The Vaginal Microbiome: How Estradiol, Progesterone & Testosterone Influence Vaginal Odor, pH, and Health

| 7 min read

If you’ve ever noticed changes in vaginal odor, you’re not alone. It’s a topic many women hesitate to discuss, yet it’s incredibly common—especially after the age of 30, when perimenopause hits. This gets progressively worse as women age – with its greatest impact during menopause. What many women don’t realize is that vaginal odor, vaginal itching and vaginal dryness are related to estradiol, progesterone, and even testosterone. They all play a key role in maintaining a healthy, balanced vaginal microbiome. Vaginal odor is coming from bacteria that shouldn’t be in the vagina!. So, let’s talk about what’s going on and what you can do to support your body naturally.

Estrogen: The Guardian of Vaginal Health

Estradiol is essential for keeping vaginal tissues healthy, thick, and well-lubricated. It also helps maintain an acidic pH, which prevents the overgrowth of harmful bacteria and pathogens like bacterial vaginosis (BV), yeast, and even HPV. Studies have shown that estrogen supports the dominance of Lactobacillus species, which produce lactic acid to sustain an acidic environment, lowering the risk of bacterial vaginosis and other vaginal infections. In fact, Lactobacillus acidophilus needs estradiol to make its food! Without estradiol, this bacteria can’t thrive and maintain proper pH. When estradiol levels drop, vaginal dryness and vaginal itchiness can increase, leading to pH imbalances that encourage bacterial vaginosis and unwanted vaginal odor. Estradiol and progesterone declining also leads to vaginal dryness, which promotes the growth of unwanted bacteria, and increases risk for vaginal infections like yeast and even HPV. This is because yeast and HPV cannot survive in an acidic environment.

Progesterone: The Unsung Hero

Progesterone plays a significant role in vaginal health by modulating inflammation and promoting a stable vaginal microbiome. It supports the protective role of estradiol, helping to maintain an optimal pH and prevent pathogenic bacterial overgrowth. Additionally, progesterone enhances blood flow to the vaginal tissues, promoting natural lubrication, which helps reduce vaginal odor and vaginal dryness. Bioidentical progesterone, on the other hand, appears to have a gentle, balancing effect on the vaginal microbiome.

Testosterone: A Potential Disruptor

While testosterone is essential for libido and muscle maintenance, excessive levels — whether due to conditions like polycystic ovary syndrome (PCOS) or hormone therapy — can negatively impact the vaginal microbiome. Studies have found that increased androgen levels can suppress Lactobacillus populations, leading to a less acidic pH and higher susceptibility to bacterial vaginosis, vaginal itchiness, and infections. Women undergoing only testosterone therapy should be mindful of potential shifts in vaginal health and consider adding on progesterone and estradiol to maintain balance.

The Vaginal Microbiome: Your Natural Defense System

A healthy vaginal microbiome is predominantly made up of Lactobacillus species, which produce lactic acid to keep the vaginal pH in an optimal range (~3.5–4.5). When this balance is disrupted—whether due to hormonal shifts, antibiotics, stress, or even certain hygiene products—harmful bacteria can thrive, leading to bacterial vaginosis, vaginal odor, and infections. Studies suggest that women with lower estradiol and progesterone levels often experience a reduction in Lactobacilli, increasing their risk for bacterial vaginosis and other vaginal health concerns.

What You Can Do to Support Vaginal Health

  • Optimize Hormone Levels Naturally:
    Bioidentical hormone replacement therapy (BHRT) can help restore estradiol, progesterone, and testosterone balance, supporting a healthier vaginal microbiome and reducing vaginal odor. Hormone levels drop a lot earlier than women have been led to believe — often starting in the late 20s to early 30s. This is considered perimenopause.
  • Support the Vaginal Microbiome:
    Consider vaginal probiotics containing Lactobacillus strains to maintain balance and prevent bacterial vaginosis. This should be considered even if women start a good hormone replacement therapy.
  • Choose pH-Friendly Products:
    Avoid harsh soaps, douches, and fragranced products that can disrupt your natural flora. Stick to mild, pH-balanced cleansers instead.
  • Increase Blood Flow and Lubrication:
    Estradiol and progesterone naturally enhance blood flow to the vaginal tissues, improving moisture levels and reducing vaginal dryness and vaginal itchiness, both of which can contribute to bacterial vaginosis and vaginal odor.
  • Diet and Lifestyle:
    Loose, breathable underwear — especially at night — can help prevent excess moisture, which can be a breeding ground for unwanted bacteria.

At Inner Balance, we focus on a holistic approach to women’s health, using science-backed strategies to optimize hormones and overall well-being. If you’re experiencing persistent bacterial vaginosis, vaginal odor, vaginal dryness, or other symptoms of hormone imbalance, let’s work together to restore balance naturally.

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