Sex Doc explained: Why Sex Sometimes Burns When a Man Ejaculates Inside the Vagina
I’ve had many women in my office come to me after feeling frustrated by having sex. People engage in sex all the time. In the U.S., in the 2015–2019 National Survey of Family Growth, 68.1% of women and 55.3% of men aged 15–44 reported using condoms “none of the time”. [CDC]
For many women, sex can feel pleasurable and intimate, and many report it is more intimate and connected without a condom. Women also engage in unprotected intercourse when trying to concieve a baby {TTC}—yet sometimes, an uncomfortable burning sensation happens after a man ejaculates inside the vagina. While this can be surprising or concerning, it’s not uncommon. Understanding why this burning occurs can help you address the issue and feel more at ease in your sex life.
Common Causes of Burning After Ejaculation
1. pH Imbalance
The vagina has a naturally acidic pH that helps protect against infections. Semen, on the other hand, is more alkaline. When semen enters the vagina, this shift in pH can cause temporary irritation or burning.
2. Allergy or Sensitivity to Semen
Though rare, some women experience seminal plasma hypersensitivity—an allergic reaction to proteins in semen. Symptoms can include burning, itching, swelling, or redness after sex.
3. Vaginal Dryness or Microtears
If there isn’t enough natural lubrication during sex, friction can cause tiny tears in the vaginal tissue. When semen comes into contact with those sensitive areas, it may cause a stinging or burning sensation.
4. Infections (Yeast or Bacterial Vaginosis)
Underlying infections can make the vaginal tissue more sensitive. When semen enters, the imbalance may worsen symptoms like burning, itching, or discharge.
5. Sexually Transmitted Infections (STIs)
Certain STIs—such as chlamydia, gonorrhea, or trichomoniasis—can cause burning sensations during or after sex. If the burning is frequent and accompanied by discharge, odor, or pelvic pain, it’s important to see a healthcare provider.
6. Lubricant Sensitivity
Sometimes the burning is not semen-related but caused by lubricants, or spermicides. If the sensation only happens with certain products, a sensitivity may be the culprit.
When to See a Doctor?
Occasional mild burning may not be a cause for concern, especially if it resolves quickly. But you should seek medical care if:
The burning is severe or persistent
You notice itching, unusual discharge, or odor
You experience pain, swelling, or redness
You or your partner may have been exposed to an STI
A gynecologist can run simple tests to rule out infections or allergies and recommend treatment.
How Sex Therapy Can Help?
While the root of burning after sex is often physical, the emotional impact is just as important. The brain develops associations between experiences and feelings. If unprotected baby making sex often results in vaginal burning and discomfort, sometimes women can develop a subconscious (or conscious) aversion to sex in fear of the discomfort. Discomfort during intimacy can lead to anxiety, avoidance of sex, or tension in relationships.
Dr. Carli Blau is a sex therapist who works hand in hand with medical doctors on a weekly basis. With an abundance of medical knowledge herself, Dr. Carli works with other doctors to make sure that you’re well supported. She is also able to understand and teach you about the biological responses that you may be experiencing and how to sexually cope or adjust your sex life to be more comfortable. Dr. Carli Blau is also certified in Women’s Hormone Health, which allows her to understand what is hormonally going on in your body that could also contribute to discomfort.
Working with Dr. Carli Blau or a sex therapist on her team can help you:
Navigate the stress and emotions that come with painful sex
Improve communication with your partner about what feels safe and comfortable
Explore ways to maintain intimacy while addressing medical concerns
Rebuild confidence in your sexual experiences
Burning after a man ejaculates inside the vagina is a common issue with several possible causes—from pH changes to infections or sensitivities. While medical evaluation is important to rule out underlying conditions, support from sex therapy can help you and your partner stay connected and reduce the stress around intimacy.
