The blood service is looking for volunteers to take part in a new study to see if donors can give blood more frequently.
The two year study being carried out by Cambridge University along with Oxford University and the NHS, is the first of its kind in the world.
They're looking for 50,000 donors to take part. The research will be conducted at 25 blood donor centres across the country including Cambridge and Luton.
Until now men can donate blood every 12 weeks. Women at 16 weeks. Now as part of the study the gap between sessions has been shortened by 2 weeks.
Over the next 2 years scientist will look at the effect that shortened gap will have on blood donors.