Colchicine does not cause weight gain. In clinical trials, people taking colchicine showed no meaningful increase in body weight compared to those on placebo. If anything, the drug’s most common side effects pull in the opposite direction, making minor weight loss more likely than gain during treatment.
What the Clinical Evidence Shows
In a randomized controlled trial of adults with metabolic syndrome, those taking colchicine lost an average of 0.1 kg over the study period, while the placebo group gained 1.1 kg. That difference of about 1.2 kg wasn’t statistically significant, meaning colchicine can’t be credited as a weight loss tool either. But the data clearly show it doesn’t promote weight gain. Other body composition measurements in the same trial also showed no significant changes between the two groups.
Weight gain is not listed among colchicine’s recognized side effects in clinical literature. The drug has been used for decades to treat gout flares, familial Mediterranean fever, and pericarditis, and no pattern of weight gain has emerged from that long track record.
Why You Might Lose Weight Instead
The side effects colchicine does cause tend to reduce appetite and calorie absorption rather than increase them. Diarrhea is the most common side effect, occurring in about 23% of users. Vomiting affects roughly 17%, and nausea ranges from 4% to 17%. These gastrointestinal symptoms can lead to temporary weight loss, especially during gout flares when colchicine doses may be higher.
Colchicine also interferes with nutrient absorption in the small intestine. Research published in the New England Journal of Medicine found that oral colchicine reduces vitamin B12 absorption by altering how the lining of the lower small intestine functions. This effect is reversible once the drug is stopped, but it illustrates how colchicine can disrupt normal digestive processes. Over time, impaired nutrient absorption could contribute to modest weight loss rather than gain.
Colchicine’s Effect on Fat and Metabolism
Interestingly, colchicine may have subtle metabolic benefits. A study in adults with obesity and metabolic syndrome found that colchicine improved how the body uses insulin to regulate fat breakdown. Specifically, it reduced the rate at which fat cells release fatty acids into the bloodstream, a process that becomes dysregulated in people with insulin resistance. The same research group previously reported that colchicine significantly reduced a standard measure of insulin resistance compared to placebo.
These findings are preliminary and don’t mean colchicine is a metabolic treatment. But they reinforce the picture: colchicine’s metabolic effects, if any, lean toward improving fat regulation rather than promoting fat storage.
Why Gout Patients May Gain Weight Anyway
If you’re taking colchicine for gout and noticing weight gain, the drug probably isn’t the cause, but the underlying condition could be a factor. Gout is tightly linked to obesity and metabolic syndrome. In one multicenter study, 43.6% of gout patients met criteria for metabolic syndrome, compared to just 5.2% in the general population. Higher BMI was the strongest risk factor for metabolic syndrome in that group. So people taking colchicine are often already on a trajectory toward weight gain because of the same metabolic factors driving their gout.
Other medications used alongside colchicine can also contribute. Corticosteroids like prednisone, sometimes prescribed for severe gout flares, are well known to cause weight gain through increased appetite, fluid retention, and changes in fat distribution. If you started a corticosteroid around the same time as colchicine, that’s a far more likely explanation for any weight change.
What to Watch For
While weight gain isn’t a concern with colchicine, the gastrointestinal side effects are worth tracking. Persistent diarrhea or nausea can lead to dehydration and nutrient deficiencies over time, particularly vitamin B12. If you’re on long-term colchicine and experiencing ongoing digestive issues or unexplained fatigue, those symptoms are worth raising with your doctor. They’re solvable problems, but they won’t resolve on their own if the drug is the cause.
Unexplained weight changes in either direction while taking colchicine are more likely related to your underlying health conditions, diet, activity level, or other medications than to colchicine itself.