In this guide17 sections
- Key Points
- What Is HYAcorp Filler?
- HYAcorp MLF1 vs MLF2: What Is the Difference?
- How Is HYAcorp Body Filler Different From Facial Filler?
- Can HYAcorp Be Used for Hip Dips?
- How Much HYAcorp Filler Do You Need for Your Buttocks?
- What Happens During HYAcorp Buttock Filler Treatment?
- How Long Does HYAcorp Filler Last in the Buttocks?
- Is HYAcorp Filler for Buttocks Safe?
- Is HYAcorp Dangerous? The Dutch Withdrawal Explained
- Who Is a Good Candidate for HYAcorp Butt Filler?
- HYAcorp Filler vs BBL: Which Is Better?
- Is HYAcorp Butt Filler Legal in the UK?
- How Much Does HYAcorp Filler Cost for Buttocks?
- Frequently Asked Questions
- HYAcorp Fillers in London
- References
Key Points
- HYAcorp is a CE-marked hyaluronic acid body filler. It is made by BioScience GmbH specifically for the body, in 10 ml syringes, and is not the same as the filler used in the lips or cheeks.
- HYAcorp MLF2 is the version made for the buttocks. MLF1 has smaller gel particles and is designed for calves, hands and small dents; MLF2 has larger particles for buttock volume, lift and hip dips.
- The change is modest. Studies of hyaluronic acid buttock filler typically use around 40 ml to 200 ml in total, compared with 1,600 to 2,000 ml of fat in a full surgical BBL.
- Results last around 12 to 18 months. The gel is slowly broken down by the body, so a top-up is needed to keep the shape, and it can be dissolved with hyaluronidase if needed.
- Published safety data are reassuring but limited. Most side effects are swelling, pain and redness that settle within a week, but serious complications have been reported with buttock filler, which is why technique and setting matter.
- UK rules are tightening. On 21 October 2026 the government proposed that fillers injected outside the face, including liquid BBLs, become cosmetic surgery that only doctors may perform.
HYAcorp filler for buttocks is a thick, cross-linked hyaluronic acid gel made for the body rather than the face, injected under the skin to add modest volume, lift and roundness to the bum and to soften hip dips, without surgery. HYAcorp MLF2 is the product designed for the buttocks. Results are visible straight away, usually last around 12 to 18 months, and can be reversed with an enzyme called hyaluronidase. It cannot match the size or permanence of a surgical BBL.
At Centre for Surgery we use HYAcorp as the only filler for our non-surgical butt lift, injected by surgeons in a sterile theatre under ultrasound guidance. This guide covers HYAcorp MLF1 vs MLF2, how body filler differs from facial filler, how much you need, safety evidence, who it suits and how it compares with a Brazilian butt lift. For a broader look at non-surgical options, including other products sold as bum filler, see our guide to the liquid BBL in the UK.
What Is HYAcorp Filler?
HYAcorp is a range of hyaluronic acid (HA) body fillers made by BioScience GmbH, a German company. Hyaluronic acid occurs naturally in skin and connective tissue, where it binds water and gives tissue bulk. In a filler, the HA is cross-linked into a gel so that it holds its shape and lasts for months rather than days.
According to the manufacturer, each millilitre of HYAcorp body filler contains 20 mg of cross-linked HA and 2 mg of non-cross-linked HA, and it comes as a single-use 10 ml pre-filled syringe[1]. Key features:
- Biphasic gel. Sized particles of cross-linked HA sit in a carrier of free HA; particle size separates one HYAcorp product from another.
- Non-animal origin. The HA is produced by fermentation rather than from animal tissue.
- Made for the body. It is placed in the subcutaneous tissue (the fat layer under the skin) or on the surface of bone, depending on the area[1]. The manufacturer states that it must not be used for breast or genital augmentation[2].
- CE-marked medical device. HYAcorp is marketed in Europe and the UK as a CE-marked medical device. CE marking covers the product, not the clinic that injects it.
HYAcorp MLF1 vs MLF2: What Is the Difference?
There are two HYAcorp body fillers. Both have the same HA concentration on paper; what differs is the size of the gel particles and how firm the gel behaves:
- HYAcorp MLF1: particle size 200 to 350 µm. Designed for smaller areas: calf reshaping, hand rejuvenation and correction of concave dents in the body contour[3]. It can be used for small touch-ups around the hips and buttocks where only a slight change is wanted.
- HYAcorp MLF2: particle size 300 to 500 µm. Designed for augmentation and contouring of the gluteal area: adding volume and lift to the buttocks and filling lateral hip dips[1]. This is the HYAcorp butt filler most people are searching for.
