Nerva App Review: What Its Own Trial Found

Nerva is a six-week gut-directed hypnotherapy app for IBS, and unlike most gut apps it has a published randomised controlled trial behind it. That trial reported that 81% of people using the hypnotherapy program had a clinically meaningful improvement in symptom score. It also reported that 63% of people using the same app without any hypnotherapy content got there too, and that number is missing from the marketing.

That is not a scandal. It is the single most useful fact about this app, because it tells you roughly how much of the benefit is the hypnotherapy and how much is six weeks of daily attention to your gut. This review works through the trial in detail, the company's own real-world usage data, the one digital hypnotherapy trial that failed, and the specific complaints people raise in r/ibs. For the broader question of whether gut-directed hypnotherapy works at all, we have a separate deep dive on whether gut-directed hypnotherapy works for IBS; this page is about Nerva specifically.

What Nerva actually is, day to day

Nerva is a self-guided smartphone program that delivers gut-directed hypnotherapy as daily audio, alongside short education lessons. It is made by Mindset Health, and its site describes it as "an evidence-supported program for gut-brain disorders like IBS", structured as "one 15-minute audio session a day, at home, with a quick check-in after" (Mindset Health).

The published trial is more precise about the dose: it was a "42-session daily digital program", which is six weeks of daily sessions with no rest days (Anderson 2025). That number matters, because it is the thing you are actually committing to.

What the sessions feel like is best described by people who have done them. A long thread in r/ibs about one person's experience produced a consistent picture across the replies: guided visualisations, delivered in a calm voice, working through scenes such as a beach, a river flowing through you, a forest being cleared, or a control room where you turn down dials (r/ibs thread). A second thread adds a bookstore narrative, a period of gut-specific suggestion once you are relaxed, and a closing sequence that brings you back out (r/ibs thread). People also describe short readings about the gut-brain connection, breathing exercises, and CBT-style thought challenges.

None of that is exotic. It maps closely onto the published Manchester Protocol for gut-focused hypnotherapy, which involves an induction, deepening, gut-specific imagery and suggestion, and a return, delivered over a course of sessions (Vasant 2019). The difference is that the Manchester Protocol is delivered by a trained therapist who adapts it to you, and an app plays the same recording to everyone.

The trial: what happened, in full

The key study randomised adults with IBS to the six-week Nerva program or to an active control: the same daily digital program structure, for the same 42 days, without the hypnotherapy content (Anderson 2025).

Here is what it found.

The groups were 121 on the hypnotherapy program (median age 38, 90% female, baseline IBS-SSS 321) and 119 on active control (median age 36, 91% female, baseline IBS-SSS 303).

A word on the scale. IBS-SSS runs to a maximum of 500, with scores above 300 counted as severe, 175 to 300 moderate, 75 to 175 mild, and under 75 equivalent to remission. Its author validated a 50-point change as the threshold that reliably indicates improvement (Francis 1997). So both groups started in the severe range and both ended, on median, in the moderate range. The hypnotherapy group ended lower.

Doing the subtraction yourself

An 81% response rate sounds like a treatment that works for four people in five. It is not, because 63% of a comparison group reached the same threshold on an app with the hypnotherapy taken out.

The honest arithmetic:

• Symptom score: 81% minus 63% is 18 percentage points. Turn that into a number needed to treat and you get roughly 6. That is, for every six people who run the hypnotherapy program instead of an equivalent non-hypnotherapy program, about one extra person reaches the response threshold.
• Abdominal pain: 71% minus 35% is 36 percentage points, which is a number needed to treat of about 3. This is the strongest result in the trial and it gets less marketing attention than the 81%.
• Psychological symptoms: no separation at all. Both groups improved on the DASS-21 to a similar degree.

That last row is worth sitting with, because it cuts against the most common assumption about this app. People often describe Nerva as "an anxiety app for your gut". In its own trial, it did not beat the control on anxiety, depression or stress scores. What it beat the control on was abdominal pain and overall gut symptom severity. If you go in expecting it to fix anxiety, the trial does not support that.

