"Biopolymers" and modelantes are loose names for permanent, non-medical substances (often industrial-grade liquid silicone, oils or unknown gels) injected into the buttocks, hips, breasts, legs or face, frequently by unlicensed people. Once injected, they can't simply be dissolved or drawn back out. They can cause chronic inflammation, hard lumps, infection, migration and disfigurement years later. If someone offers permanent body enlargement by injection, especially cheaply, outside a medical facility or without naming the product, don't do it.
This explainer covers how these substances differ from approved fillers and from fat transfer, the sales pitches to watch for, how to check what's actually being injected, and what to do if you already had injections in the past.
In this guide
What "biopolymers" and "modelantes" really are
The word "biopolymer" sounds scientific and reassuring, which is part of the problem. In everyday Latin American usage it has become a catch-all for permanent liquids or gels injected to add volume. In practice, what goes into the syringe may be industrial liquid silicone, mineral or vegetable oils, paraffin, or a product with no reliable label at all. Modelantes ("shapers") is another common name for the same idea.
These substances are generally not approved for injection to enlarge the body. In the US, for example, the FDA has publicly warned against injectable silicone for body contouring and filling. In Colombia, injecting products without proper health registration and outside a qualified medical setting puts people at serious risk. Colombian authorities have also given the problem public attention. If you're researching specific laws, check current official sources, because rules and bills on this topic have been debated and can change.
Permanent means that if something goes wrong, the body can't break it down and a doctor can't easily remove it. The material can spread into surrounding tissue, so there's often no single implant to take out.
How they differ from approved fillers and fat transfer
People sometimes lump all "injections" together. The differences matter enormously.
| Factor | Biopolymers / modelantes | Approved fillers (e.g. hyaluronic acid) | Fat transfer |
|---|---|---|---|
| What it is | Non-medical or unidentified permanent substance | Regulated product with known composition and registration | Your own fat, moved by liposuction and grafting |
| Who should perform it | Often unlicensed people, salons, homes, "spas" | Trained, licensed clinicians | A qualified plastic surgeon in an operating room |
| Used for body volume? | Marketed that way, but not appropriate | Mainly face and small areas, not large body volumes | Yes. This is the standard surgical way to add the body's own volume. |
| Reversible? | No. It can migrate and is very hard to remove. | Hyaluronic acid fillers can usually be dissolved | Not reversible, but it's living tissue that integrates |
| Long-term problems | Chronic inflammation, hard nodules, infection, migration, skin damage | Usually limited and treatable when done properly, though complications do occur | Surgical risks, including serious ones with BBL, plus fat loss and cysts |
Swipe to see the full table →
Fat transfer has serious risks of its own, particularly in the buttocks, and must be done by a qualified surgeon in an accredited setting. But it's an established surgical procedure with known risks you can discuss and consent to. An unknown liquid injected in a salon isn't. For legitimate non-surgical options, see our guide to non-surgical aesthetics in Colombia.
What can go wrong, and why it can take years to show
Problems may appear soon after injection or many years later. That's one reason people underestimate the danger: friends who had injections may look fine for a while. Complications that doctors describe with these substances include:
- Chronic inflammation: the body reacts to foreign material by walling it off. This can cause pain, hardness and recurring swelling.
- Lumps and hardening: nodules or large firm areas, sometimes visible through the skin.
- Migration: material can travel downward or into other areas, for example from the buttocks toward the thighs.
- Skin changes: redness, discoloration, thinning, ulcers or open wounds over injected areas.
- Infection: sometimes recurring, and harder to clear when foreign material remains.
- Systemic and emergency problems: injected substances can enter the bloodstream, and serious reactions, including to the lungs, have been reported. Some can be life-threatening.
During or after any injection you develop shortness of breath, chest pain, coughing blood, confusion, fainting or a high fever. Call 123 in Colombia (911 in the US) and tell the team exactly what was injected, or that you don't know.
