What is the difference between odorless and burpless fish oil?

November 26, 2025 •

4 min read

Research indicates that fishy burps are a primary reason many individuals discontinue their fish oil supplements. To avoid this unpleasant experience, it is crucial to understand what is the difference between odorless and burpless fish oil, as each addresses a different aspect of the issue.

Quick Summary

Odorless fish oil primarily uses refinement to remove the fishy smell and taste from the oil, while burpless supplements feature an enteric coating that delays digestion until the capsule reaches the small intestine, preventing reflux.

Key Points

Mechanism of Action: Odorless fish oil uses processing and flavoring to mask the inherent fishy smell and taste of the oil, while burpless fish oil uses an acid-resistant enteric coating to prevent the capsule from dissolving in the stomach.
Targeted Problem: Odorless products address the initial smell and taste of the oil, whereas burpless products specifically prevent the fishy aftertaste and burping that occurs due to stomach digestion.
Cause of Burps: Fishy burps are often caused by the fish oil floating to the top of stomach contents, and are sometimes worsened by low-quality, rancid oil, not just poor processing.
Choosing a Supplement: The best choice depends on whether your primary issue is the initial smell or the later digestive reflux. For burps, a high-quality, enterically-coated product is best.
Indicator of Quality: A fresh, high-quality fish oil, even without special coatings or flavorings, will have minimal odor or fishy repeat. A strong fishy smell is often a sign of oxidation or rancidity.
Additional Tips: Simple steps like taking fish oil with meals, storing it properly, or even freezing capsules can also significantly reduce the likelihood of fishy burps.

Decoding the Fish Oil Formula: Odorless vs. Burpless

Fish oil supplements are a popular way to get the heart-healthy omega-3 fatty acids EPA and DHA, especially for those who don't eat enough fatty fish. However, many people are put off by the characteristic fishy odor and aftertaste, which can lead to unpleasant burps. Manufacturers have addressed this with two distinct types of products: odorless and burpless fish oil. While the end goal for both is a more pleasant experience, their methods and focus are different. Understanding these differences is key to choosing the right supplement for your needs.

The Science Behind Odorless Fish Oil

Odorless fish oil focuses on tackling the fishy smell and taste directly at the source. This is primarily achieved through advanced processing and refinement techniques during manufacturing.

Deodorization: After extraction, fish oil undergoes a process called deodorization, which uses high temperatures and steam to neutralize the compounds responsible for the fishy smell and taste. This step is critical for removing volatile, off-flavor molecules.
Added Masking Agents: Many odorless formulas also include added flavors, such as lemon or vanilla, to mask any remaining taste or odor. Some patents even mention using thyme essence to eliminate the fishy characteristics.
Oxidation Control: Quality fish oil is highly perishable and prone to oxidation, which causes it to go rancid and produce a strong, unpleasant smell. Reputable odorless brands use careful handling and processing, often in the absence of oxygen, to prevent this from happening. Some add natural antioxidants like vitamin E to enhance freshness.

The Mechanism of Burpless Fish Oil

Burpless fish oil works by changing where in your digestive system the capsule dissolves. The technology focuses on preventing the fish oil from being released in the stomach, which is the primary cause of fishy reflux.

Enteric Coating: This is the key feature of a burpless supplement. The softgel is coated with a special, acid-resistant layer that prevents it from breaking down in the acidic environment of the stomach.
Delayed Digestion: Instead of dissolving in the stomach, the enteric-coated capsule passes through to the small intestine, where the environment is less acidic. The coating dissolves here, releasing the fish oil much further down the digestive tract.
Prevention of Reflux: Since the oil is released past the stomach, it doesn't float to the top of the stomach contents where it can be eructated (burped) back up through the esophagus. This eliminates the fishy aftertaste entirely.

What Causes Fishy Burps?

Understanding the source of the problem helps in choosing the right solution. Fishy burps can be caused by several factors:

Oil Floating: Fish oil is less dense than stomach fluids and food, causing it to rise to the surface of the stomach. When the lower esophageal sphincter relaxes during a normal burp, a small amount of the oil comes up with the air.
Rancidity: Low-quality or improperly stored fish oil can oxidize and go rancid. The byproducts of this oxidation are what create the foul taste and smell associated with bad fish burps.
Digestion Issues: For some, slower digestion or insufficient stomach acid can cause the capsule to linger in the stomach for longer, increasing the chances of reflux.

