CaHA
Calcium hydroxylapatite (CaHA) aesthetic injectables combine mineral microspheres with a carrier. The practical reading is therefore two-part: the carrier contributes the early physical presentation, while the microspheres are discussed in relation to longer tissue support and collagen response.
Radiesse is the first CaHA reference product in Injectable Index. CaHA should not be treated as a synonym for Radiesse, and other calcium-containing products should not inherit its evidence or instructions.
At a glance
Section titled “At a glance”| Question | Practical answer |
|---|---|
| What is being injected? | CaHA microspheres suspended in a product-specific gel carrier |
| Immediate correction | Yes, for presentations in which the carrier is used for structural correction |
| Ready to use? | The standard product is supplied as an injectable implant; any mixing or dilution is a separate product- and use-specific question |
| Initial product | Radiesse |
| Main caution | Standard structural use and diluted biostimulatory use should not be collapsed into one protocol |
Microspheres and carrier have different roles
Section titled “Microspheres and carrier have different roles”Merz describes Radiesse as a structural filler and biostimulator, while current product materials identify CaHA microspheres in a water-based gel (Merz Aesthetics product portfolio 🔗; Radiesse patient information 🔗).
The carrier can contribute immediate correction. That early structural effect should be separated from later observations attributed to tissue response around the CaHA microspheres.
This distinction helps prevent three common errors:
- describing every CaHA use as purely delayed
- treating the carrier as clinically irrelevant
- assuming that dilution preserves the same immediate structural behavior
Product identity
Section titled “Product identity”| Field | Radiesse reference |
|---|---|
| Material | Calcium hydroxylapatite microspheres |
| Carrier | Product-specific aqueous gel system |
| Presentation | Injectable implant |
| Company context | Merz Aesthetics |
| Regulatory context | Indications and instructions differ by product variant and market |
The current FDA-hosted Radiesse instructions provide indication, study, contraindication, warning, and adverse-event context for the reviewed US product rather than for CaHA as a universal material (FDA Instructions for Use 🔗).
Standard, diluted, and hyperdiluted discussions
Section titled “Standard, diluted, and hyperdiluted discussions”Dilution changes the practical objective and physical behavior of a CaHA product. A page or table should always identify:
- exact product
- product variant
- diluent and any anesthetic
- mixing ratio
- intended anatomical area
- intended structural or skin-quality objective
- source type
- whether the technique is labeled, published, consensus-based, or off-label
Do not use diluted CaHA or hyperdiluted CaHA as if either term defined one standardized recipe.
Immediate correction versus tissue response
Section titled “Immediate correction versus tissue response”For structural use, the gel carrier contributes visible early correction. Over time, carrier resorption and tissue response alter what maintains the result. The measured duration of a study should not be converted into a guarantee for every anatomy, dilution, or patient.
Systematic review evidence for facial CaHA and PLLA supports clinical activity while showing heterogeneous products, endpoints, and follow-up periods (facial CaHA and PLLA systematic review 🔗).
Safety interpretation
Section titled “Safety interpretation”CaHA should not be approached as an HA filler with a different texture. Important distinctions include:
- no simple class-wide enzymatic dissolution pathway
- product persistence and microsphere-related imaging considerations
- vascular-event risk shared with injectable implants
- product- and technique-specific nodule or inflammatory-event context
- different behavior after dilution
Management depends on the event and cannot be reduced to whether a carrier contains water or gel.
Related materials
Section titled “Related materials”- Nodules and delayed reactions separates descriptive findings from assumed diagnoses.
- Vascular and visual emergencies provides a non-HA emergency-readiness framework.
- PLLA commonly requires reconstitution rather than arriving as the same type of prefilled gel-carrier implant.
- PDLLA includes products with and without an HA hybrid component.
- PCL includes both carrier-based microsphere and manufacturer-described solubilized presentations.