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Trimix Injections for ED: Effectiveness, Side Effects & More

Mike Bohl, MD, MPH, ALM

Reviewed by Mike Bohl, MD

Written by Geoffrey C. Whittaker

Published 11/28/2022

Updated 01/14/2024

Oral erectile dysfunction medications are a great way to treat ED. These pills, like Viagra®, are safe, approved by the Food and Drug Administration and can be self-administered without a urologist present. Unfortunately, they don’t work for everybody. 

For men whose erectile tissue doesn’t respond to oral medications or who can’t tolerate oral medications, there’s another possible option: an injection of medication directly into the side of the penis. Enter Trimix injections.

If reading “injection into the side of the penis” made you squirm, we get it, but truth be told injections for erectile dysfunction aren’t the most out-of-pocket ED treatment. While pills from a gas station might be easier to come by than prescription medication, they could be more dangerous than a needle of medication used properly. 

Below we’ve shared science says about the effectiveness of Trimix injections for your ED, as well as the side effects and other cautions you’ll want to be aware of. Let’s start with some background.

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What are Trimix Injections?

Trimix is an injectable medication containing three active pharmaceutical ingredients: alprostadil, papaverine and phentolamine. Alprostadil is the most important of these — it’s a vasodilator that increases blood flow to your erectile tissues. Alprostadil, on its own, is FDA approved to treat erectile dysfunction and is sold under the brand name, Caverject®. And if you want to stop reading about penile injections now, you should know that alprostadil and Trimix are also available in a cream or gel.

The other two compounds in Trimix medication are papaverine and phentolamine. 

Papaverine is a phosphodiesterase inhibitor that keeps your erection from going soft by inhibiting a compound that reduces blood flow, similar to medications like Viagra and Cialis. 

Phentolamine is an alpha blocker that increases blood flow, which can have positive effects on your erectile function. 

Together, these medications are a sort of triple threat against erectile dysfunction, or at least that’s what some research says. 

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How Does Trimix Work?

Trimix is administered into the corpora cavernosa (two chambers of spongy tissue in the penis that fill with blood to create an erection) before it’s time for intimacy. After the injection, the user (that’d be you) should apply pressure to the injection site for a few minutes. 

Within five to 20 minutes, you should get an erection that will peak around half an hour after the injection. In most cases, your erection will disappear after an hour.

We say “should” and “in most cases” partly because, as of this time, the FDA hasn’t approved Trimix for ED — the information we have comes from the FDA’s approval of alprostadil for ED, studies and manufacturer information, which means it may not be the most accurate guidance for the compounded medication.

Are Trimix Injections Effective?

Alprostadil, on its own, is FDA approved, meaning it has passed clinical trials showing it is safe and effective for the treatment of erectile dysfunction 

Trimix isn’t a drug with just a single active pharmaceutical ingredient drug. It’s a compounded medication that’s produced at compounding pharmacies, which are usually more expensive, and the dose of each of the individual ingredients may vary. Research does suggest that the efficacy of Trimix is similar to the efficacy of alprostadil.

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Trimix Side Effects: Are The Injections Safe?

We know that alprostadil can cause side effects, including:

  • Dizziness and headache

  • Rash or swelling of the penis

  • Hypotension or hypertension

  • Penile infections 

  • Injuries to the penis

  • Penile function issues like prolonged erection (priapism)

Alprostadil can also potentially cause penile fibrosis — a type of scarring that can reduce the penis’s elasticity. Penile fibrosis can cause anatomical deformation, which is a complicated way of saying it could cause your penis to curve.

Papaverine can also cause penile fibrosis. As for phentolamine, it’s rarely used in injections by itself, and so our picture of its side effects is blurry at best. 

There’s also the question of user error. Because this medication is typically taken as a self-injection, it’s important to understand proper technique and location for giving yourself the medication to avoid tissue damage and other potential issues. 

Since any  intracavernosal injection could lead to injuries with the wrong injection technique, make sure to have a urology expert, urologist or other trained healthcare professional show you how to safely remove the needle from the rubber stopper and properly apply pressure to the plunger.

Given these risks, Trimix might be a second…or third or fourth…option for addressing ED after trying other treatment options, like oral medication

Before jumping to injections, you’ll want to try management options like changes in diet, increased exercise, weight loss, going to therapy for psychological causes of ED, quitting smoking or reducing drinking, discontinuing illicit drug use and, ED pills.

