Scientific Comparison of the 4 Vagus Nerve Stimulators – Nurosym, Gammacore, Pulsetto, Sensate

Mental and physical well-being are essential to living a healthy, happy life. Recently, vagus nerve stimulation (VNS) has been gaining popularity as a non-invasive therapy to support overall wellness [1]. 

The vagus nerve is responsible for regulating heart rate, blood pressure, digestion, respiration, and many other bodily functions, making it a crucial component of our nervous system [1].  

Vagus nerve stimulation is a groundbreaking approach to enhancing quality of life. Stimulating the vagus nerve, which plays a crucial role in the functioning of the parasympathetic nervous system, can quickly lead to a significant reduction in stress, improved mood, enhanced cognitive function, improved gastrointestinal function, and more––all without drugs or psychotherapy [2]. 

Historically, vagus nerve stimulation required surgical intervention where a device is implanted in the chest with wires leading to the neck to directly stimulate the nerve. However, this method is costly, invasive, and carries surgical risks [3]. 

In recent years, at-home VNS devices have emerged as a more accessible and affordable alternative, allowing people to take control of their mental and physical health from the comfort of their own homes [4].

However, due to the social media hype around the vagus nerve and that strict regulations around vagus nerve stimulation are only starting to develop, many devices started popping up with little evidence of safety and efficacy. That’s why our team put together this extensive analysis that cuts through the noise and determines the safest and most reputable device for vagus nerve stimulation [4].

How to Choose a Vagus Nerve Stimulator

With a variety of different devices on the market, it’s important to do the proper research and make the choice that’s right for you. Most importantly, you need to be sure that the intervention you’re looking at has been scientifically proven to target the vagus nerve. 

Here are a few of the key factors to consider when making a decision:

• Consult with your health care professional
  Before starting any new medical intervention, it’s always a good idea to consult with a medical professional first. For vagus nerve stimulation, choose a neurologist or specialist who is familiar with VNS devices, so they can correctly advise you on if it will help your specific symptoms.
• Compatibility with your symptoms
  VNS devices are designed to improve specific symptoms, including depressive states, chronic tiredness, gastrointestinal issues, and brain fog. Make sure that vagus nerve stimulation has been studied and evaluated for its effectiveness for your specific health needs. VNS devices also have different stimulation locations, such as the neck and ear. Sensate, which is not a VNS device, claims to stimulate it through the chest. However, Nurosym’s AVNT approach and Gammacore’s approach both have scientific evidence of precise targeting and safety. Other approaches at any location are at best playing the piano out of tune and at worst actively dangerous.
• Safety & Wearable Device Status
  Many devices claim to be VNS devices and be safe, but it’s important to evaluate the scientific research done on each device to understand its safety profile. Sensate and Pulsetto say that they activate the vagus nerve, but they don’t have any scientific evidence to confirm it. Different methods of vagus nerve stimulation are associated with different side effects too, so it’s good to understand all the risks before you buy. Devices that have obtained certified Wearable Device status are key––this certification requires rigorous quality testing and safety studies to ensure that they don’t harm the nervous system
• Effectiveness & Research
  Be sure to look for devices backed by scientific research and ideally, placebo-controlled studies. A reputable device will have published research to back up its claims. Randomised placebo-controlled testing ensures that a device’s effects are not based on placebo, giving confidence in the device’s actual therapeutic benefits. Similarly, peer-reviewed studies reduce the risk of biased results and prove the credibility of the device tested.

  Many devices quote generic VNS research but they haven’t conducted any safety and efficacy studies on their device. Just because a device emits an electrical current where the vagus nerve is located, doesn’t guarantee that it activates the vagus nerve or impacts it positively. Most research on vagus nerve stimulation was done with invasive methods, not portable devices. So a handheld device that references invasive VNS research is falsely representing the data to sell their product.

• Stimulation vs Modulation
  It’s also important to be aware that some devices, like Pulsetto or GammaCore, provide high-intensity stimulation which may increase the chance of side effects and may harm people with chronic symptoms whose nervous systems are already dysregulated. Nurosym with 45 energy levels offers precise control of modulation to provide the same benefits with fewer risks.

