Many self-help books claim that if you want to develop a good habit, you should at least practice it for 21 days. Some studies also support this 21-day phenomenon using data. However, a team of researchers from the University of South Australia doesn’t agree. 

They performed one of the most detailed studies on the matter and concluded that it takes longer to build a habit: around two months.

The researchers combed through 20 studies involving 2,601 participants trying to develop various habits related to improving their health, diet, personality, and behavior. This meta-analysis (a study of studies) revealed some surprising results.

“Brief 21-day challenges or kickstarts are unlikely to be sufficient to firmly ingrain new habits. Individuals should anticipate a timeframe of at least two to five months to develop automaticity in new health habits, rather than the commonly cited 21-day period,” the study authors said.

Automaticity demands time and patience

In their study, the researchers explain that habit formation occurs in four stages:

1. The first stage is when a person decides to take action, which means that he or she has thought of making a change.
2. The second stage is when the person begins taking action i.e. translating thoughts into action.
3. The third stage is when the individual repeats the behavior or action.
4. After some time finally comes to the fourth stage called automaticity. This is when the habit is ingrained in their routine and becomes a part of their lifestyle. At this stage, a person doesn’t have to think about practicing the habit, they do it without any external or internal motivation. 

Essentially, only after the fourth stage is completed the habit is truly formed.

“While the first three stages are common to behavior change in general, the development of automaticity is unique to habit formation, occurring through consistent repetition of behavior in a stable context over time. Automaticity is where a behavior displays some or all the following features: lack of awareness, efficiency, uncontrollability, and unintentionality,” the study authors explain,” the study authors explained.

The meta-analysis suggests that habits form somewhere between 59 to 66 days for the quickest learners and 106 to 154 days for the slowest — meaning that on average it takes two to five months for a person to reach habit automaticity. 

However, the average number does not apply to all and can vary from person to person. For example, the analysis also reports cases where a habit formed in just four days, while in other cases, it took up to 335 days for a person to master a habit. Some people are naturally more inclined towards certain things while most others have to develop the skills.

“Having a realistic expectation that habit formation takes time can help individuals stay motivated and persist through the initial stages of behavioral change,” the study authors added. 

This isn’t the final verdict on habit formation

The meta-analysis provides reasonable insights into the science of habit formation, offering a more relevant perspective compared to the widely popular 21-day theory. However, it also has some limitations. 

For instance, the analysis includes only 20 studies with a small sample size, the majority of which focus on developing habits related to diet. This makes it susceptible to various biases, a point with which the study authors also agree. They clearly mention that most of the studies included in their meta-analysis had a high risk of bias rating.

“To better understand the duration of habit formation, future research should prioritize high-quality experimental designs, particularly randomized controlled trials (RCTs) with larger sample sizes to reduce bias and improve reliability,” Ben Singh, first author of the study, and a research fellow at the University of South Australia told Gizmodo.

The meta-analysis is published in the journal Healthcare.