From 'Top-Ups' to Long-Game: How Often You Really Need Botox, Filler, Skin Boosters and Collagen Stimulators

Written By Analytics Sandstorm

By Alice Henshaw, RN, NMP, Founder and Medical Director, Harley Street Injectables

Key Takeaways

  • Anti-wrinkle injections (Botox, Alluzience) typically last three to four months, but the right interval depends on the area treated, your metabolism, your muscle strength, and your treatment history. The minimum safe interval is 12 weeks, and treating more frequently increases the risk of developing neutralising antibodies1Neutralising antibodiesImmune proteins the body can develop in response to repeated botulinum toxin exposure that block the toxin's action. that can make the treatment stop working altogether.
  • Dermal filler does not dissolve as quickly as we once thought. MRI evidence from Master et al. (2024) in Plastic and Reconstructive Surgery Global Open confirmed hyaluronic acid2Hyaluronic acid (HA)A naturally occurring molecule in the skin that attracts and retains water. Most dermal fillers are HA-based. filler presence in all 33 mid-face patients studied, persisting for two to 15 years after injection.
  • Skin boosters like Profhilo work on a different cycle: two sessions four weeks apart, then maintenance every six months. They are not fillers. They do not add volume. They improve skin quality from within.
  • Collagen stimulators (Sculptra, JULÄINE) require an initial course of two to three sessions, then annual or biannual maintenance. Results build gradually and last two years or more.
  • More is not always better. Over-treating is one of the most common mistakes in aesthetic medicine, and it is almost always driven by treating to a schedule rather than treating to a need.

I get asked this question more than almost any other. Not "what should I have done?" or "how much does it cost?" but "how often do I need to come back?"

It is a completely reasonable question. You are investing time and money. You want to plan ahead. You want to know what you are committing to before you start.

And the answer you will find on most clinic websites is maddeningly vague. "Results vary." "Everyone is different." "Your practitioner will advise." All true, all unhelpful.

So here is what I actually tell my patients at Harley Street Injectables, based on over a decade of treating faces, correcting other people's work, and watching how these products behave in real tissue over real time. I am going to be specific. I am going to give you the numbers. And I am going to be honest about the places where I think the industry has been getting the intervals wrong.

Why Duration and Intervals Actually Matter

Before we get into the specifics, I want to explain why this matters beyond simple logistics.

Treatment intervals are not just about maintaining a look. They are a medical consideration. Every injectable product you put into your body triggers an immune and biological response. The frequency of that exposure matters.

With anti-wrinkle treatments, injecting too frequently increases your cumulative dose3Cumulative doseThe total amount of a product you have received across all treatment sessions combined. of the botulinum toxin4Botulinum toxinThe purified protein used in anti-wrinkle injections. It temporarily blocks nerve signals to muscles, preventing dynamic wrinkles. protein, which raises the risk of developing neutralising antibodies. A literature review by Lee et al. (2024) in Life examined immunogenicity across multiple clinical and cosmetic indications and found that the incidence of neutralising antibody formation was significantly higher in patients receiving repeated injections (14.5%) compared to those receiving fewer treatments (4.5%). The total cumulative dose and the number of treatment cycles were identified as critical risk factors. Once your body develops these antibodies, the treatment simply stops working, sometimes permanently.

With dermal fillers, the risk runs in the opposite direction. We now know that hyaluronic acid filler persists in tissue far longer than we were originally taught. Years, not months. If you are topping up on a product that has not fully metabolised, you gradually accumulate volume, and the result is that slow, insidious drift toward the overfilled look that nobody wants but too many people end up with.

Getting the interval right protects your results, your safety, and your long-term relationship with these treatments. It is not a minor detail. It is arguably the most important variable in the whole plan.

How Long Botox Realistically Lasts in Different Areas

Let me start with the treatment I perform most often: botulinum toxin, which most people call Botox, though we also use Alluzience at the clinic, a newer formulation without complexing proteins5Complexing proteinsAdditional proteins in some botulinum toxin products. Alluzience is formulated without these..

The standard answer is "three to four months." That is broadly correct but also an oversimplification. Here is what I actually observe.

Forehead and frown lines tend to last three to four months for most patients. These are high-movement areas. You use your frontalis and corrugator muscles constantly, often without realising it. The toxin is working against significant, repetitive force, and it wears off accordingly.

