Skin treatments
Polynucleotide Injections for Sagging Skin in Knightsbridge: What They Can (and Can’t) Do
How polynucleotides improve skin firmness and elasticity, which areas of mild laxity respond, why they are not a facelift, how they compare with HIFU, radiofrequency and threads, the treatment course, realistic results and cost.
By Fatemeh, Founder & Lead Practitioner, Levirgo Aesthetics Clinic 15 min read
Reviewed December 2025 
Two different problems people call “sagging”
| Skin-quality laxity | Structural sagging | |
|---|---|---|
| What it looks like | Thin, crepey, loose-feeling skin; fine folding; “tired” texture | Jowls, heavy neck bands, deep nasolabial folds, descent of fat pads |
| What’s happened | Collagen/elastin depletion in the skin itself | Ligament laxity, fat pad shift, bone changes, gravity |
| Best tools | Polynucleotides, skin boosters, microneedling, resurfacing | HIFU/RF tightening, threads, filler for support, surgery |
| Polynucleotide role | Primary treatment | Adjunct — improves the skin over whatever is done structurally |
Most people have a mix. An honest assessment separates the two so the plan targets the right one.
The expectation to set
Polynucleotides make lax skin firmer, thicker and more elastic. They do not create a jawline, remove jowls or lift a brow. If someone promises a “non-surgical facelift” from injections alone, be sceptical.
How polynucleotides firm the skin
Polynucleotides are purified DNA fragments from cold-water fish. Placed in the skin they reduce inflammation, scavenge free radicals and stimulate fibroblasts to produce more — and better-organised — collagen and elastin. Over weeks the dermis becomes thicker and more resilient, so lax, crepey skin looks tighter and smoother and holds light better.
Areas that respond well
- Jawline and lower face — softens early skin laxity and improves definition of the skin envelope
- Neck — crepe texture, fine horizontal “tech neck” lines, thin skin
- Under-eye — crepiness and thin, shadowed skin (a signature use)
- Cheeks — dull, lax, fatigued skin quality
- Décolletage — sun-damaged, wrinkled chest skin
- Arms, elbows and knees — crepey, loose-feeling skin
How they compare with tightening treatments
| Treatment | Mechanism | Best for | Downtime |
|---|---|---|---|
| Polynucleotides | Improves skin thickness & elasticity | Thin, crepey, poor-quality skin | Bumps/bruises 1–2 days |
| HIFU | Focused ultrasound heats deep layers (SMAS) | Mild–moderate structural laxity | None to minimal |
| Radiofrequency (incl. RF microneedling) | Heats dermis to tighten & remodel | Skin laxity + texture | 1–3 days redness |
| PDO threads | Physically lift & anchor tissue | Moderate jowl/brow descent | 3–7 days bruising/tightness |
| Dermal filler | Restores volume & structural support | Volume loss contributing to sag | 1–3 days |
Combinations are common — e.g. HIFU or RF for tightening plus polynucleotides for the skin surface.
The treatment course
- Assessment
Your practitioner separates skin-quality laxity from structural sag, sets expectations and photographs the areas.
- Session 1
Numbing cream, then the product is placed with a fine needle or cannula as a series of points or a light mesh. 20–30 minutes.
- Sessions 2–3
At 2–4 week intervals. Two sessions for maintenance-level skin, three for thinner or more sun-damaged skin.
- Review & maintenance
Assessed at 8–12 weeks against baseline photos; then a single session every 6–9 months.
Is your “sagging” a skin problem or a structural one?
Book a complimentary assessment. We’ll tell you which it is and whether polynucleotides — alone or with a tightening treatment — are the right answer.
Results and timeline
Illustrative share of the final visible improvement in firmness and texture at each point after a full course.
Early on, skin looks more hydrated and slightly plumper. The lasting firming — better elasticity, thicker skin, smoother crepe texture — develops over two to three months as new collagen and elastin form. It’s a refinement, not a transformation, and it stacks well with tightening devices.
Downtime, safety and who should wait
- Small bumps at injection points for a few hours to a day; possible minor bruising, especially on the neck and under the eyes.
