Toxin-Based Treatment · Off-label · In-office
Priapus Toxin™
(commonly called “Bocox”)
Priapus Toxin™ refers to botulinum toxin injected directly into the corpus cavernosum — the erectile tissue of the penis — to relax smooth muscle and support blood flow for erectile dysfunction. You’ll also see this widely nicknamed “Bocox” across the industry. Both names are covered here, along with what’s actually true about each and what the published evidence shows.
A note on the two names
“Priapus Toxin™” vs. “Bocox” — what’s actually true about each
Two different names circulate for this treatment, and they aren’t equivalent in status. Priapus Toxin™ is a registered trademark filed by Dr. Charles E. Runels — the same physician behind the P-Shot® and Priapus Shot® — describing his specific method of injecting botulinum toxin into the corpus cavernosum for erectile function. Allergan, the maker of Botox®, agreed not to challenge his use of that name.
“Bocox” is a widely used industry nickname — essentially a portmanteau of “Botox” — that’s appeared across many independent clinics. It is not a registered trademark: Dr. Runels himself attempted to trademark it, and Allergan specifically objected, declining to consent. So while “Bocox” is the more commonly searched term, it isn’t owned by anyone, isn’t officially sanctioned by Allergan, and shouldn’t be treated as an official product name — it’s informal shorthand that’s become common usage.
The underlying treatment is the same regardless of which name is used: botulinum toxin injected into penile erectile tissue. The name doesn’t change the mechanism, the evidence, or the regulatory status — it’s simply a naming and branding distinction worth understanding.
PhallusMD uses generic “botulinum toxin” terminology to describe the treatment itself throughout this page, since multiple toxin brands (Botox®, Dysport®, Xeomin®) could theoretically be used, and reserves “Priapus Toxin™” specifically for Dr. Runels’ trademarked method.
Mechanism
How botulinum toxin is thought to help erectile function
Botulinum toxin injected into the corpus cavernosum is believed to relax the smooth muscle within the erectile tissue, which may improve blood flow into the penis during arousal — a different mechanism from how PDE5 inhibitors (like sildenafil) work, and distinct from the wrinkle-relaxing use most people associate with the drug.
A comprehensive 2024 systematic review found 6 studies on botulinum toxin for erectile dysfunction meeting inclusion criteria. Across those studies, erectile function scores (IIEF-EF) improved in 41–57.4% of treated patients, with benefits reported lasting up to 6 months. A separate 2022 meta-analysis of intracavernosal botulinum toxin injection found measurable improvement in both erection hardness scores and penile blood flow velocity.
This is a genuinely promising signal for an off-label treatment — but it remains a small evidence base with no large randomized controlled trials yet, consistent with every other toxin-based application covered on this site.
What to expect
The procedure
Consultation
Your provider reviews your ED history, prior treatment attempts, and overall health to determine candidacy.
Injection
Botulinum toxin is injected into the corpus cavernosum, typically split between both sides. A commonly reported protocol uses 100 units total (50 on each side), though dosing varies by provider and product used. Topical numbing is often used for comfort.
Gradual onset
Effects build over roughly a week, with changes in erectile quality typically noticeable within several weeks.
Temporary — repeat treatment needed
Reported benefit lasts up to about 6 months based on published studies. This is not a one-time or permanent treatment; repeat injections are needed to sustain any benefit.
How it compares
Botulinum toxin vs. other ED treatments
| Feature | Botulinum Toxin (this page) | Viagra® / Cialis® | Shockwave Therapy |
|---|---|---|---|
| Mechanism | Smooth muscle relaxation via nerve blockade | PDE5 inhibition | Vascular repair via acoustic waves |
| Evidence base | 6 studies, small evidence base | Decades of large trials | 20+ RCTs |
| FDA-approved for ED? | No — off-label | Yes | No — off-label in US |
| Duration of effect | Up to ~6 months per treatment | Hours per dose | Longer-lasting per course |
| Invasiveness | Injection | Oral | Non-invasive |
Is it right for you?
Who typically considers this treatment
Men with ED who haven’t responded adequately to oral PDE5 inhibitors
Men interested in an alternative mechanism to standard medications
Men comfortable with an off-label treatment supported by a still-limited evidence base
Men who understand this requires repeat treatment roughly every 6 months
Common questions
Frequently asked questions
Is “Bocox” a real, trademarked treatment name?
No. “Bocox” is a widely used informal nickname, not a registered trademark. Dr. Charles Runels — who does hold the trademark for “Priapus Toxin™” — attempted to trademark “Bocox” as well, but Allergan (the maker of Botox®) specifically objected and declined to consent. It remains in common industry use as an informal term, not an officially sanctioned brand.
Is this FDA-approved?
No. Botulinum toxin is FDA-approved for various indications (cosmetic use, migraine, overactive bladder, and others), but not for erectile dysfunction. Its use here is off-label, which is legal and common in medicine but means the FDA has not reviewed evidence specifically for this application.
How does this compare to Viagra or Cialis?
They work through completely different mechanisms. PDE5 inhibitors like sildenafil and tadalafil work on demand, requiring arousal each time. Botulinum toxin injection aims for a longer-lasting effect from a single treatment — up to about 6 months based on published studies — but requires an in-office procedure rather than a pill, and has a much smaller evidence base behind it.
What are the risks?
As an off-label injection treatment with a limited published evidence base, risks and side effect data are less established than for first-line ED treatments. Discuss your specific risk profile, including any bleeding disorders or prior penile surgery, with your provider before proceeding.
Related
Other options to consider
Find a provider
Search our directory of vetted physicians offering this treatment, or ask anonymously in the forum first.
Key sources: Henriques et al., “A Systematic Review on Administration of Botulinum Toxin in the Management of Male Sexual Dysfunctions,” Andrology (2024) · “Intra-Cavernosal Injection of Botulinum Toxin in the Treatment of Erectile Dysfunction: a Systematic Review and Meta-Analysis” (2022) · “Priapus Toxin™: A Specific Method of Using Botulinum Toxin for Erectile Dysfunction,” PR Newswire (2023)
This page is for informational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations. This is an off-label use of botulinum toxin, not FDA-approved for erectile dysfunction. Priapus Toxin™ is a trademark of Dr. Charles E. Runels / Cellular Medicine Association. “Bocox” is an informal industry term, not a registered trademark or an officially sanctioned Allergan product name. Always consult a licensed physician before pursuing any treatment.
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