A high control response is not evidence of nothing happening. Placebo and non-specific response rates in IBS are famously large: pooled across trials of licensed IBS drugs, placebo abdominal-pain response rates under strict FDA criteria were 40.2% in IBS with diarrhoea and 34.6% in IBS with constipation (Barberio 2022). A 63% response on an engaging daily digital program in an unblinded trial is entirely in keeping with that. The researchers deserve credit for choosing an active control rather than a waiting list, which is exactly what makes this trial informative.

What I could not verify

Nerva's site states that "results were maintained at 6 months". The published trial does say questionnaires were collected six months after the program ended, but the abstract does not report what those six-month numbers were, and the full text sits behind a paywall that I could not get through this run. So the six-month claim is plausible and consistent with the trial design, but I have not read the figures that support it, and I am not going to repeat a number I have not seen.

There is also a small reporting oddity in the abstract: it reads "Of 240/244 randomized participants", then describes 121 plus 119, which is 240. Whether 244 were randomised and 240 analysed, or 244 were assessed and 240 randomised, is not resolvable from the abstract. Either way the analysed sample is 240 and the effect estimates above are what the paper reports.

The digital hypnotherapy trial that failed

Nerva is not the only gut-directed hypnotherapy app with a randomised trial, and the other one is a useful corrective.

Regulora is a prescription digital therapeutic in the United States delivering gut-directed hypnotherapy over 12 weeks. It was cleared by the FDA in November 2021 under 510(k) number K211463, held by metaMe Health (FDA 510(k) K211463). Its trial randomised 378 people, 362 of whom were treated and analysed, comparing it with digital muscle relaxation delivered the same way. It missed its primary endpoint. The proportion reaching a 30% reduction in average daily abdominal pain in the four weeks after treatment was 30.4% on hypnotherapy and 27.1% on muscle relaxation, p = 0.5352 (Berry 2023).

The paper does report that hypnotherapy beat muscle relaxation during the last four weeks of treatment (30.9% versus 21.5%, p = 0.0232) and across the whole treatment period (29.3% versus 18.8%, p = 0.0254). Those are secondary outcomes. A trial that misses its primary endpoint and hits secondaries is a trial that failed on the question it was designed to answer.

I could not read a funding statement or a conflict-of-interest statement for the Regulora trial: neither appeared in the PubMed record, and I did not obtain the full text. So I cannot tell you who paid for it.

Two things follow. First, a digital gut-directed hypnotherapy program can be tested properly and come out flat, so Nerva's positive result is not a foregone conclusion of the format. Second, the choice of comparator decides a lot: Regulora was measured against digital muscle relaxation, which is itself an active relaxation intervention, while Nerva was measured against a digital program with the hypnotherapy removed. Those are different questions, and neither answers "does it beat nothing".

Note also the regulatory inversion. Regulora, which missed its primary endpoint, holds FDA clearance and needs a prescription. Nerva, which hit its primary endpoint, states plainly on its own site that it "has not been evaluated by the FDA, TGA, MHRA, or equivalent bodies" (Mindset Health). Regulatory clearance and trial success are not the same thing, and neither implies the other. Our review of Cara Care and the prescription digital therapeutic model goes through how that gap opens up.

Follow the funding

Both published Nerva studies were paid for by the company that makes Nerva. This is stated in the papers themselves, not inferred.

The randomised trial lists a single funder: Mindset Health Pty Ltd. The PubMed record for it carried no conflict-of-interest statement that I could read, so I cannot tell you what the individual authors declared (Anderson 2025).

The real-world usage study is explicit: "Mindset Health has funded the current research. GE serves on Mindset Health's Scientific Advisory Board and provides consulting services to Mindset Health" (Simicich 2024).

Industry funding does not make a result wrong. It does mean the result should carry a discount, and it makes the independent evidence more important. For contrast, the publicly funded comparators in this space reported their own funding too: the IMAGINE trial of individual and group hypnotherapy declared funding as "None" (Flik 2019), and the ACTIB trial of web-delivered CBT for IBS was funded by the UK Department of Health (Everitt 2019). The network meta-analysis that ranks psychological therapies against each other declared no competing interests (Black 2020).

