Does hyaluronic based fillers gradually absorb away little by little?

Hello and thank you for your great question. HA fillers differ in their duration based on the type of filler, the amount injected and also where it is injected. On Average the range is between 4- 24 months. The product is being gradually absorbed by the body over some time. You never want to wait until the entire product is absorbed and should be on a maintenance regimen every 12 months or so.  The first injection appointment is really about replacing the volume lost and the subsequent appointments are about maintaining that look. You break down the product and you also get older each year, which you have to take into account as well. This is a gradual process which varies from person to person.  You should get an expert consultation to be able to address your concern and ideally build the treatment plan for you.

Hi cll12345,
This is a great question, with a somewhat complicated answer. 
The short answer is:To maintain filler results you should repeat the injections at the midpoint of the filler treatment duration.

Here is an example: For fillers like Restylane and Juvederm Ultra that last 12 months you may overlap treatments by 6 months. 
After the third injection you may find the results lasting even longer.

Remember of course you are also aging and losing volume over time and may need more filler to maintain the desired look.
The long answer is:Hyaluronic Acid (HA) fillers create and restore volume to the face in 3 ways:

1.     They physical volume of the filler.

2.     The physical volume of the water absorbed by the filler.

3.     The collagen synthesis that is stimulated by all fillers.
When HA fillers are injected, depending on the filler, different amounts of water are absorbed and this adds to the volume.
As the filler is slowly degraded it turns into water and CO2 and is absorbed by the body. 

During the initial months, as the physical volume of the filler decreases, the remaining filler may absorb slightly more water, maintaining the same visible effects of the treatment.

So at about the midpoint in the duration of the filler enough of the filler will have degraded so there is a visible decrease in the results.

Finally, some of the newly synthesized collagen will persist even after the filler is gone.

So in summary:

For the first half of the HA filler treatment, the results will look about the same. At the halfway point, the results will visually start to decrease. And because of collagen synthesis some of the visual improvement will remain long term after the filler has been degraded.

You should consider re-treatments usually at 6 months intervals and should need less volume over time as results start to last longer.
I hope this information was helpful.Dr. David Mabrie