Larger particles give a firmer gel, which matters in an area you sit on. A 2026 laboratory comparison of four HA body fillers found that HYAcorp MLF1 and MLF2 had higher elasticity and stiffness values (G′ and G*) than the softest product tested, and that their performance was stable under both slow and quicker loading, which the authors linked to suitability for high-load areas such as the buttocks[4]. This was a laboratory study, co-authored by the manufacturer, and did not measure clinical results.
In practice, your surgeon chooses the product and the volume. Most buttock and hip dip treatments use MLF2, sometimes with MLF1 to refine small dents.
How Is HYAcorp Body Filler Different From Facial Filler?
Bum filler is not simply a lot of lip filler. The main differences:
- Volume. A facial treatment usually uses one or two syringes of around 1 ml each. Buttock treatments use tens of millilitres per side, which is why body fillers come in 10 ml syringes.
- Firmness. Body fillers need to hold their shape under body weight and movement. The rheology study above found clear differences in stiffness between body fillers, and that body filler should be chosen for the mechanical demands of the area rather than borrowing facial filler data[4].
- Depth. Facial filler is placed in fine layers in the skin and over bone. Buttock filler goes into the subcutaneous fat, above the gluteal muscle. Filler should never be placed into the muscle, where large blood vessels run.
- Risk profile. The buttock has a rich blood supply and a thick layer of tissue that makes the needle tip harder to judge by feel alone. A 2025 review of gluteal ultrasound describes how ultrasound shows the skin, fat, fascia and muscle layers and the filler itself, and helps detect complications early[5].
Can HYAcorp Be Used for Hip Dips?
Yes. Filling the lateral hip dip, the inward curve between the hip bone and the top of the thigh, is one of the main uses of HYAcorp MLF2[1]. A small volume placed in the dip can smooth the line from waist to thigh. Where the dip comes mainly from the shape of the pelvis, filler softens it rather than removing it. Our guide to hip dip surgery explains the anatomy and the surgical alternative using your own fat.
How Much HYAcorp Filler Do You Need for Your Buttocks?
There is no single dose. The volume depends on your starting shape, your goal and whether you are treating the buttocks, the hip dips or both. The published studies give a useful guide:
- Around 40 to 45 ml: a prospective study using a different HA body filler gave each woman up to 60 ml, with an average of 43.6 ml[6].
- Around 85 ml: in a 2025 multicentre study of HYAcorp MLF2 published in Plastic and Reconstructive Surgery Global Open ↗, 35 people received an average of 85.1 ml[7].
- Around 200 ml or more: a systematic review of ten studies found an average of about 207 ml[8], and a 2026 study from Seoul injected 200 to 360 ml per patient[9].
To put that in context, a full surgical BBL at Centre for Surgery transfers around 1,600 to 2,000 ml of purified fat, and even a mini BBL uses 800 to 1,000 ml. Filler shapes; it does not create a large increase in size. If you compare 100 ml or 200 ml bum filler before and after photos online, remember that early photos include swelling.
At Centre for Surgery, treatment is planned over one to three sessions, so volume can be built up gradually and assessed once swelling has settled.
What Happens During HYAcorp Buttock Filler Treatment?
The non-surgical butt lift at Centre for Surgery follows the same steps every time:
- Consultation. Your surgeon examines your buttocks and hips, discusses what filler can and cannot do, and checks your medical history, including any previous filler, silicone or other injections in the area.
- Preparation. Treatment takes place in a sterile operating theatre, not a treatment room. Numbing cream is applied and the areas are marked with you standing.
- Injection under ultrasound. After local anaesthetic, your surgeon injects HYAcorp into the subcutaneous layer using real-time ultrasound to see the tissue layers and confirm the filler is placed where it should be. The treatment takes about 45 to 60 minutes.
- Aftercare. You go home the same day. Avoid direct pressure on the buttocks for 24 to 48 hours, then sit normally. Exercise can usually resume after 24 to 48 hours. Swelling and bruising typically settle in two to five days, and a follow-up is arranged at two to four weeks to review the result and plan any further session.
Only surgeons perform injectable treatments at Centre for Surgery; we explain why ultrasound matters for any buttock procedure in our article on ultrasound-guided BBL.
How Long Does HYAcorp Filler Last in the Buttocks?
Results from HYAcorp buttock filler usually last around 12 to 18 months. The manufacturer quotes up to 18 months for MLF2, noting that duration depends on the amount used, the area treated and how much it moves[1]. A systematic review of HA buttock filler estimated an average duration of effect of about 16 months across the studies it included[8].
