How Do Delay Sprays Work? The Science Explained (2026)

Written by the Dynamo Delay Team · Last Updated: February 2026

You've probably seen delay sprays on a pharmacy shelf and wondered whether the science behind them is real or just marketing. Reasonable question. Delay sprays are actually one of the most clinically studied treatments for premature ejaculation, with randomized controlled trials dating back decades and measurable, reproducible results.

Understanding how they work gives you a real advantage. When you know the mechanism, you can choose the right product, apply it correctly, and get consistent results instead of guessing. So let's walk through what happens at the nerve level when you use one.

Your Ejaculatory Reflex, Explained

Ejaculation isn't a decision. It's a reflex. And like all reflexes, it fires when sensory input crosses a threshold.

The glans (head) and frenulum (underside ridge) of your penis contain roughly 4,000 nerve endings, mostly free nerve endings that detect fine touch, pressure, and temperature. During sexual stimulation, these nerve endings generate electrical signals that travel via the pudendal nerve to the spinal ejaculatory center located in the lumbar spine (L1-L2 segments).

When those incoming signals accumulate past a certain point, the spinal center triggers a two-phase reflex: emission (semen moves into the urethra) followed immediately by expulsion (rhythmic contractions push it out). The whole sequence takes about 3–10 seconds and, once triggered, can't be voluntarily stopped.

In men with premature ejaculation, that threshold is lower. The nerve endings may transmit signals faster, the spinal center may fire with less input, or serotonin levels in the brain (which help inhibit the reflex) may be lower than average. The result: ejaculation happens before you want it to.

How Delay Sprays Interrupt the Cycle

Delay sprays contain topical anesthetics, the same class of drugs your dentist uses before a procedure. Except the dose is much smaller and the target is more specific.

These anesthetics work by blocking voltage-gated sodium channels in nerve cell membranes. Nerve cells communicate by opening tiny sodium gates that generate an electrical impulse. Topical anesthetics physically plug those gates, slowing down or preventing the impulse from forming.

The effect is dose-dependent. At low concentrations, you reduce the speed and intensity of nerve signaling without shutting it down. You still feel pressure, warmth, and pleasure. But the hypersensitive fine-touch signals that trigger early ejaculation are dampened. You're turning a 9/10 sensitivity down to maybe a 6/10. Not to zero.

This raises your ejaculatory threshold. The same amount of stimulation that would have triggered ejaculation at 2 minutes now takes 8 or 12 minutes to build past the threshold. Your reflex still works. It just takes longer to fire.

The Three Active Ingredients in Delay Sprays

Not all delay sprays use the same drug. Three topical anesthetics are used in PE products, and they differ in ways that matter. Our benzocaine vs. lidocaine breakdown covers the two most common ones in detail.

Property	Lidocaine	Benzocaine	Prilocaine
Drug Class	Amide anesthetic	Ester anesthetic	Amide anesthetic
Typical Concentration	7–13%	3–7.5%	2.5% (combined with lidocaine)
Onset Time	5–10 minutes	3–5 minutes	5–15 minutes
Duration	20–30 minutes	15–20 minutes	30–45 minutes
Delivery Format	Spray (metered dose)	Wipes, gel	Spray (Fortacin/PSD502)
Allergy Risk	Very low (<1%)	Moderate (ester class)	Very low
Clinical Evidence for PE	Extensive (most studied)	Moderate	Extensive (as combination)
Availability (US)	OTC (Dynamo Delay, K-Y Duration, Trojan)	OTC (Roman Swipes, Dynamo 4 Wipes)	Prescription only (EU approved)

Lidocaine is the most widely used and clinically studied. It's an amide-type anesthetic, which means it's metabolized by the liver (not the blood plasma like esters), resulting in a more predictable effect and lower allergy risk. Dynamo Delay uses 13% lidocaine USP, the highest OTC concentration available. We cover the full pharmacology in our article on how lidocaine works for premature ejaculation.

Benzocaine is the second most common. It's an ester-type anesthetic with faster onset but shorter duration, and it's the active ingredient in most delay wipes. The ester class carries a slightly higher risk of contact dermatitis, though severe allergic reactions are still rare.

Prilocaine is used in combination with lidocaine (the EMLA/Fortacin formulation, marketed as PSD502). It's approved in Europe for PE but remains prescription-only. The combination targets different nerve fiber types simultaneously, providing broad-spectrum desensitization.

What the Clinical Trials Actually Show

This isn't theoretical. Delay sprays have been tested in rigorous, placebo-controlled clinical trials, the same standard used for pharmaceutical drugs.

The largest trial was Dinsmore & Wyllie (2009), published in BJU International. In this Phase III randomized controlled trial, men using a lidocaine-prilocaine spray (PSD502) saw their average IELT increase from 0.6 minutes to 3.8 minutes, a 6.3x improvement. The placebo group went from 0.6 to 1.1 minutes. The spray also significantly improved ejaculatory control, sexual satisfaction, and personal distress scores.

Henry & Morales (2003, International Journal of Impotence Research) ran a proof-of-concept study using topical lidocaine-prilocaine and measured a mean increase of 8.7 minutes in ejaculatory latency. Some men went from under a minute to nearly ten.

Busato & Galindo (2004, BJU International) conducted a double-blind, placebo-controlled study showing statistically significant improvement in IELT compared to placebo, with no serious adverse events.

Atherley-John et al. (2006, International Journal of Impotence Research) tested topical lidocaine alone, without prilocaine, and found significant improvement in ejaculatory latency. This confirmed that lidocaine as a single agent is effective for PE.

What stands out is the consistency across studies. Different research teams, different countries, different formulations, and the results all point the same direction: topical anesthetics reliably extend ejaculatory latency time.

