If you have been researching collagen-stimulating injectables recently, you will almost certainly have come across HarmonyCa, JULÄINE and SuneKOS. All three are generating considerable interest in the UK aesthetic market, all three are described as biostimulators, and all three claim to improve skin quality, firmness and collagen production. So far, so confusing.
The honest truth is that whilst these treatments share a broad category, they are quite different in how they work, what they are best suited to and what kind of result they produce. This matters, because choosing the wrong one for your particular skin and goals is a very easy mistake to make, especially when the language used to describe them can sound almost interchangeable.
I offer all three at Health & Aesthetics. This blog is my attempt to explain each one clearly, set out the genuine differences between them and give you a practical framework for thinking about which might be right for you. As always, the final answer comes from a proper consultation rather than a blog post, but this should give you a solid foundation.
HarmonyCa-vs-Julaine-vs-SuneKOS at Health & Aesthetics
First, What Actually Is a Biostimulator?
A biostimulator is an injectable treatment that works by triggering the body’s own biological processes to produce new collagen, elastin or other structural proteins. Unlike a traditional dermal filler, which adds volume by introducing a gel beneath the skin, a biostimulator’s primary purpose is to stimulate the skin’s own regenerative capacity.
The results of biostimulatory treatments are therefore gradual rather than immediate, because they depend on the body doing its own biological work. They also tend to last longer than conventional fillers, because the improvement is based on genuine tissue change rather than a product sitting in the skin and slowly metabolising.
HarmonyCa is something of a hybrid: it has an immediate effect from its hyaluronic acid component alongside its biostimulatory mechanism. JULÄINE and SuneKOS are more purely biostimulatory in their approach, though they use entirely different active ingredients and mechanisms. Understanding that difference is the starting point for everything that follows.
HarmonyCa: Immediate Results with Long-Term Biostimulation
HarmonyCa is manufactured by Allergan Aesthetics, the company behind Juvederm. It combines two active ingredients in a single ready-to-use product: crosslinked hyaluronic acid and calcium hydroxyapatite (CaHA) microspheres, with lidocaine included for comfort during treatment.
What it does
The hyaluronic acid component does what HA always does: it provides immediate volume, lift and hydration the moment it is injected. Patients leave the clinic looking noticeably better on the day of treatment. This is what distinguishes HarmoniCa from the other two treatments in this blog, and it is a significant practical advantage for patients who want to see a clear result straight away.
The CaHA microspheres are where the biostimulation happens. Once in the tissue, they act as a scaffold that triggers the body’s fibroblasts to produce new collagen and elastin. This effect develops progressively over two to three months after treatment and continues to build. The combination of the two mechanisms means that the result you see on the day of treatment is only the beginning; the full effect develops over the following months as the CaHA does its work.
Clinical data supports results lasting 12 to 18 months or longer. HarmoniCa is administered using a cannula, which reduces trauma to the tissue and makes the experience comfortable for most patients.
Best suited to
HarmoniCa works best for patients with laxity and volume loss in the mid and lower face, particularly the cheeks and jawline. It is an excellent choice for someone who wants both an immediate visible improvement and a longer-term biostimulatory benefit from a single treatment session. It is not used in the lips, under the eyes or in areas requiring very superficial injection.
An important point about reversibility
Because HarmonyCa contains both HA and CaHA, it is only partially reversible. Hyalase can address the HA component, but the calcium hydroxyapatite cannot be dissolved; it biodegrades naturally over time. This is not a reason to avoid the treatment, but it does make careful patient selection and thorough pre-treatment consultation non-negotiable.
JULÄINE: Pure Collagen Rebuilding, Nothing Else
JULÄINE is manufactured by Nordberg Medical, a Swedish biotech company. It is a pure poly-L-lactic acid (PLLA) biostimulator, made using proprietary LaSynPro technology that produces highly uniform microspheres. PLLA is a biocompatible and biodegradable material with a long track record in medicine; it is the same material used in dissolvable sutures.
