Peanut Allergy: Why Early Introduction Matters — and How to Do It Safely

Reviewed July 23, 2026 · Dr. Carlos Yu

Parents ask me some version of this constantly: "When can I give my baby peanut butter?" It's a good question, and the answer has actually changed for the better over the past decade. We used to tell families to wait. Now the evidence points the other way — for most babies, introducing peanut early is one of the best things you can do to lower their risk of developing a peanut allergy. Here's what the current guidance says, and how to do it safely.

What changed

For years, common advice was to delay peanut and other allergenic foods, out of worry that early exposure would trigger allergy. It turned out to be backwards. The landmark LEAP (Learning Early About Peanut Allergy) trial randomized infants at high risk of peanut allergy to either early peanut introduction or avoidance until age 5 — and found an 80% reduction in peanut allergy in the early-introduction group. That result, replicated and reinforced since, is why current Canadian Paediatric Society (CPS) guidance — and U.S. guidance from NIAID/AAP — now actively encourages early introduction rather than avoidance.

What current guidance recommends

Timing: Introduce common allergenic foods — peanut and egg are the two best-studied — at around 6 months of age, not before 4 months, once your baby is developmentally ready for solids (can sit with support, has good head control, shows interest in food).
Don't introduce just once. This is the part that's easy to miss: a single early taste isn't enough. Current guidance emphasizes ongoing, regular ingestion — offering peanut a few times a week, on a continuing basis — to actually build and maintain tolerance. One exposure and then stopping doesn't get you the protective effect.
Other allergenic foods (egg, dairy, wheat, tree nuts, fish, sesame) don't need to be delayed either, once your baby is ready for solids generally — there's no evidence-based reason to introduce them one at a time with long waiting periods between, though it's reasonable to introduce new foods gradually and watch how your baby does.

How to introduce peanut safely (choking matters)

Whole peanuts, peanut pieces, and spoonfuls of thick or chunky peanut butter are choking hazards for infants and toddlers — never give these directly. Instead:

For younger infants: thin smooth peanut butter by mixing it with warm water, breast milk, or a purée your baby already tolerates (like apple or sweet potato), to a runny consistency.
For infants a bit older who are eating more textures: smooth peanut butter spread thinly on toast, or age-appropriate peanut puff snacks (like Bamba), work well.
Give the first exposure at home, not at daycare or a restaurant, when you have time to watch your baby afterward — not because a serious reaction is expected, but so you're not guessing later about what caused a rash or fussiness.

Talk to your doctor first if…

This is the part I want to be really clear about: early introduction is meant to be safe for the great majority of babies, but a subset need a conversation with their doctor — sometimes an assessment — before starting:

Your baby has moderate-to-severe eczema
Your baby already has a known or suspected food allergy (to anything, not just peanut)
Your baby has a first-degree relative (parent or sibling) with eczema, food allergy, asthma, or significant allergic rhinitis, and you're unsure how to proceed

For these higher-risk babies, your doctor can help decide whether to introduce peanut at home as usual, do the first introduction in a clinical setting, or arrange allergy testing first. Don't let a family history of allergy talk you into indefinite avoidance on your own — but don't skip the conversation either. This is exactly the kind of judgment call that's worth 10 minutes with your family doctor.

The bottom line

For most babies, the message has flipped from "wait" to "don't wait, and keep it up." Start around 6 months (not before 4), use safe choking-free forms, keep offering it regularly rather than as a one-off, and loop in your doctor first if your baby has significant eczema, an existing food allergy, or a strong family allergy history. It's a small, manageable routine that can meaningfully lower your child's lifetime risk of a peanut allergy.

General information, not a substitute for individual medical advice. Every baby is different — if you're at all unsure how this applies to yours, talk to your family doctor before starting.

— Dr. Carlos Yu, Ajax Harwood Clinic