The Composition of Implanon: A Plastic Rod
To directly address the query, Implanon is made of a flexible, non-biodegradable, medical-grade plastic, specifically an ethylene vinyl acetate (EVA) copolymer. It is not made of any metal. The implant itself is a single rod, approximately 4 cm long and 2 mm in diameter, designed to be inserted just under the skin of the upper arm. The EVA copolymer serves as the matrix that holds and slowly releases the synthetic progestin hormone, etonogestrel, into the body over a three-year period.
The use of plastic, rather than metal, is an intentional design choice for several important reasons. A flexible plastic rod is biocompatible, meaning it is not rejected by the body and can remain safely in place for years. Its flexible nature also makes it relatively easy to insert and remove with minimal discomfort to the user. The specific formulation is optimized for the slow, consistent release of the hormone, ensuring continuous contraceptive protection without daily attention.
Implanon vs. Nexplanon: Key Material Differences
For many people, the confusion regarding Implanon and its material comes from its relationship with its successor, Nexplanon. Implanon is no longer manufactured in many parts of the world and has been replaced by Nexplanon. While both devices are physically similar and made of the same core plastic (EVA copolymer) containing the same hormone (etonogestrel), there is one critical difference in their composition.
Nexplanon contains a small amount of barium sulfate, which makes it radiopaque. This means it is visible on X-ray, CT scans, and other radiological imaging. Implanon, by contrast, does not contain this material and is therefore radiolucent (not visible on X-ray). This change was made to help doctors confirm the placement of the implant after insertion and to locate it more easily for removal, significantly improving patient safety and confidence.
Here is a comparison table outlining the key differences between Implanon and Nexplanon:
| Feature | Implanon (Discontinued) | Nexplanon (Current) |
|---|---|---|
| Core Material | Ethylene Vinyl Acetate (EVA) copolymer | Ethylene Vinyl Acetate (EVA) copolymer |
| Radio-opacity | No (Not visible on X-ray) | Yes (Visible on X-ray) |
| Hormone | Etonogestrel | Etonogestrel |
| Status | Discontinued in most markets | Currently available |
| Purpose | Long-acting reversible contraception | Long-acting reversible contraception |
How the Plastic Implant Delivers Contraceptive Protection
The plastic rod of the contraceptive implant is more than just a vessel; it is a critical component of the delivery system. Once inserted under the skin, the etonogestrel hormone is released slowly and steadily into the bloodstream. This hormone works in three primary ways to prevent pregnancy:
- Ovulation suppression: The steady dose of etonogestrel suppresses the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary gland. This prevents the ovaries from releasing an egg each month, which is the main mechanism of action.
- Cervical mucus thickening: The hormone thickens the mucus in the cervix, creating a barrier that makes it difficult for sperm to travel into the uterus.
- Endometrial thinning: It also causes the lining of the uterus to thin, making it less receptive to a fertilized egg if one were to get through.
These three actions work together to provide over 99% effectiveness. The plastic matrix ensures this process occurs consistently for up to three years, after which the hormone levels decrease, and a new implant is required for continued protection.
The Insertion Process and the Role of a Metal Tool
While the implant itself is plastic, the insertion process does involve a metal device. A trained healthcare professional uses a specialized, single-use, metal introducer tool to place the implant just under the skin. The process is straightforward and typically takes only a few minutes. A local anesthetic is used to numb the area, making the procedure nearly painless.
Here is a step-by-step overview of the insertion process:
- A healthcare provider cleans and numbs a small area on the inner side of your upper arm.
- Using the metal introducer, they insert the plastic implant just beneath the surface of the skin.
- The implant is released from the introducer, which is then removed.
- The healthcare provider may palpate the area to confirm the implant's correct placement. With Nexplanon, confirmation can also be done via X-ray if needed.
- A small bandage is applied to the insertion site.
It is important to remember that the metal introducer is only used for insertion and is removed immediately, leaving only the plastic implant behind.
Conclusion: Implanon is a Plastic, Not Metal, Implant
In summary, the answer to is Implanon metal or plastic is definitively plastic. Both Implanon and its successor, Nexplanon, are composed of a flexible, medical-grade plastic rod (EVA copolymer) that is designed for safe, long-term use within the body. While the original Implanon is radiolucent, the newer Nexplanon is radiopaque, a key safety feature that aids in visualization. Understanding this fundamental difference can clarify a common point of confusion. For any questions or concerns about the implant, it is always best to consult a trained healthcare professional.
For more information on the official product labeling, including composition and function, you can refer to the FDA label for Implanon.
