diff --git a/ippisite/requirements-core.txt b/ippisite/requirements-core.txt
index 716be042065584d7dea85bbceeba60efcef7abcd..584aac22008865d9c5899c5865f31a901642e1e6 100644
--- a/ippisite/requirements-core.txt
+++ b/ippisite/requirements-core.txt
@@ -17,6 +17,7 @@ xlwt
 bioservices
 bioblend
 bs4
+requests-cache==0.5.2
 chembl_webresource_client==0.10.2
 # libraries to compute PCA
 scikit-learn==0.23.2