The biggest cryptocurrency was down 7.1% to $18,993 at 0906 GMT, having earlier touched $18,732, its lowest since December 2020.
It is down about 59% this year, while rival cryptocurrency Ethereum-backed ether is down 73%.
The digital currency sector has been pummelled this week after cryptocurrency lending company Celsius froze withdrawals and transfers between accounts.
The sector has also suffered losses after companies such as Coinbase Global Inc, Gemini and Blockfi said they would lay off thousands of employees as investors ditch risky assets.
(Reporting by Jahnavi Nidumolu in Bengaluru; Editing by Andrew Heavens)