The maker of Ozempic and Wegovy is suing a rival firm for selling what it says are unsafe, knock-off versions of its weight-loss drugs in the US. Danish company Novo Nordisk asked US courts on Monday to ban Hims & Hers' range of weight-loss pills and injections, which it says are not approved by US authorities and infringe on its patent. The legal drama began on Friday after Hims & Hers launched a new weight-loss pill, leading to an initial threat from Novo Nordisk. Over the weekend, Hims & Hers said it would stop selling the pill. On Monday, its share price slumped as it called Novo Nordisk's decision to press ahead with the lawsuit a blatant attack.

What we still don't know about weight-loss drugs Weight-loss drugs have been back in the news this week. First, we heard that Eli Lilly, the company behind Mounjaro and Zepbound, became the first healthcare company in the world to achieve a trillion-dollar valuation. But we also learned that, disappointingly, GLP-1 drugs don't seem to help people with Alzheimer's disease. And that people who stop taking the drugs when they become pregnant can experience potentially dangerous levels of weight gain. On top of that, some researchers worry that people are using the drugs postpartum to lose pregnancy weight without understanding potential risks. All of this news should serve as a reminder that there's a lot we still don't know about these drugs.

Explains: Let our writers untangle the complex, messy world of technology to help you understand what's coming next.

After losing nearly six stone since December with the help of weight-loss injections, Emilly Murray has been left with an unwanted reminder of her former body - loose skin. I can't wear what I want to wear, says the 35-year-old from Liverpool. I cannot get my legs out because the skin hangs over my knee so much. While she doesn't regret losing weight for the benefit of her health, Emilly says the loose skin on her thighs really does get me down as it makes her feel self-conscious, and the way she looks naked makes her feel like a catfish. It looks okay when it's all pulled in, but then I feel like, when I take my clothes off, I look like a 90-year-old woman.

Networks programmed directly into computer chip hardware can identify images faster, and use much less energy, than the traditional neural networks that underpin most modern AI systems. That's according to work presented at a leading machine learning conference in Vancouver last week. Neural networks, from GPT-4 to Stable Diffusion, are built by wiring together perceptrons, which are highly simplified simulations of the neurons in our brains. In very large numbers, perceptrons are powerful, but they also consume enormous volumes of energy. Part of the trouble is that perceptrons are just software abstractions--running a perceptron network on a GPU requires translating that network into the language of hardware, which takes time and energy.