Understanding the key mechanisms underlying sleep and wake states is essential for developing effective treatments for sleep disorders. Here, the authors discuss how the orexin (also known as hypocretin) system — a central regulator of sleep and wakefulness — is a key target in the development of treatments for sleep disorders.

In this Review, the authors describe evidence linking the gut microbiota to bone fractures. They discuss findings from rodent models and human studies on the effects of the gut microbiota on bone and muscle and explore the mechanisms through which the gut microbiota is associated with bone fractures.

In this Review, the authors discuss how endocannabinoids, endocannabinoid-related lipids and the gut microbiome respond to factors such as diet. Research into gut microbiota production of lipids within the endocannabinoidome, endocannabinoidome signalling and the potential implications of these functions for host metabolism are also covered.

Hypochondroplasia is a rare genetic condition resulting in disproportionate short stature and relative macrocephaly. Owing to its phenotypic variability and often subtle presentation, diagnosis of hypochondroplasia can often be delayed. This Consensus Statement provides expert-led recommendations for the diagnosis of hypochondroplasia through a combination of clinical, radiological and genetic approaches.

As highly potent weight loss drugs become available, interest grows in whether repeated cycles of weight loss and regain can exacerbate obesity. We argue that weight cycling might contribute to the development of obesity in susceptible lean individuals but seems to have little effect on the progression of obesity and its complications.