What Are Body Fillers?

Body fillers are injectable products that may be used to restore lost volume, improve body shape and address certain uneven areas, such as dents or differences between the two sides of the body. They can improve the appearance of selected areas without surgery.

Common treatment areas may include the buttocks, hands, calves, upper arms and décolletage (the upper chest area). Whether treatment is suitable depends on the product used, the area being treated and the individual patient's circumstances.

Filler Types:

There are different types of fillers:

• Hyaluronic acid fillers (made from a substance naturally found in the body that helps retain moisture and add volume).
• Biostimulators, such as poly-L-lactic acid and calcium hydroxylapatite, which stimulates collagen production to help improve volume and skin structure over time.

Non-permanent fillers are commonly used because they generally offer a more established safety profile than permanent fillers. One advantage of hyaluronic acid fillers is that they can be dissolved using an enzyme called hyaluronidase if needed. However, this does not eliminate all risks or guarantee that every complication can be reversed.

Permanent synthetic fillers are less commonly used and are banned or restricted in some countries because of their higher risk of complications, which may be difficult to treat or reverse.

Body fillers are usually injected beneath the skin using a blunt-tipped needle called a (micro)cannula. Its rounded tip may help reduce bruising and the risk of injury to blood vessels compared with a sharp needle, although it does not eliminate these risks.

Using a (micro)cannula rather than a sharp needle for body filler injection is generally recommended for a few well-documented reasons:

• Reduced risk of blood vessel injury. A cannula has a blunt, rounded tip that may push blood vessels aside rather than puncturing them. This can reduce the risk of injecting filler into a blood vessel, which may block blood flow and cause tissue damage. In rare cases, filler entering the bloodstream can cause serious complications. This is particularly important when treating areas such as the buttocks, where larger blood vessels may be present and larger volumes of filler may be used.
• Fewer injection points and broader coverage. A single-entry point may allow the cannula to reach different parts of the treatment area, reducing the need for multiple separate injection points.
• Less bruising and tissue trauma. Because the blunt tip separates tissues rather than cutting through them, cannula use may cause less bruising and tissue damage, potentially making recovery more comfortable.
• More even, controlled placement. A cannula can help the surgeon place filler within the intended tissue layer, supporting a smoother and more even distribution of the product across the treatment area.

It is important to understand that using a cannula reduces certain risks but does not eliminate them. Blood vessel injury and blockage can still occur. The injector's training, knowledge of the body's anatomy and careful injection technique remain essential, regardless of whether a cannula or needle is used.

*ISAPS does not endorse any named company or product.

Mechanism of Action

Different fillers work in different ways.

Hyaluronic acid (HA) attracts and holds water, helping to add volume soon after injection. The way the product is formulated affects its thickness, how it holds its shape and how long the results last.

Biostimulators work differently. Calcium hydroxylapatite (CaHA) provides immediate volume and also supports the body's production of new collagen, a protein that helps give the skin structure and support. Poly-L-lactic acid (PLLA) stimulates the body's natural collagen-producing processes, so improvements in volume develop gradually over time rather than appearing immediately.

Contraindications

Body filler treatment may not be suitable for everyone. Treatment should generally be avoided if there is an active infection at or near the injection site, or a known allergy to the filler or one of its ingredients.

Fillers are generally not recommended during pregnancy or breastfeeding because there is insufficient safety information. Certain autoimmune conditions or inflammatory skin conditions affecting the treatment area may also require additional assessment.

Medicines that affect blood clotting, including anticoagulants and antiplatelet medicines, is a relative caution for bruising. Patients should discuss all their medicines and supplements with their surgeon and should not stop prescribed medication unless advised doing so by an appropriate healthcare professional.

Danger Zones and Technique

When treating the body, particularly the buttocks, the surgeon must carefully avoid important blood vessels and ensure that filler is not injected into a blood vessel or muscle.

Certain fillers, including some hyaluronic acid products and PLLA, require expertise when used for buttock enhancement. These treatments should only be performed by appropriately trained and experienced plastic surgeons because complications can include lumps, inflammatory reactions and, rarely, serious blood vessel-related events.

Evidence supporting filler-based buttock enhancement remains limited. Published research includes a small number of clinical reports, many of which have important limitations. Patients should discuss the potential benefits, uncertainties and risks before deciding whether to proceed.

Complication Management

The injector must be prepared to recognise and manage complications promptly.

If a blood vessel becomes blocked, urgent assessment and treatment are needed to protect the affected tissue. Hyaluronidase, an enzyme that dissolves hyaluronic acid filler, may be used when appropriate. Patients can ask whether their injector has the necessary emergency supplies and protocols available. Hyaluronidase does not dissolve every type of filler.

If lumps or inflammatory reactions develop, treatment depends on the cause and may include dissolving the filler where appropriate, prescription treatments or antibiotics if an infection is suspected. Surgical removal may occasionally be necessary for persistent or difficult-to-treat lumps.

Severe allergic reactions, including anaphylaxis, are rare but can occur with injectable treatments. They require immediate emergency treatment by a trained healthcare professional.

Who are body fillers for?

Body Fillers may be suitable for patients who are looking to improve:

• Body contour
• Correct irregularities
• Enhance specific areas without surgery.

Suitability will depend on overall patient health and expectations.

Preparation

Before treatment, patients undergo:

• A consultation to assess patient wishes about treatment areas and goals
• Review of medical history, medications and allergies
• Advice on avoiding blood-thinning medications or supplements if appropriate (plastic surgeon will evaluate every patient individually and give detailed information)