diff --git a/CoinGecko/Clients/BaseApiClient.cs b/CoinGecko/Clients/BaseApiClient.cs
index 3004b8a..fc1be1f 100644
--- a/CoinGecko/Clients/BaseApiClient.cs
+++ b/CoinGecko/Clients/BaseApiClient.cs
@@ -105,7 +105,7 @@ private Uri CreateUrl(string path, Dictionary<string, object> parameter)
             {
                 urlParameters.Add(par.Value == null || string.IsNullOrWhiteSpace(par.Value.ToString())
                     ? null
-                    : $"{par.Key}={par.Value.ToString().ToLower(CultureInfo.InvariantCulture)}");
+                    : $"{par.Key}={par.Value}");
             }
 
             var encodedParams = urlParameters