• Price
  The device you choose must fit in your budget. Some devices have a subscription model that requires ongoing payments over time. Others like Nurosym and Sensate are one-time purchases. Because the benefits of using VNS require consistent use, the more they are used, the better the outcomes. Therefore, when considering getting a device, think long term how the costs of long term use would stack up. Taking Nurosym as an example, the cost of the device averages out to approximately 2 EUR per day over a year, and after that there are no more payments. Meanwhile, GammaCore is preloaded with 3 months of sessions. After that, you’ll need to purchase more sessions to continue using it. Pulsetto offers a paid app subscription, so long term costs of use might add up.

Testing Protocol

Since these devices are NOT created equal, it’s essential to carefully evaluate their features, effectiveness, and user experience before making a decision. So we set out to compare four of the most popular devices that people purchase for vagus nerve stimulation – Pulsetto, Sensate, Gammacore, and Nurosym. However, it’s important to note that unlike Nurosym and GammaCore, Pulsetto and Sensate are not certified VNS devices. 

For an accurate comparison, we had each device evaluated by a team of PhDs and medical health care professionals. I used each device for one month, with a one-month break after each to avoid any carryover effects. I started with Sensate, then Pulsetto, Nurosym, and finally, GammaCore.

Here are the results and rankings:

	Nurosym	Gammacore	Pulsetto	Sensate
Evaluated in and supported by peer-reviewed placebo-controlled scientific studies	✓	✓	Χ	Χ
Number of scientific studies conducted	40+	20+	0	0
Scientific studies investment	$10M+	$50M+	$0	$0
Usable without app	✓	Χ	Χ	Χ
Available without prescription	✓	Χ	✓	✓
Mode of action	Auricular Vagal Neuromodulation Therapy (AVNT)	Non-invasive Cervical Vagus Nerve Stimulation (ncVNS)	No validated mode of action	No validated mode of action
Target site	Auricular branch of the vagus nerve	Cervical branch of the vagus nerve	Neck	Chest
Delivery	Proprietary (Electrical)	Proprietary (Electrical)	Electrical	Vibration
Pleasantness of stimulation	Pleasant, mild	More intense, can clench a jaw	More intense	No direct stimulation, pleasant vibratio
Is gel needed to use?	No	Yes	Yes	No
Battery Life	>1 month	1 week	1 week	1 week
Easy to travel with	Yes	No	No	Yes
Device type requiring regulatory review and approval before marketing	Required	Required	Required	Χ
Approved to be used by the public	✓	✓	Χ	n/a
Certified Wearable Device	✓	✓	Χ	Χ
Medical evaluation process on purchase	✓	✓	Χ	Χ
Documented safety controls	✓	✓	Χ	Χ
SAE (serious adverse events) reported in scientific study	0	0	No scientific evaluation. Adverse events have been reported online	No scientific evaluation.
Risk profile	Low risk based on scientific studies	Low risk based on scientific studies	High risk based on lack of scientific studies and user reports	Low risk based on delivery (vibration)
Initial cost	£599	£350 (first 3 months only)	£209.20	£299
Additional costs	£0	£466 every 3 months	£99.99 GBP per year Paid app with more features	£50 per year Paid app with more features
Total estimated cost over 5 years of daily use	£599	£10,718	£709.15	£549
Overall Recommendation	Our top pick – Highly recommended	Recommended for headache sufferers	Not recommended	Can be used as a supplementary tool

Nurosym
Recommendation: Our top pick – Highly recommended
Price: 699 EUR (599 GBP)

Nurosym is the first CE-Marked non-invasive vagal neuromodulation system in our evaluation, which means that its safety and efficacy have been scientifically validated. In fact, Nurosym established a new device category with their Auricular Vagal Neuromodulation Therapy (AVNT), which led to acquiring wearable device status and paving the way for a new standard in vagus nerve technology. Also, unlike GammaCore, you don’t need a prescription to purchase it. 

Unlike other devices on the list, it’s backed by 40+ peer-reviewed scientific studies including many Randomised Placebo Controlled Studies conducted on renowned academic institutions such as Harvard, UCLA, Bart’s Health NHS Trust, and more. It is the most extensively studied and utilized non-invasive VNS device by researchers and health care professionals. 

