How long do allergy shots take to work?
Short answer
Medication question
Allergy shots are a gradual treatment, not a quick fix. Injections start with a 3-6 month build-up phase given about once a week, and most people notice meaningful symptom improvement within the first year on the maintenance dose. The full, lasting benefit develops over a 3-5 year course of treatment.
This is a general research summary, not medical advice. A pharmacist can confirm it for your situation.
Key facts
The build-up phase of allergy shots involves injections about once a week and generally lasts three to six months before reaching the maintenance dose.
It can take as long as 12 months on the maintenance dose to notice a clear improvement in allergy symptoms.
If allergy shots are successful, maintenance treatment is generally continued for three to five years to achieve lasting benefit.
Here's the nuance
A one-liner rarely tells the whole story. This is the honest detail behind the short answer above.
Allergy shots (subcutaneous immunotherapy) are designed to retrain your immune system over time, so they work gradually rather than giving instant relief the way an antihistamine does. Treatment has two phases. In the build-up phase, you receive injections with slowly increasing amounts of allergen about once a week, and this phase usually lasts three to six months until you reach an effective maintenance dose. Some people begin to feel a little better during build-up, but the goal of this stage is to safely raise the dose, not to deliver full relief.
Once you reach maintenance, injections are spaced further apart, commonly every two to four weeks. This is when improvement becomes most noticeable. According to the American Academy of Allergy, Asthma & Immunology, it can take as long as 12 months on the maintenance dose to notice a clear improvement in symptoms, so the first year is the realistic window for judging whether the treatment is helping.
If allergy shots are working, maintenance treatment is generally continued for three to five years. Staying the full course is what produces lasting benefit, and many people keep experiencing relief for years after finishing. If you have had no improvement after about a year on the maintenance dose, that is the point to discuss alternatives with your allergist rather than waiting indefinitely.
Sublingual immunotherapy such as allergy drops follows a similar timeline of gradual, months-to-years improvement. Curex offers an at-home subcutaneous program with once-weekly build-up and a maintenance schedule individualized by the prescribing allergist, plus a Curex Sublingual Alternative (allergy drops, not shots) for people who prefer a needle-free route. Either way, patience is essential: immunotherapy is a long-term investment, not a same-week fix.
The key points
The handful of things that decide the answer — skim these if you only read one section.
Two phases, different timelines
The build-up phase (about once-weekly injections) lasts roughly 3-6 months; the maintenance phase, with injections every 2-4 weeks, is where most improvement is felt.
Give it up to a year
It can take as long as 12 months on the maintenance dose to notice clear symptom improvement, so the first year is the realistic window for judging results.
Not a quick fix like an antihistamine
Immunotherapy retrains the immune system gradually. Unlike a pill that works in an hour, allergy shots deliver relief that builds slowly and then lasts.
Full course is 3-5 years
If shots are helping, treatment usually continues for three to five years; completing the course is what produces durable, long-lasting benefit.
Reassess if no change after a year
If symptoms have not improved after about a year on the maintenance dose, talk with your allergist about alternatives rather than continuing indefinitely.
Please read before acting on this
General information — not medical advice
This page is a general research summary about the medication in question. It does not account for your specific health, other medicines you take, or your dose, and it can go out of date. It is not medical advice, a prescription, or a substitute for professional judgment.
Ask your pharmacist or prescriber before starting, stopping, changing, or continuing any medication — they can check it against your situation in minutes.
❓Frequently Asked Questions
Some people feel a little better during the 3-6 month build-up phase, but meaningful improvement usually comes on the maintenance dose. Expect the first year to be the realistic window: it can take up to 12 months on maintenance to notice a clear reduction in symptoms.
Allergy shots gradually retrain your immune system to tolerate the allergen instead of overreacting to it. That immune change takes months to develop, which is why relief builds slowly. In exchange, the benefit tends to last for years, unlike antihistamines that only work while the medicine is active.
If allergy shots are helping, maintenance treatment is typically continued for three to five years, sometimes longer. Completing the full course is what produces lasting benefit, and many people continue to experience relief for years after their treatment ends. Your allergist decides when it is reasonable to stop.
Not really. Sublingual immunotherapy (allergy drops or tablets) follows a similar gradual timeline, with improvement building over months and a recommended course of several years. The main difference is the route: drops are taken at home without needles, but both are long-term treatments rather than quick fixes.
Reviewed by
Curex Editorial TeamReviewed for accuracy
Last reviewed August 2026
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- 1Allergy Shots (Immunotherapy) — American Academy of Allergy, Asthma & Immunology (AAAAI)
- 2Allergy Shots (Immunotherapy) — American College of Allergy, Asthma & Immunology (ACAAI)
- 3Allergy Immunotherapy — StatPearls, NCBI Bookshelf
- 4Allergic rhinitis — MedlinePlus Medical Encyclopedia (U.S. National Library of Medicine)
This content is for general informational purposes only. It is not medical advice, a prescription, or a substitute for professional judgment, and it does not account for your health, other medications, or dose. Always ask your pharmacist or prescriber before starting, stopping, or changing any medication.