- Back to normal the same day; make-up after 12–24 hours.
- Avoid strenuous exercise, saunas, alcohol and active skincare for 24–48 hours.
Not suitable / discuss first
Pregnancy or breastfeeding, a true fish allergy, active skin infection or cold sore in the area, autoimmune disease, or a tendency to keloid scarring. Space treatment a couple of weeks from dental work and other injectables.
What it costs in London
| Option | Typical London price |
|---|---|
| Single session (face or neck) | £250–£400 |
| Course of 2 | £480–£750 |
| Course of 3 | £600–£1,000 |
| Combined plan with HIFU/RF | Quoted together after assessment |
| Maintenance session (6–9 monthly) | £250–£400 |
Consultation is complimentary and redeemable. Your plan and price are confirmed after assessment.
How Levirgo approaches lax skin
- An honest assessment that separates skin-quality laxity from structural sagging, so the plan targets the real cause.
- Polynucleotides where skin quality is the issue; tightening devices or threads where descent is the issue; often both.
- Cannula technique on the neck and under the eyes to reduce bruising.
- Medical-grade, traceable product and baseline/follow-up photography.
- A written course and maintenance plan with itemised pricing.
- CQC-registered clinic in Knightsbridge with a 24-hour aftercare contact.
Frequently asked questions
Can polynucleotide injections lift sagging skin?
They firm and thicken the skin and improve its elasticity, which visibly tightens mild to moderate laxity and crepiness. They do not lift or reposition tissue, so true jowls, heavy necks and deep folds need tightening devices, threads or surgery — often with polynucleotides added to improve the skin itself.
How much do they cost in Knightsbridge?
A single session for the face or neck is about £250–£400 in London, with a course of two around £480–£750 and a course of three £600–£1,000. Maintenance sessions every six to nine months are priced like a single session.
How many sessions will I need?
Two to three sessions two to four weeks apart — two for maintenance-level skin, three for thinner or more sun-damaged skin. Results are then held with one session every six to nine months.
When will I see a difference?
Skin looks more hydrated within a week or two. The firming and texture improvement builds over 8–12 weeks as new collagen and elastin form, and is best judged against baseline photographs.
How are they different from Profhilo or filler?
Polynucleotides contain no hyaluronic acid, so they don’t add volume. Profhilo is a hyaluronic-acid bio-remodeller focused on hydration and glow; filler adds structural volume. Polynucleotides specifically target skin repair, thickness and elasticity, which is why they suit thin, crepey, lax skin.
Can I combine them with HIFU or radiofrequency?
Yes, and it’s a common plan: an energy device tightens the deeper layers while polynucleotides improve the quality of the skin over the top. Your practitioner will sequence the treatments appropriately.
Do they work under the eyes?
The under-eye is one of the best areas for polynucleotides — they improve thin, crepey skin and can reduce the tired, shadowed look when it’s caused by poor skin quality. They don’t correct pigmentation or deep tear-trough volume loss.
Is there much downtime?
Minimal — small bumps at the injection points for a few hours to a day and possible minor bruising, especially on the neck and under the eyes. You can return to normal the same day.
Will crepey skin on my arms or knees improve?
Often yes. Crepey, loose-feeling skin on the arms, elbows, knees and décolletage responds to the skin-thickening effect, though these areas may need a full course of three and regular maintenance.
Who shouldn’t have them?
Anyone pregnant or breastfeeding, with a true fish allergy, an active skin infection or cold sore in the area, an autoimmune condition, or a tendency to keloid scarring. These are checked at consultation.
Levirgo Aesthetics Clinic · Knightsbridge
Firmer, better-quality skin in Knightsbridge
A doctor-led plan that targets skin quality and structure separately, with results measured against baseline photos. No obligation to proceed.
Sources & further reading
This article is general information about polynucleotide injections for skin laxity and is not medical advice. Suitability, results and risks vary between individuals and can only be assessed in a personal consultation. Prices are indicative London ranges for 2026 and are confirmed in writing after assessment.