The 31% nobody puts on the landing page

The most interesting Nerva paper is not the trial. It is a retrospective analysis of 14,898 people who downloaded and used the app between January and September 2022. The headline finding: about 31% of users persisted with the program (Simicich 2024).

The abstract calls this "promising adherence rates". In one sense that is defensible, because the bar for consumer health apps is on the floor. In a panel-based analysis of 93 popular mental health apps on Android, the median 30-day retention rate was 3.3%, and the median daily open rate was 4.0% (Baumel 2019). That study measured mental health apps, not IBS apps, and it measured free-to-install apps rather than a paid program, so it is context rather than a like-for-like comparison. Against that context, 31% is genuinely high.

In another sense, 31% means roughly two in three people who start do not get through. And the trial's 81% response rate was measured in people who completed a supervised six-week trial protocol, not in the general population of app downloaders. Those are different populations, and the gap between them is the gap between "does this work?" and "will this work for me, as I actually live?"

I could not read the full text of this paper. Europe PMC returned server errors on its full-text endpoint across multiple attempts this run and the publisher's page returned HTTP 403, so I could not check exactly how "persistence" was defined, what proportion completed all 42 sessions, or how paying subscribers differed from free-trial users. One detail from the abstract is worth flagging: the persistence analysis reports a chi-square with N = 6,745, less than half the 14,898-user cohort, and without the full text I cannot explain why.

Does it work for IBS-C or IBS-D?

Nerva's published trial did not report results split by IBS subtype, so it cannot answer this. What we have is indirect.

The Regulora trial reported that improvements in abdominal pain, stool consistency and stool frequency were "consistent across IBS subtypes", though that trial missed its primary endpoint overall, which limits how much weight that observation can carry (Berry 2023). A face-to-face group hypnotherapy trial in refractory IBS found that "gender, age, disease duration and IBS type did not have an influence on the long-term success" (Moser 2013). Taken together, subtype does not look like a strong predictor of whether gut-directed hypnotherapy helps.

The complaint people actually raise is different, and it is about imagery rather than efficacy. A commenter in r/ibs with IBS-D described the flowing-river visualisation as exactly wrong for their symptoms: their gut is already a free-flowing river, and that is the problem (r/ibs thread). Others in the same thread argued the sessions read as generic across a condition that is not remotely uniform. That is lived experience rather than evidence of lower efficacy, but it is a real and specific objection, and it is the kind of thing a therapist working one to one would adapt. If you are not sure which subtype you have, our guide to the difference between IBS-D and IBS-C covers how the categories are defined and how unstable they are.

Why some people finish it and feel nothing

Gut-directed hypnotherapy has never worked for everyone, and no app changes that. A systematic review of the randomised evidence found six of seven IBS trials reported significant symptom reduction, with response rates among people receiving hypnotherapy ranging from 24% to 73% (Peters 2015). Meta-analysis of eight RCTs in 464 patients put the number needed to treat at 5 at the end of therapy and 3 at long-term follow-up, with about 54% achieving long-term adequate relief in refractory IBS (Schaefert 2014).

Even in Nerva's own trial, close to one in five people in the hypnotherapy arm did not reach the response threshold.

Nobody can predict in advance who responds, and the mechanism work has ruled out several tempting explanations:

• It is not motility. A randomised study measured gastric emptying, small bowel transit, colonic transit and antroduodenojejunal manometry before and after 12 weeks of gut-directed hypnotherapy and found no significant changes (Lindfors 2012).
• It is not rectal sensitivity, at least not measurably. In a study of severe IBS, rectal pain thresholds, rectal smooth muscle tone and autonomic function were unaffected by hypnosis treatment, while somatisation and psychological distress fell substantially. The authors concluded the benefit runs through psychological distress and somatisation rather than the physiological parameters they measured (Palsson 2002).
• It is not simply believing in it. People in r/ibs report both outcomes: one described being a committed sceptic who improved anyway, another described believing fully, doing every session, and finishing with nothing (r/ibs thread).

The most comprehensive review of hypnosis for GI disorders concluded that the mechanisms remain unclear, while noting evidence for both modulation of gut function and changes in how the brain handles sensory signals from the gut (Palsson 2015). That is an honest position, and it is more honest than most of the marketing on either side.

