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  • Fact Checked
  • August 15, 2025
  • 6 min read
Dealing with Infections

What Is Trichomonas Vaginalis? Understanding this Under the Radar STI Parasite

  • Written by Hans Graubard

    COO & Co‑Founder, Happy V

    Hans Graubard

    Dietary supplement manufacturing, regulatory and product development, and DTCt; leadership experience...

    Learn More
    • Updated on April 17, 2026
  • Updated on April 17, 2026
  • Fact checked by Lenia Lopez
  • Edited by Liz Breen
Table of Contents
  1. 1. What Is Trichomonas vaginalis?
  2. 2. What Is Trichomoniasis?
  3. 3. Diagnosis: How Do You Know It’s Trich?
  4. 4. Treatment for Trichomoniasis
  5. 5. Complications from Untreated Trichomoniasis
  6. 6. Supporting Vaginal Health After Treatment
  7. 7. When to See a Healthcare Provider
  8. 8. Final Thoughts
  9. 9. Keep the Conversation Going

Key Takeaways

  • Trichomonas vaginalis is a protozoan parasite that causes trichomoniasis, a common but underdiagnosed sexually transmitted infection (STI).
  • Trichomoniasis often mimics other vaginal infections like bacterial vaginosis, making accurate diagnosis from a health care provider essential.
  • While antibiotics like metronidazole or tinidazole treat the infection, supporting your vaginal microbiome with probiotics may reduce the risk of reinfection and restore balance.


You’ve probably heard of sexually transmitted infections (STIs) like chlamydia and gonorrhea, but what about trich? Short for trichomoniasis, this common STI is caused by a parasite called Trichomonas vaginalis1…and it’s way more widespread than most people think.

Because its symptoms often overlap with other vaginal infections like bacterial vaginosis or a yeast infection, trichomoniasis can easily go misdiagnosed, which is dangerous, since, left untreated, it can increase your risk of complications like pelvic inflammatory disease, low birth weight, and even other STIs.

Let’s get to know the parasite behind the infection, how trichomoniasis affects your body, and how to bounce back after an infection.

This post is for informational purposes only and does not constitute medical advice. See full disclaimer below.

What Is Trichomonas vaginalis?

Trichomonas vaginalis (or T. vaginalis) is a protozoan parasite that causes trichomoniasis, a sexually transmitted disease primarily spread through sexual intercourse2. Unlike bacteria or viruses, this tiny organism moves with a whip-like tail, allowing it to migrate through the vaginal canal, urethra, or cervix (depending on who’s infected).

This parasite thrives in the urogenital tract and can live in both men and women, although it’s diagnosed far more often in women. The tricky part? Many infected people never show symptoms, which means T. vaginalis can silently spread from one sexual partner to another.

What Is Trichomoniasis?

 

Educational graphic titled "What is Trichomoniasis?" featuring a circular microscopic image of Trichomonas vaginalis parasites. The text defines "Trich" as a common STI caused by a parasite, noting that it is often missed because symptoms can overlap with BV or yeast infections, or be entirely absent.

 

Trichomoniasis, or "trich," is a sexually transmitted infection (STI) caused by the parasite Trichomonas vaginalis. In fact, it's one of the most common and the most underdiagnosed STIs here in the US. According to the Centers for Disease Control and Prevention (CDC), millions of Americans contract trich each year, but it is hard to get an exact number because many people who have trich remain asymptomatic (though they can still pass it to others).

When symptoms do show up, they can be hard to attribute to trich, at least initially, because they often resemble other infections like bacterial vaginosis, vaginitis, or candidiasis3.

Educational infographic titled "What are some of the trich symptoms?" It notes that symptoms often mimic other vaginal infections. The graphic lists symptoms such as yellow-green frothy discharge with strong odor, itching, burning with urination, "strawberry cervix," and symptoms in men like urethritis.

 

The most common symptoms of trich include:

  • Vaginal discharge that's thin, yellow-green, or frothy with a strong odor
  • Itching or soreness around the vulva4
  • Burning during urination or after sex5
  • Redness of the cervix, sometimes referred to as "strawberry cervix"
  • In men: discharge from the urethra, urethritis, or painful urination

Diagnosis: How Do You Know It’s Trich?

 

Educational image showing a doctor's examination room with medical equipment like a blood pressure monitor and otoscope on the wall. A text box in the center states that the only way to confirm trichomoniasis is through a healthcare provider via a pelvic exam and vaginal swab.

 

The only person who can diagnose Trich is a healthcare provider. They will do this by asking you about your symptoms, performing a pelvic exam, and then taking a vaginal swab6. They will use the swab to look for the parasite through a test like:

  • Wet mount microscopy7
  • Antigen test
  • Nucleic acid amplification test (NAATs)

NAATs are the most sensitive of the three tests and the one recommended by the CDC for spotting Trich. 

Because Trich is often asymptomatic, it's important to get tested routinely (not just if you have symptoms). Trich is included in most standard STI tests. If you're sexually active, have a new sexual partner, or have multiple sexual partners, make STI testing a part of your annual exam.

