I have some advice to stop this.
There are many reasons why you could be hooking the ball, so I’ll give you the basics to check first and then we’ll go from there. The equipment you play with can determine the shape of shots you hit. For example, if you have clubs with flexible shafts and thin grips then this will definitely promote a hook.
A very easy way to quite down a hook is to take your clubs into a pro-shop and get them to put a couple of layers of tape under the grips to thicken them up. Doing this automatically slows down your hand action through the ball because your grip will naturally be more in the palms rather than the fingers.
Fattening up the grips is something to try, but I don’t guarantee it solving the problem completely. But you should try this first and then see the results. If you’re still hooking the ball get your shafts checked to see if they match your swing and swing speed. Now that we’ve looked at some equipment causes let’s move to some setup and technical causes of a hook.
When you practice your long game check your alignment, because the swing is a chain reaction and your hook will be caused by one of your setup positions (if you’re still hooking it after making the equipment changes I suggested above).
Check your feet and your shoulder alignment to make sure they are parallel left of your target. To do this hit balls and have a club lying along your toe line that is slightly left of your target (imagine a railway track going to the target).
Once you have setup to a shot check your shoulder alignment by holding a club along your shoulders to see where they are pointing. Your feet and shoulders should be parallel left of your target and definitely not closed. Also check your ball position and make sure it’s positioned off your left heel. Have it further forward if anything to encourage a straighter shot.
After you’ve checked all of these aspects of your setup start hitting balls. And it’s a good idea to try to slice each shot. Set a goal of making 20 balls in a row curve from left to right and if one goes the other way then start again. Vow not to leave the practice range until you’ve done this.
When you can slice each shot then bring the flight of the ball back to either a fade or a draw. You will be able to do this by changing your setup for the type of shot you want. For example, if you want a fade or at worst a slice the ball then, have a slightly open setup and the ball off the left heel. If you want to draw or at worst hook the ball then have a slightly closed setup with the ball positioned further back in your stance.
If you are trying to slice balls but can’t then hit balls off a slope where you are above the ball. This slope will encourage a more upright swing, which will naturally produce a fade/slice. Also experiment with weakening your grip. I used to hook the ball all the time and it wasn’t until I changed my grip to a neutral one, instead of a strong one that stopped hooking the ball.