Hyaluronic acid (HA) is temporary and can usually be dissolved. PMMA-based fillers are designed to be permanent. This page explains what that difference means in practice and what published studies report for each.
In brief
Short answer
HA filler is gradually absorbed and can usually be dissolved with hyaluronidase if there is a problem. PMMA-based fillers contain microspheres intended to stay in the tissue permanently, and there is no enzyme to remove them. Published studies report girth gains with both, and one prospective study found a higher rate of local adverse events with PMMA than with HA. Paraffin, silicone oil and similar substances are a separate category: they are not medical fillers and are associated with serious complications.
Comparisons
Injectable materials used for penile girth fall into two broad groups. Temporary fillers, such as cross-linked hyaluronic acid, are broken down by the body over months. Permanent fillers, such as those based on polymethylmethacrylate (PMMA), contain small synthetic microspheres that are intended to remain in the tissue indefinitely.
The appeal of a permanent material is obvious: no top-ups. The concern is equally clear: if the result is uneven, if the material moves, or if a complication develops, the material cannot simply be dissolved. With HA, the result fades if you do nothing, and it can usually be dissolved sooner if needed. The hyaluronic acid filler guide explains how the gel works.
Comparisons
| Factor | HA filler | PMMA-based filler |
|---|---|---|
| Material | Cross-linked hyaluronic acid gel | Synthetic PMMA microspheres in a carrier |
| Duration | Temporary; gradually absorbed | Intended to be permanent |
| Reversibility | Usually reversible with hyaluronidase | No dissolving agent |
| Irregularities | Lumps and asymmetry documented; often correctable with hyaluronidase or additional filler | About half of men in one large series noticed irregularities |
| Local adverse events in one prospective study | 7.2% | 14.3% |
| Repeat treatment | Top-ups when the gel is absorbed | Not usually needed for volume, but problems persist with the material |
Comparisons
752 men were treated with a PMMA-based filler, with data reported on 729. Girth rose from 10.2 cm to 13.7 cm.
The reported complication rate was 0.4%, but about half of the men noticed irregularities. That gap is a reminder that a low formal complication rate does not mean a smooth result for everyone.
A prospective single-surgeon study followed 301 men: 125 treated with HA, 134 with polylactic acid (PLA) and 42 with PMMA.
Local adverse events occurred in 7.2% of the HA group, 11.9% of the PLA group and 14.3% of the PMMA group.
For HA, a 2025 audit of 324 men (a conference abstract) reported foreskin migration in 7.7%, asymmetry in 6.1%, lumps in 4.6% and infection in 1.5%, all managed with hyaluronidase, additional filler or oral antibiotics. The risks and safety guide covers these in detail.
These figures come from different settings, techniques and definitions of a complication, so they should not be read as a precise ranking. A 2021 systematic review rated the overall evidence for penile enhancement procedures as low quality. Individual results vary.
Comparisons
With a temporary filler, the long-term question is mainly whether and when to repeat treatment; the longevity guide covers the published data. With a permanent filler, the long-term question is what happens if something changes years later: the tissue ages, the material shifts, or a lump develops. Because there is nothing to dissolve, problems with permanent materials are generally managed in other ways, which can include surgery.
Permanence also affects later decisions. A man with permanent filler who later wants a different treatment, or needs unrelated penile surgery, brings that material with him. Any treating doctor needs to know it is there.
Comparisons
Medical PMMA-based fillers are manufactured products used by clinicians. They should not be confused with non-medical substances such as paraffin, mineral oil, liquid silicone or other oils, which are sometimes injected into the penis outside proper medical settings.
These substances can cause a chronic tissue reaction known as sclerosing lipogranuloma, or paraffinoma. Published reviews of these cases describe complications that frequently need surgical treatment. This is a different problem from the complications of medical fillers, and the two should not be grouped together.
Seek urgent medical care if you have had any substance injected into the penis and develop increasing pain, spreading redness, fever, skin colour change or difficulty passing urine.
Comparisons
Men who have previously had PMMA, silicone or an unknown substance injected sometimes ask whether HA can be added on top to even out the result. That is not a decision that can be made from a description or a photograph. It needs an in-person examination by a specialist, and the outcome may be a recommendation not to inject further.
At Hardrock Clinic, assessment includes a history of previous penile procedures for this reason. Be as specific as you can about what was injected, when and by whom, and bring any records you have. The physician may advise against HA treatment if the existing material makes it unsafe or unpredictable. Previous injections are also relevant to the wider choice of girth enhancement options.
Professional bodies, including the Sexual Medicine Society of North America and the International Consultation on Sexual Medicine, advise caution and careful patient selection for all cosmetic penile procedures. European urology guidelines recommend psychological evaluation for men of normal size seeking augmentation.
Questions
Permanence avoids top-ups but removes the option of dissolving the material. One prospective study reported a higher local adverse-event rate with PMMA (14.3%) than with HA (7.2%). The right choice depends on your priorities and a specialist assessment.
No. Hyaluronidase acts only on hyaluronic acid. Problems with permanent fillers are managed in other ways, which can include surgery.
No. Liquid silicone, paraffin and similar oils injected into the penis are not medical fillers and are associated with sclerosing lipogranuloma, which often needs surgery.
Possibly not, and never without an in-person specialist examination. Tell the physician exactly what was injected and bring any records.
More answers are collected on the penile filler FAQ page.
Next step
General information cannot tell you whether this treatment suits you. The patient coordination team can answer practical questions, and suitability and volume are decided by the physician at an in-person assessment.
Sources
Published sources cited on this page. Conference abstracts are identified as such; they have not been through full peer review as journal articles.