Comparison Table: Odorless vs. Burpless Fish Oil


Feature	Odorless Fish Oil	Burpless Fish Oil
Primary Mechanism	High-level refining and deodorization to remove smell/taste compounds.	Enteric coating to delay capsule digestion until it reaches the small intestine.
Target Issue	The fishy smell and taste of the capsule itself and any mild aftertaste.	The unpleasant fishy burps (reflux) caused by stomach digestion.
Cost	Typically comparable to regular fish oil, but high-quality processing may increase price.	Often slightly more expensive due to the additional enteric coating process.
Effectiveness for Burps	May reduce the intensity of burps by masking the flavor, but does not prevent the underlying reflux mechanism.	Highly effective at preventing fishy burps by bypassing stomach digestion.
Purity Indicator	High-quality odorless oil should not have a strong odor, which can indicate freshness.	Effectiveness in preventing burps can also indicate a high-quality product, as low-quality, rancid oil may still cause issues even with a coating.

How to Choose Between Odorless and Burpless

Making the right choice depends on your specific sensitivities and priorities. Consider these factors before buying:

Assess your problem: Do you mainly object to the smell of the softgel before you take it, or are the fishy burps your primary concern? If it's the aftertaste, a burpless formula is the direct solution. If you simply dislike the smell of the capsules, odorless is the way to go.
Prioritize Quality: No matter which type you choose, prioritize product quality. Look for third-party certifications like IFOS (International Fish Oil Standards) or NSF, which test for purity, concentration, and freshness. A truly high-quality, fresh fish oil, regardless of special coatings or flavoring, is less likely to cause strong fishy burps in the first place.
Try Other Techniques: In addition to choosing the right product, you can minimize fishy burps with a few simple strategies:
- Take your supplements with food, preferably a meal that contains healthy fats.
- Split your dose and take smaller amounts throughout the day.
- Consider storing your capsules in the freezer, as the colder oil may be digested more slowly.
- Take the supplement at bedtime to sleep through any potential minor discomfort.

Conclusion

While both odorless and burpless fish oil aim to make your omega-3 supplementation more tolerable, they employ different strategies. Odorless fish oil eliminates or masks the oil's initial smell and taste through refinement and flavoring, while burpless fish oil prevents the capsule from dissolving in the stomach via an enteric coating. For those most bothered by fishy reflux and burping, a high-quality, burpless supplement is the most direct and effective solution. However, ensuring you choose a fresh, high-quality product with good processing is the single most important factor, regardless of which type you select. For more information on quality and certification, visit the IFOS website.

Frequently Asked Questions

Not necessarily. Odorless fish oil is refined to remove or mask the initial smell and taste, but it does not use the enteric coating that is characteristic of most burpless formulas to prevent fishy burps from reflux.

Enteric coating is an acid-resistant layer applied to the capsule that prevents it from dissolving in the stomach. The capsule then passes to the small intestine before releasing the oil, which is too far down the digestive tract to cause a fishy burp.

While a very strong, foul-tasting burp can indicate rancid oil, not all fishy burps are a sign of poor quality. The normal process of digestion can cause the oil to float and repeat. However, high-quality, fresh oil is less likely to produce a strong fishy aftertaste.

Yes, many odorless formulas use flavor additives like lemon or vanilla to mask any remaining fishy taste. Other methods also use refining processes to remove the compounds that cause the fishy smell.

Yes. Taking your supplement with a meal, splitting your daily dose, or storing the capsules in the freezer can help slow digestion and reduce the chances of fishy reflux.

Many experts suggest choosing the triglyceride form, as it is closer to the natural form found in fish and is generally more bioavailable and less likely to cause burps. Ethyl esters are a more processed form that can increase the risk of burping.

Look for third-party testing certifications like IFOS (International Fish Oil Standards) or NSF, which ensure the product has been tested for purity, concentration, and freshness. A strong, foul fishy smell when you open the bottle can also be a sign of rancidity.