3 Possible Side Effects of Collagen Supplements You Should Know About

Adding a powdered collagen supplement to a flavored drink, like coffee or a smoothie, can help you avoid its aftertaste.
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Collagen supplements and collagen peptides are all the rage in the health and beauty world, and they have plenty of research-backed benefits.

Collagen is a protein — the most plentiful protein in your body, according to the Cleveland Clinic, and its production decreases as you age. Collagen in your muscles, bones, tendons, ligaments, organs, blood vessels, skin, intestinal lining and other connective tissues.


Collagen aids in healing and repairing damaged bones and cartilage. Collagen also helps to maintain the resistance, elasticity and mobility of joints and connective tissue. You can take collagen supplements to improve your collagen levels, but these come with a few possible side effects.

Collagen Supplement Side Effects

1. Bad Taste in the Mouth

Some oral collagen supplements can leave a bad taste in the mouth, according to the U.S. National Library of Medicine (NLM).


Collagen supplements made from marine or bovine sources usually have a taste and odor that is not very pleasant to most people.

Choosing a high-quality collagen supplement and mixing it into a flavored beverage can help reduce the unfavorable taste.

2. High Calcium Levels

High calcium levels, or hypercalcemia, may occur as a possible side effect of shark cartilage collagen supplements specifically, according to the NLM.


According to the Mayo Clinic, too much calcium in the body can cause constipation, bone pain, fatigue, abnormal heart rhythms among other side effects.

Taking calcium supplements together with shark collagen should be done with caution, only under the supervision of a doctor or dietitian.

3. Allergic Reaction

People allergic to fish may have an allergic reaction to marine-based collagen, per an October 2020 report in The Journal of Allergy and Clinical Immunology: In Practice.


A case study published October 2016 in Allergology International found that fish collagen caused an allergic reaction in a 30-year old woman with a known marine allergy even when the supplement was produced using high-heat methods.

Signs of an allergic reaction, according to the Mayo Clinic, may include:

  • Tingling or itching in the mouth
  • Hives, itching or eczema
  • Swelling of the lips, face, tongue and throat or other parts of the body
  • Wheezing, nasal congestion or trouble breathing
  • Abdominal pain, diarrhea, nausea or vomiting
  • Dizziness, lightheadedness or fainting

If you have a known shellfish allergy or other marine allergies, it's important to avoid these supplements, as an allergic reaction could be life-threatening.

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How to Take Collagen Supplements Safely

Always follow the manufacturer's recommended dosing on your collagen supplement.

Oral collagen doses ranging from 2.5 grams to 10 grams per day for up to 24 weeks were found to be generally safe with no adverse effects according to a January 2019 review in the Journal of Drugs and Dermatology.

If you're considering adding a collagen supplement to your routine, the safest choice is to check with your doctor first. This is especially true if you have any current medical conditions, take medications or are pregnant or breastfeeding.

Can Too Much Collagen Be Harmful?

Because there's no Tolerable Upper Intake Level (UL) for collagen established by the Institute of Medicine, it's impossible to say how much collagen you could take before experiencing harmful effects.

Most research has found no adverse effects when taking between 2.5 to 10 grams of collagen daily.

Benefits of Collagen Supplements

Research done over the past several years has found numerous potential collagen supplement benefits, particularly for your skin, nails and joints.

As your body's natural ability to produce collagen decreases as you age, supplementing with collagen peptides can help to replace your body's stores.

1. Smoother Skin

Collagen pills may be best known for their effect on the skin.

Collagen can help increase skin hydration and improve skin elasticity, which may help skin appear and feel younger. A 12-week trial of women ages 35 and over showed significant improvements in skin elasticity, roughness and density with an oral collagen supplement in an August 2019 study in Nutrients.

Oral collagen supplements have also been found to increase skin elasticity, hydration and dermal collagen density, according to the ​Journal of Drugs in Dermatology​ review. Increased dermal collagen density helps decrease the appearance of fine lines, sagging and wrinkles.

2. Longer Nails

If you have a difficult time growing your nails, or keeping them from breaking, an oral collagen supplement could help.

Women who took a daily collagen supplement for 24 weeks had a 12 percent increase in their nail growth rate and a 42 percent decrease in nail breakage in a small August 2017 study published in the ​Journal of Cosmetic Dermatology.

3. Stronger Joints

Collagen is a key part of the cartilage where your bones meet, aka your joints. This cartilage can deteriorate over time and with use, leading to arthritis and/or joint pain.

A February 2021 study in ​Nutrients​ gave 180 active 18 to 30-year-olds who experienced joint pain with activity either 5 grams of collagen peptides or a placebo for 12 weeks​.​ Those who took the oral collagen supplement had significantly decreased joint pain with activity compared to the control group.