Crow's feet can often last a little longer, closer to four months for many patients, because the orbicularis oculi tends to be a thinner muscle that does not generate the same contractile force as the forehead complex.

Jaw slimming and bruxism is where things get interesting. The masseter is a very large, powerful muscle. The first treatment might last only two to three months as the muscle fights back. But with consistent treatment, the masseter actually atrophies (thins), which means subsequent treatments tend to last progressively longer. I have patients who started on a 12-week cycle and are now comfortably at 16 to 20 weeks between sessions.

Trapezius Botox (Traptox) follows a similar pattern to masseter work. The initial treatment may need refreshing at three to four months, but with repeated sessions the muscle responds with longer-lasting relaxation.

Lip flip and chin treatments use smaller doses in smaller muscles, and the effect can be shorter, sometimes only six to eight weeks. This is normal and does not mean the treatment has failed.

The 12-Week Rule

Here is where I want to be direct, because I know other clinics do this differently.

At Harley Street Injectables, we do not treat with botulinum toxin more frequently than every 12 weeks. This is a firm clinical policy, not a guideline.

The reason is immunological. Torres et al. (2013), publishing in Clinical, Cosmetic and Investigational Dermatology, reported five cases of patients who developed neutralising antibodies after repeated aesthetic botulinum toxin injections, resulting in complete secondary treatment failure. The same study found that, compared to non-resistant patients from the same cohort, these five individuals had received more frequent injections, more "top-up" sessions two to three weeks after initial treatment, and higher cumulative doses.

That paper is from 2013, and since then the evidence has only grown stronger. The Lee et al. (2024) review I mentioned earlier pooled data across 24 studies and confirmed the dose-dependent pattern: more frequent exposure means more antibody risk.

What does this mean practically? If your Botox is wearing off at ten weeks, the answer is not to come back at ten weeks. The answer is to adjust your dose, your technique, or your product at your next 12-week appointment. A skilled practitioner can almost always extend your duration without shortening your interval. That might mean slightly higher doses in specific areas, treating the muscle from different injection points, or switching from onabotulinumtoxin (Botox) to abobotulinumtoxin (Alluzience), which has a different protein profile.

Two-week "top-ups" are, in my view, one of the worst practices in aesthetic medicine. By the time you are two weeks post-injection, the nerve endings are already fully blocked. Any additional toxin you inject at that point is not being taken up meaningfully. You are adding antigen load to your immune system for no clinical benefit.

A Note on "Baby Botox"

Baby Botox uses lower doses for a more subtle, movement-preserving effect. The trade-off is that it may wear off a little sooner, sometimes closer to ten weeks rather than 14. That is fine. You still wait until 12 weeks to retreat. The subtle look in between is part of the approach, not a failure of it.

Wondering if your Botox schedule is right for you? We will assess your muscle movement, review your treatment history, and build a plan that protects your results long-term.

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Filler Longevity by Site and Product Type

Now the one that nobody in the industry wants to talk about honestly. How long does dermal filler actually last?

The answer used to be simple: six to 12 months for hyaluronic acid fillers, up to two years for thicker products. That is what the manufacturers tell you. That is what most clinic websites still say. And it is, based on recent MRI evidence, significantly underestimating how long this product actually stays in your face.

Master, Azizeddin, and Master (2024) published a landmark study in Plastic and Reconstructive Surgery Global Open that used MRI scanning on 33 patients who had received hyaluronic acid fillers in the mid-face. Every single patient still had detectable filler present. Among them, 21 had not received any injections for two to five years, 12 for over five years, and some for up to eight to 15 years after their last treatment. No complete dissipation was observed in any patient at any time point.

Let me sit with that for a moment. Filler that was supposed to last 12 months was still visible on MRI 15 years later.

This does not mean the effect lasts 15 years. The cosmetic correction does diminish over time because the filler slowly integrates, spreads, and is partially metabolised. But the product is still there, occupying space. And if you keep topping up on top of product that has not gone, you are stacking volume. This is how you end up looking overfilled without anyone meaning for it to happen.

What This Means for Your Treatment Schedule

Here is how I approach filler longevity at the clinic, area by area.

Lip filler is the area that genuinely does metabolise fastest. The lips are highly vascular, constantly moving, and exposed to relatively more enzymatic activity. Most patients see a noticeable reduction in volume by six to nine months. A realistic maintenance schedule for lips is nine to 12 months, though some patients stretch to 14 or 15 months comfortably. The key is to assess what remains before adding more.

