How Does Stud 100 Spray Work in the Body
Chemical Composition, Mechanism of Action & Metabolic Effects Explained
Key Takeaways: How Stud 100 Spray Works
- Active Ingredient: Lidocaine (9.6 mg per spray) – a local anaesthetic
- Primary Action: Blocks sodium channels in nerve endings, reducing penile sensitivity
- Onset: Numbing effect starts within 5–10 minutes after application
- Duration: Reduced sensitivity lasts approximately 30–45 minutes
- Requirement: Must be applied before intercourse; can be washed off or used with a condom
- Not absorbed systemically: Minimal entry into bloodstream, so no whole‑body effects
Stud 100 Spray contains lidocaine, a well‑known local anaesthetic that temporarily desensitises the nerves of the penis. By raising the threshold for sensation, it helps men with premature ejaculation last longer during intercourse. The effect is purely local and reversible.
Important Medical Advice
Do not apply Stud 100 to broken or irritated skin. If you experience severe swelling, rash, or difficulty breathing, stop use and seek medical help immediately. Avoid contact with eyes. If swallowed, get emergency help right away.
Chemical Composition & Molecular Structure
Lidocaine hydrochloride is the active ingredient in Stud 100 Spray. It belongs to the amide class of local anaesthetics and has a specific chemical structure that allows it to block nerve signals.
Lidocaine Properties
2-(diethylamino)-N-(2,6-dimethylphenyl)acetamide hydrochloride
The aromatic ring and amide linkage are key for receptor binding.
C14H22N2O · HCl
14 carbon atoms, 22 hydrogen, 2 nitrogen, 1 oxygen plus hydrochloride.
270.8 g/mol (free base: 234.34 g/mol)
The hydrochloride salt improves water solubility for spray formulation.
Formulation Details
| Ingredient | Concentration | Role |
|---|---|---|
| Lidocaine Hydrochloride | 9.6 mg per metered spray | Active anaesthetic agent |
| Ethanol | ~60% v/v | Solvent and drying agent |
| Propylene Glycol | q.s. | Humectant and skin penetrant |
🗒️ Pharmaceutical Insight: The lipophilic aromatic ring allows lidocaine to cross nerve membranes, while the hydrophilic amine group binds to sodium channels. This dual nature makes it highly effective as a topical anaesthetic.
Mechanism of Action: How Lidocaine Delays Ejaculation
Lidocaine reversibly blocks the propagation of action potentials along nerve fibres. In the context of premature ejaculation, it reduces the sensitivity of the penile nerves, raising the threshold for the ejaculatory reflex.
Normal Ejaculation Reflex
- Stimulation: Sensory nerves in the glans and shaft send signals via the pudendal nerve.
- Spinal integration: Signals reach the sacral spinal cord (S2–S4).
- Motor output: Sympathetic nerves trigger seminal emission and ejaculation.
- Climax: Rhythmic contractions of pelvic muscles.
Lidocaine Intervention
| Step | Normal | With Stud 100 |
|---|---|---|
| 1. Sensory input | Full sensation reaches spinal cord quickly | Sensation is dampened; fewer signals reach spinal cord |
| 2. Ejaculatory threshold | Low threshold, quick trigger | Threshold elevated, allowing longer stimulation before reflex |
| 3. Time to ejaculation | Typically <1 minute (PE) | Increases by 2–6 fold in clinical studies |
🗒️ Physiological Insight: Lidocaine does not affect the motor pathways or the ability to achieve orgasm – it simply delays the sensory overload that triggers premature ejaculation.
Sodium Channel Blockade: The Science of Numbing
Lidocaine exerts its effect by binding to voltage‑gated sodium channels in nerve cell membranes, preventing the influx of sodium ions required for depolarisation.
Molecular Action
1. Binding Site
Lidocaine binds to the S6 segment of domain IV of the sodium channel α‑subunit.
2. Use‑dependent Block
More effective when nerves are firing rapidly – exactly the condition during sexual stimulation.
3. Reversibility
As lidocaine diffuses away, normal nerve function returns within 30–60 minutes.
Selectivity for Sensory Fibres
Small, unmyelinated C‑fibres (pain and touch) are more susceptible to lidocaine than large motor fibres, which is why motor function remains intact.
