diff --git a/.env.example b/.env.example
index 5847460..d15dc4f 100644
--- a/.env.example
+++ b/.env.example
@@ -3,7 +3,8 @@
 ETH_CLIENT_ADDRESS=https://sepolia.infura.io/v3/<key>
 
 # Private key of testnet where you have sepolia ETH that would be staked into RLN contract.
-# e.g. 0116196e9a8abed42dd1a22eb63fa2a5a17b0c27d716b87ded2c54f1bf192a0b
+# Note: make sure you don't use the '0x' prefix.
+#       e.g. 0116196e9a8abed42dd1a22eb63fa2a5a17b0c27d716b87ded2c54f1bf192a0b
 ETH_TESTNET_KEY=<YOUR_TESTNET_PRIVATE_KEY_HERE>
 
 # Password you would like to use to protect your RLN membership.