21 Days Later: The Myth Behind Making a New Habit

Raise your hand if you’ve heard the rule, “It takes 21 days to form a new habit.” (I’m assuming you are all raising your hands. Alone. By yourself. Staring at a computer.) Have you ever wondered where this rule came from? People tend to say things like, “They say it takes 21 days to make a new habit.” But who’s they? Today, you’ll find out where this rule came from and why it’s one big fat lie.

The big fat lie that is the 21 day rule
I couldn’t resist.

It all starts with a 1950s plastic surgeon, Dr. Maxwell Maltz. He took notice in his office that his patients, after undergoing reconstructive surgery, took about 21 days to become familiar with their new face. He also dealt with amputee patients who complained of phantom limb pain up until about 21 days after their surgery. He then tested the 21 day theory on himself by attempting to form a new habit in the allotted time. After he completed his “experiment,” he released a statement to the public saying that it takes at least 21 days to form a new habit or mindset.

How we read it today? It takes at least 21 days to form a new habit or mindset. Because the opinion of a plastic surgeon on the subject of psychology from 65 years ago is 110% credible, right?


We can’t deny today that we are an impatient generation. We want results and we want them now. That’s why the 21 day rule has become so popular. It’s attainable. Like many people, I am trying to be better about eating healthy and staying active every day and the thought of those two things becoming second nature within 21 days is a relieving thought. But it’s just not true.

A new study came out of the University College London done by Dr. Phillipa Lally, a health psychology researcher. She and her team studied 96 people over the course of 12 weeks while they attempted to form new habits, and the subjects remarked every day on whether or not the motion or habit felt natural.

Her findings? Dr. Lally found it takes a minimum of 2 months, or 66 days, to form a strong, lasting habit. Yet, as with all experiments, there were outliers. For some it took as little as 18 days, for others it took as much as 8 months. Depending on the habit you are attempting to instill, it may take you more or less time to make it feel like second nature.

The good news? Unlike the 21 day rule, where you are pushed to work every day for those 21 days to form that new habit, Dr. Lally proved that while it may take longer to form a healthy new habit, missing a day or two here and there does not diminish the work you have already put into it. So if you are trying to run every day for 15 minutes, having a rest day once a week won’t hurt your progress.

So no, you won’t form a new habit (at least not likely) in only 21 days. But the longer you stick at it, the more natural that habit will become and it will stick around for the long haul. So start with 21 days, and then keep looking forward.


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