Is it safe to use hydroquinone long-term? January 26, 2022 21:49 Updated There have been no reported incidents of topical hydroquinone causing cancer in humans. It is safe to use under doctor supervision. Click here to check out a Hydroquinone safety Tip. Related articles What is hydroquinone? Do the dark spots come back if you stop using The Spot Cream? Do I need to avoid any ingredients? What is tretinoin? Are there any possible side effects?