Recent Ethereum gas fee fluctuations have significantly impacted DeFi user activity. High fees during peak congestion periods deter small-scale users, reducing transaction frequency, as seen in on-chain data showing a 20-30% drop in daily active addresses on major DeFi protocols like Uniswap and Aave. Conversely, lower fees during off-peak times correlate with slight upticks in activity, but overall user retention suffers. Layer-2 solutions like Arbitrum see increased adoption as users seek cost relief, with transaction volume rising 15% weekly. However, sustained high fees risk pushing users to cheaper alternatives, potentially fragmenting the DeFi ecosystem.