Short answer: downtime after skin boosters is usually short. In a study of polynucleotide injections in the lips, most reactions faded within hours on the same day, and all bumps and bruises were gone by week 3. With Profhilo, bruising and swelling cleared in 3 to 10 days in an early study. With PDLLA boosters such as Juvelook, most people had mild swelling for 3 to 4 days. All three are given as a series, two or three sessions three to four weeks apart, so one trip usually fits one session. None of them has an FDA approval record.
What skin boosters are
Skin boosters are injections placed in or just under the skin to improve hydration, texture and fine lines, rather than to add volume like filler. Three types are common in Korea:
- Polynucleotides (PN), such as Rejuran, made from DNA fragments.
- Hyaluronic acid boosters, such as Profhilo, which spread through the skin.
- Poly-D,L-lactic acid (PDLLA), such as Juvelook, which stimulates collagen over weeks.
Regulatory status
The FDA’s list of approved dermal filler materials includes hyaluronic acid, calcium hydroxylapatite, poly-L-lactic acid and PMMA, but not polynucleotides or PDLLA. We found no FDA approval or clearance record for Rejuran, Profhilo or Juvelook. Profhilo is described in the research literature as a class III medical device in Europe. We could not find a primary record from Korea’s Ministry of Food and Drug Safety to cite. Ask your clinic for the product’s approval details.
Downtime and results by type
| Type | Downtime in studies | Usual series | When results show |
|---|---|---|---|
| Polynucleotide (e.g. Rejuran) | At 30 minutes everyone had some swelling and 22 percent had lumps or bruising; most faded within hours (Rho 2025). Side effects typically resolve within a week (review of 9 studies). | 3 sessions, 3 to 4 weeks apart | Best at about 3 months after two sessions (under-eye study) |
| Profhilo | Bruising 14 percent, swelling 8 percent, gone in 3 to 10 days (Sparavigna 2016). Bumps usually gone within 72 hours. | 2 sessions, 30 days apart | Texture from week 4, wrinkles from week 8 |
| PDLLA (Juvelook) | Mild swelling for 3 to 4 days (Park 2026). Injection into the skin was more painful than just under it. | 3 sessions, 4 weeks apart | Comparable to poly-L-lactic acid in one split-face trial |
What the evidence does not show
Most skin booster studies are small, and many have authors linked to the manufacturers. In a small blinded trial, Profhilo did not increase skin thickness more than saline, and about half the participants were dissatisfied (Zanella et al., 2026). For PDLLA, lumps are the main later risk: one case report described firm nodules three weeks after injection under the eyes (Seo et al., 2025), and lactic acid fillers in general can cause nodules one to two months later. A 2014 Korean trial of Rejuran that is still cited in some reviews was retracted, so we do not use it.
How long to stay in Korea
The British Association of Aesthetic Plastic Surgeons (BAAPS) groups procedures for people who travel abroad. Treatments done under local anaesthetic in under 90 minutes are in its lowest group, with no extra time in the destination country needed for travel reasons. The NHS advice about waiting before flying is written for surgery, not for treatments like this one.
So what decides the length of your stay is the treatment itself: how visible the bumps are and the session gap. Polynucleotide and hyaluronic acid boosters usually settle within a few days, and PDLLA swelling within about four days. Because each series needs sessions three to four weeks apart, a short trip usually fits one session, with the rest on later visits or at home.
A sample 4 to 5-day plan
| Days | Plan |
|---|---|
| Day 1 | Arrive. Consultation, product choice and price in writing. |
| Day 2 | Skin booster session. Indoor afternoon. |
| Days 3 to 5 | Sightseeing with sunscreen once bumps settle, then fly home. |
Replace every date with the ones your clinic gives you. The Clinic KR trip planner lays them out day by day and flags a flight that is booked too early.
Questions to ask your clinic before you book flights
- Which product is this, and what approval does it have in Korea?
- How many sessions do I need, and can later sessions be done at home?
- How deep will you inject, and will it be by hand or with a device?
- What should I do if I feel a lump weeks later?
FAQ
How long is Rejuran downtime?
In a lip study most reactions faded within hours, and all lumps and bruises were gone by week 3. A review found side effects typically resolve within a week.
How long do Profhilo bumps last?
Usually up to 72 hours. Bruising and swelling cleared in 3 to 10 days in an early study.
How long does Juvelook swelling last?
Most people had mild swelling for 3 to 4 days in a split-face trial.
Are skin boosters FDA approved?
We found no FDA approval or clearance record for Rejuran, Profhilo or Juvelook.
Sources
- US Food and Drug Administration. FDA-approved dermal fillers. Checked October 9, 2026.
- British Association of Aesthetic Plastic Surgeons. BAAPS Cosmetic Tourism Guidelines, September 2023, v1.
- Rho NK, Park HJ, Kim HS. Clinical Efficacy and Safety of a Highly Purified Polynucleotide for Dry and Chapped Lips: A Prospective, Multicenter Study. J Cosmet Dermatol. 2025;24(5):e70224. PubMed 40402866.
- Lampridou S, Bassett S, Cavallini M, et al. The Effectiveness of Polynucleotides in Esthetic Medicine: A Systematic Review. J Cosmet Dermatol. 2025;24(2):e16721. PubMed 39645667.
- Ziade G, Keyrouz E, El Maalouf J, et al. Prospective Observational Study of Polynucleotide Injections for Periorbital Rhytides. J Cosmet Dermatol. 2026;25(2):e70736. PubMed 41689167.
- Sparavigna A, Tenconi B. Efficacy and tolerance of an injectable medical device containing stable hybrid cooperative complexes of high- and low-molecular-weight hyaluronic acid: a monocentric 16 weeks open-label evaluation. Clin Cosmet Investig Dermatol. 2016;9:297-305. PubMed 27713647.
- Zanella G, de Souza Ataíde FT, de Lima Bonato TC, et al. Effects of Profhilo® Tissue Bioremodeling on Skin Texture and Perioral Wrinkles: A Randomized Controlled Triple-Blind Clinical Trial. Aesthetic Plast Surg. 2026;50(11):4324-4332. PubMed 41731228.
- Park JY, Im DJ, Jeon HD, et al. A Split Face Study Comparing the Effect of a PDLLA Based Product and PLLA on the Nasolabial Fold (NLF). Skin Res Technol. 2026;32(1):e70324. PubMed 41532837.
- Seo SB, Wan J, Yi KH. Energy-Based Device Management of Nodular Reaction Following Poly-D, L-Lactic Acid Injection for Tear Trough Rejuvenation. J Cosmet Dermatol. 2025;24(1):e16575. PubMed 39283001.
This guide gives general information, not medical advice. Read how we research and check these guides.