Woman suffering from stomach pain, one of collagen side effects

Collagen Side Effects: What They Are & How To Avoid Them

Wondering about collagen side effects? Chances are pretty good you’re in one of two situations. You may not be sure if you should start taking collagen and want to know what you’re in for. Or, you may be already taking collagen and wondering if it’s the source of your recent discomfort. 

In both cases, you’ll need to know what you can do to avoid collagen side effects, and how to treat them if they happen. The great news is, the side effects of collagen are typically rare and very mild. And nearly all of them are easily fixed without cutting collagen out of your diet.

To understand why collagen side effects are so rare, let’s take a quick look at what collagen is. Then, we can discuss why people might take it and what collagen side effects to look for. Finally, we’ll talk about how you can prevent those side effects.

What is collagen?

Collagen is the most abundant protein in the human body. There are more than 32 different types of collagen, and it’s found all over your body – from skin and hair, to blood vessels and bone.

Collagen contains 8 of the 9 essential amino acids. Amino acids are molecules our body needs to survive. “Essential” amino acids are molecules that the body can’t generate on its own. That means you can only get them through food – including supplements. 

Collagen is also rich in several non-essential amino acids. Though they’re called “non-essential”, our body still needs them to survive. The only difference is, your body can rearrange other molecules into non-essential amino acids when it needs to.

When these molecules are built into collagen, they form a connective base across many parts of the body. Your cartilage, tendons, muscles, skin, and blood vessels are all largely made of collagen. 

Why do people take collagen?

There are many reasons why people choose to supplement with collagen. 

Taking collagen with an exercise program can help build muscle and improve muscle health

Collagen supplements are also a low-calorie to no-calorie source of protein, making them helpful for people who are trying to attain weight loss or workout goals.

Collagen has also been shown to reduce joint inflammation by supporting the cartilage and ligaments in the joint, and has even been shown to reduce skin aging

The best collagen supplements are made from collagen peptides (also known as hydrolyzed collagen). This is a kind of collagen that has been broken down into smaller molecules to make it easier to digest. Collagen peptides benefits cover a wide range of health and wellness goals.

But can collagen harm your health? And can you be allergic to it?

Can you have an allergic reaction to collagen?

Collagen itself is one of the most basic elements of the human body. However, some people do have an allergic reaction to collagen supplements. Fortunately, allergic reactions are one of the most rare collagen side effects. 

Most likely, it’s not an allergic reaction to collagen itself, but an allergy to the source of the collagen (or one of the other ingredients in the supplement). 

Some collagen supplements are made using fish, shellfish, or pork, which can be common allergens. Others can contain fillers or added ingredients that might cause collagen powder side effects, even if you aren’t allergic to the collagen itself.

If you suspect you’re having an allergic reaction, seek medical care immediately. Signs of an allergic reaction can include: 

  • Itching or tingling of the skin
  • Wheezing/swelling of the throat
  • Severe abdominal pain
  • Nausea/vomiting

As long as you find a collagen supplement that doesn’t contain additives, and is produced by a trusted company, you shouldn’t have an allergic reaction to collagen. Of course, if you have a shellfish allergy, make sure to find a supplement made with bovine or chicken collagen!

Despite all its benefits, being concerned about collagen side effects still makes sense – even if you aren’t allergic to it. If you’re trying to improve your health, it’s only normal to think carefully about what you’re putting into your body. 

So let’s discuss the most common collagen side effects – and how to prevent them. 

What are the most common collagen side effects and what causes them?

Collagen side effects are generally very mild. Typically, they’re the result of your body getting more protein than normal. Sometimes, they may even fade with time. However, if you notice a side effect that’s persistent, or gets worse over time, contact a healthcare professional immediately. 

And while this is technically not a side effect, you might be wondering, “Does collagen affect menstrual cycles?” Collagen will not make your period come late or last longer than usual, but it may ease some of the inflammatory symptoms you experience at certain times of your cycle. 

Now, let’s look at collagen powder side effects that may not produce such happy results.

Digestive issues

Collagen is a protein, and that means that for some people, it can cause stomach upset. This can include gas, constipation, diarrhea, or bloating. 

So does collagen make you gain weight? Not exactly. Bloating is often caused by the excess fluid in your digestive system. Collagen is hydrophilic, meaning it attracts water, which is what causes bloating and diarrhea.

Taking too much collagen, or taking a collagen protein that has not been hydrolyzed, is what can lead to gas or constipation. 

In either case, your body cannot break down the protein fast enough. This leads to larger molecules than normal entering the digestive system and causing these collagen side effects.


Hypercalcemia occurs when you have too much calcium in your blood. Taking too much collagen over an extended period of time can cause this condition, and lead to a number of dangerous collagen side effects. 

This can also happen when you’re taking a medication that interacts badly with collagen. Before you begin taking any supplement, it’s a good idea to talk to a trusted healthcare professional about how to do it safely with your current medical history. 

