The fat under the skin gets denser and healthier-looking on scans even when the amount of that fat doesn’t change much — the drug is improving its quality directly.

The drug makes the fat around the organs healthier-looking on scans more than the fat under the skin — it works better on belly fat than on thigh or arm fat.

The same HIV patients with belly fat who responded to tesamorelin also saw their under-the-skin fat become denser by 3.5 points on CT scans after 26 weeks, regardless of fat amount changes, indicating healthier fat tissue.

Even when scientists account for how much belly fat was lost, the fat that’s left still gets denser and healthier-looking on scans — meaning the drug is doing something beyond just shrinking fat.

Before treatment, the fat under the skin looked just as healthy on scans in both the drug and placebo groups — so any changes later were caused by the drug.

For HIV patients with belly fat who responded to tesamorelin, denser subcutaneous fat (on CT scans) was linked to less subcutaneous fat area, showing that fat quality and quantity are related.