diff --git a/pyproject.toml b/pyproject.toml
index fa076ce..99aa788 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -120,6 +120,7 @@ requires = [
 "3.9" = ["3.9"]
 
 [tool.tox.env_run_base]
+install_command = "python -m pip install --only-binary :all: {opts} {packages}"
 commands = [[
     "pytest",
     "-s",