And for good reason––the results of Nurosym’s studies are striking. For example, researchers found in various scientific populations a 35% improvement in anxious thoughts, 45% improvement in depressive states score, a 19% improvement in sleep, and a 48% improvement in fatigue, just to name a few.

Nurosym’s scientific results show significant improvement in a wide range of chronic and acute symptoms affecting millions of people worldwide.

Personally, Nurosym was transformative for my anxious thoughts and fatigue. As we age, our sympathetic nervous system becomes overactive, leading to increased inflammatory processes throughout the body. By harnessing the power of advanced neuromodulation technology, Nurosym offers a safe, easy, and effective solution for restoring your health and well-being.

After just a week of use, I noticed a huge difference in my overall well-being and I felt amazing by the end of the month. It is convenient to wear on the ear, and doesn’t require a gel which makes a huge difference. I found it easy to build a routine of daily use as with all VNS devices, consistency of daily use is important to see results. It is also easy to travel with and the battery lasts a lifetime. I did not have to charge it even once within the period of the test.

Best of all, it is a scientifically-validated technology trusted by leading medical institutions and used by hundreds of health care professionals worldwide.

Key Benefits & Drawbacks:

 

• • Scientifically validated in 3,000,000+ therapy sessions for safety & efficacy

• • Patented technology targeting the vagus nerve for rapid results

• • Precise stimulation strength adjustment to meet your specific needs

• • Easy to use and comfortable to wear like an earphone any time of day use

• • Portable design that’s easy to travel with in your pocket

• • Doesn’t require a gel to use

• • Long battery life (battery lasted for a month)

• • Durable construction and 1-year warranty

• • No subscription necessary

• • 30-day risk-free guarantee and full refund guarantee

• • Reasonable price: only 2 EUR per day over a year

Overview

Nurosym
Price	699 EUR
How it’s used	Worn on the left ear
Ease of use	Excellent
Targeting the vagus nerve	Unilateral targeting of vagus nerve through the left ear
Battery life	1 month
Key risks	No serious adverse events identified in scientific studies and peer-reviewed studies
Scientific benefits	40+ peer-reviewed studies showing positive results in relieving symptoms of fatigue, gastrointestinal issues, mood, anxious thoughts, depressive states score, cognitive performance and heart rate variability
Risk Profile	Very low
Scientific assessment	Highly recommended

Learn more on Nurosym website.

GammaCore
Recommendation: Recommended for headache sufferers
Price: 2,079.33 EUR for the first year (415.87 EUR first 3 months then 554.49 EUR per 3 months after that)

GammaCore is a non-invasive vagus nerve stimulator specifically designed to provide relief from cluster headaches. It’s a simple and easy-to-use device that’s applied externally to the neck to deliver gentle electrical stimulation to the vagus nerve.

Like Nurosym, GammaCore is a fully validated wearable device, backed by numerous peer-reviewed scientific studies demonstrating its efficacy in the management of headaches. Users using GammaCore have experienced significant reductions in the frequency and severity of their headaches, with some reporting relief within 15 to 30 minutes of use. This makes it a valuable tool for those who suffer from debilitating headache symptoms and are seeking a non-drug option for managing their symptoms.

The device is also sleek, compact, and portable, allowing for convenient use whenever you need it.

However, it comes with a couple of big drawbacks. First, you need a prescription from a health care professional to purchase it, so you’ll need to pay for a health care professional’s visit. Also, not all EU countries reimburse that appointment. Then, GammaCore is quite expensive, particularly if insurance coverage is not available to cover the costs. In the US, you can buy a preloaded GammaCore device for $450, but once those 3 months run out you’ll need to purchase more sessions. The refills cost $600 for every 3-month period after that. So if you want to use GammaCore for preventative care over several years, it will cost you thousands of dollars.

Also, GammaCore is designed to specifically help with headaches, so people looking for relief from other symptoms caused by a dysregulated nervous system should look elsewhere. 

