Collagen and Medicines, Kidney or Liver Conditions and Who Should Ask First
What is and is not documented about collagen supplements with medicines, kidney or liver conditions, surgery and allergy, and who should ask a clinician or pharmacist before starting.
Content last updated . This page has not been medically reviewed.
Quick answer
We did not find a source describing a specific interaction between hydrolyzed collagen and a named medicine. That is Proper evidence not found: we searched PubMed for collagen supplements and drug interactions and for kidney or liver safety, and found no usable study. It does not show there are none. The FDA says certain dietary supplements can change absorption, metabolism or excretion of a medication, and that natural does not always mean safe. [1] Because collagen has so little interaction research, a pharmacist is the right person to check your own list.
How the evidence is labeled
Official general statement is advice from a health agency about supplements as a group. Trial observation is what researchers reported in a study. Proper evidence not found means we looked and found nothing usable. A general warning is not proof that collagen causes a problem.Situation by situation
| Situation | What the sources say | Collagen-specific evidence |
|---|---|---|
| Prescription or over-the-counter medicines | FDA: dietary supplements and medicines can interact, and it advises talking to a health care professional first. [1] | Proper evidence not found |
| Blood thinners | FDA gives examples of products that thin the blood, such as warfarin, ginkgo, aspirin and vitamin E, and warns that combining them may raise bleeding risk. [1] | Collagen and bleeding: Proper evidence not found |
| Kidney conditions | NIDDK says some people with chronic kidney disease may need to consume moderate amounts of protein so waste does not build up, and to work with a dietitian or health care professional. [2] One collagen trial called its intervention protein supplementation. [3] | Kidney safety trials: Proper evidence not found |
| Liver conditions | No collagen-specific source read. | Proper evidence not found |
| Blood tests in trials | Three trials in older adults found no pathological findings in routine blood tests. [3] [4] [5] | Limited; manufacturer-supplied |
| Before surgery | FDA: your health care professional may ask you to stop supplements two or three weeks before a procedure. [1] NCCIH: some supplements may increase bleeding risk or affect your response to anesthesia. [6] | Collagen-specific: Proper evidence not found |
| Allergy to fish, beef or pork | Case reports link fish and bovine collagen or gelatin to severe reactions, including one during surgery with a bovine gelatin matrix. [7] [8] | See the allergy page |
| Pregnancy, breastfeeding, children | NCCIH: many supplements have not been tested in pregnant women, nursing mothers or children. [6] | Proper evidence not found in the sources we read |
Kidney conditions and the protein question
One trial described its collagen peptide intervention as protein supplementation, [3] and some kidney care plans manage protein. We found no study of collagen supplements in people with kidney disease, so we cannot say whether any amount is safe for them. NIDDK's advice to people with kidney disease is to work with a dietitian or health care professional on protein. [2] Kidney stone questions about collagen are separate; see collagen, hydroxyproline, oxalate and kidney stones. For other supplements and kidney function, see multiple medicines and kidney function.Liver conditions
We found no collagen-specific study of liver safety. Anyone with liver disease or on medicines processed by the liver should ask a clinician or pharmacist first.Surgery and procedures
Tell the surgical team about every supplement, including collagen, well before the date. The FDA advice above applies to supplements generally. [1] For a bovine- or porcine-derived surgical product, a case report advises allergy consultation and testing for people with beef, pork or gelatin intolerance. [8] See supplements before surgery.Added ingredients matter
A collagen product may contain vitamin C or other ingredients. [9] A medicine question may be about those ingredients, not the collagen. Bring the label. See reading a collagen label. Undenatured type II collagen is a different product; interactions for it: Proper evidence not found here, and its page is gelatin and undenatured type II collagen.If something goes wrong
For hives, swelling or trouble breathing, call 911. [10] For other side effects, NCCIH says to contact your health care provider. [6]Frequently asked questions
Does collagen interact with blood thinners?
Proper evidence not found for collagen. The FDA warns that several products can thin the blood, so ask a pharmacist. [1]
Can I take collagen with kidney disease?
Proper evidence not found. NIDDK says some people with kidney disease need to manage protein intake with a professional. [2]
Should I stop collagen before surgery?
That is for your surgeon. FDA says clinicians may ask you to stop supplements two or three weeks before a procedure. [1]
Is collagen safe with liver disease?
Proper evidence not found. Ask your clinician.
Do I need to tell my doctor about collagen?
Yes. FDA advises bringing a list of all the supplements and medications you take to each visit. [1]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Who should ask first
- Anyone taking prescription medicines, including blood thinners or medicines for kidney, liver, heart or immune conditions
- People with kidney or liver disease
- Anyone pregnant, breastfeeding, or choosing for a child
- Anyone with fish, beef, pork, egg or gelatin allergy, or alpha-gal syndrome
- Anyone with surgery or a procedure planned
The FDA suggests bringing a list of all supplements and medications, with how much and how often, to each visit. [1] Never stop or change a prescribed medicine without your prescriber. See the general guide to medication interactions, supplement safety resources and questions to ask your clinician or pharmacist.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.