Judge a gel on transfer, not on knockdown
Every buying guide talks about how fast a product kills. For cockroaches that is the wrong test. A gel that kills the first forager on the spot never reaches the nest, because the dead insect stops carrying the active ingredient home.
A professional bait is deliberately slow: the forager feeds, returns to harbourage, and the active passes secondarily through droppings and cannibalism. That secondary transfer is what collapses a colony rather than thinning the visible population.
- Delayed action is a feature, not a weakness — expect 24 to 36 hours before a visible drop.
- Non-repellent formulation matters: repellent products scatter the population into voids.
- Palatability decides consumption; a bait they walk past does nothing regardless of the active.
Tube volume is the hidden cost
Most retail roach gels ship in 5 to 10 ml tubes. A single UK kitchen and bathroom programme needs roughly 30 to 60 pea-sized dots for the first round, plus a top-up round on day 3 to 5 — which is more gel than a small retail tube holds.
Comparing price per tube hides this. Compare price per millilitre, then check the tube covers a full treatment cycle without a re-order mid-programme, because a gap in baiting lets the population recover.
- 20 ml: one room, spot treatment, or a follow-up round.
- 60 ml: a full kitchen and bathroom programme with a top-up round.
- 4 × 60 ml: heavy infestation or a multi-zone commercial site.
Safety and where you can realistically apply it
A gel you cannot use behind a kickboard or inside a cupboard hinge is a gel you cannot use properly. Look for a fine precision applicator tip, and a formulation rated safe around pets and children when applied as directed — that is, in cracks and voids out of reach rather than open surfaces.
Odour-free matters more than it sounds: it is what allows a kitchen to stay in use during treatment instead of being closed off for a spray to dry.
Everything below assumes a professional-strength bait — our cockroach gel kits ship with the applicator and placement map referenced here.
A simple comparison checklist
Before buying, score any product against five questions. Most supermarket options fail at least two of them.
- Is the action delayed enough to allow nest transfer?
- Is it non-repellent, so it does not scatter the population?
- Does one purchase cover a full cycle plus a top-up round?
- Does it come with a placement plan, or are you guessing?
- Is it safe to leave in place around pets and children as directed?