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Why Units Might Vary for Botox Lip Flip

February 27, 2023

A “lip flip” is a procedure that uses botox to tighten muscles between the nose and upper lip, which can make the lips appear fuller and eliminate a “gummy smile” and/or fine lines above the lip. Most experts say you need 4 to 6 units of botox for the procedure, but there is a lot of variation among sources out there. Read on to find out why the amount of botox used at the injection site might vary, how a lip flip differs from other cosmetic treatments–especially dermal fillers–and potential downsides to botox procedures.

Lip Flip Vs. Lip Fillers

A lip flip uses botox injections to essentially weaken the orbicularis oris muscle between the upper lip and nose. Botox is technically known as a “neuromodulator” because it stops or slows down neurons that carry messages between nerves and muscle tissue. It is approved by the Food and Drug Administration for use on “glabellar lines”, i.e. the wrinkles that form between your eyebrows, crow’s feet, and forehead wrinkles. But medical professionals are able to use the medication “off label” for other cosmetic procedures, and that includes the botox lip flip procedure.

A good candidate for a lip flip is someone who wants to give a subtle enhancement to their top lip, especially if they are looking to eliminate or reduce a gummy smile. The procedure can also help get rid of vertical lip lines that can appear above the “cupid’s bow” at the top of the lip.

Typically, lip augmentation involves some kind of dermal filler, like hyaluronic acid. Both botox treatments and hyaluronic acid-based fillers are injected by needles, but they differ the following ways:

How They Work

Botox lip flip treatment: Weakens muscles to reduce movement
Dermal fillers: Increases lip volume, typically with hyaluronic acid

How Long They Last

Botox: 2-4 months
Dermal fillers: 6-12 months

How Much They Cost

Botox: Depends on number of units, but at $10-$15 per unit and 4 to 6 units as the norm, often below $100
Dermal fillers: A full syringe of fillers can cost between $500 and $1000

Where They Work

Botox: Just the upper lip
Dermal fillers: Upper and lower lip

before and after of botox lip flip procedure

How Many Units? It Depends

Most sources we checked out recommended 4 to 6 units for a standard lip flip, which is a relatively small amount of botox when comparing to injections done in other parts of the face. Some recommended a lot more — up to 10.

The manufacturer of botox, Abbvie, recommends four units per injection site for FDA-approved use, and no more than 400 units in a three-month period. Since the lip flip is not an FDA-approved use of botox, the manufacturer hasn’t made an official recommendation on how much botox to use for the procedure.

The American Board of Facial Cosmetic Surgery says 4-6 units is standard for the lip flip. But they added that if you are getting the procedure to reduce how much of your gums are visible when you smile, the number of units can vary between 2 and 8 and is “determined in proportion with the amount of gum visible while smiling.” They also reference a study that used an average of 5 units of botox to treat a gummy smile.

Physicians posting on RealSelf generally said the number of botox units can vary on a case-by-case basis, depending on patients’ desired results, the strength of the facial muscles in the treatment area, and their individual metabolism.

And like other cosmetic injection procedures, the FDA recommends that you only go to a licensed medical professional. Some states require physicians–like a plastic surgeon or dermatologist–nurses, and/or physicians’ assistants do the injections.

map showing orbicularis oris muscle around mouth

Downsides and Risks

The side effects associated with botox are minimal, which is a big part of the reason the procedure is so popular. The most common side effects are minor bruising and swelling. However, the American Board of Facial Cosmetic Surgery outlined some downsides to the procedure, most notably that you may have difficulty “spitting, whistling, and pronouncing certain words.” That’s because the procedure weakens the muscle that controls your top lip. They warn that if you “sing, teach, talk, or lecture for a living, carefully weigh the risk of having temporarily impaired lip function against the benefit of a defined lip.”

The only other warnings that regularly accompany the botox lip flip procedure is that it may be too subtle for some, and it doesn’t last as long as dermal fillers.