🗒️ Neuropharmacology Fact: At the concentrations used in Stud 100, only superficial sensory endings are affected. Deeper nerves and muscles are unaffected, so erections and ejaculatory contractions remain normal.
Absorption & Metabolic Effects in the Body
Although applied topically, a small amount of lidocaine can enter the bloodstream. Understanding its absorption and metabolism is key to safe use.
Pharmacokinetic Profile
Absorption
Rate: Slow through intact skin; peak plasma levels occur 30–60 min after application.
Systemic bioavailability: <3% of applied dose (negligible).
Distribution
Volume of distribution: 1.1–1.7 L/kg.
Protein binding: 65–75% bound to alpha‑1‑acid glycoprotein.
Metabolism
Hepatic: Rapidly metabolised by CYP3A4 to monoethylglycinexylidide (active) and glycinexylidide.
Half‑life: 1.5–2 hours (parent drug).
Elimination
Renal: <10% excreted unchanged; metabolites in urine.
Safety Margins
The maximum recommended dose of Stud 100 is 3 sprays (approx. 28.8 mg lidocaine). The toxic plasma threshold for lidocaine is above 5 μg/mL – far higher than the levels achieved with topical penile application.
🗒️ Clinical Correlation: Because systemic absorption is minimal, Stud 100 does not cause drowsiness, numbness elsewhere, or interact with most medications. However, men with severe liver disease may have slower metabolism, so caution is advised.
Clinical Efficacy for Premature Ejaculation
Multiple studies have shown that lidocaine spray significantly increases intravaginal ejaculatory latency time (IELT) in men with lifelong or acquired premature ejaculation.
Evidence Summary
| Study | Increase in IELT | Patient Satisfaction |
|---|---|---|
| Randomised placebo‑controlled trial (n=300) | From 0.9 min to 3.8 min (4.2‑fold) | 82% reported improved control |
| Open‑label extension (6 months) | Sustained 4‑fold increase | No tachyphylaxis |
| Real‑world observational data | 2.5–6 min range | High partner satisfaction |
Optimal Use Recommendations
- Apply 5–15 minutes before intercourse.
- Use 2–3 sprays; adjust based on response.
- Wash off or use a condom to prevent partner numbness.
- Do not use more than once in 24 hours.
🗒️ GP Note: Stud 100 is a first‑line option for premature ejaculation. It can be combined with behavioural techniques (stop‑start, squeeze) for better outcomes.
Stud 100 Spray FAQs
How long does Stud 100 Spray take to work?
Numbing begins within 5 minutes and peaks around 10–15 minutes after application. This gives you a window to start intercourse with reduced sensitivity.
Can Stud 100 affect my partner?
If not washed off or covered with a condom, lidocaine can transfer and cause temporary vaginal numbness. Always rinse thoroughly or use a condom to avoid this.
Is Stud 100 safe to use with other medications?
Generally yes, because systemic absorption is minimal. However, if you take antiarrhythmics (like mexiletine) or strong CYP3A4 inhibitors, consult your doctor first.
Will I lose the ability to get an erection?
No. Stud 100 only numbs the skin; it does not affect blood flow or the erectile mechanism. Most men maintain full erectile function.
How often can I use Stud 100?
Use no more than once in 24 hours. Daily use is not recommended without medical advice, as tolerance or skin irritation could develop.
Need Help with Premature Ejaculation?
If you’re looking for a reliable way to gain control, Stud 100 Spray might be the right choice. A quick online consultation with a UK‑registered doctor can confirm if it’s suitable for you.
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Medical Content Manager
Nabeel is a co-founder, and medical content manager of Chemist Doctor. He works closely with our medical team to ensure the information is accurate and up-to-date.
Medical Doctor
Dr. Feroz is a GMC-registered doctor and a medical reviewer at Chemist Doctor. He oversees acute condition and urgent care guidance.
Medical Director
Usman is a co-founder, and medical director of Chemist Doctor. He leads the organisation's strategic vision, bridging clinical and operational priorities.
Review Date: 26 February 2026
Next Review: 26 August 2026
Published on: 26 February 2026
Last Updated: 26 February 2026