Why Some People Get Fish Burps From Fish Oil Supplements + What To Do

Whether you've taken a fish oil supplement or not, chances are you've at least heard about one famously unpleasant potential side effect: the fish burp.

Considering the omega-3s (specifically EPA and DHA) found in fish oil are important for everything from your cognitive function and heart health to your vision and mental well-being,* foul-smelling belches probably shouldn't be enough to dissuade you from adding a supplement to your daily routine. But, of course, no one wants to worry about stinky burps.

Unfortunately, this foul-smelling side effect is a pretty common one, according to mbg's vice president of scientific affairs Ashley Jordan Ferira, Ph.D., RDN. In fact, it's a top complaint1 associated with fish oil supplements. (Queasiness and GI upset are also common—especially among pregnant individuals2.)

Fun (or not-so-fun) fact: Some people are more prone to fish burps simply based on their physiology, says Ferira. You see, it's all about how quickly your stomach empties into your small intestine, a process called gastric emptying, which can vary from person to person. The slower gastric emptying happens for you, the more likely you are to find yourself belching up fishy flavor while your supplement hangs out in your stomach.

That said, a few factors can make fish burps an issue even for those who don't typically deal with them. Eating a big meal, not chewing your food enough, being dehydrated, or sipping on carbonated drinks or alcohol can all slow gastric emptying, upping your chances of belching up the scents of the sea.

In many cases, people experience fish burps anywhere from 10 minutes to hours after they take their fish oil supplement, Ferira says. The problem is so bothersome that up to 18% of people report stopping their supplements because of it.

Interestingly, fish burps can also indicate that a fish oil supplement isn't of the highest quality or hasn't been cared for correctly, resulting in oxidation (aka spoiling), according to Ferira. She puts it this way: "Oxidation of fish oil is the crux of unpleasant fish burp."

"If the oil is lower quality and does not boast low oxidation parameters (like low rancidity, spoilage, and contaminants) via state-of-the-art processing, built-in antioxidants (like rosemary and/or tocopherols, aka vitamin E), and careful handling and storage, then any burp-back reflects a lack of freshness and purity," Ferira explains.   

One important way to prevent fish burps from cropping up altogether is to select a quality fish oil supplement. Ferira specifically recommends looking for a fish oil product that focuses on preventing oxidation through careful processing of the oil during manufacturing (transparency about their sourcing and manufacturing procedures is always a good sign here) and includes antioxidants like rosemary in the formula.

Some brands opt to utilize chemical compounds to create a special coating on the supplement (called an enteric coating) that delays the release of the supplements' contents until it reaches the small intestine.

This way, once the fish oil is released, it's too far into your system to create a fishy burp. It should be noted, though, that while enteric coatings are safe, they do add quite a few extra ingredients to a product, Ferira notes. 

Other brands opt to incorporate natural botanical oils like lemon or lime oil to their formulations to mask the burps or stop them in their tracks.* 

"In addition to extremely fresh and pure fish oil from wild-caught, cold-water South Pacific anchovies from off the coast of Chile, mindbodygreen's omega-3 potency+ incorporates organic lemon oil and the herb rosemary to thoughtfully counteract fish burps and enhance the fish oil's antioxidant capacity and freshness respectively,"* Ferira explains. It's a winning combo for a top-quality (and belch-free) supplementing experience. 

That said, avoiding fish burps doesn't stop at checkout. Caring for your fish oil supplement is also important in keeping the burps at bay. Ferira recommends storing it away from heat and light and tightening the cap completely after each use to limit oxygen exposure.

Some people are naturally more prone to fish burps than others—and a few different factors can affect whether you find yourself belching up unsavory flavor after taking your fish oil supplement.

For best results, select a high-quality fish oil that is infused with a botanical oil (like citrus) and minimizes oxidation of the oil from start to finish.

From there, storing your supplement properly and ensuring you don't take it with heavy meals or certain drinks can make your overall digestion speed and fish oil experience a more positive one.