Cheek filler lasts considerably longer than most patients expect. In an area with less movement and deeper placement, cheek filler often maintains meaningful correction for 12 to 18 months, and as the MRI data shows, the product itself persists well beyond that. I typically reassess cheeks at 12 months and often find that patients need much less product than they had the first time. Sometimes they need none at all.

Chin and jawline filler sits on bone in most techniques. It is well-supported, subjected to less shear force than the lips, and tends to maintain structure for 12 to 18 months or longer.

Tear trough filler is the area where the persistence data is most clinically important. Under-eye filler, placed deep and in an area of low movement, can last for years. I have seen patients present to the clinic with filler placed elsewhere three or four years earlier that is still clearly visible and palpable. Our companion article on the modern under-eye toolkit discusses this in detail.

Nasolabial fold filler and marionette line filler sit somewhere in between: 12 to 15 months is typical, though again, the product persists longer than the visible correction.

Temple filler and hand filler can last 12 months or more, particularly when using thicker products placed deep.

The "Less, More Often" Trap

There is a school of thought that says it is better to use small amounts of filler frequently. A little here, a little there, every six months. It sounds conservative. It sounds cautious. And in practice, it is one of the most reliable ways to end up overfilled.

The problem is accumulation. If you add 0.5ml to the cheeks every six months, and the previous 0.5ml has not fully metabolised, you are stacking. After two years, you may have 1.5 to 2ml of product in a space that was only designed to hold one syringe. The effect creeps up gradually, so neither you nor your practitioner notices it until someone says "you look different" and does not mean it as a compliment.

My approach is the opposite. I prefer to do a full, proper correction with the right amount of product in one session, and then leave it alone for as long as possible. Reassess at 12 months. Photograph under clinical lighting. Compare to baseline. Only add more if there is a genuine, visible need.

This means some patients come back at 12 months and have a small amount added. Others come back at 18 months and need nothing. A few come back at two years and we do a modest refresh. The plan is driven by what the face needs, not by the calendar.

Concerned about filler accumulation? If it has been a while since your last treatment, or if you have had filler elsewhere and are not sure what remains, we can assess exactly where you stand before recommending anything.

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We photograph, compare to baseline, and only treat if there is a genuine need.

Skin Boosters: Course and Maintenance

Skin boosters are a different category entirely, and I think part of the confusion around treatment frequency comes from lumping them in with fillers. They are not fillers. They do not add volume. They improve skin quality.

Profhilo

Profhilo is the gold standard skin booster in the UK. It contains one of the highest concentrations of hyaluronic acid available in an injectable product, but it is formulated to disperse through the tissue rather than sitting in a specific location. It stimulates four different types of collagen and elastin production, hydrates from within, and improves skin tone, texture, and mild laxity.

The treatment protocol is standardised and evidence-based:

Initial course: two sessions, four weeks apart. This is non-negotiable. A single session of Profhilo gives you some hydration but does not trigger the full bio-remodelling cascade. The second session is the one that locks in the collagen and elastin stimulation.

Maintenance: every six months. Some patients with particularly good skin can stretch this to nine months. Others with more pronounced ageing, significant sun damage, or higher metabolic rates benefit from returning at five months. But six months is the standard, evidence-based interval.

There is a newer variant, Profhilo Structura, which provides slightly more structural support for the lower face and is ideal for jawline definition and mild jowling alongside the skin-quality benefits.

Skinvive by Juvéderm

Skinvive by Juvéderm is a microdroplet hydrator that works differently from Profhilo. It delivers modified hyaluronic acid into the superficial dermis in a grid pattern, providing improved smoothness and a "glass skin" quality. The maintenance schedule is similar, typically every six to nine months after the initial treatment.

Polynucleotides

Polynucleotides deserve a mention here because they function as a regenerative skin treatment, though they are not technically a skin booster. They are purified DNA fragments that stimulate fibroblast6FibroblastsThe cells in the dermis that produce collagen and elastin. activity, improve microcirculation, and regenerate skin quality from the cellular level.

The typical course is three sessions, three to four weeks apart. Maintenance is every six to nine months. I covered polynucleotides in detail in the tear trough article and the polynucleotides vs tear trough fillers comparison, so I will not repeat all of that here. But they are an important part of the modern maintenance plan, particularly for skin quality around the eyes, neck, and décolletage.

