uses JavaScript to provide the best possible experience for our content, but your browser has it disabled. Learn how to enable it here.


Collagen Supplement Side Effects -- woman with stomach pain


Collagen supplements containing collagen hydrolysate, collagen peptides and similar ingredients appear to be generally safe and well-tolerated. However, some people may experience mild side effects, ranging from gastrointestinal symptoms to skin rashes. Rarely, liver abnormalities have been reported, and people who are allergic to certain sources of collagen, such as fish, or who are allergic to sulfites, should not take collagen products containing these ingredients. Despite some concerns, there is no evidence that taking collagen supplements increases the risk of breast cancer or breast cancer recurrence. For more information, see the Concerns and Cautions section of the Collagen Supplements Review, which also includes our tests and Top Picks among products.

People with kidney disease or who are on dialysis should consult with their physician before consuming bone broth as a source of collagen, as some bone broths contain high amounts of sodium and potassium.

Join today to unlock all member benefits including full access to all CL Answers and over 1,300 reviews.

Join Now

Join now at


Join the conversation

January 25, 2021

I don't understand the use of collagen, when eaten by mouth it's broken to amino acids in the digestions, if that amino acids will go to create collagen nobody knows. Hydrolyzed collagen is the same history, is collagen broken into peptides that will result in amino acids by digestion process and nobody know if they will generate collagen or not.
Eating collagen supplement is the same as eating proteins like a piece of meat, all of them are broken down into amino acids.
January 27, 2021

Please see the "What It Does" section of our Collagen Supplements Review for information about this

July 24, 2020

I would like to see a article on collagen and heavy metals. I've heard that some brands have more than others, and I don't know, where to find the research on it.
July 28, 2020

Products in our Collagen Supplements Review were tested for the toxic heavy metals lead, cadmium and arsenic. See the third column of the Results table ( for our findings.

May 7, 2020

I would love if you could test Sports Research Collagen Peptides.

May 27, 2020

Yes, I agree on this. This brand seems very popular and receives many, many positive reviews, but are they honest reviews from actual users?

July 24, 2020

I have had good results from this. I was loosng hair and started taking this product daily.. I have had good results _ much less hair in my brush and I brush daily.

July 24, 2020


December 29, 2019

I was taking the Top Choice noted in the ratings, for collagen supplements for skin. I tried it for almost 3 months, the size is generous even though you take 4 capsules daily. I did not see improvement in my skin and was hoping there might be some joint benefit as well. I actually felt creakier in my joints, not sure if it's possible that there could be a side effect where the collagen is metabolized in such a way that it causes more problems or not, but I stopped taking it. I'm waiting to see if it eases up, and I think it has, but hard to really draw a conclusion. I had tried another form of collegen previously, Reservatrol powder, which you mixed with water or other beverage. I try to go at least 2 months when trying something and I didn't have any noticeable reaction to that brand at all, negative or positive. So I don't plan to try any further collegen supplements. I just thought I'd share my experience, because these things are not inexpensive and I'm not sure they are worth it.

September 5, 2019

I would appreciate testing of Vital Protein Collagen Peptides.
Thank you.

July 8, 2019

I've begun taking Ancient Nutrition (Dr. Axe) Multi-Collagen Protein powder, and would appreciate if you would add it to your review of collagen supplements. Thanks.
July 8, 2019

Hi Jeanette - Thank you for your suggestion.

August 12, 2019

I am also interested in this product due to physician recommendation to get more protein in diet.

September 4, 2019

I am taking Dr. Axe collagen as well. Would you please test this product.

December 29, 2019

I too am taking Dr. Axe collagen powder and it is rather expensive so it would be great to know if it's a good product.

December 30, 2019

I too use Vital Protein

June 9, 2019

I'm taking collagen hydrolysate for tendonitis and it seems to be helping but gives me constipation so I take it with prune juice to counteract the effect.

February 19, 2019

I tried collagen powder to help with hip osteoarthritis. It seemed to help somewhat with that but gave me such horrible insomnia I had to quit taking it. I believe the amino acid, Aspartic Acid, was what caused the insomnia.

January 4, 2020

I'm taking Jarrow Bone-Up for osteopenia in my hips and it has helped immensely.

February 9, 2019

I was taking a collagen product recently that made me feel extremely hypoglycemic. Every day I took it, I ate a sleeve of cookies to feel better! Has anyone ever heard of this as a side effect?

September 15, 2021

This is a delayed response but yes! I have this issue. It’s nice to know I’m not crazy.

Join today to unlock all member benefits including full access to CL Answers

Join Now

Join now at