WEDNESDAY, 1ST JULY 2026: ‘Your Gateway to Aesthetics: A Step-by-Step Introduction for NHS Clinicians’
WEDNESDAY, 1ST JULY 2026: ‘Your Gateway to Aesthetics: A Step-by-Step Introduction for NHS Clinicians’
WEDNESDAY, 1ST JULY 2026: ‘Your Gateway to Aesthetics: A Step-by-Step Introduction for NHS Clinicians’
WEDNESDAY, 1ST JULY 2026: ‘Your Gateway to Aesthetics: A Step-by-Step Introduction for NHS Clinicians’
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When you start injecting dermal fillers, hyaluronidase is one of the first things you should understand — not because things are likely to go wrong, but because knowing you have a reliable corrective tool changes how confidently you approach treatment. Hyaluronidase is the enzyme that dissolves hyaluronic acid (HA) filler. It is the antidote to the most widely used fillers in aesthetic medicine, and it serves two fundamentally different purposes: elective correction of unwanted cosmetic outcomes, and emergency treatment of vascular occlusion.
For new injectors, this drug often feels mysterious — a powder in a vial that you reconstitute and inject, with results that appear surprisingly quickly. Understanding the mechanism behind it, how to prepare and dose it correctly, and when and why to use it, demystifies the process and makes you a safer, more capable practitioner from the outset.
This guide covers everything a new injector needs to know: what hyaluronidase is, how it works, what it can and cannot do, how to use it in practice, and how its role in elective dissolution differs from its critical role in vascular emergencies. For hands-on training in hyaluronidase technique alongside your filler training, explore Acquisition Aesthetics Foundation and Intermediate courses.
Hyaluronic acid is a naturally occurring sugar molecule (a glycosaminoglycan) found throughout the body — in skin, joints, and connective tissue. In its natural form, it is broken down rapidly by the body’s own enzymes. HA dermal fillers are manufactured by cross-linking individual HA chains together using a chemical process, creating a gel that is far more resistant to enzymatic breakdown than natural HA. This cross-linking is what gives fillers their longevity. It is also what makes hyaluronidase necessary to dissolve them reliably.
| Key concept: Cross-linking Cross-linking connects individual hyaluronic acid chains into a stable three-dimensional gel network. The degree of cross-linking determines filler stiffness (G′), longevity, and resistance to enzymatic breakdown. More heavily cross-linked fillers are harder to dissolve and may require larger or repeated hyaluronidase doses. |
Different HA filler brands use different cross-linking technologies (e.g., BDDE cross-linking used by Restylane), which is why dissolution times and hyaluronidase doses vary between products. This is clinically relevant: a highly cross-linked volumising filler in the deep cheek will not dissolve as readily as a lightly cross-linked skin booster in the superficial dermis.
Hyaluronidase is an enzyme: a biological catalyst that speeds up a specific chemical reaction without being consumed in the process. The reaction it catalyses is the hydrolysis of hyaluronic acid: the cleavage of the β-1,4 glycosidic bonds that link the individual sugar units of the HA chain together.
| Plain language version Think of HA filler as a net of interconnected chains. The chains are held together by chemical bonds. Hyaluronidase acts like a pair of scissors — it cuts those bonds, breaking the net into smaller and smaller fragments until they can be absorbed by the body. The gel structure is destroyed, the volume disappears, and the tissue returns to its pre-filler state. |
In more precise terms:
Hyaluronidase works on all hyaluronic acid fillers, regardless of brand. However, the degree of cross-linking affects how readily a product dissolves. Cavallini et al. (2013) confirmed that all commercially available HA fillers are susceptible to enzymatic dissolution, but that higher cross-link density and larger product volumes may require higher doses or repeat treatment sessions.
Hyaluronidase does not work on non-HA fillers — it has no effect on calcium hydroxylapatite (Radiesse), poly-L-lactic acid (Sculptra), or polymethylmethacrylate (Bellafill).
Crucially, hyaluronidase acts on both cross-linked (filler) and non-cross-linked (natural) hyaluronic acid. It will dissolve not only the injected product but also a proportion of the tissue’s native HA. The body replenishes its own HA relatively quickly, and the effect on endogenous HA is temporary — but this is a reason to use the minimum effective dose in elective dissolution rather than excess, and to counsel patients about the possibility of temporary tissue deflation beyond what the filler was providing.
