For the instant, they have only tested the compound known as NMN in mice. They plan to start clinical trials to test its safety in 25 people later this year in Boston. DNA gets damaged every time we go out into the sun or are exposed to radiation. he ability of our cells to repair the damage decreases as we age. Giving a dose of NMN in mice’s drinking water improved the ability of their cells to repair DNA damaged by radiation or old age. “This is the closest we are to a safe and effective anti-ageing drug that’s perhaps only three to five years away from being on the market if trials go well,” said the study’s lead author professor David Sinclair, who works at the UNSW and Harvard. NASA is also working with Prof Sinclair and his UNSW colleague Dr Lindsay Wu. They want a way to help protect astronauts from having their body cells age prematurely as a result of being exposed to cosmic radiation. It was found that NMN could also help repair the damaged DNA of children with cancer who have undergone radiotherapy.