What Are the Side Effects of Collagen Supplements?

Collagen supplements, also called collagen peptides are popular in the health and beauty world, and for good reason. There are plenty of research-backed benefits of taking collagen, and for most people, the side effects of collagen are minimal.

You can add collagen powder to coffee, smoothies, oatmeal and other dishes to help support your skin and joints. But before you do, here's what you need to know about how supplements may affect you.

Collagen is a protein — the most plentiful protein in your body, according to the Cleveland Clinic, and its production decreases as you age. Collagen is found 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, and most products consist of hydrolyzed collagen (which has been broken down for better absorption). But these come with a few possible side effects.

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 cow 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.

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

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

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 person 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.

While collagen supplements are considered safe for most people, there are some who may want to avoid them.

Hydroxyproline (an amino acid in collagen) is converted into oxalate in the body, according to a 2016 review in ‌Current Protein and Peptide Science‌. And because there's also a risk of hypercalcimia with collagen supplements, it could mean bad news for your kidneys.

When oxalate accumulates to high levels in the body, it can combine with calcium and form hard crystals, or kidney stones. Over time, kidney stones can damage the kidneys and lead to kidney disease or failure, per the Mayo Clinic.

If you have kidney problems or a history of them, ask your doctor before taking collagen supplements.

Always follow the manufacturer's recommended dosing on your collagen supplement. Collagen supplements usually come in pill form or as protein powder.

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, have any allergies, take medications or are pregnant or breastfeeding.

If you're on a vegetarian diet or if you're kosher, you may need to consider the source of collagen as most are derived from cow or marine sources.

Because there's no Tolerable Upper Intake Level (UL) for collagen established by the Institute of Medicine, it's impossible to say how much is too much collagen.

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.

To see the most benefit, it's best to take collagen every day. Taking 2.5 to 10 grams of collagen daily seems to be safe and effective.

No, collagen is not linked to weight gain.

In fact, collagen is somewhat linked to weight loss because it's a protein, and a high-protein diet improves satiety and is tied to preventing weight regain after weight loss, per a September 2020 study in the ‌Journal of Obesity and Metabolic Syndrome‌.

Collagen isn't known to cause constipation.

If anything, it can help support your digestion and gut health in the long run by helping build and maintain connective tissue throughout your digestive tract, per Flushing Hospital Medical Center.

You won't notice any immediate side effects when you stop taking collagen, but you might lose out on the benefits in the long run.

There aren't any tell-tale signs of a collagen deficiency, but there is a group of autoimmune conditions called collagen vascular diseases that are autoimmune, which are likely hereditary, per Northwestern Medicine.

Symptoms of a collagen vascular disease include rashes, fatigue, joint pain and muscle weakness and aches. If you think you have collagen vascular disease, visit your doctor for a blood test.