If young, non-obese men take 500 mg of carrageenan every day for two weeks, their gut might become more leaky, which you can tell by higher levels of certain substances in their urine and blood.

Eating carrageenan, a common food additive, might make your gut leakier, letting harmful stuff from your intestines escape into your bloodstream and cause long-term swelling in your body.

Eating carrageenan — a common food additive — doesn’t seem to change how well the body uses insulin or cause brain swelling in healthy, slim young men after two weeks, even though it might make their gut leakier and trigger their immune system a bit.

Eating carrageenan — a common food additive — doesn’t change the types of bacteria in the gut of healthy young men after two weeks.

If you have a higher body weight (BMI 27 or more), taking a common food additive called carrageenan for two weeks might make your body less responsive to insulin — and this effect is stronger the more body fat you have, compared to not taking it.