Saline breast implants can be associated with breast implant illness (BII), though the risk appears lower than with silicone-filled implants. A meta-analysis published in Plastic and Reconstructive Surgery Global Open found that silicone implants carried roughly twice the risk of BII-type symptoms compared to saline implants. But “lower risk” is not “no risk,” and many patients with saline implants report the same constellation of systemic symptoms.
How Saline Compares to Silicone for BII Risk
The most direct comparison comes from a systematic review and meta-analysis that pooled data across multiple studies. Silicone-filled implants were associated with a significantly increased risk of overall BII-type symptoms, with a relative risk of 2.11 compared to saline. Intact saline implants were less likely to cause symptoms than ruptured or silicone-filled devices. That said, researchers have noted that some recent studies find BII equally present among saline implant patients, and that the issue may stem from the scar tissue capsule the body builds around any implant rather than from the fill material itself.
This is an important distinction. Every breast implant, saline or silicone, has an outer shell made of silicone elastomer. Your body is in constant contact with that shell, not the liquid inside. Research in Frontiers in Immunology has shown that the silicone shell itself can modulate immune and inflammatory responses in surrounding tissue. So even though the saline solution inside the implant is biologically inert, the shell your immune system reacts to is the same basic material in both types.
Why Saline Implants Aren’t Necessarily “Safe”
One unique concern with saline implants is microbial growth inside the device. A study published in the Annals of Plastic Surgery found that several types of bacteria and fungi can survive and reproduce inside a saline-filled implant for extended periods. Gram-negative bacteria, yeast, and mold species all grew within the implant environment during testing. In some cases, organisms appeared to migrate through the implant’s filler valve, the small port used to inflate the implant after it’s placed. Seven of ten organisms tested were able to grow inside the implant’s saline over time.
This matters because a low-grade bacterial or fungal presence could contribute to chronic inflammation without causing obvious infection. It’s one proposed explanation for why some saline implant patients develop systemic symptoms even though the fill material itself is harmless salt water.
Common Symptoms Reported
BII is not a formal medical diagnosis. The FDA acknowledges the term and the pattern of symptoms patients report but notes there are no specific diagnostic tests or recognized criteria to define it. The symptoms are real, but the mechanism linking them to implants is still being studied.
The most frequently reported symptoms across both implant types are fatigue, joint pain, and muscle pain. In a large meta-analysis of explantation outcomes, fatigue was reported by 58.3% of BII patients, joint pain by 51%, and muscle pain by 44%. Other commonly described symptoms include brain fog, sleep disturbances, skin rashes, hair loss, and general malaise. These overlap heavily with autoimmune and connective tissue disorders, which is part of what makes BII difficult to pin down.
How BII Is Identified
Because no blood test or imaging study can confirm BII, the process is one of exclusion. Your doctor will typically run blood panels looking for markers of autoimmune diseases, thyroid disorders, and other inflammatory conditions that could explain your symptoms. You may be referred to a rheumatologist or immunologist. If nothing else accounts for the symptom pattern, and your symptoms align with the BII profile, implant removal becomes a serious consideration.
The American Society of Plastic Surgeons confirms this approach: doctors try to rule out inflammatory or autoimmune diseases first, then consider whether the implants themselves may be contributing.
What Happens After Removal
The strongest indirect evidence connecting implants to these symptoms comes from explantation data. Across studies, 81.9% of patients reported symptom improvement after having their implants removed. That number includes patients with both saline and silicone devices. Many patients describe significant relief from fatigue, joint pain, and cognitive symptoms within weeks to months of explantation, though some symptoms take longer to resolve and a smaller percentage of patients see no change.
Most surgeons recommend removing the implant along with its surrounding scar tissue capsule, a procedure called en bloc capsulectomy. The rationale is that the capsule itself may harbor bacteria, silicone particles, or inflammatory compounds that could perpetuate symptoms if left behind. Recovery from explantation surgery typically takes a few weeks, with full tissue settling over several months.
The Bottom Line on Saline and BII
Saline fill does appear to carry a lower risk profile than silicone gel, based on pooled data. But the silicone shell, the potential for internal microbial colonization, and the body’s own capsular response mean saline implants are not exempt from triggering systemic symptoms. If you have saline implants and are experiencing unexplained fatigue, joint pain, cognitive changes, or other persistent symptoms that don’t match another diagnosis, BII is worth discussing with a board-certified plastic surgeon experienced in explantation.