What Are the Side Effects of Taking Collagen?

Medically Reviewed on 7/11/2022

Types of collagen 

Collagen is the protein that primarily makes up your skin, bones, and tendons. Side effects of collagen include skin rashes and kidney, liver, stomach, and heart problems.
Collagen is the protein that primarily makes up your skin, bones, and tendons. Side effects of collagen include skin rashes and kidney, liver, stomach, and heart problems.

Collagen is a structural protein. Collagen is the protein that primarily makes up your skin, bones, and tendons. It's obtained from certain foods and collagen supplements. It makes up about 30% of the total protein content in humans, making it the most abundant protein in your body. 

Collagen intake will greatly enhance your skin, bones, and muscles, but every good thing has its downsides.

There are about 28 different types of genetically identifiable collagen. The five most common include type I, type II, type III, type IV, and type V.

Collagen type I is found in skin, bones, and teeth tissue.

Collagen type II is common in cartilage tissues.

Collagen type III is prevalent in the muscles, skin, and blood vessel tissues.

Collagen type IV is a major component of the basement membrane. This membrane is responsible for your skin's elasticity and keeps your tissues in place. It also facilitates the transportation of chemical signals occurring due to chemical processes within your body.

Collagen type V is a component of hair, bones, placentas, livers, and lung tissues.

Sources of collagen 

Collagen sources may be natural or artificial. Natural collagen sources include plant and animal sources. Production of artificial sources is achieved through organized efforts between biotechnology and drug companies (pharmaceuticals).

Plant-based collagen sources include: citrus fruits, berries, garlic, leafy greens, cashew nuts, and tomatoes. 

Artificial collagen sources primarily include dietary supplements. Dosage is administrable through injections or orally. Oral collagen supplements may take the form of a beverage, capsules, powder, gel, tablets, gummies, and protein bars.

Collagen supplements are readily available over the counter, but they should be accompanied by proper dosage instructions from a medical professional.

Benefits of collagen

Collagen intake has many health benefits. It positively impacts your skin, bones, muscles, and teeth. Some of its benefits include:

  • Skin regeneration: Collagen is an anti-aging agent that enhances your skin's elasticity, ability to hold on to moisture, and ability to heal. According to research, though, you will need about twelve weeks of consistent collagen intake for noticeable change to occur.
  • Bone regeneration: Collagen strengthens and improves bone function by boosting your bone mass. It also relieves joint pain brought about by the loss of bone mass.
  • Muscle regeneration: Collagen is a significant component of skeletal muscles. According to a randomized study, men on collagen supplements who exercised displayed an increased muscle mass when compared to the other participants.
  • Improved heart health: Collagen promotes the development of blood vessels. Researchers have also discovered that it plays a role in preventing coronary artery diseases (atherosclerosis).
  • Hair and nail regeneration: Collagen enhances the rapid growth of healthy-looking hair and nails.

What causes collagen side effects?

Collagen intake has its benefits, but some people may exhibit side effects due to various factors. Some factors that may lead you to display side effects include collagen intolerance and improper collagen dosage.

Collagen side effects may, for instance, be a result of excessive collagen intake. It is advisable to cautiously watch your collagen intake as excessive consumption often leads to some mild reactions.

These side effects manifest as clinical symptoms best identified by a medical professional. These symptoms vary from one individual to another, though, and may affect the: 


Clinical symptoms include rashes, acne breakouts, or general skin inflammation. Contributing factors may include collagen sensitivity, chemical additives in collagen supplements, and contaminated natural collagen sources.


Liver fibrosis may come from the excessive accumulation of type I collagen in your liver tissue. Further collagen intake may worsen your liver's condition as unmanaged liver fibrosis gradually leads to liver cancer.


Collagen can lead to the development of kidney stones. Hydroxyproline is a major collagen amino acid that is normally disposed of through the kidneys as oxalate: a kidney stone trigger.


You can also experience digestive problems as a side effect of taking collagen. Some of the symptoms you may display include diarrhea, constipation, and heartburn, alongside feeling bloated and having a reduced appetite. Chemical additives, particularly in supplements, greatly contribute to these reactions.


Collagen can cause hypercalcemia. Hypercalcemia is an overaccumulation of calcium. Excessive calcium from collagen supplements often results in an abnormal heart rhythm.


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How to safely consume collagen

Collagen production decreases as you age, so maintaining a steady supply is essential. There are also many safety measures to help prevent yourself from suffering from any of the above side effects.

Scheduling an appointment with a doctor is strongly advised before you engage in any intake of collagen supplements. They will provide you with a proper medical prescription and conduct various tests, such as skin tests, to establish whether you are allergic to collagen.

Following your doctor's prescription is a vital step that prevents collagen overdose. Remember that collagen supplements will only be helpful if taken with the proper dosage and frequency.

Purchasing FDA-approved collagen supplements prevents the intake of contaminated collagen. Some drug companies may include chemical additives that degrade collagen or source their collagen from contaminated sources. Cases of contaminated collagen are particularly common among animal collagen sources. Doing market research on available brands in the market and backing this information up with an opinion from your doctor may be helpful. 

Collagen is a necessary building block that helps with many bodily functions. Doing what's needed and being well aware of your risk factors, meanwhile, may go a long way toward preventing collagen-related side effects.

Medically Reviewed on 7/11/2022

Goodnet: "7 Plant-Based Foods That Support Collagen."

Journal of Drugs in Dermatology: "Oral Collagen Supplementation: A Systematic Review of Dermatological Applications."

Journal of Molecular Medicine: "The roles of collagen in chronic kidney disease and vascular calcification."

Online Journal of Complementary & Alternative Medicine: "Collagen Supplements: Benefits, Uses and Side Effects."

Polymers: "A Review of the Effects of Collagen Treatment in Clinical Studies."

The British Journal of Medicine: "Collagen peptide supplementation in combination with resistance training improves body composition and increases muscle strength in elderly sarcopenic men: a randomized controlled trial."

World Journal of Gastroenterology: "Targeting collagen expression in alcoholic liver disease."