I have transplanted some marjoram and I keep cutting the top of the stem, which seems to seed faster each time it is cut.
Can I Use Marjoram That Has Started to Seed
Certified GKH Gardening Expert
Yes, you can still use it. You may find it is a bit more bitter or that it loses its flavor a bit, but it is not harmful.
If you find that your marjoram is bolting quickly, this is an indication that the plant is under stress. If you can figure out what is stressing it and correct it, it won't flower as much.