The decline is gradual rather than sudden. In a 2025 one-year prospective multicentre study in the Journal of Cosmetic Dermatology ↗, satisfaction peaked at 90% one month after treatment and had fallen to 62% at 12 months as the HA was absorbed; ultrasound confirmed the filler sat in the subcutaneous layer and was slowly integrated and absorbed, with no migration, scarring or nodules seen[6]. To keep the shape, most people plan a top-up at around 12 to 18 months. Our guide to how long butt filler lasts explains what makes it wear off faster.
Is HYAcorp Filler for Buttocks Safe?
HA body fillers have a reassuring short-term safety record in published studies, but the evidence base is small and the rare complications are serious:
- HYAcorp MLF2 multicentre study (2025): across four Italian clinics, 94% of patients and all of the doctors rated the improvement as good or very good over six months. Side effects were mild to moderate and usually resolved within two to seven days, most often swelling, pain and redness[7].
- Long-term HYAcorp study (2024): 91 people treated with HYAcorp MLF1 or MLF2 in Italy and the United Arab Emirates were followed for up to four years and seven months. No serious adverse events were reported and most side effects resolved within a week. Side effects were more common in people who had previously had a different substance injected in the same area[10].
- Independent studies of other HA body fillers: a 2026 study of 26 women found minor, self-limiting side effects in 19%, mainly swelling, bruising and temporary firmness, with no vascular problems, deep infection or migration over six months[9].
Both HYAcorp studies were co-authored by staff from BioScience GmbH, so the data are not fully independent, and none of the studies is a randomised trial. The most important caution comes from a 2023 systematic review in Aesthetic Plastic Surgery ↗ of ten studies and 168 patients. It found HA buttock augmentation to be predictable with satisfied patients and a modest complication rate, but noted that serious complications, including bleeding in the lungs (diffuse alveolar haemorrhage) and death, have been reported, and called for randomised trials[8].
HYAcorp Side Effects
- Common: swelling, bruising, tenderness, redness and discomfort when sitting for the first few days.
- Less common: lumps, unevenness or asymmetry, which can often be adjusted or dissolved.
- Rare: infection, delayed inflammatory nodules, movement of filler away from where it was placed, and vascular complications if filler enters a blood vessel. HA is broken down by the body, but the gluteal area has large vessels, and a review of buttock augmentation techniques lists material migration among the risks of HA filler[11].
Seek urgent help (call 999) if you develop breathlessness, chest pain or coughing blood after any buttock injection. Contact your clinic straight away about increasing pain, skin that turns pale, dusky or mottled, fever or a hot, red, hardening area.
Is HYAcorp Dangerous? The Dutch Withdrawal Explained
If you search for HYAcorp danger, you will find references to a withdrawal in the Netherlands. In 2014 two older hyaluronic acid products from the same brand family, Hyacorp-1000 and Hyacorp H-S (H-800), were taken off the Dutch market after reports of inflammatory reactions. A 2022 analysis of 42 patients concluded that these products were associated with more adverse events than other HA fillers, probably because they stayed in the body for longer, and that the EU Medical Device Regulation now requires stronger evidence before fillers reach the market[12].
These were different products from the MLF1 and MLF2 body fillers discussed here, and the recent clinical studies of MLF1 and MLF2 have not reported the same pattern. The lesson is that the specific product matters, and filler should only come from the authorised supply chain. HYAcorp is sold widely online; never let anyone inject a product you cannot see opened from a sealed, traceable package.
Who Is a Good Candidate for HYAcorp Butt Filler?
HYAcorp may suit you if you:
- want a subtle lift, more roundness in the upper buttock or softer hip dips rather than a large increase in size
- are slim and do not have enough spare fat for surgical fat transfer; our guide to what happens if you don’t have enough fat for a BBL explains the options
- want to see how a fuller shape looks before deciding on surgery
- want to refine a small dent or asymmetry, including after a previous BBL
- cannot have surgery for medical reasons, or cannot take the time off that surgery needs
It is unlikely to suit you if you:
- want a dramatic or permanent increase in size
- have loose or sagging skin, which filler cannot tighten; a buttock lift removes excess skin
- are pregnant or breastfeeding, have an active infection in the area or a known allergy to HA
- have had permanent or unknown substances injected into the buttocks before, such as silicone, polyacrylamide or other non-dissolvable gels; these need careful assessment, often with imaging, before anything else is added
HYAcorp Filler vs BBL: Which Is Better?
