Lidocaine and prilocaine cream (commonly sold as EMLA) typically provides numbness that lasts 1 to 2 hours after you wipe the cream off, depending on how long you left it on. The numbing effect doesn’t start the moment you apply it, though. You need to leave it on for a minimum amount of time before it kicks in, and how long you leave it on directly affects how deep and long-lasting the numbness will be.
How Long the Numbness Lasts
Once you remove the cream, the area stays numb for roughly 1 to 2 hours. If you applied it for the minimum recommended time (about 60 minutes on intact skin), expect numbness on the shorter end of that range. A full 2-hour application pushes the effect deeper into the skin and extends the duration closer to 2 hours after removal. The numbness fades gradually rather than disappearing all at once, so you may notice reduced sensation for a bit longer as feeling returns.
The maximum recommended time to leave the cream on is 4 hours. Leaving it on longer than that doesn’t meaningfully extend the numbing and increases the amount of medication absorbed into your bloodstream.
How Long Before It Starts Working
The onset depends on where you’re applying it and what you’re numbing for. On regular skin (arms, legs, torso), the cream needs at least 1 hour under an occlusive dressing, which is just a waterproof covering like plastic wrap or a Tegaderm patch that traps the cream against your skin. For more painful procedures like skin graft preparation, you need at least 2 hours of contact time.
Genital skin absorbs the cream much faster. On male genital skin, 15 minutes is enough. On female genital mucous membranes, 5 to 10 minutes provides adequate numbness. These areas are thinner and more permeable, so the anesthetics penetrate quickly without the long wait required for thicker skin on the rest of the body.
Why Application Time Matters So Much
This cream works differently from most topical products. Lidocaine and prilocaine are mixed in a 1:1 ratio that keeps both drugs in liquid form at room temperature instead of their usual crystalline state. That liquid form penetrates skin far more effectively than either drug could on its own as a standard cream. But skin is still a barrier, and the cream needs sustained contact time to push the anesthetics deep enough to block pain signals from nerve endings below the surface.
A 60-minute application numbs the top layers of skin, which is enough for needle sticks and IV placement. A 120-minute application reaches deeper, numbing enough tissue for procedures that cut into the skin. If you remove the cream too early, you’ll get partial or unreliable numbness that may wear off before your procedure is done.
How Much to Apply
The amount matters as much as the timing. For minor procedures like blood draws or IV placement, about 2.5 grams (half of a standard 5-gram tube) spread over a patch of skin roughly the size of a credit card is the standard dose. Leave it on for at least 1 hour.
For larger or more painful skin procedures, 2 grams per 10 square centimeters of skin is recommended, with a minimum 2-hour application. For female genital procedures, 5 to 10 grams applied for 5 to 10 minutes is typical. Applying more cream than recommended doesn’t make the area “more numb.” It just increases how much drug enters your bloodstream without improving the local effect.
The Occlusive Dressing Makes a Real Difference
Covering the cream with plastic wrap or an adhesive film dressing isn’t optional for most uses on intact skin. Without coverage, the cream dries out and loses contact with the skin surface, dramatically reducing how well it works. The dressing keeps the cream moist and pressed against the skin, allowing the anesthetics to absorb steadily over the full application period. If you skip this step, you’ll likely end up with patchy numbness that doesn’t last.
For genital applications, an occlusive dressing isn’t typically used because those tissues absorb the cream quickly enough on their own.
What Can Reduce the Duration
Several factors shorten how long the numbness lasts. Thicker skin (palms, soles of feet, elbows) is harder to penetrate and may not numb as deeply or as long. Areas with more blood flow tend to clear the drug faster, so numbness fades sooner on well-vascularized tissue. If you applied the cream for less than the recommended time or didn’t use a proper dressing, the effect will be weaker and shorter.
Skin that is broken, inflamed, or irritated absorbs the cream faster, which can mean a quicker onset but also a shorter duration since the drug clears the area sooner. The cream should only be applied to intact skin (with the exception of genital mucous membranes, which have their own dosing guidelines).
Timing Your Application
If you’re using this cream before a procedure at home, work backward from your appointment time. For a standard needle procedure, apply the cream with a dressing at least 60 to 90 minutes beforehand. You can apply it up to 4 hours early if needed, but the sweet spot for most people is 1 to 2 hours before the procedure. After removal, the numbness holds well for about an hour, giving you a comfortable window.
For at-home cosmetic uses like waxing or microneedling, the same timing applies. Put the cream on, cover it, wait at least an hour, then wipe it off right before you start. Working quickly after removal gets you the best numbness, since the clock starts ticking the moment the cream comes off.