Treatment for Trichomoniasis

 

Educational graphic titled "Is trich treatable?" featuring a 3D illustration of three medicine pills in pink, purple, and blue. The text explains that trichomoniasis is highly treatable with medicines like metronidazole or tinidazole, noting that success depends on treating all partners and avoiding alcohol and unprotected sex during treatment.

 

While no one ever wishes for an STI, the good news is that trich is very treatable8. Most people are prescribed the antibiotic metronidazole or tinidazole, usually as a single dose or a brief course9. These antibiotics are part of the CDC’s treatment guidelines for sexually transmitted diseases.

During treatment your doctor may advise you to:

  • Avoid alcohol for 24 hours after taking the meds
  • Inform and treat all sex partners to avoid reinfection
  • Practice safe sex (using condoms) until cleared

Complications from Untreated Trichomoniasis

Regular STI testing is crucial, especially for trich. Leaving even asymptomatic trich untreated can increase your risk of:

Persistent inflammation of the vagina and genital tract also compromises long-term reproductive health10.

Supporting Vaginal Health After Treatment

 

An educational graphic titled "Supporting your vaginal microbiome after treatment." It features six illustrated tips: 1. Use condoms or barrier methods. 2. Stay consistent with STI screening. 3. Wear breathable cotton underwear. 4. Avoid douching and irritating products. 5. See provider for persistent symptoms or known exposure. 6. Add daily probiotics with proven strains.

 

While antibiotics may help to clear an active Trich infection, they are not the end of your treatment journey. After any sort of antibiotic treatment, it's important to support your body and your vaginal microbiome to protect against future infections. 

See, antibiotics don't just wipe out the infection-causing bacteria; they actually wipe out all the bacteria living in your vagina, including healthy Lactobacillus bacteria11. Daily probiotics, especially following antibiotic use, can help restore these bacteria levels and strengthen your natural immunity.

Happy V's Prebiotic + Probiotic contains clinically studied strains of Lactobacillus like L. acidophilus and L. rhamnosus, which have been shown to help restore balance, maintain vaginal pH, and defend against overgrowth of pathogens.

In preclinical testing, Happy V's probiotic blend also showed a reduction in harmful bacteria, including those that cause yeast infections and BV, two of the most common secondary infections following STI treatment.

Along with taking high-quality probiotics, you can also support your body by:

  • Not douching, since this can worsen bacterial imbalances
  • Wearing breathable, cotton underwear
  • Using condoms or other barrier methods 
  • Staying on top of regular STI screenings

When to See a Healthcare Provider

Any unusual vaginal symptoms, such as unusual vaginal discharge, itching, or burning all signal that your body needs some support. Also, if you have recently had sexual contact with someone who has Trich, make an appointment with your doctor to get tested, even if you don't have symptoms yet. A quick swab test will save you from developing symptoms or passing Trich to another partner.

Final Thoughts

It's hard to say how common Trichomoniasis even is because it often flies under the radar. But even asymptomatic Trich can lead to health issues down the road if left untreated, not to mention be passed to another partner. This is why routine STI testing is important for anyone who is sexually active.

When spotted, Trich is easily treated, and after treatment, daily probiotics and protective habits will keep it from coming back.

Keep the Conversation Going

 

Disclaimer: This blog is for informational and educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Statements about supplements have not been evaluated by the Food and Drug Administration. For more information about trichomoniasis or other STIs, visit cdc.gov or speak to a licensed health care provider.

FAQ

Can Happy V Vaginal Probiotics be taken with prescription medication?

Happy V is a natural dietary supplement that uses probiotics in its formula. Probiotics are generally recommended as safe (GRAS) by the FDA and do not tend to have side effects when consumed with medications. However, it is always best to ask a healthcare professional before mixing supplements and medications.

How do I take Happy V Vaginal Probiotics?

Take two capsules of Happy V Vaginal Probiotics daily, with or without food, or as directed by a healthcare professional.

Who can take Happy V Vaginal Probiotics?

Happy V Vaginal Probiotics is recommended for those who want to optimize the balance of ph, bacteria, and yeast in their vaginal flora. It is beneficial for those who have suffered from recurring yeast infections and bacterial vaginosis.

[1] Think You Have a Vaginal Infection? Here’s What You Need to Know. The American College of Obstetricians and Gynecologists.

[2] Centers for Disease Control and Prevention. Trichomoniasis – CDC Fact Sheet (Detailed). Centers for Disease Control and Prevention.

[3] Achkar JM, Fries BC. Clinical presentation of genitourinary candidiasis. Clin Infect Dis. 2010;50(1)
Available at: Candida Infections of the Genitourinary Tract. PMC.

[4] Huang SH, Hsu HC, Lee TF, et al. Prevalence, Associated Factors, and Appropriateness of Empirical Treatment of Trichomoniasis, Bacterial Vaginosis, and Vulvovaginal Candidiasis among Women with Vaginitis. Microbiology Spectrum. 2023;11(3):e00161-23. doi:10.1128/spectrum.00161-23.

