How Long Does It Take for Guanfacine to Work?

Published on: 28 Jun 2023
Clinically Reviewed by Minkyung Chung, MS, LMHC
How Long Does It Take for Guanfacine to Work

Guanfacine is a prescription drug and non-stimulant medication prescribed to treat adolescent attention-deficit hyperactivity disorder (ADHD) and other conditions, like comorbidly occurring oppositional defiant disorder (ODD). It’s also sometimes used off-label to treat anxiety in children. Certain medications like Guanfacine target the brain’s receptors to help improve focus and reduce impulsivity. If you’re considering this medication, you’re likely wondering how long does Guanfacine take to work to improve symptoms?

How long it takes for Guanfacine to work depends on multiple factors, including age, medical history, and general well-being. Many people start to see symptom improvement after just a couple of weeks, but according to the National Alliance on Mental Illness (NAMI), the full effects of the ADHD medication might not be felt for 4 to 8 weeks. 

It’s important to remember that people can respond differently to medication, so one person might see results quickly while another may take longer to respond. 

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Continue reading to learn how long Guanfacine takes to work and what you should do if it doesn’t have the impact you expect. 

How Quickly Does Guanfacine Start Working?

The question of how long Guanfacine takes to kick in depends on several factors, including dosage, frequency of use, and individual response.

The time it takes for Guanfacine to start working will vary from person to person. The main effects of Guanfacine can often be felt within 1 – 2 hours of taking the medication. As noted, though, it can take a few weeks to get the full impact of regular use.  

How Do You Know If Guanfacine Is Working?

Guanfacine works by activating specific areas of the brain associated with regulating hyperactivity and impulsivity. 

“Tenax (Guanfacine) is a class of antihypertensive medication. This is an alpha-two receptor blocker that brings the sympathetic overflow under control. It’s used in psychiatry to manage various symptoms of ADHD and oppositional defiant disorder. It reduces arousal and hyperactivity.”

Talkspace psychiatrist Muhammad Munir

Guanfacine’s efficacy can be assessed by observing changes in behavior.

For example, if someone seems calmer and more focused after taking Guanfacine, that could indicate the medication has taken effect. Some parents notice children being able to stay on task longer or complete tasks with greater ease than before taking Guanfacine. Another way to know if Guanfacine is working is through reports from teachers or other adults who interact with your child regularly. They may provide feedback on if they’ve noticed any behavioral changes in your child since beginning treatment with Guanfacine. 

Doctors may also track improvements in ADHD symptoms over time using rating scales such as the Vanderbilt Assessment Scale and Conners’ Rating Scales-Revised (CRS-R). These scales measure impulsivity, hyperactivity, distractibility, and other behaviors associated with ADHD so healthcare providers can better gauge whether treatment plans are effective.

How does Guanfacine make you feel?

Some people report feeling calmer, more focused, and less impulsive after taking Guanfacine. Common signs that indicate a favorable response include:

  • Increased focus and concentration
  • Reduced impulsivity
  • Better mood regulation
  • Improved sleep patterns
  • Decreased hyperactivity
  • Fewer disruptive behaviors in social situations or school/workplace settings

Factors That Affect the Onset of Action for Guanfacine

How long does Guanfacine take to work? Knowing what factors affect how quickly Guanfacine starts working to treat ADHD is important.


Studies have shown that age can be instrumental in how quickly Guanfacine takes effect. It might be possible that younger patients respond more rapidly. Children may see results within days, while adults may need weeks or even months before they notice effects from the drug. More research is necessary to understand the role age plays in Guanfacine’s efficacy.

Weight and metabolism

Weight can also affect how quickly Guanfacine takes effect. Due to the body’s swiftness in metabolizing the drug, those with a faster metabolic rate may require a lower dose of Guanfacine and can experience its effects more quickly. Guanfacine can also have an impact on weight itself. While Guanfacine weight gain isn’t a guaranteed symptom, it may occur.  


The dosage of Guanfacine taken also affects how quickly it can work. Typically, higher doses are needed for those who don’t respond well at lower doses — adjusting dosage is common with ADHD medications.

What to Do When Guanfacine is Not Working

When Guanfacine isn’t working as expected, it can be incredibly frustrating and disheartening.

If, after some time, the medication isn’t offering symptom improvement, it’s crucial to take action and seek medical advice. Discussing potential causes of the ineffectiveness with a doctor should be the first step you take. They might decide to adjust the dosage or combine Guanfacine with other medications. 

Whatever you do, don’t try to stop the medication cold turkey, as this can result in Guanfacine withdrawal. Whether it’s because of its ineffectiveness or the side effects of Guanfacine (i.e. blurred vision, confusion, irregular heart rate, dizziness, or fatigue), you should talk to your doctor if you want to stop taking the medication.

Get Personalized Mental Health Treatment with Talkspace

Talkspace is an online mental health platform that provides personalized mental health treatment for those who need it. With Talkspace, you can connect with a licensed therapist or online psychiatrist from your home. From learning how long Guanfacine takes to work to finding the right treatment plan for your exact needs, Talkspace has everything you need to improve your mental health. 

If you’re interested in getting a prescription for Guanfacine online, connect with a prescriber at Talkspace today.


  1. Bello N. Clinical utility of guanfacine extended release in the treatment of ADHD in children and adolescents. Patient Preference and Adherence. 2015:877. doi:10.2147/ppa.s73167. Accessed March 27, 2023.
  2. Bello N. Clinical utility of guanfacine extended release in the treatment of ADHD in children and adolescents. Patient Preference and Adherence. 2015:877. doi:10.2147/ppa.s73167. Accessed March 27, 2023.
  3. NICHQ Vanderbilt Assessment Scales. NICHQ. Published May 18, 2021. Accessed March 27, 2023. 
  4. Gurley JR. Conners’ parent rating scales – revised. Encyclopedia of Child Behavior and Development. 2011:404-405. doi:10.1007/978-0-387-79061-9_670. Accessed March 27, 2023.
  5. Black BT, Soden SE, Kearns GL, Jones BL. Clinical and pharmacologic considerations for Guanfacine use in very young children. Journal of Child and Adolescent Psychopharmacology. 2016;26(6):498-504. doi:10.1089/cap.2014.0159.  Accessed March 27, 2023.

Talkspace articles are written by experienced mental health-wellness contributors; they are grounded in scientific research and evidence-based practices. Articles are extensively reviewed by our team of clinical experts (therapists and psychiatrists of various specialties) to ensure content is accurate and on par with current industry standards.

Our goal at Talkspace is to provide the most up-to-date, valuable, and objective information on mental health-related topics in order to help readers make informed decisions.

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