In the UK, the most commonly used preparation is Hyalase® (hyaluronidase 1500 IU, ovine-derived, supplied as a lyophilised powder for reconstitution). It is a prescription-only medication, which means it must be prescribed before it can be stocked and used by an aesthetic clinician. This has implications for how clinics set up their medicines management and prescribing governance.
| Property | Hyalase (UK Standard) |
| Source | Ovine (sheep) testicular extract — purified hyaluronidase |
| Presentation | Lyophilised powder, 1500 IU per vial |
| Reconstitution | Typically dissolved in 1mL sodium chloride 0.9% for a 1500 IU/mL solution, or further diluted to 150 IU/mL for precise low-dose elective work |
| Storage | Room temperature before reconstitution; use immediately once reconstituted (or within a few hours if refrigerated) |
| Prescription status | Prescription-only medicine (POM) in the UK |
| Shelf life | Check manufacturer guidance; reconstituted solution should not be stored |
Recombinant human hyaluronidase preparations exist (used in oncology and ophthalmology) but are not standard in UK aesthetic practice. The ovine-derived Hyalase remains the established clinical tool, with a well-characterised efficacy and safety profile in aesthetic use.
As a new injector, confirming that Hyalase is stocked, within date, and available at every treatment session is a non-negotiable element of clinical preparation — not an optional extra. Signorini et al. (2016), in a global consensus statement, explicitly emphasised that hyaluronidase availability at the point of care is a patient safety requirement, not a guideline aspiration.
Hyaluronidase is used in two clinically distinct contexts that differ in urgency, dosing, and intent. New injectors should understand both clearly — and never confuse the dosing or approach of one with the other.
Elective dissolution refers to the planned, non-urgent removal of HA filler to correct an unwanted outcome. Common indications include:
The published literature does not support fixed regional dose tables. King et al. (2018), in the most widely referenced UK guideline on hyaluronidase use, state clearly that the dose required is dependent on multiple product-specific factors — whether the filler is particulate or non-particulate, the degree of cross-linking, and the HA concentration — and that it is recommended to inject as much hyaluronidase as required to obtain the desired effect, titrating to clinical response rather than following a fixed dose.
As a starting framework, a consensus in the literature holds that approximately 5 IU of hyaluronidase is required to break down 0.1mL of a 20mg/mL HA product, though Woodward et al. recommend 30 IU per 0.1mL for denser products, and other published examples span a wide range (King et al., 2018). In practice:
| ⚠️ Elective Dissolution: Practical Reminders for New Injectors Always obtain consent for dissolution, including the possibility of temporary under-correction and the risk of dissolving endogenous HAPhotograph before and after every dissolution treatmentAllow at least 2 weeks before reassessing and re-treating — dissolution continues for up to 2 weeks post-injectionDo not offer immediate re-injection with new filler on the same day as dissolution unless clinically justifiedDocument the product dissolved (brand, estimated volume, approximate age) if known |
In a vascular emergency — when HA filler has occluded a facial artery through direct intravascular injection or external compression — hyaluronidase is a life-saving (or rather, tissue-saving) intervention. The approach is fundamentally different from elective dissolution:
| 🚨 Emergency Use: Key Differences from Elective Dissolution Do NOT delay to confirm diagnosis — administer on clinical suspicion of vascular occlusionHigh doses: 200–500 IU or more per affected vascular territory, not the conservative elective dosesInject broadly across the entire ischaemic distribution, not just at the original injection siteRepeat every 60 minutes until signs resolve — total dose in serious events may exceed 1500 IU |
The high-dose pulsed protocol, established by DeLorenzi (2017), represented a significant shift in how the aesthetic community approaches vascular events — away from cautious underdosing and toward aggressive, immediate enzymatic dissolution. As a new injector, the single most important thing to understand is: if you suspect a vascular event, do not start by reaching for the elective dissolution dose. The emergency dose is categorically different.
Hyalase comes as a white lyophilised powder in a glass vial. It must be reconstituted before use. The concentration you prepare depends on the clinical application.
| 💉 Step-by-Step Reconstitution (Standard Clinical Preparation) Draw up 1mL of sodium chloride 0.9% (normal saline) into a 1mL syringeInject the saline slowly into the Hyalase vial — do not shake; gently swirl until the powder is fully dissolvedThe resulting solution is 1500 IU/mL — this is your stock concentrationFor elective low-dose work: draw 0.1mL of stock (= 150 IU) and dilute with 0.9mL saline to make 1mL at 150 IU/mLFor emergency use: use the 1500 IU/mL stock directly, or as directed by your emergency protocolLabel the syringe immediately with drug name, concentration, date, and time of preparationUse immediately or within a few hours if refrigerated — do not store reconstituted solution |
Always check the vial for clarity after reconstitution. The dissolved solution should be clear and colourless. Do not use if particulate matter is visible or if the powder has discoloured.
