Bocox and botulinum toxin: putting an end to penile retraction at rest

The phenomenon that no one talks about — and that bothers a great many men

Penile shrinkage —the retraction of the penis at rest—is a common phenomenon… but rarely discussed. Yet, it can be a real source of embarrassment in everyday life.

In some men, this retraction is particularly pronounced: in situations of stress, cold, or anxiety, the penis contracts strongly. The discrepancy between perceived size at rest and actual size then becomes a real source of insecurity. Locker rooms, swimming pools, unexpected intimate moments… this situation can significantly impact self-confidence.

Bocox (penile Botox): injection of botulinum toxin into the corpora cavernosa. Its main objective is to relax the muscles responsible for retraction.

And the result: a more relaxed, larger and more stable penis at rest — even in situations where it would normally tend to retract.

But before going any further, one essential point: this treatment is not a universal solution .

As always, everything depends on the mechanism involved — and that’s what we’re going to clarify.

My honest position on Bocox: what I would have told you in a video

I filmed a video on the subject some time ago. And in this video, I express a clear reservation about the term “Bocox” as it circulates on the internet — and in particular about the combined Botox + PRP version which is spreading from the United States.

Here is what I say in this video, and what I stand by in this article:

The term ” Bocox ” comes from the United States and refers to a combination of Botox and PRP in the same syringe. I have reservations about this systematic combination—not because the two products are bad, but because every patient is different . PRP is suitable for dysfunctions originating in the tissues. Botox is suitable for dysfunctions related to excessive muscle tone. These two profiles rarely overlap—and mixing the two products without a specific indication is more about commercial logic than medical practice.

What I offer in my practice is botulinum toxin alone , used selectively in patients for whom the mechanism of muscle hypercontraction is clearly identified. It’s not a routine injection offered to everyone—it’s an indication determined after consultation, clinical examination, and discussion of alternatives.

Having made this clarification — and it is important — let’s see together what penile Botox can really do.

My explanatory video on the Bocox

I made this video to clarify my position on Bocox—the American term, the combined Botox + PRP treatment—and what I honestly think about it as a practitioner. I encourage you to watch it before or after your consultation.

Duration: approximately 3 minutes . Dr. Beley explains the origin of the term Bocox, his reservations about the systematic combination of PRP + Botox, and in what clinical context he uses penile botulinum toxin.

How Botox works on the penis: the mechanism explained

The cavernous smooth muscle: responsible for retraction

The penis contains smooth muscle fibers—different from the striated muscles you voluntarily control—that constantly regulate the tone of the erectile tissue. These fibers are under the control of the autonomic nervous system (sympathetic and parasympathetic).

In situations of rest, relaxation and sexual stimulation, the parasympathetic system takes over: the fibers relax, the cavernous arteries dilate, blood flows in — an erection occurs.

In situations of stress, cold, or anxiety, the sympathetic nervous system takes over: muscle fibers contract, arteries constrict, and the penis retracts. This is known as shrinkage . And in some men, this contraction mechanism is chronically overactive—even at rest, even without any objective reason.

In summary, the penis has two opposing states:

  • Stress / cold contraction shrinkage
  • Relaxation , release, normal volume

What botulinum toxin does

Botulinum toxin — Botox — is a substance that blocks neuromuscular transmission at the junctions between nerves and smooth muscle fibers. By injecting it into the corpora cavernosa, it locally inhibits the excessive contraction of these fibers.

The result: the penis remains more relaxed at rest . It is larger and less prone to situational retraction. And by inhibiting this excessive baseline tone, tissue compliance to blood flow during sexual stimulation is also improved—which can enhance the quality of erections in affected patients.

Botox does not increase penis size. It simply allows it to return to its natural resting size.

Problem: What’s happening ? What Botox does?
Hypercontraction of smooth muscle fibers: The cavernous muscles remain too contracted at rest — the penis retracts. Targeted relaxation of the fibers — the penis returns to its natural resting size.
Excessive vascular tone, chronic vasoconstriction, limited blood flow at rest, decreased tone, improved basal cavernous perfusion
Erections related to excessive muscle tone; difficulty achieving an erection despite normal stimulation; improved tissue compliance with blood flow
Situational shrinkage (cold, stress, anxiety): Contraction in response to the sympathetic nervous system; Reduction of smooth muscle reactivity to sympathetic stress

How does a Bocox session work?

Before the session: the evaluation consultation

No session without a prior consultation. This is a rule I apply to all my procedures—and penile Botox is no exception. During this consultation, I assess your erectile profile, the nature of the problem you are experiencing, and whether muscle hypercontraction is indeed the underlying mechanism.

I also check for any contraindications: neuromuscular disorders, certain medications, active infections. And above all, I explain what the treatment can do in your case—and what it can’t. This dialogue is what allows us to determine the right treatment for you.

