Most people who gamble online lose money over time. That is the design of the product, not bad luck, and a comparison site that does not say so is not being straight with you.
Warning signs worth taking seriously: chasing losses with larger stakes; gambling with money set aside for something else; hiding how much or how often you play; borrowing to fund it; and finding that a session you meant to keep short routinely does not stay short.
Tools that work. Deposit limits are the single most effective control and every operator listed here offers them. Set one before your first session, when it is easy, rather than after a bad one, when it is not. Session reminders, loss limits and cooling-off periods are usually in the same account menu.
Self-exclusion has a gap you need to know about. Registering with your provincial lottery corporation excludes you from that province's regulated sites. It does not propagate to any offshore operator, including every site listed on this page. If you are self-excluding, exclude at each offshore operator individually as well, and consider blocking software such as Gamban or BetBlocker, which works at the device level and covers sites you have not thought of.
Free, confidential help across Canada. The Problem Gambling Helpline on 1-888-230-3505 operates nationally. ConnexOntario on 1-866-531-2600 covers Ontario around the clock. Gamblers Anonymous runs meetings in every province. Provincial health services offer free counselling for gambling harm, including for family members, who are often affected first and served last.
If you are reading this because of someone else's gambling, the helplines above take those calls too.