Overall, GammaCore stands out as a robust, scientifically supported option for vagus nerve stimulation for people seeking an effective, non-invasive solution for headaches. However, you need to consider the long-term costs when making your decision.

Key Benefits & Drawbacks:

 

• • Scientifically certified device
  • Simple and sleek device
  • Can be challenging to locate the correct position on the neck  
  • Rapid relief (users experience results in 15 minutes or less)
  • Adjustable stimulation settings
  • Minimal side effects in scientific studies
  • Only validated for headaches
  • Expensive and ongoing costs
  • Requires a prescription from a health care professional to purchase

•  

• •  

Overview

GammaCore
How it’s used	Handheld stimulation through the neck
Ease of use	Good
Targeting the vagus nerve	Non-specific targeting on the neck
Battery life	6-7 hours for a full charge. Each device is preloaded with 93 days of consecutive sessions
Key risks	Minimal side effects
Scientific benefits	Provides effective relief for headaches
Risk Profile	Very low
Scientific assessment	Highly recommended for people suffering from headaches.

Learn more on GammaCore website.

Sensate
Recommendation: Can be used as a supplementary tool
Price: 277 EUR (233 GBP)

Sensate is technically not a vagus nerve stimulator, but a sensory stress relief device that uses vibrations and sound to lower stress. To be clear: Sensate is not a wearable device. It’s a relaxation tool that will not give you clear and defined Scientific benefits. So even though this product mentions the vagus nerve, it is not a validated device for vagus nerve stimulation.

Rather than directly stimulating the vagus nerve, this device claims to offer vagal toning to produce gradual results. Users may start to notice the effects after around 10 minutes, but they’re rather subtle. Plus, Sensate lacks peer-reviewed scientific studies so any results felt from its use might be due to placebo.

Its grounding design resembles a large rock and differs quite a bit from other stress-relief devices. While it may not be the best option for those seeking meaningful results, Sensate does offer a unique multisensory experience combining touch and sound.

The device has a long battery life, allowing for extended use, and is built with durability in mind. However, since Sensate is not a vagus nerve stimulator its distinctive design and longer session times may not suit everyone’s preferences or lifestyle.

Key features:

 

• • Gentle and safe design

• • Provides a multisensory experience with touch, sound, and vibration

• • Takes around 10 minutes to produce effects

• • Long battery life

• • Unique rock-inspired design

• • Durable construction

• • No peer-reviewed scientific studies

Overview

Sensate
How it’s used	Placed on the chest
Ease of use	Good
Targeting the vagus nerve	No evidence, but claims non-specific targeting on the chest in conjunction with deep breathing
Battery life	One week
Key risks	Low risk
Scientific benefits	No peer-reviewed studies
Risk Profile	Lack of safety studies, but probably low risk
Scientific assessment	Neutral. Low risk but no supporting evidence on benefits

Learn More on Sensate website.

Pulsetto
Recommendation: Not recommended
Price: 250 EUR (209 GBP)

Pulsetto does not have wearable device certifications or evidence that it activates the vagus nerve. However, it is a user-friendly device that offers different programs for users to target specific issues like stress, sleep problems, pain management, and anxious thoughts. 

The key difference between Pulsetto vs. Nurosym or Gammacore is that Pulsetto makes claims about its device that it can’t substantiate. Without any peer-reviewed studies, there’s no way to trust that the device actually does what it says it will do.

While some consumers mistakenly rely on FCC certification as a proxy for safety, it’s important to understand that this certification only pertains to electromagnetic compatibility and radio frequency emissions, not the safety of electrical signals sent to the vagus nerve. This type of safety is rightly so under the remit of health bodies that also approve the drugs that we put in our bodies. In contrast, a CE-certified wearable device ensures that a product meets strict EU health, safety, and environmental protection standards. Not all CE-certified devices are wearable devices, and this distinction matters to guarantee the safety and efficacy of medical products.

Pulsetto uses high-intensity bilateral neck stimulation, which is untested for efficacy and safety. Since we didn’t find any scientific studies for the device, there might be a risk of cardiovascular side effects, stress reactions, and potential damage to the vagus nerve. If you are looking to try a device at the neck, we’d recommend putting your safety first and choosing Gammacore.

