Zyppah Reviews: What the 91% Claim Actually Means
If you searched for Zyppah reviews, you have already seen the number. 91%. Clinically proven. Peer reviewed. It is on the box, in the ads, and on the product page, and for most buyers it is the reason they reach for a card.
So I pulled the study.
The 91% is in there. It is real, and it is published. But it does not say what the advertising says it says, and the difference is the whole ballgame.
Read this first. I am David Hernandez, founder of VitalSleep. We sell a competing anti-snoring mouthpiece. I am not a neutral reviewer and you should not treat me as one. Every claim below is sourced to a document you can open yourself. Check my work. Last reviewed: July 12, 2026. If you believe anything on this page is inaccurate, email support@vitalsleep.com and I will correct it.
What Zyppah Is
Zyppah is a hybrid mouthpiece. Part mandibular advancement device, meant to move the lower jaw forward, and part tongue retaining device, using a rubber strap the company calls a seatbelt for the tongue.
It is FDA-cleared, made in the USA, and fitted with a boil-and-bite mold. It was created by Dr. Jonathan Greenburg, a dentist. It runs about $100, most users replace it every 9 to 12 months, and it carries a 91-day guarantee.
The tongue strap is the pitch. Zyppah's argument is that everyone else moves your jaw and stops there, while they also handle the tongue.
The 91% Says Something Softer Than You Think
Zyppah's site states that the trial demonstrated a 91% success rate at stopping snoring.
Here is the sentence in the paper:
91% of users reported benefits from the device.
Read those two side by side.
Reporting a benefit is not the same as stopping snoring. A benefit could be sleeping a little better. It could be a partner saying it was not as bad. It is a satisfaction response on a questionnaire, and it is the softest, most generous measure in the entire paper.
The study did measure actual snoring, and it reported those results too:
| What was measured | Reported improvement |
|---|---|
| Snoring Severity Scale | 67% |
| How much the snoring bothered the partner | 60% |
| Frequency of snoring | 57% |
| How much the snoring bothered the individual | 52% |
Sixty-seven percent. Sixty. Fifty-seven. Fifty-two.
Those are the numbers on snoring. The number on the box is the one that measures whether people liked it.
I am not calling that a lie. It is in the paper, word for word. I am saying the strongest-sounding figure they own is the one that promises the least, and it is the only one you ever see.
Who Ran the Study
The trial is registered as NCT03128307. The sponsor is Zyppah, Inc. The principal investigator is Dr. Jonathan Greenburg.
Dr. Greenburg is the founder and CEO of Zyppah.
The paper discloses this plainly, and I want to be fair about what it means. Company-funded research is normal. Founders run trials on their own devices all the time, and disclosure is exactly what you are supposed to do. Zyppah did it.
But it is context you deserve when a company tells you its product is the only one with a clinical trial. The trial was theirs. Their CEO was the investigator. There was no control group, the follow-up was ten days, and the data came from an online questionnaire the participants filled out about themselves.
That is not a fraud. It is a customer satisfaction survey with a journal citation attached.
The Jaw Question
Here is the part I keep turning over.
The paper describes the device as one that restrains the tongue, and it distinguishes it from traditional mandibular repositioning devices. Restraining the tongue is presented as the mechanism, and as the thing that makes it different.
The marketing sells jaw advancement as half the product. The 2-in-1. The lower jaw propped gently forward.
I do not know how to square those. Maybe the device does both and the paper simply emphasized the novel half. That is plausible. But the study built to prove the product works talks about the tongue, and it sets the device apart from the jaw-moving category.
If jaw advancement is a reason you are buying, that is a question worth putting to them directly before you spend the money.
What Buyers Actually Report
How to read this. These are themes from comments posted publicly by individual users. They are those people's opinions, not my findings. I have not verified anyone's identity or confirmed they used the product. Experiences vary.
The tongue strap is the dividing line. Nearly everything in Zyppah's feedback comes back to it. The people it suits tend to be loud advocates. The people it does not describe gagging, or an inability to tolerate the sensation, or pulling it out at two in the morning without remembering doing it.
Zyppah does not hide this. Their own site acknowledges that some customers initially struggle to get comfortable. That is honest of them. It is also an admission that a real share of buyers cannot live with the strap.
If you have a strong gag reflex, think hard about this one.
Beyond the strap, the recurring notes are familiar: some find the fit bulky, most need a week or two to adapt, and the device wears out in 9 to 12 months at roughly $99.95 to replace. Budget for it as a yearly cost, not a purchase.
The Question Almost No Review Asks
Snoring stops when the lower jaw is advanced far enough to open the airway. How far is far enough is different for every person alive. It depends on your anatomy and how your airway collapses.
So the only question that really matters is this: after you fit the thing, can you change how far forward it holds your jaw?
With Zyppah, the position comes from the mold. The Sleep Foundation states the Zyppah mouthpiece is not laterally adjustable, though it does offer a boil-and-bite custom fit. Zyppah does not advertise a graduated advancement mechanism anywhere I could find.
So you get one setting. If it is close but not enough, there is no next step. There is only a return.
Why I Built Mine the Way I Did
I have sold snoring mouthpieces since 2011. Over 600,000 customers. In fifteen years the most common thing I hear is not "it did not work."