The session's progress

The procedure is performed entirely in the office, without hospitalization. Discomfort is minimal thanks to the prior local anesthesia.

  1. Application of an anesthetic cream — left in place for 20 to 30 minutes to eliminate local sensitivity
  2. Injection of botulinum toxin into the corpora cavernosa — a precise and rapid procedure, performed with a fine needle
  3. Progressive relaxation of smooth muscle fibers in the days and weeks following the injection
  4. Gradual results — the maximum effect is reached approximately 6 weeks after the session

Session duration: 20 to 30 minutes
Anesthesia: Local anesthetic cream only
Hospitalization: None — immediate return home
Time to effect: 2 to 6 weeks (maximum effect at 6 weeks )
Duration of effects: 3 to 6 months depending on the patient
Frequency: Renewal possible depending on developments

After the session: instructions and follow-up

The after-effects are mild. Slight discomfort at the injection site is possible for a few hours. I recommend avoiding sexual intercourse for 48 hours after the injection, and avoiding strenuous physical activity for 24 hours .

I see the patient again at 6 weeks to assess the response. It is at this point that the effect of Botox is fully established — and that I can judge whether the treatment has correctly targeted the mechanism identified during the consultation.

For whom is penile Botox recommended?

The situations where I think about it first

  • Chronic shrinkage — penis usually retracts at rest, even without cold or particular stress, with a real impact on confidence and social comfort
  • Severe situational retraction — marked shrinkage in situations of stress, anxiety, or cold, which exceeds the physiological norm and bothers the patient
  • Erectile dysfunction related to excessive muscle tone — an erection that is difficult to achieve despite normal stimulation, without advanced tissue breakdown
  • Improvement in erection quality with age, linked to an increase in cavernous basal tone
  • Desire for a more relaxed and fuller appearance at rest — without surgery or volume injections
  • Premature ejaculation associated with sympathetic nervous system hyperactivity — Botox can reduce this hyperactivity

Cases where I do not recommend this approach

  • Severe erectile dysfunction of advanced vascular or neurological origin — Botox acts on muscle tone, not on deep vascular damage
  • Expectation of permanent lengthening or volume increase — Botox does not alter anatomical structure
  • Neuromuscular diseases (myasthenia gravis, ALS, etc.) — absolute contraindication
  • Taking aminoglycosides or certain antibiotics — potentiates the effects of the toxin
  • Unrealistic expectations — the patient who wants a radical transformation will not be satisfied with this treatment

What I appreciate about this treatment for suitable candidates is the simplicity of the procedure and the clarity of the mechanism. When hypercontraction is truly the cause, the response to Botox is often remarkable—and the patient sees a significant difference within the first few weeks. But it’s essential to have identified the correct indication.

Bocox vs P-Shot: two treatments, two approaches

Since the two are often mentioned together — especially under the American term “Bocox” — it is useful to clarify how they are fundamentally different, and why I do not systematically combine them.

Bocox
criterion (penile Botox) P-Shot (penile PRP)
Active ingredient: Botulinum toxin (Botox) Platelet-rich plasma (your blood)
Mechanism: Relaxation of cavernous smooth muscles; regeneration of damaged cavernous tissue
Ideal patient profile: Excessive muscle tone, shrinkage, ED related to hypercontraction; damaged tissue (diabetes, prostatectomy, smoking, Peyronie’s disease)
Effect on rest: Penis more relaxed, larger at rest; progressive improvement of vascularization
Effect on erection: Improved compliance with blood flow; Improved overall erectile quality
Onset of action : 2–6 weeks (maximum effect at 6 weeks). 4–8 weeks after the complete cycle.
Duration of effects : 3–6 months ; 6–12 months (annual cycle)
Anesthesia Local cream Local cream + light local
Hospitalization: None (office) None (office)
Can it be combined? Yes — with P-Shot as specified. Yes — with Bocox as specified.
Level of evidence : Limited — studies in progress
Indicative price €500–1,000 / €700–1,500 per cycle

Can they be combined?

Yes — but only if the patient presents both problems simultaneously : degraded cavernous tissue (indication for PRP) AND excessive muscle tone (indication for Botox). These two profiles can overlap, particularly in diabetic patients or after prostate surgery.

In this specific case, a targeted— but not systematic —combination may be considered. This is not the pre-mixed “Bocox” sold as a universal solution. It is an individualized clinical decision, made after a thorough evaluation.

Level of evidence and transparency: what science says today

As with the P-Shot, I must speak frankly to you about the level of evidence for penile Botox.

Level of evidence: currently being validated (not yet in official recommendations).

Pilot studies, notably published in The Journal of Sexual Medicine and Translational Andrology and Urology , show positive results on erectile function and erection quality after intracavernosal Botox injection. However, the sample sizes are small, the protocols vary, and no standard has yet been established.