Collagen Stimulators: The Genuine Long Game

If skin boosters are about quality, collagen stimulators are about structure. These are treatments that trigger your body to build new, real collagen. The product itself is a vehicle. The result is biological. And the timelines are different from anything else we have discussed so far.

Sculptra (Poly-L-Lactic Acid)

Sculptra is the treatment I recommend most often for patients who want structural improvement without looking "filled." It works by triggering a controlled inflammatory response that stimulates the body's own collagen production over weeks and months. The product itself metabolises relatively quickly, but the collagen it generates stays.

Initial course: two to three sessions (occasionally four for significant volume loss), spaced four to six weeks apart.

Onset: gradual. Do not expect to see much in the first few weeks. Results build from around month two and continue improving for up to six months after your final session. This is the treatment for people who understand that the best results take time.

Duration: two years or more. This is where Sculptra genuinely shines compared to hyaluronic acid filler. Because the correction is made of your own collagen, it integrates naturally and degrades on your body's own biological timeline rather than the enzymatic timeline of a synthetic product.

Maintenance: a single session annually, using one to two vials rather than the three to six vials of the initial course. Think of it as keeping the collagen production ticking over rather than starting from scratch. Some patients find they can stretch to 18 or even 24 months between maintenance sessions, particularly if their initial course achieved full correction.

I wrote about Sculptra's role in post-weight-loss facial rejuvenation in the Ozempic Face article, where it is one of the cornerstone treatments in Phase 1 of the rebuilding plan.

JULÄINE

JULÄINE is the other collagen stimulator we use regularly. Like Sculptra, it triggers the body's own collagen production, but it uses a different delivery mechanism. The treatment schedule is similar: an initial course of two to three sessions, then annual or biannual maintenance depending on individual response.

HArmonyCa

HArmonyCa is a hybrid product that combines hyaluronic acid with calcium hydroxylapatite (CaHA), giving you both immediate structural correction (from the HA) and long-term collagen stimulation (from the CaHA). It is an excellent option for the mid-face, jawline, and chin where you want visible results from day one but also want the collagen-building benefit. Longevity is typically 12 to 18 months, which reflects both components working in sequence.

Ready to invest in the long game? If you are considering Sculptra, JULÄINE, or a collagen-building plan, the first step is understanding what your face needs now and mapping out the phases. We will walk you through the timeline, the costs, and what to expect at every stage.

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Signs You Are Over-Treating

This is the section I wish every patient would read before their next appointment.

Over-treatment is one of the most common problems in aesthetic medicine, and it almost never happens intentionally. It happens incrementally. A little more filler each time. Botox slightly more frequently than ideal. Another round of skin booster "just because it has been six months." Each individual decision seems reasonable. The cumulative effect is not.

Here are the signs I look for:

Your face looks different in a way you cannot quite explain. Not better or worse, just... different. If family or close friends have noticed a change and you are not sure why, it is worth pausing and assessing.

Your Botox is not lasting as long as it used to. If you started at four months between treatments and you are now needing it at ten weeks, you may be developing early antibody resistance. This is the time to space out, not speed up.

Your skin feels "full" or slightly puffy, especially in the morning. Hyaluronic acid attracts water. If you have accumulated filler, it can create a subtle, chronic fullness that is most noticeable on waking.

You cannot remember the last time you skipped a maintenance appointment. Not every treatment needs repeating at every interval. Sometimes the most clinical decision is to say "you look great, come back in six months and we will reassess."

Your practitioner never says no. A good practitioner should periodically tell you that you do not need anything. If every single appointment ends with a syringe in your face, that is a red flag.

At Harley Street Injectables, we photograph every patient at every visit under standardised clinical lighting. We compare to baseline. We have the conversation honestly. And we say no more often than most patients expect. That is not commercially optimal in the short term. It is clinically optimal in the long term, and it is the only way I am willing to practice.

Example Annual Plans

Let me give you three realistic scenarios for what a year of maintenance might look like. These are illustrative. Your plan should come from a consultation where we assess your face, discuss your goals, and build something specific to you. But I know that having a rough idea of timelines and budgets helps with planning, so here are three common profiles.

Profile 1: The Maintenance Patient (Anti-Wrinkle Focus)

Goal: keep the upper face smooth and rested. No fillers currently needed.

