diff --git a/core/admin/Dockerfile b/core/admin/Dockerfile
index 5b02f07f..05ab88ff 100644
--- a/core/admin/Dockerfile
+++ b/core/admin/Dockerfile
@@ -37,7 +37,7 @@ WORKDIR /app
 COPY requirements-prod.txt requirements.txt
 RUN set -eu \
  && apk add --no-cache libressl curl \
- && pip install --no-cache --extra-index-url=https://www.piwheels.org/simple -r requirements.txt --only-binary=:all: --no-binary=Flask-bootstrap,PyYAML,SQLAlchemy \
+ && pip install --no-cache-dir --extra-index-url=https://www.piwheels.org/simple -r requirements.txt --only-binary=:all: --no-binary=Flask-bootstrap,PyYAML,SQLAlchemy \
  || ( apk add --no-cache postgresql-libs mariadb-connector-c \
  && apk add --no-cache --virtual build-dep libressl-dev libffi-dev python3-dev build-base postgresql-dev mariadb-connector-c-dev cargo \
  && pip install --upgrade pip \