Delve into our extensive evidence base

Flow uses a technology called tDCS (or transcranial Direct Current Stimulation) which has been researched for the past 25 years.

There are now over 20 large, high quality Randomised Controlled Clinical Trials (RCTs) in the literature. Several meta-analyses of these trials have concluded that there is class A evidence (meaning definite effect) for the ability of tDCS to improve depression.

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Lifestyle headset

Flow has made tDCS accessible

So why haven’t you heard about tDCS before? Despite the significant amount of research supporting tDCS as a safe and effective depression treatment, historically it has been hard to access. tDCS devices were mainly designed for research, were difficult to use, lacked regulatory approval or were very expensive.

Flow has changed that by designing the first tDCS device which is easy to use, affordable and has regulatory approval to treat depression.

Clinical trial results

In 2023 leading researchers from University of East London and Kings College ran a Randomised Controlled Clinical Trial (or RCT) which compared Flow to a placebo. Participants underwent 10 weeks of tDCS depression treatment using the Flow headset. Results showed that 57% went into remission1 (not clinically depressed) within 10 weeks, and there were no serious side effects2 connected to the use of the device.

Not clinically depressed at 10 weeks
Serious side effects

Our work with the NHS

Flow’s tDCS device is now being used in the NHS across primary care, community mental health, perinatal mental health and crisis services. Northamptonshire Health Foundations Trust has published three papers endorsing the use of Flow in the NHS.

Clinician rounded

Primary Care

The 2023 paper concludes “The results...provide support for offering Flow as a primary care-delivered treatment option for people with symptoms of depression. Access to Flow should not be restricted by being able to afford to buy it.”

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Community Mental Health

The 2024 paper concludes “These findings provide support for the approach of offering tDCS and at the same time wellbeing behaviour therapy training for CMHT patients experiencing depression. Some people do not wish to try or do not respond to antidepressants or psychotherapy, so it is vital to offer an additional choice of an effective evidence-backed depression treatment that could work for them.”

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Primary Care

The 2024 paper concludes “PHQ-9 reliable improvement and remission rates were 58.1% and 32.3%. There was a significant improvement in PHQ-9 and WSAS with large effect sizes…Flow tDCS can be delivered through a primary healthcare general practice service...tDCS has evidence as an effective depression treatment, the widespread availability of tDCS in primary care general practice should be considered."

Real world data from Flow users

The Flow app asks users to fill in a short medical questionnaire3 once per week so that they can track how their symptoms are changing over time. Analysis of aggregated questionnaire data from 4,000 users shows that 46% go into remission or response by week 10.

In remission or response by week 10

Remission is no longer clinically depressed. Response is at least a 50% reduction in depression score.

Leading Doctors and Academics support Flow

Allan Young full size

Flow’s exciting and encouraging data raise the prospect of a real advance in the treatment of depression…a helpful intervention for many people suffering from major depression.

Allan Young

Chair of Mood Disorders, King’s College London

Corey Keller full size

Flow’s results show a clear separation of active and sham treatment in a large, multisite randomised controlled trial… a very promising development in mental health treatment.

Corey Keller

Assistant Professor of Psychiatry and Behavioural Sciences, Stanford University


Flow has gained popularity among our patients. This positive reception speaks volumes about the effectiveness and patient satisfaction associated with Flow.

Azhar Zafar

GPA Director of Research, NHS GP


With Flow’s brain stimulation headset our highly respected experts now have a new tool to treat depression.

Elena Touroni, PhD

Clinical Director, Chelsea Psychology Clinic


Home-based treatment that is safe and evidence-based. A major step forward for patients with depression.

Sophia Frangou, MD PhD

Professor of Psychiatry, Mount Sinai & Editor-in-Chief of European Psychiatry


By combining tDCS with behavioral therapy, the Flow team has created a powerful treatment solution.

Andre Brunoni, MD PhD

Assoc. Professor of Psychiatry, University Hospital of Sao Paulo


Yes. The Flow device was designed by experts and is based on tDCS techniques that have been used in clinics for over a decade to treat depression. The Flow device has undergone research that confirms it is a safe and effective treatment for depression. tDCS is also listed as a treatment for depression on the NHS website.

Read more about Safety and Precautions here.

If the Flow treatment is helpful for the first 10 weeks of your treatment, we recommend you to continue for at least another 6 to 12 months, even if you have become symptom-free.

Our team of clinicians have developed detailed guidance on how to use Flow which you can read here.

Using the headset feels different for everyone. A number of factors will affect how you experience Flow, for example, sleep quality and skin sensitivity and therefore sensations may vary among sessions. It usually feels a little more intense during the first 3 minutes of a stimulation session.

Some people have reported not feeling anything while others have reported feeling an itchy, slightly tingling sensation; like a stinging or a mild burning sensation on the forehead.

A stimulation session takes 30 minutes and can be done whenever works best for you. Whether that be while you eat breakfast to start your day, while replying to emails at work, or even reading while winding down for bed. Flow is a wireless headset that can go wherever you go. Just remember to charge it before use.

Some users have reported feeling energized after stimulation and for those, it would be recommended to use Flow earlier in the day. Some users have reported feeling sleepy after stimulation and for those, it would be ideal to use Flow before going to bed.

Most users do not feel sleepy or energized after a stimulation so it does not matter when the stimulation takes place during the day.

We recommend following the behavioural therapy courses in the app to further support the creation and maintenance of healthy habits that have been proven to help reduce depression.

If you don't want to do that, you don't have to. You can listen to music, watch TV, some of users do puzzles or sudoku whilst stimulating.

It is important to note that the Flow headset should not be used while operating heavy machinery, near water, or while performing intense exercise.

The headset also requires continuous contact to the forehead.

Our real-world data shows that 77% of Flow users experience improvement after just 3 weeks of use.

However, if you’re not happy with your Flow headset for any reason, you can ask to return it within 30 days and receive a full refund.

Please visit our Help Centre to find answers to other commonly asked questions.


1As measured by the MADRS-s questionnaire, a widely used depression assessment tool which was administered by a qualified clinician.

2Serious side-effects follow the definition of serious adverse events found in MDR Article 2(58).

3This data is measured using the MADRS-s. The MADRS-s gives an indication of symptom change over time and should not be used for diagnosis.