Horseshoe crabs were crawling along the shallow sandy bottoms of Earth’s oceans 200 million years before the first dinosaurs came on the scene. But some populations have declined dramatically with the rise of humans, raising concerns they may be headed toward extinction. One of the biggest drivers of their population collapse is their unsustainable harvest for their blood to be used in pharmaceuticals. Now, two major pharmaceutical companies, Amgen Inc. and Abbott Laboratories, have publicly announced they will shift toward synthetic blood instead.
The copper-based blood of horseshoe crabs contains an extract called limulus amebocyte lysate (LAL) that can help detect bacterial endotoxin contamination in vaccines, injectable drugs and many other pharmaceutical products. To maintain the safety of those drugs, thousands of horseshoe crabs are captured from the wild annually for their blood. The animals, which are more closely related to spiders than to crabs, are returned to the sea after their blood has been drawn, but many don’t survive the ordeal. Coastal development and habitat degradation are also taking a toll.
Synthetic replacements for LAL were developed in 2016, but not widely adopted by pharmaceutical companies — until now. Amgen and Abbott Laboratories announced in February 2026 that they’re transitioning away from horseshoe crab blood for biomedical testing.
Kendyl Van Dyck is a biodiversity associate with As You Sow, a nonprofit that promotes corporate responsibility. She told Mongabay in an email that the pharmaceutical industry was slow to move away from harvesting horseshoe crabs, “because endotoxin testing is highly regulated, pharmaceutical manufacturers have been inclined to follow known methods even when there is an opportunity to innovate.”
Van Dyck noted that there’s no fixed end date for either company to completely cease horseshoe crab-derived testing, nor is there an independent third-party monitoring program.
Still, conservationists have welcomed the pharmaceutical companies’ announcement. Atlantic horseshoe crabs (Limulus polyphemus), which are the most targeted species for their blood, lay massive amounts of eggs that fuel migrating shorebirds along the Atlantic coast of North America.
In an interview with NJ Spotlight News last year, David Mizrahi, vice president of research and monitoring at the New Jersey chapter of bird conservation nonprofit Audubon, said a shift toward synthetic blood “will save thousands of horseshoe crabs a year, protecting shorebirds and coastal ecosystems, while also providing supply chain stability and ensuring patient safety. It’s a powerful and responsible step forward for all concerned.”
Banner image: A horseshoe crab in the sand. Image by Perry Bill, U.S. Fish and Wildlife Service via Wikimedia Commons (Public domain).
Credits
