276 reviews

Functional Activator

The Functional Activator is a sealed mewing mouth guard that trains tongue posture. Its double-arch design guides your tongue to rest on the roof of your mouth, and because it has no breathing holes, it encourages nasal breathing.

SIZE GUIDE

Find Your Perfect Fit

The right size makes the Functional Activator comfortable enough to wear every night. Use the guide below to choose yours.

Functional Activator

Measure the distance in a straight line from the outer edge of one canine tooth to the outer edge of the opposite canine tooth.

A smile with the right and left canine teeth marked and a double arrow between their outer edges reading 36 millimetres

Designed to support proper tongue and jaw position overnight.

Small, Medium and Large shown side by side, each a smile measured between the canine teeth at 28, 36 and 42 millimetres
SizeMeasurement
Small33 millimetres or less
Medium34 to 37 millimetres
Large38 millimetres or more

Not sure? Refer to the detailed guide with measurements and photos.

View complete Functional Activator size guide

Still unsure?

Our team is here to help you choose the right size.

Contact support
Sale price: $279.00 Regular price:$329.00Save $50

Size Small selected

Functional Activator
$279.00$329.00

How to use your Functional Activator

Follow these simple steps.

  1. Start Gradually

    Give your mouth time to adapt to your mewing mouth guard.

    Start with 15 to 20 minutes, 2 to 3 times during the day. Increase your wear time gradually as the Functional Activator becomes more familiar.

    Woman squeezing the sides of the Functional Activator mouth guard to place it over her teeth
  2. Relax, Don't Bite

    Let the tongue posture device do the work.

    Place the Functional Activator comfortably in your mouth. Keep your jaw relaxed and your lips gently closed. You do not need to clench or bite down to keep it in place.

    Close-up of lips around the Functional Activator mouth guard, shown open and then closed
  3. Tongue Up. Breathe Through Your Nose.

    This is the tongue posture you are working toward.

    Let your tongue rest gently against the roof of your mouth, with your lips closed and your jaw relaxed. Breathe through your nose comfortably rather than forcing the position.

    Illustration of a woman's head in cross-section wearing the Functional Activator mouth guard, with her tongue resting against the palate and air flowing in through the nose

The Only Mouthguard That Addresses Tongue Posture

Poor tongue posture is the hidden cause of mouth breathing, jaw clenching, and forward head position. Regular night guards ignore it completely. The Functional Activator trains your tongue to rest at the roof of your mouth while you sleep. This opens your airway, relaxes your jaw, and lets your body actually recover overnight.

Choose the size that fits your mouth.

One measurement decides it. Take the reading, find the row it falls in, and that row is your size. If the reading sits on a boundary, the full guide shows how to resolve it.

Sizes and the measurement each one suits
Small 33 millimetres or less Younger users or smaller mouth size.
Medium 34 to 37 millimetres Most adults. Fits the majority.
Large 38 millimetres or more Larger mouth size or broader jaw.

Small

33 millimetres or less

A smile measured between the canine teeth, reading 28 millimetres
Younger users or smaller mouth size.

Medium

34 to 37 millimetres

A smile measured between the canine teeth, reading 36 millimetres
Most adults. Fits the majority.

Large

38 millimetres or more

A smile measured between the canine teeth, reading 42 millimetres
Larger mouth size or broader jaw.

Small, Medium and Large, with the mouth size each one suits.

A mother and her young son sitting together, holding the Functional Activator

Buying the Functional Activator for your child?

Get a little more guidance before you begin.

If you're unsure whether your child's jaw is developing evenly, you can submit five simple photos for review and receive guidance on whether additional functional support may be appropriate.

I just want the
Functional Activator

Continue with the Functional Activator and standard usage instructions.

CONTINUE SHOPPING

GET GUIDANCE FOR YOUR CHILD

I'd like guidance
for my child

Take five guided photos of your child's face and bite to begin a functional review.

Takes about 5 minutes. No diagnosis from photos.
Your images are reviewed as part of the assessment process.

Functional Activator

Frequently Asked Questions

Measure from molar to molar using dental floss. Place the floss against a ruler.

  • Under 33mm = Small
  • 34-37mm = Medium
  • Over 38mm = Large

The Functional Activator reveals imbalances in your bite that were already there. If your jaw closes unevenly, say, your back molar on one side touches before the other, that asymmetry gets amplified during wear. You're not creating a problem. You're feeling one that was hidden.

This is actually useful information. It tells you where your jaw is compensating. Most people find the soreness decreases within 1 to 2 weeks as the tongue repositions and jaw tension releases.

If soreness persists in one specific spot: You may have a significant bite asymmetry worth addressing with a practitioner.

Your mouth has adapted to incorrect tongue posture, possibly for decades. The Functional Activator puts your tongue where it should be, which can feel unfamiliar.

Start with 5 minutes during the day. Increase gradually. Most people adapt within 1 to 2 weeks.

Trim if needed: Use scissors to remove 1mm from any edge pressing into your gums. Keep the wave shape intact.

It's designed that way. The Functional Activator is wider than your jaw on purpose. It's made from flexible material that adapts to your mouth.

How to insert:

  • Squeeze the sides together with your thumb and index finger
  • Place your upper and lower teeth into the gutters while still squeezing
  • Bite down gently to find your position
  • Release your fingers. The activator expands to fit your jaw width

It should feel snug, not forced. The width self adjusts once you release.

Start with 5 minutes during the day. Your mouth has adapted to incorrect tongue posture, possibly for decades. The correct position feels unfamiliar at first.

If the edges press into your gums: Trim 1mm at a time with scissors. Keep the wave shape intact.

Most people adapt within 1 to 2 weeks.

Customer Reviews

5.0 Based on 263 Reviews
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A Posturepro Customer
EM
Evelyn M.
05/29/2016

I have learned to live with neck pain my whole life. This device changed that! I recommend ++

A Posturepro Customer
PB
Prince B.
02/14/2016

A Posturepro Customer
JL
Jean-sebastien L.
06/11/2016

Smooth on the teeth. I am stronger with this when I train. Really nice.

A Posturepro Customer
HF
Hubert F.
05/28/2016

No more clenching!!! Amazing.

B
Brabara
Canada Canada
I recommend this product
03/14/2021

Impressive

I’ve tried many mouthguards in the past and this one has really really made a great difference for me.