It is "it worked a little."
That is an adjustment problem. The jaw was not forward enough. And if the device cannot move, neither can the person wearing it.
VitalSleep advances the lower jaw in 1mm steps, up to 8mm, with a built-in screw mechanism. You move one small step at a time until the snoring stops, then you leave it alone. No strap. No part to reorder.
| Feature | Zyppah | VitalSleep |
|---|---|---|
| Device type | Hybrid: jaw plus tongue strap | Mandibular advancement device |
| Jaw adjustment after fitting | Set by the mold | Accu-Adjust, 1mm steps up to 8mm |
| Tongue strap | Yes. The core mechanism | No |
| Custom fit | Boil-and-bite | Boil-and-bite, remoldable |
| Regulatory status | FDA-cleared | FDA-cleared |
| Where it is made | USA | USA |
| Sizing | One size | Men's and women's sizes |
| Guarantee | 91-day guarantee | 60-night guarantee, 1-year warranty |
| Evidence | Company-sponsored study, 570 users, 10 days | 600,000+ customers served since 2011 |
Their guarantee window is longer than mine. I am telling you that because it is true and you would find it in thirty seconds anyway. And no, I have not run a clinical trial. They have. I would rather say that out loud than pretend otherwise.
Put them side by side yourself in the full snoring mouthpiece comparison, and read what our customers say, including the ones who were not happy.
So Should You Buy Zyppah?
If your snoring is driven by your tongue, and you can sleep with a strap holding it down, Zyppah may genuinely be your device. The tongue is a real cause of snoring and very few products go at it directly. Some people swear by this thing.
Just go in with your eyes open.
The 91% measures whether people reported a benefit, not whether they stopped snoring. The snoring numbers are 67, 60, 57 and 52.
The study was sponsored by Zyppah and led by Zyppah's CEO, over ten days, by questionnaire, with no control group.
Whatever jaw position your mold sets is the one you keep. There is no adjustment if it falls short.
Ask me the same kind of questions. Ask everyone in this category. The company that answers you straight is the one that has earned the sale.
Want a mouthpiece you can actually adjust?
VitalSleep is FDA-cleared, made in the USA, molded to your bite, and adjustable in 1mm steps up to 8mm. 60-night guarantee. 1-year warranty.
See VitalSleepFrequently Asked Questions
Is Zyppah FDA-cleared?
Yes. Zyppah is FDA-cleared and made in the USA. Clearance means the device was reviewed for its intended use. It does not mean it will work for you.
Is Zyppah really 91% effective at stopping snoring?
The study reports that 91% of users reported benefits from the device. That is a satisfaction measure, not a measure of snoring stopping. The study's snoring measures improved 67%, 60%, 57% and 52%. Zyppah's marketing describes the 91% as a success rate at stopping snoring, which is a stronger claim than the sentence in the paper.
Who ran the Zyppah clinical study?
The trial is registered as NCT03128307. Zyppah, Inc. sponsored it, and the principal investigator was Dr. Jonathan Greenburg, Zyppah's founder and CEO. The paper discloses this. It ran ten days, used a self-reported online questionnaire, and had no control group.
Does Zyppah move your jaw forward?
Zyppah's marketing says it advances the lower jaw. The study describes the device as one that restrains the tongue and distinguishes it from traditional mandibular repositioning devices. If jaw advancement is why you are buying, ask Zyppah to clarify.
Can Zyppah be adjusted after fitting?
The jaw position is set by the boil-and-bite mold. The Sleep Foundation states the device is not laterally adjustable, and Zyppah does not advertise a graduated advancement mechanism. If the initial position is not enough, there is no further setting.
Is the tongue strap uncomfortable?
It depends on the person. Some adapt quickly. Others report gagging or an inability to tolerate it, and Zyppah's own site acknowledges that some customers initially struggle to get comfortable. If you have a strong gag reflex, weigh this carefully.
How long does Zyppah last?
Most users replace it every 9 to 12 months, at roughly $99.95 for a replacement. Treat it as a recurring yearly cost.
What is a good alternative to Zyppah?
If you want jaw advancement you can adjust after fitting, with no tongue strap, look at VitalSleep. It is FDA-cleared, made in the USA, and adjusts in 1mm steps up to 8mm, with a 60-night guarantee and a 1-year warranty. I make it, so weigh that accordingly.
Sources and disclaimers. Study: Cozean J, Greenburg J, Cozean C (2019), Novel Anti-Snoring Mouthpiece to Reduce Snoring in At-Home Study, Journal of Sleep Disorders and Management 5:022. Trial registration: NCT03128307. Marketing claims quoted from Zyppah's own website. Adjustability sourced to the Sleep Foundation's published review. Zyppah is a trademark of Zyppah, Inc. VitalSleep is not affiliated with, sponsored by, or endorsed by Zyppah, and Zyppah has not reviewed this page. Product features, pricing, and policies change. Verify current details with the seller before purchasing. Information current as of July 12, 2026. VitalSleep is intended to reduce snoring in adults. It is not intended to diagnose, treat, cure, or prevent sleep apnea or any medical condition. If you experience gasping, choking, or pauses in breathing during sleep, speak with a qualified healthcare professional.
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