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Posted 6th Mar 2024

What is the Keyhole Lip Filler Technique?

TOP BOX Keyhole Lip Filler Technique Advice - Harley Academy medical aethetics training courses London UK doctors dentists nurses clinical pharmacists

What is the keyhole lip filler technique? Dr Janine Rothburn – clinical trainer and aesthetics specialist – answers the most frequently asked questions regarding approaches, tools and patient assessment.

Lip fillers are one of the most popular injectable treatments. The keyhole technique is an approach that, as aesthetics practitioners, you can add to your skill set to enhance your offering.


What is the keyhole lip filler technique?

“The keyhole lip filler technique is where the lips are filled with a small gap in the centre where the top and bottom lip meet. This makes it look like a keyhole”, Dr Janine states.

Is this technique safe and valid?

Dr Janine explains, “Yes, this is a safe and valid technique. It uses hyaluronic acid (HA) based dermal filler to create a space between the lips that can be seen when the lips are at rest. However, it’s a ‘trend’ and in general we need to consider the pros and cons.”

When to use the keyhole approach to lip filler

“This technique is mostly used if the patient naturally has – or had when they were younger – a small gap between their upper and lower lips at rest. If they want to enhance this feature then the keyhole lip filler technique is a good option for them,” Dr Janine notes.

‘Fighting’ baseline structure of the lip is usually futile and can set patients up for unrealistic expectations, so should be avoided.


Patient selection for keyhole lips

“Managing expectations in aesthetic medicine is paramount to the relationship between the patient and the injector,”points out Dr Janine.

“Good candidates are those who are aware that no result is the same. We can only really enhance one’s natural, pre-existing anatomy.”

Age, gender and ethnicity play a crucial role in patient selection, as well as using the right approach. For example, more mature aesthetics patients may require a different technique to your usual lip filler injections.

She further highlights, “Patients with a natural keyhole pout at rest will achieve better results with this technique. They will also have a more noticeable result.”

The best injection techniques and product selection for keyhole lips

Dr Janine states, “The key – pun intended – is to inject filler into the lips, ensuring it looks natural.

“The filler is injected slightly more laterally, leaving a midline ‘deficiency’ instead of complete fullness across the whole lip. After the treatment, there should be a natural-looking tiny gap between the upper and lower lips.

“Some injectors use dental floss or a piece of string in between the upper and lower teeth

and inject around this.” This appears unlikely to prevent filler movement in the dynamic lip post-procedure, so theoretically has limited impact on the overall outcome.

She continues “A needle or cannula could be used for this injection technique, ensuring a soft or medium filler is used to create more natural results.” You could argue that a needle will give more precise control of the final look. However a cannula may be considered safer, so this is up to injector preference.

By understanding the basic rheological properties of dermal fillers, including G prime, you'll be able to choose the best filler type from any range. This means you won't be beholden to a specific brand. You can learn more about lip filler product selection in our article on how to choose the correct filler type for each treatment area.

How to Inject Lip Filler Safely and Effectively

Considerations when treating lip filler patients

Dr Janine explains, “Keyhole lip filler is a trend and it’s important to be cautious with such trends in aesthetic medicine. As medical aesthetics practitioners, our goal is to enhance pre-existing anatomy. What looks good on one patient, may not suit another.

“There are techniques that we can use to help change the shape of the lips and create definition. However, in some cases, this can look unnatural.”

She continues, “If you believe your patient has unrealistic expectations, my advice would be not to treat.” Turning away patients can feel daunting, however, it’s important to trust your instincts.

Develop your lip filler expertise through mentoring

If this is an area you’re struggling to treat, you may want to grow your injecting confidence with targeted aesthetics training. Our Perioral & Lip Filler Masterclass will teach you to safely and ethically rejuvenate the perioral and lip region. You’ll also be able to master your needle and cannula lip filler injection techniques in a small group of your peers. As well as observing a narrated demonstration by an aesthetics specialist, you’ll treat your own patient under specialist supervision and learn about complications management.

For broader, Master’s level aesthetics training, our Level 7 Diploma in Botox & Dermal Fillers is open for doctors, dentists, nurses and clinical pharmacists. You’ll learn all about different injecting techniques and even get your own patients to treat, under the watchful eye of your mentor.

Want to hear more about what medical aesthetics training we offer? Book a call with one of our course advisors and they’ll help find the perfect path for you.

All information correct at the time of publication

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