Why Delivery Method Matters

A spray isn't just a convenient format. It's a precision tool. Metered-dose sprays deliver the same volume with each pump, typically 7.5–10 mg of active ingredient per spray. That consistency matters because the difference between "perfect control" and "too numb" can be a single spray.

Creams and gels require eyeballing the amount, which leads to inconsistent dosing and unpredictable results. Wipes provide a fixed dose per wipe but offer less flexibility for fine-tuning.

Absorption rate also varies by delivery method. Sprays use alcohol or propylene glycol as carriers that enhance skin penetration and evaporate quickly. The anesthetic reaches the nerve endings faster and leaves less residue that could transfer to a partner. Our step-by-step guide covers proper application technique.

Why Concentration Isn't Everything

A common misconception: higher percentage equals stronger effect. The reality is more nuanced.

Concentration determines the maximum potential effect per spray, but your actual experience depends on:

• Number of sprays used — 2 sprays of 13% delivers more anesthetic than 2 sprays of 7%, but 4 sprays of 7% could deliver more than 2 sprays of 13%
• Carrier formulation, and how efficiently it helps the drug penetrate the skin
• Wait time. Longer wait means deeper penetration, which means stronger effect.
• Individual sensitivity, because nerve density and skin thickness vary between men

Higher-concentration products like Dynamo Delay's 13% lidocaine have one clear advantage: you can achieve effective desensitization with fewer sprays, which means more precise dose control. If 3 sprays is too much, try 2. That granularity is harder to achieve with lower-concentration products where you'd need 5–6 sprays for the same effect.

Safety: What 80+ Years of Data Tell Us

Lidocaine was first synthesized in 1943 and has been in continuous clinical use since 1948. That makes it one of the most extensively studied drugs in medicine. It's on the WHO's List of Essential Medicines and is used in everything from dental procedures to cardiac care.

Topical application to the penis at delay-spray concentrations results in minimal systemic absorption. The amount that enters your bloodstream is a tiny fraction of what's used in dental or surgical anesthesia. Serious adverse events from topical PE products are essentially unheard of in published research.

Common mild effects include temporary numbness (that's the intended effect), mild tingling during onset, and occasional skin irritation. These are all local and resolve on their own. Our side effects guide has the complete breakdown with clinical data.

The primary practical concern is partner transfer. If excess spray isn't wiped off before intercourse, your partner may experience mild numbness. Easily prevented: wait the recommended 5–10 minutes and wipe the application area before contact.

In Summary

Delay sprays aren't magic and they aren't a gimmick. They're pharmacologically active products backed by decades of clinical research. They work by raising your ejaculatory threshold through targeted nerve signal reduction, the same mechanism used safely in medical settings worldwide.

Choosing the right one comes down to active ingredient, concentration, and delivery method. Our top 10 delay sprays ranking compares the best options available today.

Frequently Asked Questions

Do delay sprays actually work?

Yes. Multiple randomized, placebo-controlled clinical trials confirm that topical anesthetic sprays significantly increase ejaculatory latency time. The largest Phase III trial showed a 6.3x improvement — from an average of 0.6 minutes to 3.8 minutes (Dinsmore & Wyllie, 2009). Results are consistent across studies using lidocaine, benzocaine, and prilocaine formulations.

How long does it take for a delay spray to kick in?

Lidocaine-based sprays typically take 5–10 minutes to reach full effect. Benzocaine products work slightly faster at 3–5 minutes. The exact onset depends on concentration, how many sprays you apply, and individual skin absorption rates. Most manufacturers recommend waiting at least 5 minutes before intercourse.

Do delay sprays reduce pleasure?

They reduce hypersensitivity, not all sensation. At proper doses, most men report still feeling pleasure, warmth, and pressure — just without the hair-trigger response that causes early ejaculation. The clinical trials measured sexual satisfaction alongside latency, and satisfaction scores improved with spray use. The key is finding your right dose — start with fewer sprays and increase gradually.

What's the difference between lidocaine and benzocaine delay sprays?

Lidocaine (amide class) has more clinical research backing for PE, lower allergy risk, and longer duration (20–30 min). Benzocaine (ester class) has faster onset (3–5 min) but shorter duration (15–20 min) and slightly higher allergy potential. Lidocaine is typically found in sprays; benzocaine is more common in wipes. Both are effective.

Are delay sprays safe to use regularly?

Yes. Lidocaine has over 80 years of clinical safety data and is on the WHO's List of Essential Medicines. Topical application at delay-spray concentrations results in minimal systemic absorption. There is no evidence of dependency, tolerance buildup, or long-term adverse effects from regular use. Men in clinical trials used these products over multi-week periods without safety issues.

Sources

1. Dinsmore WW, Wyllie MG. "PSD502 Improves Ejaculatory Latency, Control and Sexual Satisfaction." BJU International. 2009;103(7):940-949.
2. Henry R, Morales A. "Topical Lidocaine-Prilocaine Spray for the Treatment of Premature Ejaculation." International Journal of Impotence Research. 2003;15(4):277-281.
3. Busato W, Galindo CC. "Topical Anaesthetic Use for Treating Premature Ejaculation: A Double-Blind, Randomized, Placebo-Controlled Study." BJU International. 2004;93(7):1018-1021.
4. Atherley-John YC, Cunningham SJ, Hawkins DA. "Topical Lidocaine for Treatment of Premature Ejaculation." International Journal of Impotence Research. 2006;18(5):439-441.
5. McMahon CG, Althof SE, Kaufman JM, et al. "Efficacy and Safety of Dapoxetine for the Treatment of Premature Ejaculation." Journal of Sexual Medicine. 2011;8(2):524-539.

Disclaimer: This content is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare provider for personalized guidance.