  • Botox (forehead, frown, crow's feet) every 12 to 16 weeks: three to four treatments per year
  • Profhilo maintenance: two treatments per year (every six months)

Annual appointments: five to six
Rough annual budget: £1,800 to £2,400

This is the bread-and-butter plan for patients in their late twenties to mid-thirties who are investing in prejuvenation: keeping things looking good before they start looking different. It is also the plan for patients in their forties and beyond who are happy with their structural volume and just want to maintain skin quality and muscle relaxation.

Profile 2: The Combined Patient (Anti-Wrinkle + Volume + Skin Quality)

Goal: comprehensive facial maintenance across all three pillars.

  • Botox every 12 to 16 weeks: three to four treatments per year
  • Cheek filler reassessment at 12 months: zero to one syringe depending on need
  • Lip filler maintenance at nine to 12 months: 0.5 to 1ml
  • Profhilo maintenance: two treatments per year

Annual appointments: six to eight
Rough annual budget: £3,000 to £4,500

This is the most common plan for patients in their late thirties to fifties who want to maintain a natural, rested, well-cared-for look across the whole face. The important word is "reassessment" on the filler: we look before we inject. If cheeks still look good at 12 months, we leave them alone.

Profile 3: The Collagen-Building Patient (Long-Game Focus)

Goal: structural rebuilding through bio-stimulation rather than filler, with anti-wrinkle support.

  • Botox every 12 to 16 weeks: three to four treatments per year
  • Sculptra maintenance: one session annually (one to two vials)
  • Polynucleotides maintenance: one to two sessions per year (every six to nine months)
  • Thermage FLX annually or biennially for skin tightening

Annual appointments: six to eight
Rough annual budget: £4,000 to £6,000

This is the plan for patients who want to invest in collagen-led rejuvenation. It tends to produce the most natural-looking long-term results, because you are building real tissue rather than adding product. The cost is higher in year one (when the initial Sculptra course requires multiple sessions), but from year two onwards the maintenance costs are actually quite comparable to a combined filler plan, with results that look less "done."

For actual treatment pricing, our price list is available online and is updated regularly.

Want a plan built around your face, not a brochure? Every patient profile above started with a consultation. Yours should too. We will assess what you need, what you do not need, and give you an honest annual plan with realistic timelines and costs.

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When to Start and When to Stop

I wanted to add this because it is a question I get asked often and one that most articles do not address.

When to start depends on what you are starting. Prejuvenation with low-dose anti-wrinkle treatment and skin boosters can be appropriate from the mid to late twenties if you are starting to notice dynamic wrinkles7Dynamic wrinklesLines that appear when you move your face (frowning, squinting, smiling) as opposed to static wrinkles, which are visible at rest. at rest. Fillers are rarely needed before the mid-thirties unless there is a specific structural concern. Collagen stimulators are most useful from the late thirties onward, when the body's own collagen production has meaningfully declined.

When to stop is a harder question, and I think the honest answer is: you do not have to stop, but you should periodically ask whether you still need what you are doing. I have patients who have been having Botox for 20 years and are completely happy. I also have patients who came in for a routine top-up and we agreed together that they looked better than they had in years and could comfortably skip a cycle. Both are good outcomes.

The worst outcome is treating on autopilot. Every appointment should involve a fresh assessment, a clinical photograph, and an honest conversation about whether the plan still makes sense.

What to Take Away From This Article

If you remember one thing from this article, make it this: the best treatment plan is not the one that keeps you coming back most often. It is the one that gets you the best result with the least intervention, and preserves your ability to benefit from these treatments for decades.

Twelve weeks minimum between toxin sessions. Filler assessed by need, not by calendar. Skin boosters on a six-monthly rhythm. Collagen stimulators as the long-game foundation. Clinical photography at every visit. And a practitioner who is willing to say "you look great, let's leave it."

That is how you build a plan that works for your face, your budget, and your long-term safety.

If you would like to discuss what a realistic treatment plan looks like for you, we offer complimentary consultations at Harley Street Injectables. We will assess your face, walk through the options, give you honest timelines and budgets, and build a plan that starts from where you are, not from where a brochure says you should be.

You might also find these articles useful:

Glossary of Terms

Quick definitions for every clinical term marked in the article. Hover or tap a footnote number to see at a glance, or scroll here for the full list.