We evaluated Pulsetto’s programs and detected no difference between them, suggesting that this is deceptive marketing. Without any meaningful scientific research, we couldn’t verify the efficacy of their programs. 

So while Pulsetto is easy to use, the lack of double-blind scientific studies on the device and potential risks put this one at the bottom of our list with a warning on use. 

So to wrap this up, if you’re looking for a relaxation product, Sensate is lower risk. If you are looking for a neck-based product, GammaCore is a safer and likely more effective choice.

Key Features:

 

• • Paid app with subscription and programs to target specific issues

• • Design is difficult to adjust on the neck

• • Not very portable

• • Battery life only lasts for one week

• • Claims quick-acting results in 4 minutes

• • Uses bilateral neck stimulation which is untested and may carry the risk of cardiac side effects

• • Permanent discounts on the website seem to be fake

• • They seem to copy user testimonials in ads from other companies

Overview

Pulsetto
How it’s used	Worn on the neck
Ease of use	Good
Targeting the vagus nerve	Non-specific targeting on both sides of the neck
Restrictions on use	Not specified
Battery life	One week
Key risks	Lack of safety studies, potential risks of cardiovascular side effects, stress reactions, or damage to the vagus nerve.
Scientific benefits	No peer-reviewed studies
Risk Profile	High
Scientific assessment	Recommend to avoid use based on risk profile.

Learn more on Pulsetto website.

 

The Challenge of Precise Targeting in Vagus Nerve Stimulation

Imagine trying to play a symphony on a piano. Each key, when pressed, produces a separate note, by hitting the right keys at the right time, you can create a harmonic melody. Now imagine the same attempt, only without the ability to play the piano, and without knowing the sound responsible for the keys, and now add that the piano has 100,000 keys, just like the number of fibres of the vagus nerve. This analogy reflects the challenges faced in vagus nerve stimulation (VNS) therapy. The vagus nerve is like the piano, with its numerous fibers representing the keys, each linked to different bodily functions. The challenge lies in targeting the correct fibers at the precise time and through the appropriate access points to produce the desired therapeutic effects without causing unwanted side effects [5].

Understanding the Vagus Nerve’s Complexity

The vagus nerve is one of the most complex and multifaceted nerves in the human body. Originating in the brainstem, it extends down through the neck and into the abdomen, innervating multiple organs along the way. It plays a crucial role in regulating the unconscious (autonomic) nervous system, heart rate, gastrointestinal function, immune response, and mood, among other things. This vast network of functions is controlled by approximately 100,000 fibers within the vagus nerve, each with specific roles [5].

The Difficulty of Precise Targeting

In VNS, electrical impulses are used to target specific fibers in the vagus nerve, aiming to project to the brain and other organs in the body to elicit therapeutic responses for a variety of symptoms such as low mood, heart problems, and inflammatory diseases. However, the nerve’s intricate structure poses significant challenges [6]. Targeting the right fibers to achieve the desired effect without activating other off-target effects that could be dangerous or cause adverse reactions [4] is akin to pressing the correct piano keys at the right place at the right time, where certain keys are responsible for the beating of our heart, breathing of our lungs and encoding of information in our brain. 

Types of Vagus Nerve Stimulation Devices

Targeting the vagus nerve is not easy. A device can emit an electrical signal to an area of the skin, but that signal doesn’t necessarily activate the vagus nerve. Only placebo-controlled scientific studies measuring vagus nerve activity can prove that a device actually stimulates the vagus nerve in a medically significant way [7].

There are a few different ways in which devices claim to stimulate the vagus nerve. The table below shows the methods, in this case, vibration or electrical impulses, as well as the target locations. 

