Different
HA fillers do result in different ultimate volumes, but this has less to do with their thickness (G′) and more to do with their hydrophilicity—their ability to absorb water after injection.
All
HA fillers are hydrophilic, but some absorb significantly more water than others. Think of them like sponges: the more hydrophilic the filler, the more volume expansion you’ll get post-injection. Interestingly, thicker fillers with higher G′ generally have lower water uptake, while softer fillers tend to absorb more water and thus result in greater apparent volume over time.
Examples of water uptake:
Filler Max. Water Uptake (%)
Juvederm Ultra Plus ≈ 515 %
Restylane Refyne ≈ 516 %
Juvederm Voluma ≈ 227 %
Restylane Lyft/SubQ < 100 %
Clinical relevance:
• I typically tell patients that Voluma results in a ~15 to 25% increase in volume over the first 2–3 weeks as it hydrates.
• While Voluma may give less visible volume compared to some of the “cheaper,” softer fillers, you still get more than what was physically injected.
• The advantage of using Voluma is not the expansion—it’s the longevity. Voluma has excellent firmness (high G′) and typically lasts almost twice as long as most other
HA fillers.
Bottom line:
Equal syringe volumes do not yield equal clinical volume. Choose your filler based on the desired firmness and duration of effect, not just cost or initial volume.
Dr. S