"Is it normal to almost fall asleep?"

Yes, and it comes up in nearly every Nerva thread. Multiple people in r/ibs describe being so relaxed by the end of a session that they are close to sleep, and at least one reported their dog falling asleep alongside them (r/ibs thread). Deep relaxation is the intended first half of a gut-focused hypnotherapy session: the induction and deepening exist precisely to get you there before the gut-specific suggestions arrive (Vasant 2019).

If you fall fully asleep and miss the suggestion phase, most people simply repeat that day's session. Nobody has studied whether staying awake changes the outcome, so that is a practical workaround rather than an evidence-based instruction.

A related complaint from the same threads: some people find the pacing frustrating, describing being prompted to notice three things they can hear, then interrupted before they have finished. One reply argued the interruption is deliberate, as a way of tiring conscious attention. There is no published evidence for that explanation, and it should be read as a theory from the community rather than a fact about the program's design.

The "IBS is not caused by food" framing, and why it grates

One of the most-discussed things about Nerva in r/ibs is not the program at all, it is the advertising. A thread titled "What is Nerva.. They saying like ibs is not caused because of food we eat" drew 40 replies, and the top response made the sharpest version of the objection: the gut-brain axis is one piece among many, and saying food is not the cause is "misleading at best" (r/ibs thread). Another reply put the risk plainly: emphasising the gut-brain axis, messaged badly, lands as "it's all in your head", which is dismissive and can itself trigger anxiety.

That objection is worth taking seriously, because it is the exact failure mode people with IBS have spent years fighting in clinic. Our piece on getting your doctor to take IBS seriously covers the structural reasons that dismissal happens.

The evidence supports a middle position rather than either extreme. Gut-directed hypnotherapy and a low FODMAP diet were compared head to head in a randomised trial of 74 people: improvements were similar across hypnotherapy, diet and the combination, with 72%, 71% and 72% respectively achieving a 20mm improvement on a visual analogue scale, and no additive effect when they were combined (Peters 2016). Hypnotherapy did better on psychological measures. Diet did not do better on gut symptoms, and hypnotherapy did not do better on gut symptoms. They landed in the same place.

So the defensible claim is that a brain-gut approach can produce comparable symptom relief to a dietary approach, not that food is irrelevant. If you have already found that diet alone does not get you far enough, that trial is genuinely encouraging, and our guide on what to do when low FODMAP does not work covers the other branches. If diet is clearly doing work for you, nothing here argues for abandoning it.

The same logic applies to the stress question. Stress and IBS symptoms genuinely feed each other, which is the mechanism gut-directed hypnotherapy is aiming at, and we cover what the IBS-specific evidence does and does not show in can stress cause an IBS flare up.

How it compares with seeing a hypnotherapist

No trial has compared an app with a therapist directly, so this is a comparison of separate evidence bases.

Clinician-delivered gut-directed hypnotherapy has the deeper record. The original randomised trial in 1984 found a "dramatic improvement in all features" in severe refractory IBS compared with psychotherapy plus placebo (Whorwell 1984). A follow-up of 204 patients found 71% initially responded and 81% of those maintained improvement for up to five years, though this was an uncontrolled study relying on patients' own retrospective classification of themselves as responders (Gonsalkorale 2003). The IMAGINE trial, in 354 patients across 11 Dutch hospitals, found adequate relief at 12 months in 40.8% of individual hypnotherapy patients and 49.5% of group hypnotherapy patients, versus 22.6% of controls, with group therapy non-inferior to individual (Flik 2019). A trial in refractory IBS found 60.8% improved after group hypnosis versus 40.9% on supportive talks, with the confidence interval for that post-treatment difference running from 0 to 40.2%, and a more convincing separation at 15 months (Moser 2013).

The guidelines reflect that record, not the app. The ACG suggests gut-directed psychotherapy be used to treat global IBS symptoms (Lacy 2021). NICE positions referral for psychological interventions including hypnotherapy for people whose symptoms have not responded to pharmacological treatment after 12 months (NICE CG61). The BSG guidelines and the Rome Foundation's working team report on brain-gut behaviour therapies both cover it in detail (Vasant 2021; Keefer 2022).

