My Bra Strap Is Tight/LooseUpdated 9 months ago

It sounds like the strap adjustment may not be holding due to tension. 

You might try a smaller band size while keeping the same cup size to see if that offers a more secure fit. 

Alternatively, you could try a band size that is 1–2 inches longer so that the strap adjustment isn’t under as much tension, which may help prevent slipping.