NewsAnalysis
Shark cartilage is still sold with cancer claims. Here is what trials found
Shark cartilage supplements still turn up online with cancer claims. A claim-check on what NCI reports from trials in people, and what the findings do not mean.
Original commentary from the Cancer Explained editorial team.
Please note: this page is educational only — it is not medical advice, and it does not speculate about anyone’s health beyond reliable public reporting. For questions about your own health, talk with your healthcare team.
Why shark cartilage keeps coming back
The claim is that shark cartilage can treat or cure cancer.
What the lung cancer trial found
The National Cancer Institute says the FDA has not approved cartilage as a treatment for cancer. NCI describes a large trial in 379 people with advanced non-small cell lung cancer. Adding a shark cartilage product to chemotherapy and radiation did not help people live longer than a placebo did. A smaller trial in advanced breast and colon cancer found no difference in survival or quality of life.
What this does not mean
This does not mean every question about cartilage is closed, or that a person who took it did something wrong. It means the products tested in people did not show the benefit the claim promises. It also does not mean a supplement is harmless. NCI lists nausea, vomiting, and stomach cramps as common side effects.
Before you buy a supplement
- Read our full claim-check: Does Shark Cartilage Cure Cancer?
- Tell your care team about any supplement you take or are thinking about.
- Ask whether a clinical trial could fit you if you want to try something new.
An AI-assisted editorial system helped prepare this page. No named medical reviewer has reviewed it unless one is listed. See something wrong? Tell us on our corrections page.
Put the story in context
Prevention, possible warning signs, screening, and diagnosis
The information below is general, and not every point applies to every cancer. Personal advice depends on age, symptoms, family history, exposures, and medical history.
Prevention and risk reduction
Not every cancer can be prevented. Avoiding tobacco, protecting skin from ultraviolet radiation, limiting alcohol, staying active, and receiving recommended HPV or hepatitis B vaccination can lower the risk of certain cancers. A risk factor is not a prediction or a cause in one individual.
Symptoms and possible early signs
Possible signs vary and are often caused by conditions other than cancer. Changes worth discussing include a new lump, unexplained bleeding or weight loss, a persistent cough, lasting bowel or bladder changes, a changing skin spot, or symptoms that persist or worsen. Some early cancers cause no symptoms.
Screening and early detection
Screening looks for certain cancers before symptoms begin. Recommended tests exist only for some cancers and depend on age and risk. Screening can have benefits and harms; it is not the same as evaluating a new symptom, and there is no single routine scan or blood test that reliably screens for every cancer.
How cancer is diagnosed
Diagnosis may involve a history and exam, imaging, laboratory tests, and often a biopsy. Pathology can identify the cancer type and may test biomarkers that guide treatment. Symptoms, screening results, tumor markers, or online stories alone cannot confirm cancer.
A news story may encourage questions, but it should not be used to estimate your risk or choose testing. Contact a healthcare professional about a persistent or concerning change. Seek urgent care for severe or rapidly worsening symptoms.