Hyaluronidase

Hyaluronidase is an enzyme that breaks down hyaluronic acid. In aesthetic medicine, it may be used to reduce or dissolve dermal filler made from hyaluronic acid, but it does not dissolve every type of filler.

It is also not automatically the right treatment for every lump, swelling, asymmetry or unwanted change after filler. The product that was injected, where it is located and the likely cause of the problem all matter before hyaluronidase is considered.

If you are still researching dermal fillers more generally, see our guide to fillers.

What is hyaluronidase?

Hyaluronidase is an enzyme that acts on hyaluronic acid. Hyaluronic acid is naturally present in the body and is also the main material used in many temporary dermal fillers.

Hyaluronic acid used in fillers is modified and cross-linked so that it remains in the tissue for longer. Different filler formulations can therefore respond differently when exposed to hyaluronidase.

This means hyaluronidase does not act on the general category of "filler". It acts on hyaluronic acid. Knowing what product was previously injected is therefore important.

For more detail about this filler material specifically, see what hyaluronic acid fillers are.

Hyaluronidase and Hyalase: what is the difference?

Hyaluronidase is the active enzyme. Hyalase is a UK medicine containing hyaluronidase.

Hyalase 1500 I.U. contains 1,500 international units of hyaluronidase and is a prescription-only medicine in the UK.

Its authorised medical uses include helping injected substances spread through tissue and promoting the absorption of excess fluid or blood in tissue. Dissolving cosmetic dermal filler is not one of its authorised indications.

Is hyaluronidase for filler dissolving off-label in the UK?

Yes. Using hyaluronidase to dissolve dermal filler is an off-label use in the UK.

Off-label means a medicine is being used for a purpose outside its authorised indications. It does not by itself mean that the use is inappropriate, but the reason for using the medicine, expected benefit, limitations and relevant risks should be considered in the individual clinical situation.

Which fillers can hyaluronidase dissolve?

Hyaluronidase can break down hyaluronic acid filler. It does not work as a universal dissolving agent for fillers made from other materials.

Hyaluronic acid fillers

These contain the material on which hyaluronidase acts. How much a particular filler changes after treatment can vary according to the formulation, amount of filler, where it sits in the tissue and how the enzyme reaches it.

Non-hyaluronic acid fillers

Fillers based on materials such as calcium hydroxylapatite or poly-L-lactic acid are not broken down by hyaluronidase in the same way. Hyaluronidase should therefore not be presented as an antidote for every injectable filler product.

What if you do not know which filler was used?

If the product is unknown, this uncertainty matters. The original treatment record, product information from the previous clinic and further assessment may help establish what is likely to be present.

The appearance of a lump, swelling or area of asymmetry alone does not reliably confirm which filler material was injected.

When is hyaluronidase not automatically the right treatment?

Not every unwanted change after dermal filler is caused by hyaluronic acid filler that needs to be dissolved.

A visible or palpable change may relate to filler position or amount, but other explanations can include temporary swelling, inflammation or another filler-related problem. Previous treatments in the same area can make the assessment more complex.

Further assessment is particularly important when:

• the previous filler product is unknown;

• it is unclear what is causing the problem;

• several treatments have been performed in the same area;

• the injected material may not be hyaluronic acid;

• there are signs that the issue could be a complication rather than an elective cosmetic correction.

The aim is to establish what is actually being treated before assuming that additional hyaluronidase is the answer.

Can filler be partially dissolved with hyaluronidase?

A practitioner may aim to reduce only part of an unwanted hyaluronic acid filler result rather than remove as much material as possible. However, this should not be understood as selecting an exact percentage of filler to dissolve.

Hyaluronidase spreads through the treated tissue and different cross-linked hyaluronic acid fillers may respond differently. The position and amount of filler also affect how predictable a limited correction can be.

A treatment can therefore be targeted, but the cosmetic outcome cannot be controlled to an exact percentage or millimetre.

How quickly does hyaluronidase work?

Hyaluronidase can start acting on hyaluronic acid after it is administered, but the visible appearance immediately afterwards does not necessarily show the final effect.

The injection itself can temporarily alter the area through swelling, tenderness or other local reactions. This can make early visual assessment misleading.

If a concern remains, further assessment may be needed before deciding whether additional treatment is appropriate. More hyaluronidase is not automatically the correct next step simply because the area does not yet look as expected.

Risks and important information about hyaluronidase

Elective and emergency use of hyaluronidase are different

Hyaluronidase may be discussed for a planned correction of unwanted hyaluronic acid filler, but it can also have a role in the management of certain complications involving hyaluronic acid filler. These are not the same clinical situation.

An elective correction allows time to assess the filler, the reason for changing it and the desired outcome. A suspected vascular complication after filler requires prompt professional assessment and should not be approached as routine filler dissolving.

For a broader explanation of warning signs and different filler problems, see filler complications.

When can ultrasound help before hyaluronidase?

Ultrasound can help a practitioner visualise previously injected filler and surrounding structures. This may be useful when the position of the filler is uncertain or the treatment history is more complex.

It can be particularly relevant when several previous injections have been performed in the same area, the location or depth of the material is unclear, or a more targeted assessment is needed.

Ultrasound is not automatically necessary before every use of hyaluronidase. Whether it adds useful information depends on the treatment history, area being assessed and the clinical question that needs to be answered.

Want to know what having filler dissolved involves?

This page focuses on hyaluronidase itself: what the enzyme does, the filler material it can act on and the main limitations and medical considerations around its use.

If you are considering an elective correction and want to understand how the assessment and treatment process works, continue to our guide to dissolving filler with hyaluronidase.

Treatment is not automatically necessary simply because you are dissatisfied with an area. Depending on what is causing the concern, further assessment or allowing more time may also be discussed.

Frequently asked questions about hyaluronidase