Hypercalcemia can cause heart problems, kidney problems, and neurological issues. Hypercalcemia due to collagen supplementation is rare, but if you have symptoms of this condition for any reason, talk to your doctor right away.

Allergic reactions and ingredient sensitivities

Allergic reactions to collagen can occur, but they are most frequently due to an allergen in the supplement, and not the collagen itself. If you have any kind of shellfish or pork allergy, it’s critical to get a collagen supplement that’s sourced with pure, 100% beef. 

Ingredient sensitivities can cause skin problems. However, some skin problems are collagen side effects due to the extra protein and will level off after a few days or weeks. These can include small rashes, itchy skin, and acne. 

And skin isn’t the only thing that can be affected by a sensitivity. People who are new to supplementing with collagen sometimes wonder: Can collagen cause headaches

Occasionally, an individual will have a sensitivity to glutamic acid. This is one of the amino acids in collagen, and an excess of, or sensitivity to, it can cause headaches in some people. 

If you’re experiencing headaches, try adjusting your dosage to lower the amount of glutamic acid in your body.

How can you avoid collagen powder side effects?

Collagen side effects aren’t life-threatening, and the benefits of collagen are well worth the small risk of encountering them. Of course, when you look online, you might find an oddly large number of people reporting side effects with specific brands.

Over many different brands, people have reported a number of side effects. Some of these may have been caused by the ingredients and processes the brand uses. Others may have been caused by the dosage being too high. 

There’s one thing all of these causes of collagen side effects have in common. They’re all things you can take steps to avoid. 

Collagen powder side effects are the last thing you want to worry about, so choose your collagen powder carefully. You’ll also want to make sure you’re taking the collagen correctly so your body can get all the benefits with none of the unpleasant side effects.

Adjust your routine

Collagen is a protein that’s rich in many different nutrients. However, especially if you’re taking a supplement, that protein may not settle in your stomach smoothly. 

Eating something at the same time as you take your supplement is a great way to avoid digestive discomfort. Everyone’s body is different, so you may want to experiment with when you take collagen, whether you eat with your supplement, and how much you eat. 

When you take collagen supplements regularly, you’ll also want to make sure you stay hydrated. Besides helping replenish the water that collagen attracts, staying well hydrated can keep your kidneys healthy and prevent hypercalcemia. 

By eating something alongside your supplement and drinking plenty of water, you can avoid two common collagen side effects. Best of all, you can keep taking collagen and unlock its health benefits.

Take the right dosage

It’s important to take the right dosage of collagen. Too little, and you may not see any results at all. Too much, and you open the door to bloating, feeling too full, nausea, hypercalcemia, and even liver damage.

To prevent this, you’ll want to make sure you’re taking the correct dose. You can find dosage suggestions online, ask your healthcare provider, or simply follow the package instructions. 

You may also want to slightly decrease or increase the amount of collagen taken, depending on how your body responds and if you’ve noticed any collagen side effects. 

Ultimately, the ideal dosage is going to vary from person to person. The only way to know for sure is to test and talk to your healthcare providers along the way. 

Taking the right dosage is one of the best ways to avoid dealing with a negative reaction to your collagen supplement, especially over time.

Find a high-quality supplement

Most importantly, you need to find a high-quality supplement. Many people never learned how to read nutrition labels and aren’t sure what to look for. The first thing to know when you’re looking for a high-quality supplement is the difference between a nutrition label and a supplement label. 

Visually, the differences are very subtle. The real difference between them, however, is that a supplement with a nutrition label is FDA regulated and considered “medical-quality”. This means that the ingredients, effectiveness, and safety are more closely reviewed and approved by the doctors and scientists in the FDA. 

Finding a medical-quality supplement ensures you’ll get collagen that is more safe and effective than anything else on the market. High-quality supplements can prevent collagen side effects because they likely have fewer fillers and preservatives.

You’ll also want to look for a collagen supplement that has a complete amino acid profile. Remember, on its own, collagen only has 8 of the 9 essential amino acids. The one it’s missing, tryptophan, is still highly important. With low tryptophan in their diets, people can feel anxious, irritable, and restless. 

If you find a collagen supplement with tryptophan added in, you ensure you’re receiving the full amino acid profile your body needs. 

Overall, collagen side effects are rare and often preventable. When they do occur, treating them at home is typically all you need, and making some small changes in your collagen routine can prevent them from reoccurring. 

For most people, preventing side effects is simple. Adjust your routine to include taking collagen with a meal when needed and staying well hydrated. This can head off digestive side effects, as well as hypercalcemia. 

Make sure you’re taking the right dosage, and check with your doctor about any medications that might interact with your collagen. 

Finally, look for a high-quality, medical-grade collagen supplement for maximum effectiveness and the cleanest ingredients.

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