The Myth of the 21 Day Habit

Do you remember playing the game Telephone when you were a child? You would whisper a comment to a friend who would repeat it to another friend and so on through several people. When the whispered comment finally came back to you, it was unrecognizable. Belief in the 21 day habit came from a large-scale game of telephone.

Don’t Blame Dr. Maltz

Dr. Maltz was a plastic surgeon in the 1950’s. When Dr. Maltz amputated a limb or sculpted a new nose, he noticed that patients needed approximately 21 days to get used to their new reality.

The doctor further noticed that it took him a similar length of time to personally adopt a new behaviour. In 1960, Dr. Maltz published a book called Psycho-Cybernetics in which he wrote these fateful words,  “These, and many other commonly observed phenomena tend to show that it requires a minimum of about 21 days for an old mental image to dissolve and a new one to jell.”

Psycho-Cybernetics was an enormous hit, selling more than 30 million copies. Self-help gurus the world over quoted Dr. Maltz. They are still quoting him. Unfortunately, in a multi-decades game of Telephone, the words “a minimum of about” were dropped and we have come to believe in the 21 day habit.

The Seductiveness of the 21 Day Habit

We have known for at least a decade that Dr. Maltz was misquoted, yet the myth of the 21 day habit endures. In an article published five days ago a blogger begins, “Research shows that it takes 21 days to develop a habit.” (It doesn’t.)

There are 21 day retreats to change your life, 21 day fixes to reset your body, and 21 day meditation challenges to calm your mind.

The allure of the 21 day habit is understandable. It is appealing to imagine that we can reboot some aspect of our lives with just three weeks of intense effort. A month sounds too long. But three weeks? Three weeks feels doable. Unfortunately, most of the time it isn’t.

Good habits are worth being fanatical about.

John Irving

What the Research Really Shows

A 2009 study by scientists at University College in London examined how long it would take to develop a new habit to the point of automaticity–no resistance or second thoughts. 96 volunteers were given the option of forming a new habit in eating, drinking, or exercise and asked to implement it in the same context each day for twelve weeks.

Participants chose behaviours such as “eating a piece of fruit at lunch”, “drinking a bottle of water with lunch” and “running for 15 minutes before dinner.” They logged on to the study website each day and completed a 12 question self-report.

Results are based on only 82 participants (14 dropped out) and on self-reports. Researchers were unsure if answering the same questions day after day might have affected participants’ responses.

Nevertheless, caveats and qualifications aside, some interesting information emerged from the research:

  • Extremely simple habits, such as drinking water with lunch, can become automatic in as few as 18 days.
  • Complex behaviours, like exercising, can take as many as 254 days to become automatic.
  • The average time required to reach the point where a habit was automatic was 66 days.
  • Contrary to popular opinion, it doesn’t hurt to miss the occasional day. It didn’t matter whether the misses were early in the 12 weeks or later.
  • Lapses (missing an entire week), however, were disastrous, resulting in people leaving the study.
  • Even amongst volunteers motivated to create new habits, fifty percent of them didn’t do the habit enough to make it automatic.

 Which habits have been easy for you to develop to the point of automaticity? Which ones are still a challenge? Let us know below. 



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  1. Interesting article, Karen. I always believed that different patterns worked for different people, depending on the habit desired (or abjured). Being a creature of habit, doing something every single day seems to work best for me. More importantly, sticking to the same routine (like every Thursday, or even every six days) also works well. But as soon as my habit is broken (even once) it becomes very easy for me to talk myself out of something, and to get off track. If I really want to start a new habit, having a simple plan, a commitment, and telling others that I am doing it is essential.

  2. Good advice, Donna. Even though there are indeed many individual differences when it comes to habits, the points you’ve mentioned are identified in the research as being essential for everyone. Thanks for commenting!

  3. Quitting smoking has been my biggest habit to break. My first attempt was through tapering down the number of cigarettes slowly and recording my totals every day in a day planner (to keep me honest). That worked well and I managed to quit for a little over a year. One big stressor and BAM I was back to smoking full time starting at a pack a day. My second attempt was done through the use of Champix and I guess the method was the daily habit of taking the medication and eventually the medication is what makes quitting possible. So far I am smoke-free 4 years, and almost two months now. I don’t forsee that changing anytime soon either! 😉

    Currently, I am trying to get into the habit of drinking more water every day. I don’t really have a set method in place but I do make things more convenient, by keeping bottles of water on the fridge door so I can easily grab one. I find that is helping as I grab one to take with me before we go out in the car. I am also finding that having it easy and available I now tend to drink more water on a regular basis. My tea/coffee consumption has been cut in about half (which my doctor will be thrilled with the next time I see him). I am also using water drinking before meals to help with weight loss. I have read about drinking water first thing in the morning before tea or coffee in order to help your organs and body recover from all night with no liquid coming in. I am trying to incorporate that into the water drinking habit too. As a result, my effort to build the habit of drinking more water per day is coming along just fine. I now find it automatic to grab water first. It took me about five weeks or so to get to this point. 😀

    1. A very timely comment, Susan. I’ve been thinking about writing a post about drinking water and now will be sure to do that!
      It doesn’t surprise me that it has taken you about five weeks to get to the point of automatically going for water first. Although the research I looked at said that a simple behaviour like drinking water can take as few as 18 days to reach automaticity, that was in the case of drinking a glass of water at one certain moment in the day – i.e., after lunch. The habit you are building is more complex because the cue is complex. Instead of thinking about water just at lunchtime, you are training your brain to think of it every single time you want to drink anything and, when you are getting some to take in the car, you’re even thinking about it in anticipation of a time when you’ll want something to drink.
      Awesome work, Susan. I’m going to close now… and go get some water.

      1. Thanks, Karen, and I will be looking for that post on drinking water. I do find I am feeling better the more water I consume and will be interested in seeing what your research uncovers. Your posts are always so thoroughly researched and well written. 😀 Enjoy your water!

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