Dermatoporosis is more than ordinary dry skin. It is an age-related fragility syndrome often seen on the forearms, where the skin becomes thin and minor trauma may lead to purpura or slow recovery.
In 2026, the Journal of Cosmetic Dermatology published a prospective study of CaHA-CMC diluted 1:2 for forearm dermatoporosis. The study included only six participants, with a mean age of 67.3 years; five were women. It was a small exploratory study rather than a randomized controlled trial and cannot establish clinical efficacy or the frequency of rare adverse events.
The researchers used a specific finished CaHA-CMC product, Radiesse, not isolated CaHA microspheres or general HAp powder. Product composition, dilution state, anatomical site, and outcome measures all define the scope of the findings. The results do not apply to CaHA materials as a class.
How Was the Study Arranged?
For each participant, the forearm with more severe lesions was treated at Day 0. The other forearm remained untreated until Day 45 and then received the same intervention. This delayed-start contralateral design allowed the opposite forearm to serve as an early within-person comparator.
Allocation was not random: the more severely affected arm was always treated first. The two sides therefore started from different baselines, leaving the results open to natural fluctuation and regression to the mean. One participant also missed the Day 45 assessment, so the early paired comparison was incomplete.
| Assessment | What it recorded |
|---|---|
| Standardized photographs with ImageJ analysis | The proportion of the forearm assessment area covered by visible lesions such as purpura |
| High-frequency ultrasound | Changes in dermal thickness |
| Skin biopsy with Masson's trichrome staining | Collagen-stained area in tissue sections |
What Happened During the First 45 Days?
Mean lesion coverage on the treated side fell from 5.60% to 1.92%, a statistically significant within-arm change (P=0.041). The untreated side changed from 2.95% to 1.80%, which was not statistically significant.
That does not establish a clear treatment advantage between the two arms. When the investigators compared the magnitude of change on each side, the difference-in-differences analysis was not statistically significant (P=0.1875). Because the treated side was also more severely affected at baseline, the early finding is best read as a signal that requires confirmation.
What Does the Reported 73.4% Mean?
After Day 45, both forearms had received treatment. The investigators then aligned observations by time since each arm was treated and pooled the data for approximately 45 days and one year after treatment.
In the pooled analysis, mean lesion coverage fell from 4.27% before treatment to 1.16% at approximately 45 days and 1.14% at about 320 to 365 days. The paper described this as a reduction of approximately 73.4%.
This figure describes the relative change in lesion-covered area in photographs. It is not a cure rate or the percentage of patients who responded. There was also no continuing untreated control at the one-year assessment, so the result describes a post-treatment trajectory without excluding natural change or other influences.
Did Photography, Ultrasound, and Biopsy Point in the Same Direction?
At 45 days, the paper reported a 36.05% increase in mean dermal thickness and a 69.7% increase in collagen-stained area on Masson's trichrome sections. These findings moved in the same direction as the reduction in photographed lesion area, but the percentages came from different endpoints and should not be compared as measures of effect size.
| Outcome | Reported change | Interpretive limit |
|---|---|---|
| Lesion coverage in photographs | Approximately 73.4% lower at about one year than at baseline | Pooled treated-arm data without a concurrent untreated control |
| Dermal thickness | 36.05% higher at 45 days | A structural measure obtained by high-frequency ultrasound |
| Collagen-stained area | 69.7% higher at 45 days | Stained area in biopsy sections, not total-body collagen content |
The study did not rely on before-and-after photographs alone; it added ultrasound and histology. Compared with the previously reviewed randomized study of diluted CaHA-CMC for décolleté wrinkles, this study had a much smaller sample and weaker comparative design, but it provided a different set of structural observations.
How Should the Safety Findings Be Read?
One transient nodule was reported and resolved with massage. No other adverse events were recorded. A six-patient study can describe what occurred in those participants, but it cannot assess rare complications or longer-term safety.
The study also excluded people using systemic or topical corticosteroids and others whose treatments could affect skin status. The findings therefore do not represent every patient with fragile skin and cannot replace clinical assessment of underlying disease, medication use, or individual risk.
The conflict-of-interest statement reports speaker, research, or consulting relationships between de Almeida and AbbVie and Merz. McCarthy was a Merz employee; the other authors declared no conflicts. Because the study examined a specific Merz product, these disclosures should be considered alongside the small sample, nonrandom allocation, and outcome design.
What Does the Study Add?
The study does not establish hyperdiluted CaHA-CMC as a standard treatment for dermatoporosis. It offers an exploratory observation: with one finished product diluted 1:2 and used on the forearm, photographed lesion area, ultrasound-measured dermal thickness, and histological staining changed in the same general direction.
From a materials perspective, the paper also shows why a clinical report cannot stop at the statement that CaHA was used. The finished system, dilution state, anatomical site, and endpoint determine how far the results can be interpreted. The 1:2 terminology follows the earlier global consensus on diluted and hyperdiluted CaHA, but the same ratio does not make different products materially or clinically equivalent.
This article reviews the design and findings of a small clinical study of one finished CaHA-CMC product. It does not provide injection instructions, recommend a medical product, or offer individual treatment advice.
References
- de Almeida ART, de Sousa Marins Barbosa MC, Michalany A, McCarthy AD. Hyperdiluted Calcium Hydroxylapatite for Forearm Dermatoporosis: A Prospective Delayed-Start Contralateral Case Series. Journal of Cosmetic Dermatology. 2026;25(4):e70859. DOI: 10.1111/jocd.70859.