Biodegradability and bioabsorption: what is the difference
Quick facts
- Biodegradable
- Material that breaks down through biological action, such as enzymes.
- Bioabsorbable
- Material that the body absorbs and eliminates, leaving no permanent residue.
- Practical difference
- Degrading is breaking down; absorbing is incorporating or eliminating the breakdown products.
- Examples
- Hyaluronic acid, polylactic acid and PDO threads are considered absorbable.
- Contrast
- Permanent materials are not absorbed.
The two words seem like synonyms, but they describe different stages. Biodegradable describes a material that breaks down through biological action, such as that of enzymes. Bioabsorbable describes one that the body absorbs and eliminates, leaving no permanent residue. In facial harmonization (known in Brazil as HOF, orofacial harmonization), almost every temporary material is both, and the distinction helps in understanding what stays in the tissue.
How does each material fit?
| Material | Behavior |
|---|---|
| Hyaluronic acid | Broken down by enzymes and absorbed over months |
| Polylactic acid | Absorbed over months, with collagen stimulation |
| PDO (threads) | Hydrolyzed and absorbed over months |
| Calcium hydroxylapatite | Microspheres absorbed gradually, with collagen stimulation |
| Permanent filler | Not absorbed |
The pace changes with the product, the cross-linking, the area, the volume and the metabolism. For this reason, durations are always usual ranges, not deadlines.
Why does the difference matter?
An absorbable material usually allows correction over time and, in the case of hyaluronic acid, with hyaluronidase, which is a safety advantage. Permanent materials, by contrast, offer no such way out, and reactions can appear years later. The breakdown of hyaluronic acid is the most studied example.
And biostimulators?
In collagen biostimulators, the material is absorbed, but the effect on the tissue (neocollagenesis) can continue for longer. This detail explains why the effect does not coincide with the presence of the material.
Also called: resorption of the material, absorption.
Frequently asked questions
If the filler is absorbable, does the effect disappear completely?
The material is absorbed over time, but the pace varies by product, area, volume and patient. Some effects, such as collagen stimulation, can last longer than the material itself.