Does Rituo hurt? Pain, anaesthesia and how long bruising lasts

The claim is everywhere; the number behind it is rarely quoted. Fifty people had hyaluronic acid filler placed in the nasolabial folds in a split-face comparison (Clin Cosmet Investig Dermatol. 2023;16:959–972).

That is 6.6 points. On a 100-point scale, 6.6 is “slightly less” — not the difference between a painful treatment and a comfortable one. We should also record that the study was manufacturer-supported.

There is a result in the other direction too. In a randomised crossover study of hyaluronic acid under the eye, no difference in efficacy, safety or satisfaction was found between the instruments (Aesthet Surg J. 2022;42(3):285–297).

Before the instrument, the layer. Rituo targets the dermis — shallow, spread across many small entry points.

The evidence favouring cannulas came from the deep plane. In cadaver foreheads injected deep, the proportion staying in the intended plane split 100% against 40%, with horizontal spread of 25.6 mm against 13.5 mm (J Drugs Dermatol. 2017;16(9):866–872, 10 cadavers). That study did not compare intradermal injection.

A survey of 235 Korean dermatologists reported the technique for this category as a 33G needle, multiple punctures, intradermal (J Cosmet Dermatol. 2024, from the abstract). For shallow placement across many points, a fine needle is the natural choice.

So “the cannula is better” is a sentence from deep-plane injection, and not about the layer Rituo goes into.

Plainly: we could not find a trial comparing the benefit of sedation for this treatment. So we cannot tell you it is needed, or that it is not, on evidence.

What we can offer instead. Shallow intradermal placement across many points is generally within what topical anaesthetic covers, and few of our patients ask for sedation. Sedation, meanwhile, carries its own risk and recovery time.

So we say this: if pain worries you, talk to us about dividing the area treated in one visit before you think about sedation. That too is our clinical judgement rather than a trial result.

On bruising the direction is reasonably consistent: in the 50-subject study the cannula produced significantly less. But the effect size was not reported, so we cannot tell you how much less.

Practical points that do help.

• Tell us the date you need to look normal. The area and the instrument can be planned around it.
• The eye area is handled separately. Thin skin makes the same marks more visible.
• Tell us about medicines or supplements affecting clotting. Whether to pause them is a question for whoever prescribed them, so we do not decide it unilaterally.

Pain and bruising are inconvenience; vascular events are a different category. In a survey of 370 dermatologists recalling the past decade, vascular occlusion was estimated at one per 6,410 needle treatments and one per 40,882 cannula treatments (JAMA Dermatol. 2021;157(2):174–180).

The authors listed the limits themselves: it is recall-based, it is not a comparative trial, and it is not adjusted per patient. Read it only as an estimate.

What matters more than frequency, in our view, is the plan. “That can happen” and “if this occurs we do this, and if it has not settled by this point we do that” are different answers, and the difference is audible in a consultation.

Note also that this category has no established dissolving agent as hyaluronic acid does; we could not verify a primary study of any reversal agent. Hearing the adverse-event plan beforehand matters more here than elsewhere.

This is the order we work through when pain is the concern.

• We do not try to solve pain with the instrument. The measured gap was 6.6 points out of 100 and the authors called it clinically unimportant.
• We match the instrument to the layer. The cannula’s advantage was demonstrated deep; Rituo goes shallow into the dermis.
• We do not propose sedation first. No trial of its benefit here, and sedation carries its own risk. If you want it, we discuss it.
• We ask about your calendar first. If bruising would be a problem on a given date, we divide the area.
• We give the adverse-event plan before treatment — more important in a category with no established reversal agent.

Which treatment suits you depends on your skin condition, how much change you want, and what you have already had. Pain and downtime are among the conditions that go into that decision.

• Rituo in Daegu: five things worth checking · Which skin it suits
• Where the Rituo evidence stands
• Needle or cannula · Bruising and swelling
• Before treatment · Adverse events by class
• Re2O product reference · CellreDM

Lee Chi-Hak, Director, Miso Clinic Daegu

4F Bombom Building, 125 Dongdeok-ro, Jung-gu, Daegu, Korea (Exit 1, Kyungpook National University Hospital Station)

+82-53-428-2700 · www.clinicmiso.co.kr

• Any study comparing needle and cannula for hADM — every pain and bruising figure above comes from hyaluronic acid filler research.
• Any trial of the benefit of sedation for this treatment.
• How much less bruising occurs — the effect size was not reported.
• Any primary study of a reversal agent for this material.
• National adverse-event tallies for hADM in Korea.
• Any study validating our practice of dividing the treated area to reduce discomfort — it is clinical judgement.