Disadvantage of forex is that it is time-consuming, as you have to spend many time for research, analyzing and monitoring the market. 

High level of risk associated with market volatility and the potential for substantial financial losses.

Disadvantage of forex is the high volatile of market  because of different foreign exchange in market 

One disadvantage of engaging in forex market is that the market can change a lot which makes it risky, this risk could cause trader to lose a lot of money

The forex market can be extremely volatile, especially during major economic events, central bank announcements, and geopolitical crises. While volatility can present trading opportunities, it also increases the risk of sudden and unpredictable price movements that can lead to losses.

Depending on the currency pair that you trade, the exchange rates may fluctuate wildly. This is especially true in the case of major global events that are either political or economic.

The accessibility of the forex market can lead to overtrading, where traders make excessive trades driven by emotion rather than a solid trading strategy. Overtrading can result in losses and reduced performance.

Due to the high risk nature of forex trading, there is a real possibility of losing a significant portion of your invested capital, especially if risk management strategies are not properly implemented.