5 Surprising Side Effects of Omega-3 Supplements According to Experts

July 24, 2025

We’ve all heard good things about Omega-3 supplements. “They’re great for your heart!” “Good for your brain!” “Help with inflammation!” And yes, those things are true—Omega-3s are like superheroes for your health. But like all superheroes, they have a few surprising side effects that don’t always get talked about.

At Optimal Health Bridge, we believe in being honest and helping you make the best choices for your health. So we looked into some expert info and found a few things that might surprise you about Omega-3s.

Let’s take a closer look at what your fish oil bottle isn’t saying.

A Quick Refresher: What Are Omega-3 Fatty Acids?

Omega-3s are “essential” fatty acids, which means your body can’t make them. You need to get them from food or supplements. There are three main types:

ALA (Alpha-linolenic acid) – Found in flaxseed, chia seeds, and walnuts.
EPA (Eicosapentaenoic acid) – Found in fatty fish and fish oil.
DHA (Docosahexaenoic acid) – Also in fish, very important for your brain.

Most people don’t eat enough fish or seaweed, so they take Omega-3 supplements to help out.

Types of Omega-3 Supplements

Fish Oil – The most common kind.
Krill Oil – Smaller pills, but still powerful.
Algae-Based – Great for vegetarians and vegans.
Cod Liver Oil – Has extra vitamins like A and D, but too much can be a problem.

Omega-3s are pretty awesome. But even awesome things have some side effects.

5 Surprising Side Effects of Omega-3 Supplements

You might think Omega-3s are only helpful. But like too much cake, too much Omega-3 can lead to problems. Here are five side effects to watch out for.

1. More Bleeding Than Usual

Omega-3s help your blood flow better, but they can thin it too much. That means you might:

Bruise easily
Get nosebleeds
Be at risk if you're taking blood thinners like aspirin or warfarin

Tip: Always ask your doctor before mixing Omega-3s with other medications.

2. Tummy Troubles

Your stomach might not love Omega-3s right away. Some people feel:

Stomach cramps
Diarrhea
Nausea
Burping

This usually happens if you take too much or take it without food.

Tip: Try taking your supplement with a meal or split the dose into smaller parts during the day.

3. Gross Fishy Burps

Ever had a burp that tastes like fish? It happens when:

The oil is low quality
The capsule breaks down too early
Your digestive system is slow

Try This:

Buy enteric-coated capsules
Freeze your pills before taking them
Try algae-based or deodorized formulas

At Optimal Health Bridge, our Omega-3s are super clean and designed to stop the fishy aftertaste.

4. Weaker Immune System (In Large Doses)

This one’s a little more complex. In very high doses, Omega-3s might make your immune system slower. That means you could:

Catch colds more easily
Take longer to heal
Have issues if you already have immune problems

The reason? Omega-3s help reduce inflammation—sometimes a little too much.

Tip: Most experts say to stay under 3,000 mg per day of EPA+DHA.

5. Trouble with Medications

Omega-3s can affect how other medicines work. This is especially true for:

Blood thinners
Blood pressure medicine
Diabetes medicine

These interactions can be serious, so always check with your doctor first before adding Omega-3s to your routine.

Other Possible Side Effects

These don’t happen often, but they’ve been reported by some people:

Allergic reactions (especially if you’re allergic to fish or shellfish)
Too much vitamin A from cod liver oil
Trouble sleeping or feeling restless
Weight gain (since oils have calories!)
Body odor changes (yes, fishy sweat is a thing)
Higher blood sugar (mainly in people with diabetes)
Heart palpitations (rare, but can happen)
Headaches or dizziness
Acne breakouts
Mood changes (in some sensitive people)

Don’t worry: These side effects aren’t common. Most people take Omega-3s with no problems at all.

How to Take Omega-3s Safely

Omega-3s can be great for your brain, heart, joints, and more—if you take them the right way.

Recommended Daily Doses

General health: 250–500 mg of EPA + DHA
Heart health: About 1,000 mg (ask your doctor)
For inflammation or joint support: Up to 3,000 mg (only under supervision)

Tips for Smart Omega-3 Use

Take it with food that contains fat
Start with a small dose and increase slowly
Try different sources like fish oil, krill oil, or algae oil
Pick supplements with third-party testing for safety
Look for “burpless” or coated capsules if fishy burps bother you

How to Choose a High-Quality Omega-3

Third-party tested (look for seals like IFOS, USP, or NSF)
Fresh (check the expiration date!)
Made from sustainable sources
Has a good balance of EPA to DHA (like 3:2 or 2:1)
In triglyceride form, which is better for absorption

Good news: Our Omega-3s at Optimal Health Bridge meet all these standards. We only want the best for you!

Final Thoughts

Omega-3s are one of the most trusted nutrients out there. The benefits are real, but it’s still important to know what to expect and how to take them wisely.

A good supplement helps the most when used the right way. Always read labels, listen to your body, and talk to your healthcare provider if you’re unsure.

Ready to upgrade your Omega-3 game?

Check out our top-quality Omega-3s at Optimal Health Bridge and begin your journey toward better health today.

Stay healthy, stay curious, and remember—even fish oil has a few surprises.