The list of things you’d expect to sneak past the brain’s tightly guarded borders is short: oxygen, glucose and, with great effort, certain medications. But antibodies? Not a chance — until now.

Researchers are turning to an unlikely source for inspiration: camels and llamas.

A new study published from researchers in France suggests that miniature antibodies from these animals, called nanobodies, could change how we treat brain disorders like Alzheimer’s and schizophrenia. These tiny proteins, found naturally in camelids such as camels, llamas and alpacas, are about one-tenth the size of conventional antibodies. That small stature gives them a major edge: They can slip through the brain’s formidable blood-brain barrier with ease, reaching neurons that most drugs can’t touch.

First discovered in the early 1990s by Belgian scientists, nanobodies are made of a single type of antibody chain, a biological simplicity that makes them easier to produce, purify and engineer. They’re also highly soluble, stable and less likely to cause side effects than traditional antibody drugs. In mouse studies, nanobodies have been shown to help against models of schizophrenia and other similar conditions.

Researchers say these molecular lightweights could form a new class of brain medicines — somewhere between bulky antibodies and traditional small-molecule drugs. Before clinical trials begin, however, scientists must run toxicology tests, assess long-term safety and perfect stable formulations.

If all goes well, the next big leap in brain medicine might just come from some very small antibodies — and a few very cooperative llamas.