Botulinum toxin ↩︎
The purified protein used in anti-wrinkle injections. It temporarily blocks nerve signals to muscles, preventing the contractions that cause dynamic wrinkles. Botox (onabotulinumtoxin A) and Alluzience (abobotulinumtoxin A) are the two main formulations used at our clinic.
Complexing proteins ↩︎
Additional proteins present in some botulinum toxin products that surround the active molecule. Alluzience is formulated without these, which may reduce the antigenic load on the immune system.
Cumulative dose ↩︎
The total amount of a product you have received across all treatment sessions combined. For botulinum toxin, higher cumulative doses are associated with greater risk of antibody formation.
Dynamic wrinkles ↩︎
Lines that appear when you move your face (frowning, squinting, smiling) as opposed to static wrinkles, which are visible at rest. Anti-wrinkle injections target dynamic wrinkles specifically.
Fibroblasts ↩︎
The cells in the dermis that produce collagen and elastin. Treatments like polynucleotides, Profhilo, and Sculptra work by stimulating fibroblast activity.
Hyaluronic acid (HA) ↩︎
A naturally occurring molecule in the skin that attracts and retains water. Most dermal fillers and skin boosters are HA-based. The body has enzymes (hyaluronidase) that break it down, though at a slower rate than originally thought.
Hyaluronidase
An enzyme that dissolves hyaluronic acid filler. Used to reverse bad filler outcomes or treat complications. Available at any reputable clinic as part of their emergency protocol.
Neutralising antibodies ↩︎
Immune proteins the body can develop in response to repeated botulinum toxin exposure. Once formed, they can block the toxin's action, resulting in partial or complete treatment failure.
PLLA (Poly-L-lactic acid)
The active ingredient in Sculptra. A biocompatible synthetic polymer that stimulates collagen production when injected into the deep dermis or subcutis.
Static wrinkles
Lines visible on the face at rest, without any expression. These are caused by loss of collagen, elastin, and volume rather than by muscle movement. Fillers and collagen stimulators address these; anti-wrinkle injections do not.
Tyndall effect
A bluish discolouration visible under the skin caused by hyaluronic acid filler placed too superficially. Light scatters through the translucent product, creating an unnatural colour. Corrected by dissolving the product with hyaluronidase.

Alice Henshaw, RN, NMP, is the founder and medical director of Harley Street Injectables, the largest clinic on Harley Street dedicated exclusively to non-surgical aesthetic treatments. A qualified nurse prescriber registered in the UK, Australia, and New Zealand, Alice is a Key Opinion Leader for Allergan Aesthetics, was named Best Aesthetic Injector in London by the GHP Awards, and has been featured in Vogue, Tatler, Vanity Fair, and the Tatler Cosmetic Surgery Guide. The clinic is CQC registered and offers complimentary consultations with all treatments.

To book a consultation, visit harleystreetinjectables.com or call +44(0) 3455 485 658.

Sources referenced in this article:

  1. Torres, Sebastian; Hamilton, Mark; Sanches, Elena; Starovatova, Polina; Gubanova, Elena; Reshetnikova, Tatiana (2013). “Neutralizing antibodies to botulinum neurotoxin type A in aesthetic medicine: five case reports.” Clinical, Cosmetic and Investigational Dermatology, 7, 11-17. Published 18 December 2013. DOI: 10.2147/CCID.S51938. PMID: 24379687. PMC: PMC3872090.

  2. Lee, Kar Wai Alvin; Chan, Lisa Kwin Wah; Lee, Angela Wai Kay; Lee, Cheuk Hung; Wan, Jovian; Yi, Kyu-Ho (2024). “Immunogenicity of Botulinum Toxin Type A in Different Clinical and Cosmetic Treatment, a Literature Review.” Life, 14(10), 1217. Published 24 September 2024. DOI: 10.3390/life14101217. PMID: 39459517. PMC: PMC11508269.

  3. Master, Mobin; Azizeddin, Arshia; Master, Vahid (2024). “Hyaluronic Acid Filler Longevity in the Mid-face: A Review of 33 Magnetic Resonance Imaging Studies.” Plastic and Reconstructive Surgery Global Open, 12(7), e5934. Published 15 July 2024. DOI: 10.1097/GOX.0000000000005934. PMID: 39015357. PMC: PMC11250456.

Further reading from Harley Street Injectables:

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Beyond Tear Trough Filler: The Modern Toolkit for Under-Eye Rejuvenation