Side by Side
| Material | Peak gain | Duration | Adverse events | Reversible |
|---|
| Hyaluronic acid | 2.6 cm | 12–24 months | 7.2% | Yes |
| Poly-lactic acid | 2.1 cm | Gradual decline | 11.9% | No |
| PMMA | 2.9 cm | Permanent | 14.3% | No |
| Fat transfer | Unpredictable | Reabsorbs unevenly | — | No |
| Paraffin / silicone | — | Permanent | Severe | No |
Hyaluronic Acid — the Default
HA is a sugar molecule your body already produces. Cross-linked into a gel and placed between the dartos and Buck's fascia, it adds circumference immediately.
Why it is usually the right first choice: it had the lowest adverse event rate of the three studied materials, and it is the only one that can be dissolved with hyaluronidase. If a nodule forms, if the result is uneven, or if you simply dislike it, it can be undone within a day or two.
The trade-off is maintenance: gains declined 19.2% between peak and 24 weeks in the published series, and most patients re-treat somewhere between one and two years.
Poly-Lactic Acid — Biostimulatory
PLA does not fill directly. It stimulates your own collagen, so change appears gradually — peaking at 12 weeks rather than 4. Gains were the smallest of the three at 2.1 cm, with an adverse event rate of 11.9%. Not reversible.
It appeals to patients who want a gradual change, but the combination of smaller gains, higher complication rate and no reversibility makes it a less common first choice.
PMMA — Permanent
PMMA produced the largest and most durable gain: 2.9 cm, held with minimal decline. For patients who do not want repeat treatment, that is a genuine advantage.
The counterintuitive finding
Despite producing the most girth, PMMA patients reported the smallest satisfaction gains at 24 weeks — significantly lower than either temporary material. It also carried the highest adverse event rate at 14.3%.
The data does not explain why. But it argues strongly against assuming that permanent and larger automatically means better.
Fat Transfer — Not Recommended
Fat transfer moves your own fat from elsewhere into the shaft. It sounds appealing because the material is autologous, but it has a specific problem: fat reabsorbs, and it does so unevenly, which can produce lumpiness and asymmetry that is difficult to correct.
The American Urological Association considers subcutaneous fat injection for increasing penile girth to be a procedure that has not been shown to be safe or efficacious. That position has been reaffirmed repeatedly. We do not offer it.
Paraffin and Silicone — Avoid Entirely
The SMSNA strongly recommends against permanent fillers using paraffin or silicone, citing necrosis, progressive pain and swelling, and long-term deformity requiring complex surgical removal and grafting.
These materials are responsible for most of the catastrophic outcomes in this field. They are not the same as a regulated collagen-stimulating filler — but the existence of the warning is exactly why you must know the specific product name before any injection. See the safety article.
What We Recommend
For a first procedure, hyaluronic acid — lowest complication rate, and reversible if you change your mind. Live with it for a year. If you are confident, a permanent option becomes a considered choice rather than a hopeful one. See the duration comparison for that reasoning in full.
