Meningitis explained: who is most at risk?

Grey-market injectable peptides – a category of substances with obscure, alphanumeric names such as BPC-157, GHK-Cu, or TB-500 – have developed a devoted following among biohackers and health optimisers. To understand how these unregulated substances have become mainstream and what they could be doing in our bodies, Madeleine Finlay hears from journalist Adrienne Matei and from Dr Anna Barnard, an associate professor at Imperial College London who researches peptides. Help support our independent journalism at theguardian.com/sciencepod

The Guardian’s science editor, Ian Sample, talks to Madeleine Finlay about three eye-catching science stories from the week, including a study that explores the link between exercise and brain health. Also on the agenda: the discovery that hedgehogs can hear high-frequency ultrasound and what this could mean for their conservation, and new research examining how biased AI autocomplete tools can influence the beliefs of users.. Help support our independent journalism at theguardian.com/sciencepod

Among the many justifications Donald Trump has presented for the US and Israel attacking Iran has been the supposedly imminent threat posed by its nuclear weapons programme. But how close was the country really to developing an atomic weapon? Ian Sample hears from Kelsey Davenport, the director of non-proliferation policy at the Arms Control Association. She sets out why many experts don’t believe the country even had a structured nuclear weapons programme, and explains what she thinks the impact of the war could be on nuclear proliferation around the world.. Help support our independent journalism at theguardian.com/sciencepod

The conflict in the Middle East has sent energy prices soaring, and for countries that import a high proportion of their fuel, it’s a reminder of the perils of energy dependence. As the recipient of almost 90% of Iran’s crude oil, China knows this only too well. Which partly explains why the country spent the last decade heavily investing in clean power. To find out what else could be driving the strategy, Madeleine Finlay speaks to senior China correspondent Amy Hawkins. And energy correspondent Jillian Ambrose reflects on how China’s ambitions could affect the rest of the world. Help support our independent journalism at theguardian.com/sciencepod

In the past three months, Donald Trump’s White House has reportedly used AI twice to effect regime change – once in its capture of Venezuela’s president, Nicolás Maduro, and more recently to help plan the strikes that killed Iran’s supreme leader, Ayatollah Ali Khamenei. The most recent strikes coincided with the end of the Pentagon’s relationship with the AI company Anthropic over concerns its AI tool Claude was being used for purposes the company had explicitly prohibited. The government swiftly signed a new contract with Open AI. To find out what this means for the use of AI in forthcoming conflicts, Madeleine Finlay speaks to technology journalist Chris Stokel-Walker. He explains why he thinks this moment represents a dangerous turning point.. Help support our independent journalism at theguardian.com/sciencepod