What it does
JULÄINE contains no hyaluronic acid and provides no immediate volumising effect. There is no visible change on the day of treatment. What it does instead is activate fibroblasts through direct mechanical signalling, stimulating the production of Type I collagen, the primary structural collagen of the skin, gradually over weeks and months.
The uniformity of JULÄINE’s LaSynPro microspheres is clinically relevant. Older PLLA treatments used less uniform particles, which were associated with a higher risk of nodule formation and required strict post-treatment massage protocols. JULÄINE’s highly consistent particles distribute more predictably within the tissue and do not require post-treatment massage, which simplifies the patient experience considerably.
Results build progressively over six to twelve weeks and can last well beyond 18 months, making JULÄINE one of the most durable options in this category. A standard course is three sessions, three to four weeks apart.
Best suited to
JULÄINE suits patients who want pure collagen rebuilding without any added volume whatsoever. It is particularly effective for diffuse skin laxity across the face, including nasolabial folds, marionette lines and early jowling, and can also be used on the neck and décolleté. It is the treatment of choice for patients who have experienced over-treatment with fillers and want structural improvement without adding anything further. It also suits those in their forties and beyond whose main concern is loss of firmness rather than specific volume loss.
Patience is part of the process with JULÄINE
Patients choosing JULÄINE need to understand and be comfortable with a gradual timeline. If you are looking for something that makes a visible difference in the short term, or if you have a specific event coming up, JULÄINE is not the right timing choice. If you are investing in your skin’s long-term structural quality and prepared to let the biology do its work, the results are genuinely impressive.
SuneKOS: Building Both Collagen and Elastin Simultaneously
SuneKOS is an Italian product developed by Professional Dietetics. It combines low-molecular-weight hyaluronic acid with a patented blend of six amino acids: glycine, L-proline, L-leucine, L-lysine, L-valine and L-alanine. These six amino acids are the direct building blocks of both collagen and elastin, which is what makes SuneKOS clinically distinctive.
What it does
When injected into the dermis, the amino acids provide the precise raw materials the skin needs to synthesise collagen and elastin simultaneously. The hyaluronic acid activates the extracellular matrix and supports the biological environment in which this happens, through a process the manufacturer describes as dermal biogenesis.
Most biostimulatory treatments target collagen production alone. SuneKOS targets both collagen and elastin together, and clinical evidence supports ordered, simultaneous production of both. Elastin is the protein responsible for the skin’s ability to spring back and resist sagging; its decline with age is a major contributor to the crepey, thin skin that patients often find most difficult to address. SuneKOS is particularly well suited to treating exactly this kind of concern.
At Health & Aesthetics we use SuneKOS Performa and SuneKOS 1200 together as required. Performa is the enhanced formulation for the face, under-eyes, neck, décolleté and hands, and represents an advancement on the original SuneKOS 200 with clinical data suggesting approximately 40% greater efficacy. SuneKOS 1200 uses a medium molecular weight HA to provide additional structural support in cases of more advanced laxity or deeper concerns, and is used alongside Performa rather than as a standalone treatment.
Results develop over a course of three to four sessions, spaced seven to fourteen days apart, with optimal improvement visible four to six weeks after completing the course.
Best suited to
SuneKOS is particularly well suited to patients whose concerns include fine lines, crepey or thinning skin, loss of elasticity and dull or dehydrated texture. It is one of the few treatments we use regularly around the under-eye area, where the skin is too thin and delicate for many other injectables but where the combination of amino acids and low molecular weight HA is both effective and well tolerated. It also works very well on the neck and décolleté, areas that many patients neglect but that benefit enormously from elastin as well as collagen stimulation.
Why SuneKOS targets elastin as well as collagen
Most practitioners and patients focus on collagen when talking about skin ageing, but elastin loss is equally important and often less well addressed. Collagen provides structure; elastin provides the skin’s ability to recoil, stretch and resist the effects of gravity over time. Treating both simultaneously, as SuneKOS does, tends to produce a more comprehensive improvement in skin quality than collagen stimulation alone. This is particularly noticeable in areas like the neck, décolleté and under-eyes where crepiness and lack of recoil are the dominant concerns.
