Scientists have discovered that a rare “mirror-image” version of the amino acid cysteine can dramatically slow the growth of certain cancers while leaving healthy cells largely untouched. Unlike most anticancer treatments that harm normal tissues, this molecule—called D-cysteine—is taken up mainly by some cancer cells through a specific transporter on their surface. Once inside, it shuts down a crucial mitochondrial enzyme that cancer cells rely on to produce energy and maintain DNA, effectively halting their growth.

Researchers have discovered a surprising change in how cells produce energy in people with depression. Brain and blood cells in young adults with major depressive disorder produced more energy molecules at rest but had trouble increasing energy production when needed. Scientists believe this imbalance may contribute to symptoms such as fatigue and low motivation. The finding could help pave the way for earlier diagnosis and more personalized treatments.

A new study suggests Alzheimer’s disease may be detectable through subtle shape changes in proteins found in the blood. Researchers discovered that structural differences in three blood proteins closely track the progression of the disease. By analyzing these changes in more than 500 people, the team was able to distinguish healthy individuals from those with mild cognitive impairment or Alzheimer’s with impressive accuracy. The approach could help move diagnosis and treatment to earlier stages.

A newly developed antibiotic called EVG7 could offer a powerful new way to stop Clostridioides difficile, a dangerous gut bacterium that often returns after treatment. In mouse studies, researchers found that even a very small dose of EVG7 was highly effective at clearing the infection and preventing it from coming back. Unlike many current antibiotics, which wipe out large portions of the gut microbiome, EVG7 appears to spare beneficial bacteria that naturally help keep C. difficile in check.

Teenagers naturally fall asleep later, which makes early school start times a recipe for chronic sleep deprivation. Researchers studying a Swiss high school that introduced flexible start times found that students overwhelmingly chose to begin later—and ended up sleeping about 45 minutes longer each school night. The extra rest led to fewer sleep problems, better well-being, and improved academic performance.