How many days before allergy injections become effective?

Months: It can take months for allergy injections to become effective. It's always best to stay on your current allergy meds while building up immunity.

It depends: The initial doses of allergy shots r very dilute, generally not eliciting a significant immune response. Most of my patients start to feel effect half way through, around 3 months. Some feel improvenments when they reach. Highest dose, about 6 months. A few even feels better after the first couple of shots. I guess each patients immune reaction and sensitivity to symptoms r different.