Red-flag sales pitches
Illegal injections are often sold through social media, word of mouth, and "promotions". These phrases should stop you.
- "It's permanent, so you'll never need to repeat it."
- "No surgery, no anesthesia, no recovery."
- "We come to your home" or "it's done at the salon / spa / apartment."
- A price that seems far too low for the volume promised.
- Large-volume enlargement of the buttocks, hips, legs or breasts by syringe alone.
- Vague answers about the product: "it's a biopolymer", "it's medical grade", "it's imported".
- No sealed packaging, no registration number, no named licensed doctor.
- Pressure to decide today, or deposits sent to a personal account.
Some of these pitches also come from facilities that look medical. A white coat and a clinic logo don't make a product safe. That's why you have to ask what's being used. Our red flags when choosing a clinic guide covers the wider warning signs.
How to check exactly what's being injected
- Ask for the product name, in writingThe brand, the substance and the intended use. "Filler" or "biopolymer" isn't an answer.
- Ask for its INVIMA registrationINVIMA is Colombia's regulator for medicines and medical devices. A legitimate product should have a health registration (registro sanitario) you can look up on INVIMA's official website.
- Check it matches the useA registration for one use doesn't make a product appropriate for another. Ask whether it's registered for the area and volume being treated.
- See the sealed packagingAsk to see the unopened box and label before treatment, and keep a photo of the lot number.
- Verify the person injectingCheck they are a licensed doctor in RETHUS, and for anything surgical, a plastic surgeon you've verified through the SCCP.
- Walk away if any answer is vagueYou can't undo a permanent injection. Leaving costs you nothing.
If you already had injections in the past
Many people had body injections years ago, sometimes without knowing what was used. If that's you, you're not alone, and there's no shame in asking for help. Get evaluated by a plastic surgeon if you notice:
- new or worsening pain, swelling or hardness in injected areas
- redness, warmth, skin color changes or open sores
- lumps that are growing or moving
- recurring fevers or feeling generally unwell without another explanation
Write down everything you remember: when and where you were injected, the areas and approximate amounts, what you were told the product was, and any treatment since. Imaging such as ultrasound or MRI may be used to map where material has spread.
Removal is complex. Because these substances infiltrate surrounding tissue, surgery may remove some material and affected tissue but often can't remove all of it, and it can leave scars or contour changes. Treatment is individual and may involve managing inflammation rather than removing everything. Be wary of anyone promising complete removal or a quick fix. Our guide to the cost of cheap surgery gone wrong explains why fixing a complication often costs far more, physically and financially, than doing things safely the first time.
If you can't name the product and check its registration, don't let anyone inject it into your body.
Frequently asked questions
Are biopolymers the same as fillers?
No. Biopolymers or modelantes usually means permanent, non-medical substances such as liquid silicone or oils. Approved fillers are regulated products with known composition, and hyaluronic acid fillers can usually be dissolved.
Can biopolymers be removed?
Sometimes partly, but rarely completely. These substances spread into surrounding tissue, so removal surgery is complex, may leave scars or contour changes, and should be planned by experienced plastic surgeons.
How can I check if an injectable product is legal in Colombia?
Ask for the exact product name and its INVIMA health registration number in writing, then look it up on INVIMA's official website. Make sure it's registered for the use being offered, and see the sealed packaging before treatment.
I had butt injections years ago and feel fine. Should I worry?
Many people have no symptoms for a long time, but problems can appear years later. Watch for pain, swelling, hardness, redness, skin changes or lumps, and see a plastic surgeon if any develop. Telling your doctors about the injections is always wise.
Is fat transfer a safer alternative to biopolymer injections?
Fat transfer uses your own tissue and is an established surgical procedure. It still has real risks, especially in the buttocks, so it must be done by a verified plastic surgeon in a properly equipped facility after a full consent discussion.
Have questions about past injections or safer options?
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