But that record has known weaknesses. The network meta-analysis of 41 RCTs and 4,072 participants ranked gut-directed hypnotherapy among the therapies with the largest evidence base, with a relative risk of remaining symptomatic of 0.67 (95% CI 0.49 to 0.91), but found no psychological therapy superior to any other and concluded that "risk of bias of trials was high, with evidence of funnel plot asymmetry; the efficacy of psychological therapies is therefore likely to have been overestimated" (Black 2020). An updated meta-analysis of 53 RCTs of antidepressants and psychological therapies reached the same conclusion: significant heterogeneity, funnel plot asymmetry, lack of blinding, and treatment effects that may be overestimated as a result (Ford 2019).

And access is the app's real argument. Trained gut-focused hypnotherapists are scarce. The Manchester group, who developed the protocol, wrote that roughly 25% of people with functional GI disorders have symptoms refractory to existing therapies, and identified the shortage of adequately trained hypnotherapists as one of the field's main gaps (Vasant 2019; Peters 2015). If the realistic alternative where you live is a two-year wait or nothing at all, the comparison is not app versus therapist. It is app versus nothing.

One conflict-of-interest note, since I am citing the Manchester group repeatedly: their review declares that over the preceding three years one author had consulted for Allergan and Shire, and the other had consulted for or received research funding from Danone, Allergan, Ironwood and Salix (Vasant 2019).

A twelve-week way to test it on yourself

The trial ran six weeks, so six weeks is the honest test. But if you want a result you can interpret rather than a vibe, give it a baseline and a follow-up. This is a self-assessment structure, not a treatment plan, and none of it replaces advice from your own clinician.

Three things make this work better:

1. Do not start anything else at the same time. One Reddit poster began the app and a two-week antibiotic course simultaneously, which makes the result uninterpretable, and they said so themselves. If you change diet, medication and add hypnotherapy in the same fortnight, you will never know which one did it.
2. Use a scored instrument, not a feeling. IBS-SSS was validated on 141 patients and 40 controls, with a 50-point change identified as reliably indicating improvement (Francis 1997). Our guide on knowing whether your IBS is flaring covers using it as a personal threshold rather than a diagnostic number.
3. Log in the moment, not from memory. Recalled symptoms drift toward whatever you currently believe. A tracker like Clairop lets you log a meal or a symptom by voice in a few seconds and produces a summary you can take to an appointment, which is what makes a before-and-after comparison worth anything.

Is it worth paying for?

I am not going to quote a price. Nerva's pricing has changed repeatedly, differs by country, and threads in r/ibs record complaints about a shift to annual billing and about discount offers arriving after people cancelled the free trial. Any number here would be wrong for somebody reading it next month.

What you can assess is what you are buying:

• You are buying a fixed recording, not a therapist. Same sessions for everyone, no adaptation to your subtype or your particular fear.
• You are buying a six-week commitment that most people do not finish. About 31% persisted in the published real-world analysis (Simicich 2024). Be honest about whether you will do 42 consecutive days.
• You are buying an intervention with one company-funded positive RCT whose hypnotherapy-specific effect is about one extra responder in six on symptom score, and roughly one in three on pain (Anderson 2025).
• You are buying something with a very low risk profile. Across eight RCTs and 238 people receiving hypnosis, exactly one dropped out because of an adverse event, a panic attack, which is 0.4% (Schaefert 2014). That is not zero, but it is about as benign as active treatments get.

If money is the binding constraint, note that the other digital brain-gut approach with trial evidence is web-delivered CBT, which in the publicly funded ACTIB trial reduced IBS-SSS by 35.2 points more than usual care at 12 months with only minimal therapist support (Everitt 2019). Availability varies enormously by country, and in some places this is something to ask a GP about rather than something to buy.

What a hypnotherapy app cannot do, and when to see a doctor

Nerva's own site is clear that it "is not a substitute for professional medical care, diagnosis, or treatment" (Mindset Health). Take that seriously, for three specific reasons.

