diff --git a/lib/wagmi/config.ts b/lib/wagmi/config.ts
index 462cc84..2d0ac96 100644
--- a/lib/wagmi/config.ts
+++ b/lib/wagmi/config.ts
@@ -47,6 +47,7 @@ const arcTestnet = {
       address: "0xca11bde05977b3631167028862be2a173976ca11",
     },
   },
+  testnet: true,
 } as const satisfies Chain;
 
 /**
diff --git a/lib/wagmi/usdcAddresses.ts b/lib/wagmi/usdcAddresses.ts
index 17ab753..f153cbd 100644
--- a/lib/wagmi/usdcAddresses.ts
+++ b/lib/wagmi/usdcAddresses.ts
@@ -42,12 +42,10 @@ export const USDC_ADDRESSES: Record<number, `0x${string}`> = {
   [optimism.id]: "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85",
   // Testnets
   [baseSepolia.id]: "0x036CbD53842c5426634e7929541eC2318f3dCF7e",
-  // Optional additional testnets (placeholder or known deploys)
-  [sepolia.id]: "0xd6c3a3a6B523b3f30c1e03DF621cBe03b12E0A35",
-  [polygonAmoy.id]: "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
-  // Updated to official Arbitrum Sepolia USDC
+  [sepolia.id]: "0x1c7d4b196cb0c7b01d743fbc6116a902379c7238",
+  [polygonAmoy.id]: "0x41E94Eb019C0762f9Bfcf9Fb1E58725BfB0e7582",
   [arbitrumSepolia.id]: "0x75faf114eafb1BDbe2F0316DF893fd58CE46AA4d",
-  [optimismSepolia.id]: "0x09D1D7d6b9d4B4b0597F64E299fB2C89F76DdF24",
+  [optimismSepolia.id]: "0x5fd84259d66Cd46123540766Be93DFE6D43130D7",
   5042002: "0x3600000000000000000000000000000000000000",
 };
 
diff --git a/lib/wagmi/useNetworkSupport.ts b/lib/wagmi/useNetworkSupport.ts
index 652f583..da1c0f5 100644
--- a/lib/wagmi/useNetworkSupport.ts
+++ b/lib/wagmi/useNetworkSupport.ts
@@ -22,12 +22,11 @@ import { useMemo } from "react";
 import { useAccount, useChainId, useSwitchChain } from "wagmi";
 import { SUPPORTED_CHAINS } from "@/lib/wagmi/config";
 
-const MAINNET_CHAINS = SUPPORTED_CHAINS.filter(
-  (c) => !/sepolia|amoy/i.test(c.name.toLowerCase())
-);
-const TESTNET_CHAINS = SUPPORTED_CHAINS.filter((c) =>
-  /sepolia|amoy/i.test(c.name.toLowerCase())
-);
+const isTestnetChain = (c: (typeof SUPPORTED_CHAINS)[number]): boolean =>
+  Boolean((c as { testnet?: boolean }).testnet || /testnet|sepolia|amoy/i.test(c.name));
+
+const MAINNET_CHAINS = SUPPORTED_CHAINS.filter((c) => !isTestnetChain(c));
+const TESTNET_CHAINS = SUPPORTED_CHAINS.filter((c) => isTestnetChain(c));
 
 export interface NetworkStatus {
   isConnected: boolean;