The most commonly prescribed type of ED pills are phosphodiesterase-5 inhibitors (PDE5 inhibitors), which relax arterial smooth muscles to increase blood flow to your penis. Drugs like tadalafil and sildenafil, (you probably know them as Cialis® and Viagra), Stendra® (avanafil) and Levitra® (vardenafil) all fall into this category.

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Should You Inject Trimix for ED?

Sexual activity is an essential part of men’s health, and unless you and your partner have a calendar invite for sex o’clock blocked off, it’s not always predictable. Carrying a syringe around “in case” isn’t very practical. 

Health risks aside, Trimix is usually not a first-line option for ED treatment. But if you’ve seen those fail, Trimix might help you.

If you decide to use Trimix for ED, be sure to take precautions:

  • Only use Trimix as prescribed, after a professional gives you individualized medical advice on how to inject Trimix.

  • Make sure to sterilize the skin with an alcohol pad.

  • If your full erection doesn’t go away after four hours, head to the emergency room and seek immediate medical attention — this is a real medical emergency.

Trimix injections for erectile dysfunction are a potentially effective and safe second-line treatment for men who don’t respond well to other ED treatments. If you’re game for penile injection therapy, talk to your healthcare provider about your options. 

If you’re not sure where to start, it may be time to start a consultation with a healthcare professional.

5 Sources

  1. Dhaliwal A, Gupta M. PDE5 Inhibitors. [Updated 2023 Apr 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from:
  2. Jain A, Iqbal OA. Alprostadil. [Updated 2023 Jul 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from:
  3. Parker, A., Bruha, M., Akinola, O., & Welliver, C. (2016). A summary of the controversy surrounding off-label medications in men's health. Translational andrology and urology, 5(2), 201–206.
  4. HIGHLIGHTS OF PRESCRIBING INFORMATION: CAVERJECT IMPULSE® (alprostadil) for injection, for intracavernosal use. . (n.d.-a).
  5. U.S. Department of Health and Human Services. (n.d.-e). Treatment for erectile dysfunction - NIDDK. National Institute of Diabetes and Digestive and Kidney Diseases.
Editorial Standards

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references. See a mistake? Let us know at [email protected]!

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.

Mike Bohl, MD

Dr. Mike Bohl is a licensed physician and the Director of Scientific & Medical Content at a stealth biotech startup. Prior to joining Hims & Hers, Dr. Bohl spent several years in digital health focusing on patient education. He has also worked in medical journalism for The Dr. Oz Show and Sharecare and has served on the Medical Expert Board of Eat This, Not That!.

Dr. Bohl obtained his Bachelor of Arts and Doctor of Medicine from Brown University, his Master of Public Health from Columbia University, and his Master of Liberal Arts in Extension Studies—Journalism from Harvard University. He is currently pursuing a Master of Business Administration and Master of Science in Healthcare Leadership at Cornell University. Dr. Bohl trained in internal medicine with a focus on community health at NYU Langone Health.

Dr. Bohl is Certified in Public Health by the National Board of Public Health Examiners, Medical Writer Certified by the American Medical Writers Association, a certified Editor in the Life Sciences by the Board of Editors in the Life Sciences, a Certified Personal Trainer and Certified Nutrition Coach by the National Academy of Sports Medicine, and a Board Certified Medical Affairs Specialist by the Accreditation Council for Medical Affairs.

In addition to his written work, Dr. Bohl has experience creating medical segments for radio and producing patient education videos. You can find Dr. Bohl on LinkedIn for more information

Dr. Bohl lives in Manhattan and enjoys biking, resistance training, sailing, scuba diving, skiing, tennis, and traveling. You can find Dr. Bohl on LinkedIn for more information.


  • Bachelor of Arts, Egyptian and Ancient Western Asian Archaeology. Brown University |

  • Doctor of Medicine. |

  • Master of Public Health, General Public Health. |

  • Master of Liberal Arts, Journalism. |

  • Master of Business Administration. | (anticipated 2024)

  • Master of Science, Healthcare Leadership. | (anticipated 2024)


  • NYU Internal Medicine Residency—Brooklyn Community Health Track. |


  • Certified in Public Health.

  • Medical Writer Certified.

  • Editor in the Life Sciences.

  • Certified Personal Trainer.

  • Certified Nutrition Coach.

  • Board Certified Medical Affairs Specialist. Accreditation Council for Medical Affairs

  • Digital Storytelling Graduate Certificate.

  • Marketing Management and Digital Strategy Graduate Certificate.


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