“How long does it take for CBT for insomnia to work?”

Since reasonable sleep is at the heart of healthy psychological and physiological health it is important you access support around the issue of insomnia, which is unfortunately a common problem.
There are many reasons for insomnia, so depending on what might be contributing to it for your situation will inform how long it might take for CBT to help lessen the problem. It also depends on how long the insomnia has been in place and other important factors in your life. If one would be able to generalize we could say perhaps 6-8 sessions or less. Wise of you to seek support and the wishing you much success. Best, Diane Bridgeman, Ph.D.

It really depends on how disciplined you are in following the recommendations. It’s been shown to work better than medication but sometimes the combination of the two works the best.

CBT generally lasts about 6 weeks. Usually there are some followup sessions as needed. It is quite effective; trying it is a good choice.

See this link for some insight into your question:
https://www.sleepfoundation.org/insomnia/treatment/cognitive-behavioral-therapy-insomnia