Neither is better in general; they do different jobs. Filler is a temporary, low-downtime way to shape; a BBL uses your own fat for a larger, permanent change:
- What is used: HYAcorp uses an HA gel; a BBL uses your own fat, removed by liposuction and injected only into the subcutaneous layer above the muscle under ultrasound guidance.
- Volume: filler studies use roughly 40 to 360 ml in total; a full BBL transfers 1,600 to 2,000 ml.
- Anaesthesia and time: filler takes 45 to 60 minutes under local anaesthetic; a BBL takes 3 to 4 hours under TIVA as a day case, and also slims the donor areas.
- Recovery: no direct pressure for 24 to 48 hours after filler; no sitting directly on the buttocks for 2 weeks after a BBL, with a compression garment for 6 weeks and 1 to 2 weeks off work.
- Duration: filler lasts 12 to 18 months; after a BBL around 50 to 70% of the transferred fat survives and is permanent from about six months, changing with your weight.
- Reversibility: filler can be dissolved with hyaluronidase; a BBL cannot be reversed, only revised.
A review comparing implants, BBL, permanent fillers and HA fillers summarised HA filler as minimally invasive and reversible but needing periodic maintenance[11]. If you want a larger change, a surgical BBL or buttock implants are the realistic options. Our comparison of butt injections vs BBL sets out the trade-offs in more detail.
Is HYAcorp Butt Filler Legal in the UK?
Yes. As of October 2026, HYAcorp buttock filler is legal in the UK, but the rules are changing:
- August 2025: the Department of Health and Social Care announced that the highest-risk non-surgical procedures, such as the non-surgical BBL, should only be performed by qualified healthcare professionals at providers registered with the Care Quality Commission.
- 21 October 2026: the government proposed that fillers injected anywhere other than the face, including liquid BBLs, be legally defined as cosmetic surgical procedures that only doctors could perform. The draft regulations are out for consultation and are due to go through Parliament in spring 2027, with new criminal offences, unlimited fines and fixed penalties for providers who break the rules[13].
Until then, ask whether a GMC-registered doctor will inject you, whether the clinic is CQC-registered, whether ultrasound is used and whether hyaluronidase is kept on site.
Outside the UK, rules differ. In the United States, the Food and Drug Administration advises against using any injectable filler for buttock enlargement and states that no filler is approved for that use[14].
How Much Does HYAcorp Filler Cost for Buttocks?
The cost of HYAcorp filler for buttocks depends mainly on how many 10 ml syringes you need, how many areas are treated and whether you need more than one session. Current prices for the non-surgical butt lift are on our Skin and Aesthetics price list, and your surgeon confirms your treatment plan and price at consultation before anything is booked.
When comparing quotes, include top-ups every 12 to 18 months; over several years these can approach the cost of surgery, covered in our guide to BBL cost in London. Finance isn’t available for a non-surgical butt lift, including HYAcorp, so treatment is self-funded.
Frequently Asked Questions
How much does HYAcorp filler cost for buttocks?
The cost depends on the number of 10 ml syringes needed, the areas treated and the number of sessions. Studies have used from about 40 ml to more than 200 ml in total. Your surgeon confirms the plan and price at consultation, and you should allow for a top-up every 12 to 18 months.
What is the downside of hyaluronic acid fillers?
In the buttocks, the main downsides are a modest size change, a temporary result that needs repeating every 12 to 18 months, and a small risk of lumps, infection, migration or, rarely, a vascular complication. Its big advantage over permanent fillers is that it can be dissolved with hyaluronidase.
Which is better, Sculptra or hyaluronic acid?
They work differently. Hyaluronic acid gives immediate volume and can be dissolved if there is a problem. Poly-L-lactic acid, best known as Sculptra, stimulates your own collagen gradually over several sessions and cannot be dissolved. At Centre for Surgery we use HYAcorp hyaluronic acid only for buttock treatment, partly because reversibility is an important safety backstop in such a vascular area.
Do HYAcorp bum fillers hurt?
Most people feel pressure and some stinging rather than sharp pain. At Centre for Surgery, numbing cream is applied first and local anaesthetic is used during treatment. The buttocks are usually sore and tender for a few days afterwards, and simple painkillers such as paracetamol are generally enough.
Can I sit down after HYAcorp buttock filler?
Avoid direct pressure on the buttocks for 24 to 48 hours, so sit for short spells only and lean onto your thighs if you have to. After that you can sit normally. This is very different from a surgical BBL, where you avoid sitting directly on your buttocks for two weeks.
Is HYAcorp FDA approved?
No. In the United States, no injectable filler is approved for buttock enlargement, and the FDA advises against using fillers for body contouring. HYAcorp is a CE-marked medical device in Europe and the UK, where it is used for body contouring.
