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Horseshoe crabs have long been exploited by the biomedical industry for their blood, but In Defense of Animals reports that synthetic alternatives are already approved for use around the world, with the U.S. hopefully soon to follow suit.

New Changes Could Help Horseshoe Crabs Survive the Biomedical Industry
From Staff, IDA In Defense of Animals, idausa.org
January 2026

Images from Canva

Decades of exploitation by the biomedical industry have led to a massive decline in horseshoe crabs, but a number of new changes, and more in the works, could protect them and help them recover.

Unfortunately for horseshoe crabs, their blood has been deemed essential to the biomedical industry. It’s used to produce limulus amebocyte lysate (LAL), which is used to test for bacterial contaminants, known as endotoxins, in drugs and medical equipment.

Since the 1970s, millions of horseshoe crabs have endured being captured from the wild and hauled off to labs, where needles are inserted near their hearts and roughly 30% of their blood is drained from their bodies before they’re returned to the ocean in a weakened state.

According to the Atlantic States Marine Fisheries Commission, in 2024, 1,073,329 horseshoe crabs were collected for biomedical purposes, with an estimated total of 184,693 who tragically didn’t survive.

Not only has this had a detrimental impact on individuals, but in combination with even more horseshoe crabs caught to be used as bait for American eel and whelk fisheries, their population has dropped significantly, which has affected entire coastal ecosystems.

In the Delaware Bay, which is home to the largest spawning population in the world, their numbers have dropped by two-thirds since the 1990s. This has led to a troubling decline in other species whose members rely on them as well, such as red knots, who depend on horseshoe crab eggs for food during their migratory stopover there. In 2014, they were listed under the Endangered Species Act, with commercial horseshoe crab harvests cited as a main factor in their decline.

However, there are synthetic alternatives to LAL, such as recombinant Factor C (rFC), that show comparable results.

While rFC is approved for use in Europe, Japan, and China, the U.S. Pharmacopeia, which sets scientific standards for drugs in the U.S., had lagged behind in affirming rFC as equivalent to LAL.

That changed in 2024, when it finally issued new guidelines that officially recognize synthetic alternatives, including rFC and recombinant Cascade Reagent (rCR), as effective and safe for detecting endotoxins in injectable drugs and vaccines, which removed a huge barrier to their wider adoption. We issued an alert in 2021 urging the U.S. Pharmacopeia to accept synthetic alternatives, and we thank our supporters for helping to make this victory possible.

At the end of 2025, Congress also removed another barrier when it directed the U.S. Food and Drug Administration to update its guidance on endotoxin testing within one year to include the acceptance of synthetic alternatives for manufacturing products and to provide training for their use.

A scorecard is tracking changes in the pharmaceutical industry, but there’s still a long way to go.

Still, some states have also taken action to protect horseshoe crabs, who are also threatened by a loss of habitat to development, sea level rise, and pollution, among other issues.

In December 2025, New York Gov. Kathy Hochul signed the Horseshoe Crab Protection Act, which phases out horseshoe crab harvests in state waters by 2029. Once it goes into effect, it will save 150,000 individuals from being taken annually. Massachusetts is also considering legislation that would ban killing horseshoe crabs for bait.

There’s also the chance they may receive protection under the Endangered Species Act, with a lawsuit filed this month calling on the National Marine Fisheries Service to respond to a petition filed by a coalition of organizations seeking federal protection for them, which was due in May 2024.

Hopefully, these changes and growing awareness and support for safe and effective alternatives to horseshoe crab blood will lead more companies to make the switch and ensure these fascinating animals survive.

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Posted on All-Creatures.org: February 1, 2026
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