Method	Vibration	Electrical impulses
Target site	Chest	Cervical (neck)	Auricular (ear)
Device	Sensate	Gammacore  Pulsetto	Nurosym

Ear vs Neck

The best and most well-researched is a method developed by a company called Parasym (who developed the Nurosym device); targeting the auricular branch of the vagus nerve on the left ear tragus. Tragus of the ear is richly innervated by the Vagus Nerve and it contains only sensory fibres. This means that signal from this area flows directly to the  centres in the brain stem responsible for modulating the relaxation response of the parasympathetic nervous system with low risk of off-target effects

Attempting to stimulate the vagus nerve around the neck is difficult because it’s deep in the neck and not easy to access non-invasively. The neck is a complex and delicate area of the body, with vital structures like the carotid arteries, other cranial nerves, and jugular veins, as well as sympathetic (fight or flight) nerves so precise targeting is essential. Attempting neck stimulation without precision poses significant risks, including activating motor vagal fibres that directly influence the heart and can even stop its beating, resulting in extreme cases in palpitations, low resting heart rate or other severe cardiac complications [8]. Mayo Clinic researchers warned in the leading scientific journal, Scientific American, that tampering with the vagus nerve with unlicensed wearable devices can potentially result in cardiac arrest or sudden death [4].        

 

For this reason, the FDA-approved labeling for GammaCore’s vagal neuromodulation device targeting the neck specifies that they should only stimulate the left vagus nerve in the neck area inside the carotid sheath, below where the superior and inferior cervical cardiac branches separate from the vagus nerve. However other researchers emphasise that auricular VNS is safer than cervical VNS because it uses a natural pathway to activate the brain regions that send signals evenly to both sides of the heart. This approach helps prevent the risk of uneven fibres activation, which can occur with cervical VNS [9]. Additionally, except for GammaCore, no other neck stimulation device meets the FDA’s safety criteria. Pulsetto is worn on both sides of the neck, but there’s no peer reviewed studies on their device, which means safety of this stimulation cannot be established [8].   

 

Electrical stimulation vs Vibration

Then there are devices like Sensate which use vibration, not electrical current, which is a very indirect approach. The vagus nerve can be thought of as a communication highway where the language spoken is in electrical signals. Vibration is a different language so the signals are not precise or easily translatable. It can be thought of as trying to do CPR to restart the heart rather than using a defibrillator. There is no peer-reviewed research supporting the claims or the effectiveness of Sensate [9].

Nurosym’s device targets the vagus nerve via the auricular branch of the left ear. Nurosym’s targeted signal delivery safely activates pathways for modulation of the autonomic nervous system and immune system––which is supported by randomized placebo-controlled scientific studies. Nurosym’s proprietary, Auricular Vagal Neuromodulation Therapy (AVNT) reaches the brain and activates the parasympathetic nervous system centres in the brain stem. This means that instead of stimulating directly various efferent fibres of the vagus nerve, Nurosym stimulates the headquarters of the parasympathetic system in the brain without direct action on the peripheral organs hence reducing safety concerns associated with other types of stimulation.

Safety Studies & Wearable Device Certification

Sending electrical signals to the vagus nerve that have not been evaluated in scientific studies and approved by institutions such as the FDA or EMA (CE) may contribute to the ineffectiveness of the therapy or put users at risk of causing permanent damage to health [10, 11].

Even a slight change in the electrical signals will affect the physiological reaction, ranging from (best case) no effect to (worst case) complications related to heart activity (sudden cardiac death or arrhythmia), nerve damage, or worsening in chronic health symptoms. That is why it is so important to use certified wearable devices like Nurosym or GammaCore that underwent rigorous scientific studies to ensure safety & efficacy [4].

Pulsetto and Sensate are not wearable devices. While for a vibration gadget like Sensate this might not be an issue, Pulsetto uses electrical current and lack of peer-reviewed scientific studies or safety standards might put users nervous systems at risk. The company itself lacks transparency in this context as well using other certifications (FCC) to pretend they have been evaluated for safety [10].

Comparison Summary

Devices like Nurosym, GammaCore, Pulsetto, and Sensate offer varying approaches, safety, and effectiveness in vagus nerve stimulation. Depending on your specific needs, risk profile, and budget, you can select the device that best meets your needs. For us, Nurosym emerged as the clear winner of our evaluation. Be sure to check with a healthcare professional if you have any questions or concerns about vagus nerve stimulation.

Here are the websites for each of the devices, ranked by the results of our evaluation:

1. Nurosym

2.GammaCore

3.Sensate

4.Pulsetto