[5] Think You Have a Vaginal Infection? Here’s What You Need to Know. The American College of Obstetricians and Gynecologists. Published June 2022. Updated June 2023.

[6] Lyra A, Ala-Jaakkola R, Yeung N, et al. A healthy vaginal microbiota remains stable during oral probiotic supplementation: a randomised controlled trial. Microorganisms. 2023;11(499). Published February 2023.

[7] British Columbia Centre for Disease Control. BCCDC Non-Certified Practice Decision Support Tool: Vulvovaginal Candidiasis (VVC). In: Communicable Disease Control Manual: Chapter 5 – Sexually Transmitted Infections. Vancouver, BC: BCCDC;

[8] Think You Have a Vaginal Infection? Here’s What You Need to Know. The American College of Obstetricians and Gynecologists. Published September 2023.

[9] 1. Verstraelen et al., 2004 Verhelst R, Verstraelen H, Claeys G, et al. Cloning of 16S rRNA genes amplified from normal and disturbed vaginal microflora suggests a strong association between Atopobium vaginae, Gardnerella vaginalis and bacterial vaginosis. BMC Microbiol. 2004;4:16. doi:10.1186/1471-2180-4-16.

2. Russo et al., 2019 Russo R, Karadja E, De Seta F. Evidence-based mixture containing Lactobacillus acidophilus GLA-14 and Lactobacillus rhamnosus HN001 plus lactoferrin to prevent recurrent bacterial vaginosis: a double-blind, placebo-controlled, randomized clinical trial. Benef Microbes. 2019;10(1):19-26. doi:10.3920/BM2018.0075.

[10] Achkar JM, Fries BC. Candida Infections of the Genitourinary Tract. Clin Microbiol Rev. 2010;23(2):253-273.

[11] BC Centre for Disease Control. BCCDC Clinical Prevention Services Reproductive Health Decision Support Tool – Non-certified Practice: Vulvovaginal Candidiasis (VVC). British Columbia Centre for Disease Control; 2023.

[1] Think You Have a Vaginal Infection? Here’s What You Need to Know. The American College of Obstetricians and Gynecologists.

[2] Centers for Disease Control and Prevention. Trichomoniasis – CDC Fact Sheet (Detailed). Centers for Disease Control and Prevention.

[3] Achkar JM, Fries BC. Clinical presentation of genitourinary candidiasis. Clin Infect Dis. 2010;50(1)
Available at: Candida Infections of the Genitourinary Tract. PMC.

[4] Huang SH, Hsu HC, Lee TF, et al. Prevalence, Associated Factors, and Appropriateness of Empirical Treatment of Trichomoniasis, Bacterial Vaginosis, and Vulvovaginal Candidiasis among Women with Vaginitis. Microbiology Spectrum. 2023;11(3):e00161-23. doi:10.1128/spectrum.00161-23.

[5] Think You Have a Vaginal Infection? Here’s What You Need to Know. The American College of Obstetricians and Gynecologists. Published June 2022. Updated June 2023.

[6] Lyra A, Ala-Jaakkola R, Yeung N, et al. A healthy vaginal microbiota remains stable during oral probiotic supplementation: a randomised controlled trial. Microorganisms. 2023;11(499). Published February 2023.

[7] British Columbia Centre for Disease Control. BCCDC Non-Certified Practice Decision Support Tool: Vulvovaginal Candidiasis (VVC). In: Communicable Disease Control Manual: Chapter 5 – Sexually Transmitted Infections. Vancouver, BC: BCCDC;

[8] Think You Have a Vaginal Infection? Here’s What You Need to Know. The American College of Obstetricians and Gynecologists. Published September 2023.

[9] 1. Verstraelen et al., 2004 Verhelst R, Verstraelen H, Claeys G, et al. Cloning of 16S rRNA genes amplified from normal and disturbed vaginal microflora suggests a strong association between Atopobium vaginae, Gardnerella vaginalis and bacterial vaginosis. BMC Microbiol. 2004;4:16. doi:10.1186/1471-2180-4-16.

2. Russo et al., 2019 Russo R, Karadja E, De Seta F. Evidence-based mixture containing Lactobacillus acidophilus GLA-14 and Lactobacillus rhamnosus HN001 plus lactoferrin to prevent recurrent bacterial vaginosis: a double-blind, placebo-controlled, randomized clinical trial. Benef Microbes. 2019;10(1):19-26. doi:10.3920/BM2018.0075.

[10] Achkar JM, Fries BC. Candida Infections of the Genitourinary Tract. Clin Microbiol Rev. 2010;23(2):253-273.

[11] BC Centre for Disease Control. BCCDC Clinical Prevention Services Reproductive Health Decision Support Tool – Non-certified Practice: Vulvovaginal Candidiasis (VVC). British Columbia Centre for Disease Control; 2023.
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