How They Compare: At a Glance
| HarmonyCa | JULÄINE | SuneKOS | |
| Key ingredient(s) | Hyaluronic acid (HA) + calcium hydroxyapatite (CaHA) microspheres + lidocaine | Poly-L-lactic acid (PLLA) microspheres via LaSynPro technology | Low-molecular-weight hyaluronic acid + six amino acids (glycine, L-proline, L-leucine, L-lysine, L-valine, L-alanine) |
| How it works | HA provides immediate volume and lift; CaHA microspheres stimulate collagen and elastin production progressively over months | PLLA microspheres activate fibroblasts directly to produce new Type I collagen gradually, without adding any volume | Amino acids provide the raw building blocks for simultaneous collagen and elastin synthesis; HA activates the extracellular matrix (dermal biogenesis) |
| Primary goal | Immediate structural improvement with long-term collagen biostimulation in the mid and lower face | Progressive, diffuse collagen rebuilding and skin tightening across broader facial areas | Simultaneous collagen and elastin regeneration; particularly effective for fine lines, crepey skin and skin laxity |
| Results | Immediate: visible lift and volume on the day from the HA component, with ongoing improvement from CaHA over 2 to 3 months | Gradual: no immediate visible change; improvement builds over 6 to 12 weeks and continues for several months post-course | Gradual: early improvement after 2 to 3 sessions; optimal results at 4 to 6 weeks post-course |
| Sessions needed | Typically one session; review at 4 to 6 weeks if needed | Course of 3 sessions, 3 to 4 weeks apart | Course of 3 to 4 sessions, 7 to 14 days apart (Performa and 1200 used together as required) |
| Duration | 12 to 18 months; some patients report longer | 18 months or more due to genuine Type I collagen regeneration | 6 to 9 months; ongoing collagen and elastin stimulation provides continued benefit |
| Best areas | Mid and lower face: cheeks, pre-jowl area, jawline | Full face, nasolabial folds, marionette lines, temples, neck, décolleté | Face, under-eyes, neck, décolleté, hands |
| Reversible? | Partially: HA component can be addressed with Hyalase; CaHA cannot be dissolved | No: biodegrades naturally over time; no dissolving agent available | No: biodegrades naturally; no dissolving agent required or available |
| Downtime | Minimal; mild swelling and possible bruising for a few days | Minimal; mild redness and injection-site marks settling within 24 to 48 hours; no post-treatment massage required | Minimal; mild redness and small injection-site bumps, usually settling within 24 to 48 hours |
| Can combine with | SuneKOS, JULÄINE, anti-wrinkle injections, dermal fillers | HarmonICa, SuneKOS, Profhilo, energy-based treatments | HarmonICa, JULÄINE, anti-wrinkle injections, polynucleotides |
So Which One Is Right for You?
This is the question that matters, and the answer always depends on the individual. That said, here is a practical framework that covers the most common clinical scenarios:
- Choose HarmonyCa if you want an immediate visible result alongside longer-term biostimulation, particularly if your concern is laxity and mild volume loss in the cheeks and jawline. It is also a sensible starting point for patients who are newer to biostimulators and want to see a clear before-and-after effect.
- Choose JULÄINE if your primary goal is progressive, diffuse collagen rebuilding across the face and you are not looking for any added volume. It suits patients with more advanced laxity who want the most durable result available and are happy to commit to a course and wait for the biology to work.
- Choose SuneKOS if your main concerns are fine lines, crepey skin, loss of elasticity or thinning skin, particularly in delicate areas such as the under-eyes, neck and décolleté. The simultaneous collagen and elastin stimulation addresses a dimension of skin ageing that HarmonyCa and JULÄINE do not target as directly.
