Oleamidopropyl Dimethylamine
A conditioning surfactant in the CAPB family — the one to check when "CAPB-free" still isn't enough
INCIOleamidopropyl Dimethylamine
- Category
- Surfactant
- Risk level
- medium
- A CAPB cousin
- An oleic-acid amidopropyl amine, structurally akin to the cocamidopropyl betaine (CAPB) intermediate — hence the cross-reactivity
- Cross-reactivity
- May cross-react with DMAPA and CAPB; CAPB-allergic people should check for it too
- Where it hides
- Especially in conditioners and 2-in-1 products, as a conditioning/anti-static agent
Look for these names on ingredient lists
This ingredient may appear under any of these names:
Commonly found in
Possible reactions
- Allergic contact dermatitis from hair products
- Scalp irritation from shampoo/conditioner
- Hand/facial dermatitis from cleansers
- Cross-reactions with CAPB and DMAPA
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What is oleamidopropyl dimethylamine?
Oleamidopropyl dimethylamine (INCI: Oleamidopropyl Dimethylamine; OAPDA) is a conditioning surfactant made from oleic acid and aminopropyl dimethylamine. It belongs to the amidopropyl amine family — the same chemistry as cocamidopropyl dimethylamine, the intermediate used to make cocamidopropyl betaine (CAPB). That structural kinship is the root of its cross-reactivity with CAPB and DMAPA.
It's used in some shampoos, conditioners and skin cleansers as a conditioning agent — reducing static, improving combability and giving a soft feel. It's less widespread than CAPB but turns up notably in conditioners and 2-in-1 products, and the ACDS lists it as a contact allergen worth testing when hair-product allergy isn't fully explained by CAPB alone.
Why it causes reactions
OAPDA's reactive amidopropyl-amine group forms hapten-protein conjugates in skin, driving Type IV delayed hypersensitivity. Because it's structurally similar to the CAPB intermediate, people sensitised to DMAPA may cross-react to OAPDA and vice versa. Presentations mirror CAPB/DMAPA allergy — scalp dermatitis, facial dermatitis from rinse water, hand dermatitis from cleansers.
Its practical importance is as the "why am I still reacting?" ingredient: when someone switches to a CAPB-free shampoo but keeps flaring, OAPDA in a conditioner or 2-in-1 is a prime suspect.
This page exists for one specific, frustrating scenario: you did everything right — went CAPB-free — and your scalp is still unhappy. OAPDA is the usual plot twist. People scour their shampoo and forget the conditioner, where this one likes to hide. If you''re CAPB-allergic, read the conditioner label too. — Snehal
Where it's found
- Conditioners and 2-in-1 shampoos — as a conditioning active.
- Some shampoos.
- Some skin cleansers — body and hand washes.
On labels: Oleamidopropyl Dimethylamine — check conditioners and 2-in-1 products specifically.
Safer alternatives
- Polyquaternium conditioners — a different chemical class without the amidoamine concern.
- CAPB-free / OAPDA-free lines — Vanicream, Free & Clear, sensitive-scalp products.
- Rinse-through oils — a little coconut or argan oil on damp hair conditions without these allergens.
The bottom line
Oleamidopropyl dimethylamine is a conditioning surfactant in the cocamidopropyl-betaine family — and the classic reason a "CAPB-free" switch sometimes isn't enough, because it cross-reacts with CAPB and DMAPA and hides in conditioners and 2-in-1s. If you're CAPB-allergic and still reacting, check for it by name, and consider polymer conditioners or rinse-through oils instead.
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