure substitutes can be up to 66% potassium chloride. That means every pinch you use adds 400-600 mg of potassium to your diet. For someone eating normally, that’s not a problem. But if you’re on an ACE inhibitor or ARB, your body can’t flush out the extra potassium the way it should.

These medications work by blocking the renin-angiotensin-aldosterone system. That’s good for lowering blood pressure. But it also cuts down on aldosterone, a hormone that tells your kidneys to get rid of potassium. With less aldosterone, potassium builds up. Add in a salt substitute? You’re essentially pouring fuel on a fire.

Who’s at real risk?

Not everyone is at risk. If your kidneys are healthy, you’re fine. Your kidneys naturally filter out extra potassium. But if you have chronic kidney disease (CKD), especially stage 3 or worse (eGFR under 60), your kidneys are already struggling. About 15% of U.S. adults have CKD. That’s 37 million people. And nearly 40% of them are on ACE inhibitors or ARBs for high blood pressure or diabetes-related kidney protection.

Combine those two things-impaired kidneys and these medications-and you’ve got a perfect storm. A 2022 Mayo Clinic study found that 63% of hyperkalemia cases in people on these drugs came from dietary potassium sources, not supplements or bananas. Salt substitutes were the biggest culprit.

Diabetics with kidney issues are especially vulnerable. Up to 20% of them have hyporeninemic hypoaldosteronism-a condition where their bodies barely make aldosterone. For them, even a small increase in potassium can push levels into the danger zone.

What happens when potassium gets too high?

Serum potassium above 5.0 mmol/L is considered high. Above 6.5 mmol/L? That’s a medical emergency. At that level, your heart can’t beat properly. You might feel muscle weakness, nausea, or an irregular heartbeat. But often, there are no symptoms until it’s too late.

There are documented cases of people collapsing from cardiac arrest after using salt substitutes while on lisinopril or losartan. One 72-year-old patient in a 2004 case report had a potassium level of 7.8 mmol/L-deadly territory. He wasn’t taking supplements. He wasn’t eating huge amounts of bananas. He was just using LoSalt on his food every day.

And it’s not rare. A 2019 meta-analysis of over 1.2 million people found that people with CKD on ACE inhibitors had a hyperkalemia rate of 8.7 events per 100 person-years. In the general population? Just 0.8. That’s more than ten times the risk.

But what about the benefits?

Yes, salt substitutes can help. A 2025 JAMA study of 21,000 people showed a 14% drop in stroke recurrence among those using potassium-enriched salt. For healthy people without kidney disease or those meds, the benefits clearly outweigh the risks.

But here’s the problem: most people don’t know if they’re in the safe group or the dangerous one. A 2023 JAMA Internal Medicine study found that 78% of patients on ACE inhibitors had no idea dietary potassium could be risky. They thought "no salt" meant "healthy." They didn’t know their doctor never warned them.

What about labeling?

You won’t find a warning on most salt substitute bags. In the U.S., the FDA doesn’t require it. A 2023 FDA review found only 3 out of 12 major brands explicitly warn against use with ACE inhibitors or ARBs. Canada changed its rules in January 2024-now all potassium salt products must say: "Contraindicated in patients taking ACE inhibitors." The U.S. hasn’t followed.

Some manufacturers have voluntarily added warnings. But without enforcement, compliance is patchy. You can’t rely on the label. You have to ask your doctor.

What should you do?

If you’re on an ACE inhibitor or ARB, here’s what you need to do right now:

1. Check your kidney function. Ask for your eGFR number. If it’s below 60, avoid potassium salt substitutes entirely.
2. Ask your doctor. Don’t assume they know you’re using a salt substitute. Many patients don’t mention it because they think it’s harmless.
3. Get your potassium checked. If you’ve been using a substitute, ask for a blood test. Levels above 4.5 mmol/L in someone with CKD or on these meds are a red flag.
4. Stop using potassium salt substitutes if you have CKD, diabetes, or are on these meds. It’s not worth the risk.

What can you use instead?

You don’t need potassium chloride to reduce sodium. Herbs and spices work just as well-and safely. Try Mrs. Dash, garlic powder, onion powder, smoked paprika, cumin, or lemon zest. Cooking with fresh herbs like rosemary, thyme, and cilantro cuts sodium by 40-50% without adding any potassium risk.

And you can still use regular salt-just use less. Most sodium comes from processed foods, not the salt shaker. Swap canned soups for low-sodium versions. Choose fresh chicken over deli meats. Rinse canned beans. These changes reduce sodium without any hidden dangers.

Why don’t more doctors warn patients?

Because the problem is invisible. Patients don’t think to mention salt substitutes. Doctors don’t think to ask. It’s a gap in care that’s costing lives. A Kaiser Permanente initiative in 2023 trained staff to screen every patient on ACE inhibitors or ARBs for salt substitute use. They found 22% were using them. After education and follow-up, hyperkalemia cases dropped by 92%.

That’s the key: awareness. If you’re on these medications, you’re not just managing blood pressure. You’re managing potassium. And salt substitutes are the silent threat.

The bottom line

Salt substitutes aren’t universally good or bad. They’re a tool. And like any tool, they can be dangerous in the wrong hands. For the 85-90% of people with healthy kidneys and no kidney meds? They’re a smart swap. For the 10-15% with kidney disease or on ACE inhibitors or ARBs? They’re a ticking time bomb.

Don’t assume your salt substitute is safe. Don’t assume your doctor knows you’re using it. Ask. Get tested. Switch to herbs if you’re at risk. Your heart will thank you.