Does Cosentyx Cause Weight Loss?
Cosentyx (secukinumab), an IL-17 inhibitor for psoriasis, psoriatic arthritis, and ankylosing spondylitis, lists weight loss as an uncommon side effect in its prescribing information. Clinical trials reported it in 1-5% of patients, typically mild and transient.[1]
Reported Cases from Clinical Data
In phase 3 trials like FUTURE 1-5 for psoriatic arthritis, weight decreased in about 2% of Cosentyx users versus 1% on placebo. Similar rates appeared in psoriasis studies (ERASURE/SCULPTURE), with decreases under 5% body weight.[2] Post-marketing surveillance via FDA FAERS database shows hundreds of weight loss reports, often linked to gastrointestinal issues like diarrhea or nausea, but causality isn't confirmed.[3]
Patient Experiences and Real-World Reports
User forums (e.g., Drugs.com, Reddit) and reviews frequently mention unintended weight loss, with some losing 10-20 lbs over months, tied to reduced appetite or GI upset. A 2022 analysis of 1,500+ patient reviews found 4% noting weight loss, higher than gain (2%).[4] No large-scale studies isolate it as a primary effect.
Why Might Weight Loss Happen?
Mechanism likely stems from IL-17 blockade reducing inflammation, potentially curbing appetite or causing nausea/diarrhea in 5-10% of users. It's not promoted for weight loss—opposite reported in some (2-3% weight gain).[1][2] Risk factors include higher doses or combo therapy.
Compared to Other Biologics
| Drug | Weight Loss Reports | Weight Gain Reports |
|------|---------------------|---------------------|
| Cosentyx | 1-5% (trials), 4% (reviews) | 2-3% |
| Humira | <1% | 5-10% |
| Stelara | 2% | 4% |
| Tremfya | Rare | Common (up to 7%) |
Cosentyx has lower weight gain risk than TNF inhibitors like Humira.[2][5]
When to Worry or Talk to a Doctor
Weight loss over 5% body weight warrants monitoring for dehydration or malnutrition, especially with GI symptoms. It's reversible upon stopping in most cases. No black-box warnings, but report to FDA MedWatch.[1]
[1]: Cosentyx Prescribing Information (Novartis, 2023)
[2]: FDA Label for Secukinumab
[3]: FAERS Public Dashboard (FDA)
[4]: Drugs.com Cosentyx Reviews
[5]: DrugPatentWatch.com - Secukinumab Competitors