It cannot tell you your diagnosis is right. Every trial discussed here recruited people who already had an IBS diagnosis made by a clinician. NICE sets out a diagnostic process involving symptom criteria plus blood tests including full blood count, inflammatory markers and coeliac antibodies, specifically to exclude other conditions (NICE CG61). An app skips all of that.

It cannot treat inflammation. Some people in these threads have inflammatory bowel disease as well as IBS-type symptoms. Hypnotherapy does not act on inflammation, and the trials above did not enrol people with active IBD.

It cannot spot a red flag. No self-guided program can.

Myths about Nerva

"81% of people get better on Nerva." Not as a statement about the hypnotherapy. 81% is the response rate in the hypnotherapy arm, and 63% of the active control arm responded too (Anderson 2025).

"Digital gut-directed hypnotherapy is proven, full stop." It is not. The other randomised trial of a digital gut-directed hypnotherapy program, Regulora, missed its primary endpoint: 30.4% versus 27.1% on digital muscle relaxation, p = 0.5352 (Berry 2023). One positive trial and one failed trial is the accurate state of the field.

"It is FDA approved." No. Nerva's site states it has not been evaluated by the FDA, TGA, MHRA or equivalent bodies.

"It only works if you believe in hypnosis." Nothing in the evidence supports that. Mechanism studies have found no change in motility (Lindfors 2012) or in rectal sensitivity and autonomic function (Palsson 2002), and the field's own reviews describe the mechanism as unresolved (Palsson 2015). Scepticism is not a documented predictor of failure, and neither is enthusiasm a documented predictor of success.

"It proves food does not matter." The head-to-head trial found gut-directed hypnotherapy and the low FODMAP diet produced similar symptom improvement, with no additive benefit from combining them (Peters 2016). Similar is not superior. If you go down the dietary route, keep it short and structured with reintroduction, ideally with a dietitian, and see how long to stay on low FODMAP.

"It is just meditation with a subscription." People who have done both usually disagree, and so does the literature: gut-focused hypnotherapy uses a structured induction, deepening and gut-specific suggestion sequence that general relaxation does not (Vasant 2019). That said, the Regulora trial compared it with muscle relaxation and could not separate them on its primary endpoint, so the distinction is clearer in theory than it is in trial data.

"It fixes the anxiety too." In its own trial, psychological symptoms improved similarly in both arms. The hypnotherapy-specific gain was in gut symptoms and pain. If anxiety around symptoms is your main problem, IBS anxiety about leaving the house covers the approaches with more direct evidence for that.

"It is only for adults with mild IBS." The trial population was in the severe range at baseline, with median IBS-SSS above 300 in both arms. Separately, gut-focused hypnotherapy delivered in clinic has been used in adolescents, with 28 of 32 responding in one tertiary-centre series, though that was uncontrolled and involved 12 therapist-led sessions rather than an app (Vasant 2021).

The honest bottom line

Nerva is one of a small number of gut apps with a published randomised controlled trial, and that trial was positive on its primary endpoint. That puts it well ahead of almost everything else marketed to people with IBS.

The trial's real contribution is the control arm. By running the same program without hypnotherapy for the same 42 days, the researchers showed that most of the improvement people experience on this app is not the hypnotherapy. The hypnotherapy adds about 18 percentage points on symptom score and about 36 on pain, in a study funded by the company that sells it.

Meanwhile a competing digital gut-directed hypnotherapy product tested against digital muscle relaxation failed its primary endpoint, roughly two-thirds of real-world Nerva users do not persist with the program, and the wider psychological-therapy literature warns that its own effect sizes are probably overestimated because of poor blinding and publication bias.

None of that makes it a bad option. Gut-directed hypnotherapy is one of the few IBS treatments with a decades-long trial record, it is recommended in guidelines, its risk profile is very low, and getting it from a therapist is difficult almost everywhere. If you have an IBS diagnosis you trust, you have already worked through diet, and you can realistically commit to daily sessions for six weeks, it is a reasonable thing to test on yourself with a scored baseline.

Just test it knowing that the 81% on the website was never the hypnotherapy's number alone.