What Does "Hyper-dilute" Radiesse Actually Mean?
The answer is that there is no single agreed definition.
Dr Forrester, from the Surrey-based Cosmetic Doctors Company looks at the trend of Radiesse dilution.
"Hyper-dilute Radiesse" describes several techniques rather than one treatment, and the dilution ratios used in published work range from 1:1 to 1:6 and beyond.
If a clinic offers it without telling you the ratio, the diluent and the area being treated, you have not been told very much at all.
What is Radiesse to start with?
Radiesse is a Calcium Hydroxylapatite (CaHA) filler: microspheres of Calcium Hydroxylapatite, roughly 25 to 45 microns across, suspended in a gel carrier.
Used undiluted, it is a structural filler with considerable lifting capacity, suited to deep placement against bone.
It is licensed in the UK and EU for facial wrinkles and folds, for volume loss on the backs of the hands, and for jawline contour.
What sets it apart from hyaluronic acid is that the microspheres do more than occupy space.
Direct contact between fibroblasts and the CaHA microspheres appears to stimulate fibroblast activity, encouraging the production of new collagen and elastin. This helps explain why Radiesse is considered a biostimulator as well as a filler.
The result is new collagen and elastin. It is a mechanical process rather than an inflammatory one, and it is why Radiesse is considered a biostimulator as well as a filler. Read our Radiesse treatment page.
What does "hyper-dilute" mean?
It means the product has been mixed with additional fluid, usually sterile saline before injection. Beyond that, the term lacks precision.
The most widely cited expert panel calls a 1:1 mix "diluted" and anything at or beyond 1:2 "hyper-diluted".
A major 2023 review sets the line differently, treating anything above 1:1 as hyper-dilute. Merz, the manufacturer, uses "hyperdilution" for its own licensed 1:2 décolleté protocol.
Published studies have used 1:1, 1:2, 1:3, 1:4 and 1:6.5, with various diluents.
So one clinic’s hyper-dilute is another’s dilute, and the two may deliver very different amounts of active product to your skin.
The ratio is not a technicality, it determines what the treatment will and won’t do.
Why dilute a filler at all?
Not to make the product go further, as is sometimes implied.
Diluting Radiesse converts it from a volumising agent into a skin-quality stimulating treatment.
The lower viscosity lets it spread thinly across a large surface area in a more superficial plane, rather than sitting as a deposit in one place.
That is what makes it usable on the décolletage or the backs of the hands, where the aim is improving skin thickness and texture rather than projection.
There is a cellular reason too. Fibroblasts need room to reach the CaHA microspheres. When microspheres are too densely packed, fewer cells make contact and less collagen is produced.
Does more dilution mean more collagen?
No, and this is the point most often lost in the marketing.
Clinical work comparing dilution ratios found a strong collagen response at 1:1. Higher dilutions, up to 1:6.5, still produced more collagen than no treatment, but did not produce more than 1:1.
The prefix "hyper" implies an escalation in effect that the evidence does not support.
The ratio should follow the result being sought, not the desire for a more impressive-sounding treatment.
What does the evidence show, and is it safe?
The laboratory evidence is good. Histological studies consistently show new collagen, new elastin and new blood vessel formation after treatment, across a range of dilutions.
As with other injectable treatments, temporary swelling, bruising, tenderness and redness can occur. On safety, Radiesse has a long and reassuring record, but three things matter. It cannot be dissolved.
There is no equivalent of hyaluronidase, the enzyme used to reverse hyaluronic acid filler, so a poorly placed result must be waited out. As with any injectable, product entering a blood vessel remains a rare but serious risk.
How do we use Radiesse in our Surrey clinic?
At the Cosmetic Doctors Company we mainly use Radiesse for the hands and decolletage.
For the backs of the hands, we dilute Radiesse 1:1 with sterile 0.9% sodium chloride. Ageing hands present two problems at once: thin, crepey skin and genuine loss of the soft tissue that once concealed the tendons and veins.
Those problems need different things from a treatment. At 1:1 the product spreads well enough to treat the whole surface and to stimulate collagen at a ratio well supported by the published evidence, while retaining enough body to soften the hollows between the tendons. Dilute further and you lose that second effect entirely. This is precisely why the ratio should follow the anatomy rather than a fashion for higher numbers.
For the décolletage, we dilute 1:2 with sterile 0.9% sodium chloride. That is exactly the protocol the product is licensed for in this area, and exactly the protocol tested in the trial supporting that licence.
We do not use higher dilutions or treat the body areas that appear in social media content. Not because those treatments are necessarily wrong, but because we are not persuaded the evidence yet justifies recommending them, and we would rather say so.
What should you ask before agreeing to treatment?
Five questions will tell you most of what you need to know.
What dilution-ratio are you using?
What are you using to dilute?
Why is it the right treatment for what I hope to achieve?
What are the alternatives?
What happens if I am unhappy with the result, given that this product cannot be dissolved?
A practitioner who cannot tell you the ratio has not really decided what treatment they are giving you.
Consider Your Next Step
A consultation is where every good treatment starts. There will no obligation to proceed. The aim is to provide information and clarity, not pressure to have a treatment. All our consultations and treatments are performed by our team of expert medical doctors.
To arrange a consultation please use the links below to telephone or email or to fill out our contact form click here.
References
1. Lorenc ZP, Black JM, Cheung JS, et al. Skin Tightening With Hyperdilute CaHA: Dilution Practices and Practical Guidance for Clinical Practice. Aesthetic Surgery Journal. 2022
https://pubmed.ncbi.nlm.nih.gov/34192299/
2. Goldie K, Peeters W, Alghoul M, et al. Global Consensus Guidelines for the Injection of Diluted and Hyperdiluted Calcium Hydroxylapatite for Skin Tightening. Dermatologic Surgery. 2018 https://pubmed.ncbi.nlm.nih.gov/30358631/
3. Aguilera SB, McCarthy A, Khalifian S, Lorenc ZP, Goldie K, Chernoff WG. The Role of Calcium Hydroxylapatite (Radiesse) as a Regenerative Aesthetic Treatment: A Narrative Review. Aesthetic Surgery Journal. 2023
https://pubmed.ncbi.nlm.nih.gov/37635437/
4. Nowag B, Casabona G, Kippenberger S, Zöller N, Hengl T. Calcium hydroxylapatite microspheres activate fibroblasts through direct contact to stimulate neocollagenesis. Journal of Cosmetic Dermatology. 2023
https://pubmed.ncbi.nlm.nih.gov/36575882/
About the author
Dr Peter Forrester is Medical Director of The Cosmetic Doctors Company in Esher, Surrey. He has practised aesthetic medicine for over 25 years and has extensive experience in non-surgical facial rejuvenation. He believes that all good aesthetic treatment begins with a thorough consultation, straightforward advice and a commitment to providing safe, natural-looking results for every patient.