Can HYAcorp filler be dissolved?
Yes. HYAcorp is a hyaluronic acid filler, so it can be broken down with an enzyme called hyaluronidase, injected into the area. This can correct lumps and is part of the emergency treatment if filler blocks a blood vessel. Permanent fillers such as silicone or polyacrylamide gels cannot be dissolved.
What is the best injection for the buttocks?
For a temporary, reversible change, a hyaluronic acid body filler made for the buttocks, such as HYAcorp MLF2, is the most widely studied option. Avoid permanent or unknown substances such as silicone. For a larger or permanent change, fat transfer (a BBL) is usually a better choice than repeated injections.
HYAcorp Fillers in London
HYAcorp buttock filler at Centre for Surgery is performed by GMC-registered surgeons in a sterile operating theatre at our Baker Street hospital, rated Good overall by the CQC. Every treatment is injected under real-time ultrasound guidance with local anaesthetic, takes about 45 to 60 minutes and is planned over one to three sessions, with a follow-up at two to four weeks. We use HYAcorp hyaluronic acid only, so your treatment can be dissolved with hyaluronidase if needed. Your surgeon will tell you if a surgical BBL would suit your goals better. Your price, including the consultation, is confirmed in writing before any treatment. Finance isn’t available for this treatment, so it is self-funded.
Phone: 020 7993 4849 | Address: 95–97 Baker Street, Marylebone, London W1U 6RN
Contact us to schedule a consultation
References
- BioScience GmbH. HYAcorp MLF2 product information. HYAcorp Body Fillers. hyacorp.com ↗
- BioScience GmbH. HYAcorp MLF2: composition, application and contraindications. bio-science.org ↗
- BioScience GmbH. HYAcorp MLF1 product information. HYAcorp Body Fillers. hyacorp.com ↗
- Fontenete S, Alfertshofer M. Rheological and physicochemical properties of hyaluronic acid fillers for body contouring: clinical implications and anatomical considerations. Journal of Cosmetic Dermatology 2026;25(2):e70553. doi:10.1111/jocd.70553 ↗
- Ducati EPJ, Magacho-Vieira FN, Câmara CBF, et al. Reviewing the ultrasound anatomy of the gluteal region and the mapping of fillers. Journal of Cosmetic Dermatology 2025;24(10):e70499. doi:10.1111/jocd.70499 ↗
- Bussade M, Faria G, Barros M, et al. Assessment of hyaluronic acid filler in gluteal augmentation and contouring: a 1-year prospective study. Journal of Cosmetic Dermatology 2025;24(12):e70600. doi:10.1111/jocd.70600 ↗
- Crabai P, Campos-Martínez L, Marchetti F, et al. Evaluating the safety and satisfaction of HYAcorp MLF2 for noninvasive buttock augmentation: a multicenter study. Plastic and Reconstructive Surgery Global Open 2025;13(1):e6415. doi:10.1097/GOX.0000000000006415 ↗
- Mortada H, Alkadi D, Saqr H, et al. Effectiveness and role of using hyaluronic acid injections for gluteal augmentation: a comprehensive systematic review of techniques and outcomes. Aesthetic Plastic Surgery 2023;47(6):2719–2733. doi:10.1007/s00266-023-03458-0 ↗
- Hur JH, Cho YK, Song JK, et al. Clinical evaluation of hyaluronic acid filler for gluteal augmentation: a retrospective study. Plastic and Reconstructive Surgery Global Open 2026;14(7):e7962. doi:10.1097/GOX.0000000000007962 ↗
- Crabai P, Marchetti F, Santacatterina F, et al. Nonsurgical gluteal volume correction with hyaluronic acid: a retrospective study to assess long-term safety and efficacy. Plastic and Reconstructive Surgery Global Open 2024;12(5):e5792. doi:10.1097/GOX.0000000000005792 ↗
- Chacur R. Gluteal augmentation: a historical perspective on aesthetic practice. Aesthetic Surgery Journal Open Forum 2024;7:ojae124. doi:10.1093/asjof/ojae124 ↗
- Decates TS, Sayghani F, van Loghem JA, Velthuis PJ. The Dutch Hyacorp filler catastrophe: new EU legislation will prevent this from happening again. European Journal of Dermatology 2022;32(5):584–588. doi:10.1684/ejd.2022.4328 ↗
- Department of Health and Social Care. Cosmetic cowboys crackdown continues with new restrictions. GOV.UK, 21 October 2026. gov.uk ↗
- US Food and Drug Administration. Dermal fillers (soft tissue fillers). fda.gov ↗
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