Why is Silicone Safe in Breast Implants, Not Injections?

If so many doctors are against injecting silicone into other parts of the body, why are silicone breast implants considered safe?

I've read that they are likely to leak at least a little at some point -- so how is that silicone in your body any different than injecting it elsewhere? 

Doctor Answers 12

Silicone safe for breast implants, but not for injection?

Great question!

While my colleagues have predominantly talked about liquid silicone injections causing granulomas, your question (to me) still seems mostly unanswered. Dr. Aldea has given an answer that outlines why silicone injected in the form of liquid droplets within your tissues is different from a solid implant contained within its capsule (scar covering). He  explains why the tiny scars your body forms around silicone droplets (injected silicone liquid causing granulomas) can be extremely difficult if not impossible to remove surgically. Why would you want these silicone droplets out? Because the granulomas may become firm, tender, and can migrate, since there is no solid form to keep them together.

Silicone breast implants, however, are now cohesive, meaning they are a soft solid silicone elastomer that cannot leak or migrate. Truthfully, microscopic molecules of silicone ARE within your body already, since immunizations, tetanus boosters, penicillin or other medication injections, insulin shots, and other injectables (including IV catheters) are all lubricated with liquid silicone, and we all have tiny amounts of this silicone within our bodies.

Silicone is polydimethylsiloxane (PDMS), which is a polymer. The length and cross-linking of the polymer chain(s) are responsible for the physical properties of these substances. Shorter chain lengths of PDMS are oils or liquids, whereas longer-chain, cross-linked, high molecular weight silicones (PDMS) are rubbery elastomers. Even longer-chain silicones can form harder and even less pliable elastomers, like finger joints, pacemaker insulation, testicular implants, and yes, bathtub seal!

The present generation of breast implants are made up of a cohesive, high molecular weight, cross-linked silicone gel that is a soft, rubbery solid all the way through, meaning it cannot leak or rupture. (BTW, this makes the FDA recommendation for periodic MRI scans to look for "silent rupture" in the present generation of silicone implants nonsensical, though this may be appropriate if you have a problem with older silicone implants, which had a elastomer shell containing less cross-linked, spongy, sticky PDMS gels or liquids.)

So, even though injectable polydimethylsiloxane liquid has the same molecules as polydimethylsiloxane solid, the latter does not migrate in soft tissues, does not cause a granulomatous reaction, and is contained in an anatomically usable shape. The liquid silicone injections are "safe" in the sense of not causing autoimmune disease or cancer; it's just that injections can cause these unpredictable micro or macro scars (granulomas) that can be nearly impossible to remove if they become tender, inflamed, infected, or just look bad if they migrate where they are not intended.

To be sure, silicone gel implants can also become infected (requiring removal, but that is easily possible, and thankfully very rare), develop capsular contracture (usually from bleeding or bacterial contamination), or be malpositioned. Artificial hips, pacemakers, or heart valves can also develop some of these issues. How and where they are put into your body is much more of an issue than their molecular makeup! And remember, the present generation of silicone breast implants are a cohesive solid and CANNOT leak--no MRI scan needed nor advisable.

Sorry to be so technical, but I hope that explains things in a way others were not conveying! Best wishes!

Minneapolis Plastic Surgeon
4.9 out of 5 stars 255 reviews

Difference between injecting silicone and breast implants.

Silicone implants after 2006 in the USA are now highly cohesive meaning they are more like jello or gummy bear like to an extent. They are also contained in a solid silicone shell and can easily be removed at any time.. In contrast liquid silicone is an oil which can more easily travel to other areas such as lymph nodes and less predictable and nearly impossible to remove without causing collateral tissue damage.

Larry S. Nichter, MD, MS, FACS
Orange County Plastic Surgeon
4.9 out of 5 stars 154 reviews

Silicone In Breast Implants vs as an Injectable Filler

This is a great question and a very logical one that is rarely asked. Liquid injectable silicone and silicone gel in breast implants differ in numerous ways which makes for a dramatic difference in how the body reacts to them. First, injectable silicone is a low-polymerized oil that is dispersed in the tissues in small droplet form. This leaves a lot of oil surface area for the body to react to and causes more natural inflammation due to its oil state. Silicone in breast implants is in a more highly-polymerized form that is encased in its own protective bag or barrier. This results in no silicone being exposed to the body so no reaction to it occurs. If ruptured, the released silicone is further protected by the body by the natural scar (capsule) that was originally formed around the implant. The more polymerized silicone gel causes less inflammation or reaction from the body than oil even if it does become exposed to it. Lastly, silicone gel in breast implants has been highly studied and evaluated by the FDA with rigorous scientific scrutiny as to its bodily effects. Injectable silicone oil has never been exposed to such scientific scrutiny as a soft tissue filler.

Barry L. Eppley, MD, DMD
Indianapolis Plastic Surgeon
4.7 out of 5 stars 72 reviews

Why breast implants and not silicone injections

The silicone in a breast implant is contained in a silicone rubber elastomer shell and is not in contact with the tissue. Silicone injections into the breast form cysts or granulomas which become firm, calcify, and cannot be removed without removing the tissue around them which becomes disfiguring. What about a gel implant that leaks? Even small leaks will cause irritation of the breast and capsule, calcification of the capsule, and granulomas if the leak is outside of the capsule.

Best of luck,


Peter E. Johnson, MD
Chicago Plastic Surgeon
4.0 out of 5 stars 42 reviews

Why is Silicone Safe in Breast Implants, Not Injections?

Because the silicone implants are medical grade silicone gel ENCLOSED in a covering that has been FDA studied. Vs silicone injections are only acceptable in very very low doses for the face.  Do some further self research. 