- Consider combining treatments if you have more than one concern. HarmonyCa in the mid and lower face alongside SuneKOS around the eyes and neck is a logical pairing. JULÄINE for broader facial tightening alongside SuneKOS for delicate areas is another common and effective combination. We plan these courses properly during consultation rather than applying a one-size-fits-all approach.
- If you are in your thirties and your skin is generally in good condition but you are seeing early signs of elasticity loss, SuneKOS is often the most appropriate starting point. If you are in your forties or beyond with more established laxity, a combination approach often delivers the most comprehensive outcome.
The most important thing I can say is this: none of these treatments should be chosen based on what is popular at the moment or what a friend has had. They are medical treatments with specific indications, and the right choice for your face is based on your anatomy, your skin condition and your goals, all of which require a proper in-person assessment.
My View
We are in an exciting period for injectable aesthetics. The range of biostimulatory options available now is genuinely better than it was even three years ago, and all three of the treatments in this blog represent real advances over the previous generation of collagen stimulators.
If I had to summarise the three in a sentence each: HarmonyCa is the hybrid, giving you something now and something better later. JULÄINE is the long game, pure collagen rebuilding with remarkable durability. SuneKOS is the precision tool, addressing both collagen and elastin in areas where that combination matters most.
Used well, individually or in combination, these treatments can make a meaningful and natural difference to how skin looks and behaves over time. Used without proper assessment, they are an expensive and potentially disappointing investment. The difference between those two outcomes is almost always the quality of the consultation that precedes treatment.
Frequently Asked Questions
Can I have all three treatments?
Yes, in principle, though we would plan any combination carefully and in the right sequence rather than doing everything at once. Combining treatments from different biological mechanisms can be highly effective, and we regularly use SuneKOS alongside HarmonyCa or JULÄINE in the same treatment plan. What we would not do is compress multiple courses into an arbitrary timeframe; the sequencing is part of what makes a combination approach work.
Which of these treatments has the most clinical evidence behind it?
HarmonyCa’s components, HA and CaHA, have the longest combined track record in aesthetic medicine, given that both have been used in various formulations for many years. JULÄINE is newer but is built on the well-established evidence base for PLLA biostimulators, and its LaSynPro technology has been developed to address the specific limitations of earlier products. SuneKOS has a solid body of Italian clinical research supporting the efficacy of its amino acid and HA combination. All three are CE-marked products used by experienced practitioners across Europe.
Which one is least likely to cause bruising?
All three are low-downtime treatments, but individual results vary depending on skin type, the areas treated and medication such as blood thinners. HarmonyCa is administered by cannula, which generally causes less bruising than needle-based injection. SuneKOS and JULÄINE use fine needles. Avoiding alcohol, anti-inflammatory medications and fish oil for a few days before treatment reduces bruising risk for all three.
Do any of these treatments require special aftercare?
SuneKOS and HarmoniCa have straightforward aftercare: avoid strenuous exercise, heat and alcohol for 24 to 48 hours and protect the skin from sun exposure. JULÄINE has a particular advantage over older PLLA treatments in that it does not require a post-treatment massage protocol. This simplifies recovery considerably and is one of the practical reasons it has become popular in clinical practice.
I am nervous about trying something new. Which would you suggest as a starting point?
HarmonyCa is often a good starting point for patients who are new to biostimulators, because the immediate visible effect from the HA component means you can see a result on the day, which gives confidence whilst the longer-term biostimulatory effect builds. SuneKOS is another gentle starting point, particularly if delicate areas such as the under-eyes or neck are your main concern. JULÄINE requires the most patience, as there is no immediate change, and suits patients who are already comfortable with injectable treatments and understand the gradual timeline.
Ready to Find Out Which Is Right for You?
HarmonyCa, JULÄINE and SuneKOS are all treatments I use regularly at Health & Aesthetics and have confidence in. The right one for you depends on a proper conversation about your skin, your concerns and what you want to achieve. There is no pressure and no predetermined treatment plan; we start with what you need and work from there.
If you have been researching these treatments and want to talk through the options in person, booking a consultation is the most straightforward next step.
