Supplement analysis backed by scientific evidence · PT

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Limited evidenceGeneral health

Shark Cartilage

Shark cartilage is one of the clearest debunks in the supplement world: the premise that sharks don't get cancer is false, and two well-run randomized trials — including a 379-patient phase III — found no survival or quality-of-life benefit whatsoever.

What the science says

  • Treats or slows cancer Limited evidence

    A randomized phase III trial in 379 patients with unresectable stage III non-small cell lung cancer added the standardized shark cartilage extract AE-941 (Neovastat) to chemoradiotherapy and found no survival benefit, with median overall survival essentially identical between arms. An earlier randomized trial in 83 patients with advanced breast or colorectal cancer found no difference in overall survival or quality of life versus placebo, with poor tolerability. Sharks do develop cancers, including tumors of cartilage, so the founding premise is factually wrong.

  • Inhibits angiogenesis in humans Limited evidence

    Cartilage contains anti-angiogenic proteins in vitro, which is where the idea came from. But these are large molecules digested to amino acids on oral ingestion, and the trials designed specifically to test the anti-angiogenic hypothesis with a standardized liquid extract — the strongest possible version of the product — were negative in both lung and renal cell carcinoma.

  • Relieves joint pain and osteoarthritis Limited evidence

    Shark cartilage contains chondroitin sulfate, but in variable and usually undisclosed amounts, typically far below the 800-1,200 mg/day of purified chondroitin used in osteoarthritis trials. No adequately powered trial has tested shark cartilage itself for joint pain. If chondroitin is what you want, buy chondroitin at a known dose.

Dosage & safety

Studied doseThere is no supported dose because there is no demonstrated benefit. Historical protocols used 60-100 g/day of powder, or the standardized liquid extract AE-941 at 240 mL/day in the phase III trials — both negative. Capsule products typically supply 750-2,000 mg with no defined active constituent.
SafetyReported adverse effects include nausea, vomiting, abdominal pain, constipation, an intensely unpleasant taste and odor, and hypercalcemia; hepatitis has been reported in case reports. Shark tissue accumulates methylmercury and the neurotoxin BMAA, both documented in commercial shark cartilage products. The most serious harm is indirect: using it in place of, or alongside, evidence-based oncology care — discuss any use with the treating oncologist. Not for children, pregnancy, or anyone recovering from surgery or a wound, given the anti-angiogenic premise. Also a conservation concern, as several shark species used are threatened.

Scientific references

Where to buy

NOW Foods, Shark Cartilage, 100 Capsules

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