Worried that an IUD like Mirena, Kyleena, or a copper IUD might cause weight gain, acne, or depression? Patients come to Mint Reproductive Health in Vancouver all the time asking, “Will a Mirena, Kyleena, or copper IUD make me gain weight or mess with my mood?” These are valid worries—I hear them weekly. Here’s what the research shows and what matches my experience helping hundreds of patients choose and manage IUDs.
IUD Weight Gain: Fact or Myth?
Myth: IUDs cause significant, ongoing weight gain. The reality is more nuanced.
Hormonal IUDs like Mirena and Kyleena release levonorgestrel locally in the uterus, which may cause temporary water retention and bloating in the first few months, leading to about 1–5 pounds of gain for some users. Clinical trials for Kyleena showed no evidence of weight gain as a side effect, while Mirena trials reported it in about 6% of users—but researchers could not confirm it was caused by the IUD.
Copper IUDs, being hormone-free, do not cause weight gain; studies show users gain weight at the same rate as non-users (about 1–2 kg over years), likely due to age, lifestyle, or other factors.
Bottom line: Any initial gain is usually temporary water weight, not fat, and resolves after 3–6 months. Long-term weight changes are more tied to diet, exercise, and life stage than the IUD itself.
IUD causes Acne: What the Evidence Shows
Fact: Hormonal IUDs can cause acne or skin changes for some people.
Levonorgestrel in Mirena and Kyleena is a progestin that can increase oil production and affect hormones systemically, leading to acne, oily skin, or hair changes in a small percentage of users.
Product monographs list acne as a possible side effect, though it is uncommon and often improves over time as your body adjusts. Copper IUDs have no hormonal impact, so they do not cause acne and may even be a good choice if skin concerns are a priority.
What to watch for: If acne worsens significantly after insertion, track it and discuss with your clinician, they may suggest topical treatments or switching methods.
IUD and Depression or Mood Changes: The Connection
Myth with some truth: IUDs do not directly cause depression, but hormonal changes can affect mood for some.
Data from Mirena trials show about 6.4% of users reported low mood or depression over 5 years, compared to background rates in the general population.
Levonorgestrel can influence mood via progestin effects on the brain, with some users reporting anxiety, irritability, or low mood especially in the first months. However, studies do not prove causation, and many factors (stress, life changes, pre-existing conditions) play a role. Copper IUDs, lacking hormones, are not linked to mood changes beyond possible cramping-related discomfort.
Key insight: If you have a history of depression or mood disorders, discuss screening and monitoring with your doctor before insertion. Symptoms often improve over time, but removal is always an option if needed.
Comparison Table: Side Effects Across IUD Types
| Concern | Mirena (Hormonal) | Kyleena (Hormonal) | Copper IUD (Non-Hormonal) |
|---|---|---|---|
| Weight Gain | Possible temporary (water retention); ~6% reported, not proven causal | No evidence in trials; lower hormone dose may mean less bloating | None; matches non-users |
| Acne / Skin | Possible (progestin effect); uncommon | Possible, similar to Mirena but potentially milder | None |
| Mood / Depression | ~6% reported low mood; monitor if history | Similar risk; individual response varies | None (hormone-free) |
What to Do If You Experience These Side Effects
Most side effects peak in the first 3–6 months and improve as your body adjusts. Track symptoms with a journal and contact Mint Reproductive Health if:
- Weight up >5 lbs after month 3
- Acne won’t quit after week 8
- Feeling unlike yourself >4 weeks
We do check in appointments and ultrasound at 4-6 weeks for all of our patients. If the IUD is not right for you, we can often take it out the same day, or plan to monitor more closely.
Dr. Alana Shaw, ND
Naturopathic Physician, Clinic Director
Mint Reproductive Health, Vancouver