Darryl J. Blinski, MD
Miami Plastic Surgeon
4.6 out of 5 stars 173 reviews

Injected Silicone versus Breast Implants-What is all the fuss about?

While it is true that there are medical uses for injectable silicone gel such as in the eye, that is because the eye tissues react minimally to the presence of the gel when compared to other tissues of the body.  Silicone gel freely injected into the skin, subcutaneous tissues, or lets say the breast will trigger a more aggressive foreign body reaction that can result in firm, hard, and often painful lumps called granulomas.  These can be very difficult if not impossible to remove and they can develop many years after the silicone injections had be originally performed.

Breast implants differ in that all breast implants currently in use have a silastic shell which is made with silicone that is then filled with either saline (salt water) or silicone gel.  The silicone gel can vary in its cohesiveness, some being so cohesive that they have earned the nickname "gummy bear implants."  When the breast implant is placed inside the body, there is a reaction by your body to wall off the implant from the rest of the body.  This is the capsule that forms around the implant.  If the implant should rupture, then the filling material can leak out of the implant and into the pocket that is between the implant and the capsule.  If it is a silicone gel implant,  the type of gel used in implants is biocompatible but it is not bioabsorbable.  Therefore the gel will sit inside the pocket unless the capsule is torn or disrupted.  Then the silicone gel can leak out of the pocket and into the surrounding breast tissues where it can cause a foreign body reaction that can lead to painful lumps or hard spots in the breast similar to having injected the gel directly into the breast.  Modern implant shells are designed to be more durable than implants in the past and the silicone gel filling materials less likely to leak.   Again the goal with silicone gel is to keep it inside the implant shell where it is less likely to cause problems.  That is not the case when silicone is freely injected into most tissues of the body.

Hope this helps.

Herluf G. Lund, Jr, MD
Saint Louis Plastic Surgeon
4.7 out of 5 stars 83 reviews

Silicone Implants vs. Silicone Injections

Silicone is one of the safest products used in medicine. It can be applied to the skin (shampoos). It can be ingested (medications). It coats Intravenous catheters. It can be implanted as breast, chin, cheek implants. It is used for tubing for lifesaving brain shunts. However, there is a huge difference between placing silicone breast  implants and injecting liquid silicone into the body.

Silicone injections consist of injecting silicone into the body to fill wrinkles or enlarge a body part. In the past it was used for lip enlargement, non-surgical rhinoplasty, cheek and chin augmentation, and before the advent of breast implants free silicone injections were used for breast augmentation. The initial results are often fantastic, the problems occur later, and can be horific disasters. The silicone can migrate to an undesired location, and the body can react to the silicone by making hard, lumpy irregular scars.

All breast implants are a solid shell of silicone. Some are filled with saline and some are filled with a viscous silicone gel. As long as the shell remains intact, the liquid inside the shell is contained. If a silicone filled breast implant ruptures, the free gel can sometimes get out and cause the problems similar to free silicone injections. The current implants are made with a much tougher shell and are filled with a thicker gel to try an reduce the risk of gel migration.

Even so, when a breast implant leaks, it is removed (and usually replaced) to minimize the potential complications of the free gel. Since it takes time for the complications to develop, the sooner the broken implant is removed, the less likely the gel is to cause problems.

Gummi-bear or form stable implants are filled with a gel that is thickened to a solid, so gel migration is not possible.

Joseph Mele, MD
Walnut Creek Plastic Surgeon
4.5 out of 5 stars 17 reviews

Why is Silicone Safe in Breast Implants, Not Injections?

Great question.

All of us want to be able to reverse a bad decision; that is the purpose of the back arrow at the top left of Internet Explorer, erasers at the ends of pencils, Mulligans in golf  and to older members of the audience - Liquid Paper. Nothing like getting a do over without suffering the consequences of a poor decision or a complication.

Breast implants are made of a silicone shell which contains EITHER salt water or silicone gel. When the shell leaks, the silicone is keep contained in the scar pocket the body makes and is removed when the implants are replaced. On the other hand, free injections of silicone results in the silicone being placed in multiple levels within the flesh. This silicone cannot be easily removed. Its removal can be done only by mutilating removal of multiple areas of the scarred flesh resulting in hollows and depressions which are very hard if not impossible to correct.

For this reason, when we use fillers, we prefer the ones that are temporary or come with an eraser - Restylane, Perlane and other such fillers can be dissolved with an enzyme and no surgery is needed to remove them

Dr. Peter A Aldea 

Peter A. Aldea, MD
Memphis Plastic Surgeon
4.9 out of 5 stars 108 reviews

Medical grade silicone is nontoxic

Actually the FDA has cleared injectable silicone for the emergency treatment of retinal detachment, so it is considered safe enough to inject directly into your eye. The problem with nondegradable materials such as silicone when injected into the skin is that long-term the results might not look right even if they look good for the first few years. This is true for all materials that don't degrade and not related to any toxicity of silicone. However it should be pointed out that silicone can be made into different forms from a liquid to a gel to a solid, and the gel used in breast implants doesn't flow like a liquid. In fact you can slice an implant open and the gel doesn't spill out.

Richard Baxter, MD
Seattle Plastic Surgeon
4.9 out of 5 stars 52 reviews

Injected silicone causes granulomas which are harmful

Silicone implants are contained within a silicone bag and generally do not leak outside the bag.  Injected silicone causes granulomas (inflammatory nodules) throughout the breast tissue.   These granulomas can lead to inflammation in your breasts and pain.  Sometimes this condition requires removal of your breasts, called subcutaneous mastectomy.  Fibrous capsules will form around breast implants which are not harmful.

James Tang, MD
Houston Plastic Surgeon
3.4 out of 5 stars 18 reviews

These answers are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.