So the clinical results are encouraging, but the protocols still need to be standardized.

FAQ: Your questions about Bocox and penile Botox

The term “Bocox” originated in the United States and initially referred to a combination of Botox and PRP in the same injection. In my practice, I clearly distinguish between the two products: penile Botox alone (botulinum toxin in the corpora cavernosa) and P-Shot (PRP alone). I don’t routinely combine them—each product addresses a different type of dysfunction. If both indications are present in the same patient, a combination may be considered after clinical evaluation.

Yes—this is the indication where I see the best results. Penile shrinkage is linked to an over-contraction of the smooth muscle fibers in the corpora cavernosa, often in response to stress or the sympathetic nervous system. By relaxing these fibers, Botox allows the penis to remain more relaxed and larger at rest, even in situations that would normally trigger retraction. The effect is gradual—it is at its maximum approximately 6 weeks after the injection.

No—not in the anatomical sense. Botox doesn’t change the length of the corpora cavernosa. What it does is allow the penis to fully extend to its natural, flaccid size, without being restricted by excessive contraction. For a man whose penis typically shrinks by 2 to 3 cm when flaccid, regaining that volume is a real, visible difference—but it’s the restoration of existing volume, not the creation of new volume.

The injection is performed after application of a local anesthetic cream. Discomfort during the session is generally well tolerated. Slight tingling and sometimes mild local sensitivity in the following hours are possible—transient and easily managed with simple pain relievers if necessary.

The effect of penile Botox lasts on average 3 to 6 months , depending on individual sensitivity to the toxin and the volume injected. Once the effect wears off, the treatment can be repeated. Some patients choose to repeat the treatment every six months to maintain the benefits continuously.

The price of a penile Botox session generally ranges from €500 to €1,000 , depending on the volume of toxin used and the practitioner. This procedure is not covered by French national health insurance. If combined with P-Shot is considered, the overall cost will be adjusted accordingly. A detailed quote will be provided during your consultation.

As with any injection procedure, there are possible side effects: hematoma at the injection site, slight asymmetry of response, and temporarily altered sensitivity in the days following the injection. These effects are transient and rare with meticulous technique. Systemic diffusion of the toxin is theoretically possible but exceptional with the doses used in my office. I conduct a preliminary assessment to rule out any contraindications.

Yes. Penile Botox can be combined with PDE5 inhibitors (Viagra, Cialis) to enhance their effect in patients who respond partially. It can also be used in conjunction with low-intensity shockwave therapy or, in specific cases, with P-Shot—but this latter combination is decided on a case-by-case basis and is not routinely offered.

Penile Botox is based on a clear and documented physiological mechanism. Pilot studies show positive results on erectile function, particularly in cases related to muscle hypercontraction. However, it is not yet included in official recommendations due to a lack of standardized protocols. My practice is based on this available data, with full information provided to the patient on the current level of evidence. This is not an experimental treatment — it is a treatment that is being validated.

Key takeaways

Penile Botox is a treatment I offer selectively , to patients in whom the mechanism of muscle hypercontraction is clearly identified. It is not a universal solution—and it’s not what I sell.

For the man who suffers from shrinkage, who finds it difficult to cope with the retraction of his penis at rest and who is looking for a simple, non-surgical solution without recovery time — this is a real option, documented in terms of mechanism, and whose positive effects I observe in my practice.

For the man who hopes for lengthening, a permanent increase in volume, or a cure for severe erectile dysfunction — I direct him towards other solutions, more suited to his profile.

The principle is simple: to relieve an excessive contraction .

If you want to know if this approach is right for you, the first step is a consultation. Not to make a decision on the spot—to understand together what’s really going on and what the best solution is for you.

Make an appointment with Dr. Beley — Urology Practice Paris Opéra

Tel. +33 1 42 68 83 30 | Address: 82 Boulevard de Courcelles, Paris 17th arrondissement | Email: contact@beleyurologie.fr

Medical sources and references

Gur S. et al. (2018) — Botulinum toxin-A injection into the corpus cavernosum — preclinical and clinical evidence for erectile dysfunction. Andrology
https://onlinelibrary.wiley.com/journal/20472927

Abdel-Hamid IA et al. (2020) — Clostridium botulinum toxin and erectile dysfunction — what is the current state? Sexual Medicine Reviews
https://www.smr.jsexmed.org/

Ding XG et al. (2009) — Intracavernous injection of botulinum toxin A — potential treatment for vasculogenic erectile dysfunction. Int Braz J Urol
https://www.intbrazjurol.com.br/

Translational Andrology and Urology — Review of non-invasive treatments for erectile dysfunction
https://tau.amegroups.org/

European Association of Urology (EAU) — Guidelines on Sexual and Reproductive Health 2024
https://uroweb.org/

French Society of Urology (SFU) — Resources in andrology and erectile dysfunction
https://www.urofrance.org/

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