Hyalase is derived from ovine (sheep) tissue and carries a small risk of hypersensitivity reactions. Historically, patch testing — a small intradermal test injection 24 hours before treatment — was routinely recommended. Current practice is more nuanced:
| Scenario | Patch Testing Approach |
| Elective dissolution (routine) | Patch testing is no longer universally mandated but should be considered in patients with known atopy, bee or wasp venom allergy, or prior reactions to hyaluronidase. Clinical judgement required. (Murray et al. 2021) |
| Vascular emergency | Patch testing is absolutely contraindicated — there is no time. Administer hyaluronidase immediately and manage any allergic reaction as it arises. |
| Repeat treatment | If the patient has received hyaluronidase previously without reaction, repeat patch testing is generally not required unless there has been an interval of greater than 6 months or a clinical reason to reassess. |
The absolute risk of a serious allergic reaction to Hyalase in a standard aesthetic patient is low.
New injectors should be able to counsel their patients accurately about what to expect after hyaluronidase. Informed patients are better prepared, less anxious, and less likely to call in a panic after the appointment.
| What patients may notice | What to tell them |
| Swelling immediately after injection | Temporary. The injection itself causes local swelling that resolves within hours. Cooling with a clean cool compress (not ice) helps. |
| Redness or mild bruising at injection sites | Normal injection site reactions. Should resolve within 24–48 hours. |
| Results appearing faster than expected | Hyaluronidase acts quickly — softening is often visible within the hour. Full effect takes up to 2 weeks. |
| Looking ‘more deflated’ than they anticipated | Endogenous HA may also be temporarily reduced. Volume typically partially returns over 2–4 weeks as the tissue replenishes its own HA. Reassess at 2 weeks before deciding on re-treatment. |
| Area feels softer or ‘empty’ in the days after | Normal. The filler gel has dissolved. If the patient is concerned, reassure and book a 2-week review. |
| Wanting to re-inject immediately | Advise waiting at least 2 weeks to allow any residual hyaluronidase activity to resolve before re-injecting. |
| Hyaluronidase CAN | Hyaluronidase CANNOT |
| Dissolve HA filler (all brands)Act quickly — effects visible within 30–60 minutesRestore vascular flow by breaking down an obstructing HA bolusCorrect Tyndall effect, migration, overcorrection, and nodulesRemove product from any injection plane it can reach | Dissolve non-HA fillers (Radiesse, Sculptra, PMMA)Guarantee full dissolution in a single session for large or old depositsUndo fibrosis or scarring from previous complicationsAct as a substitute for correct injection techniqueBe stored after reconstitution — must be freshly prepared |
| Build Safe, Confident Filler Practice from the Start Understanding hyaluronidase is just one part of the foundation every injector needs before treating patients. At Acquisition Aesthetics, our Foundation and Intermediate courses cover anatomy, product selection, technique, patient assessment, and complication management — including hands-on hyaluronidase training — so you start your aesthetic career equipped, not guessing. ➤ Explore Foundation and Intermediate Courses |
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Cavallini M, Gazzola R, Metalla M, Vaienti L.. The role of hyaluronidase in the treatment of complications from hyaluronic acid dermal fillers.. Aesthet Surg J. 2013;33(8):1167–1174..
DeLorenzi C.. New high dose pulsed hyaluronidase protocol for hyaluronic acid filler vascular adverse events.. Aesthet Surg J. 2017;37(7):814–825..
Murray G, Convery C, Walker L, Davies E. Guideline for the Safe Use of Hyaluronidase in Aesthetic Medicine, Including Modified High-dose Protocol. J Clin Aesthet Dermatol. 2021 Aug;14(8):E69-E75. Epub 2021 Aug 1. PMID: 34840662; PMCID: PMC8570661.
Signorini M, Liew S, Sundaram H, et al.. Global aesthetics consensus: avoidance and management of complications from hyaluronic acid fillers — evidence and opinion-based recommendations.. Plast Reconstr Surg. 2016;137(6):961e–971e..
