Trial Therapy Duration Calculator

I just started a new treatment or therapy but I have no clue how long to wait to see if it actually helps

1c5onoThis is a statement we hear all the time and hope to provide an additional tool you can use as you strive for the level of health you deserve. Choosing to follow a new course of treatment can be both an exciting and nerve-racking time. When you hit a home run with the choice, which is honestly pretty rare, it is abundantly clear you made the right decision in pursuing the given therapy. The challenge is that most people get better through consistent small gains which are unfortunately rather difficult to clearly understand in the midst of treatment. For this reason it is very important to ensure that you give any treatment you choose to pursue adequate time to honestly evaluate how well it may work for you.

Problem is, most people don’t know how long to give a new therapy before knowing if it works or not. Add to that most doctors do not explain this very well or perhaps they haven’t really thought about it enough or simply do not know with some therapies.

We’d like to tell you that our Trial of Therapy Duration Calculator is based on years of validated scientific experimentation. It is not. It was a rough calculation that we started using and it seemed to be a pretty good estimate. Eventually, it may have the validation required, but for right now, it is a tool to help you evaluate any given trial of therapy. Here is a sample using 12 headache days per month. A trial of therapy should last approximately three and a half months.

You may want to “see our math” behind this calculator and we’re happy to share it. At the bottom of this post.


The underlying concept for this calculation is heavily based on how frequent one may have symptoms. For those who have symptoms at the highest frequency you are able to rapidly test or treatment and incorporated or move on to something more appropriate as rapidly as possible, thus allowing you to find a highly customized treatment plan unique to your personal needs. For those with less frequent symptoms it does take a bit longer to yield results which form a picture of your true response to the chosen treatment.

Through the use of this guidance you can ensure that you move on from treatments which don’t work as quickly as possible yet give those which are working the length of time necessary to see real symptom improvement. It is important, though, to remember this formula is only an estimate. Please trust your doctor if you are working with one.

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Trial of Therapy Duration Calculator Explanation – (Only read on if you love math)

In order to calculate the right duration, you need to know the number of days per month you suffer from the symptom in concern, let’s call it symptom frequency (SF). If your SF is not consistent or you haven’t ever taken the time answer this question, then you’ll have to observe yourself and make good notes. We like to know how many days you have the symptom each month, which is the SF portion of our formula below.  For the sake of our calculation we need the percentage of days per month you don’t have a symptom. To do this you take the number of days per month you have symptom (SF) and divide it by 30. Once you have this number you subtract it from 1 and you have the percentage of headache free days per month.

HF  30 = percentage (as a decimal) of days with a headache

1 – percentage (as a decimal) of days with a headache = percentage (as a decimal) of days without a symptom

Now that you know the percentage of days which are symptom free it is time to use determine just how many days you need to understand if a given treatment is actually working.  You can determine the optimal number of days you need to stick with a new treatment to really understand how well it meets your needs. All you need to do is multiply the answer you got for percentage of symptom free days per month by 180 and you will get the number of days necessary to fully understand how well you respond to a given treatment.

Percentage (as a decimal) of days without a headache X 180 = Number of days your trial of therapy should be

The exact equation is noted below, but if you want it made super easy, just fill out the calculator in the side bar we created to make your life even easier.

1-(HF/30) x 180 = number of days your trial of therapy should be


  1. Calculate HF first by observation
  2. Divide HF by 30
  3. Take 1 minus your answer in #2
  4. Now multiple your answer in #3 by 180

Example 1

If your HF is 18, 18/30 = 0.6; 1-0.6 = 0.4; 0.4x180 = 72 days or about 10 weeks for a trial of therapy

Example 2

If your HF is 3, 3/30 = 0.1; 1-0.1 = 0.9; 0.9x180 = 162 days or between 5-6 months for a trial of therapy

There are exceptions to this calculation on each end of the spectrum.

  1. If your HF is less than 1, choose 180 days as your trial of therapy duration.
  2. If your HF is 29, 30, or 31 choose 7 days as your trial of therapy duration.



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