Allergy Drops for Pollen: A Guide to Seasonal Sublingual Immunotherapy

Many allergists recommend beginning pollen sublingual immunotherapy a few months before your relevant season so the immune system has time to adapt before peak exposure. For grass allergy that often means starting in late winter; for ragweed it may mean starting in spring or early summer. That said, allergy drops are generally taken continuously rather than only seasonally, because durable benefit builds over years of steady daily use. Stopping and restarting each year does not give the immune system the consistent exposure it needs. Your provider will recommend a start time based on which pollens you react to and your local pollen calendar, and will tailor the plan to your symptoms.

Sublingual immunotherapy has been studied across tree, grass, and weed pollens, but the evidence is not equal across all of them. Grass pollen has the strongest and most consistent research base, including large trials of FDA-approved grass tablets. Ragweed, the dominant fall weed pollen, also has supportive evidence. Tree pollen is studied with somewhat fewer trials. A custom liquid extract can be formulated to include the specific pollens you react to, which is useful because many people are sensitized to more than one plant family. Results vary by person and by allergen, and drops are not a guaranteed fix. A board-certified allergist reviews your test results to decide what belongs in your extract.

In most cases, yes. It is common to keep using antihistamines or nasal sprays for breakthrough symptoms, especially during peak pollen days, while your immunotherapy gradually builds tolerance over months and years. The two approaches work differently: antihistamines quiet symptoms in the short term, while drops aim to change the underlying immune response over the long term. Many people find they need rescue medication less often as treatment progresses, though this varies. You should not stop any prescribed asthma or allergy medication on your own. Always tell your provider what you are taking so they can confirm there are no concerns and adjust your plan as your sensitivity changes.

No, they are related but distinct. FDA-approved sublingual tablets such as Grastek, Oralair, and Ragwitek target a single allergen, like timothy grass or ragweed, and are regulated pharmacy drugs. Custom liquid allergy drops are compounded to include several allergens at once and are used off-label in the United States, meaning they have not been approved by the FDA for this purpose. Both deliver allergen under the tongue and share the same general goal of building tolerance. The practical differences are that tablets cover one allergen and may be covered by insurance, while liquid drops can be personalized to your full trigger profile but are generally not covered. A clinician can help you weigh which fits your situation.

Grass pollen has simply been studied more and more rigorously than other pollens. It is one of the most common seasonal triggers worldwide, which made it an early focus for large, well-designed randomized trials, including the grass-tablet studies that demonstrated benefit lasting after treatment ended. Ragweed, the dominant fall weed, also has a meaningful evidence base, in part because its FDA-approved tablet required clinical trials. Tree pollens are more varied and regionally specific, so they have been studied in fewer trials, which leaves the evidence thinner even though the underlying mechanism is the same. A custom liquid extract can still include tree pollens you react to, but it is honest to say the certainty of benefit is highest for grass. Your allergist can explain what the evidence supports for your particular mix of pollens.