Before Menopause
For generations, women have been taught to associate hormone changes with a single moment in time: menopause. But according to Lexi Yoo, CEO of Yoo Direct Health & FNP-BC/CPNP, IFMCP, that narrative leaves out a critical, and often misunderstood, decade-long transition that begins much earlier than most women expect.
“Perimenopause isn’t a light switch,” Yoo says. “It doesn’t just flip on one day. It’s a slow, gradual transition that often begins in your late 30s or early 40s, sometimes even earlier.”
During this stage, many women are still having regular periods, but hormonally, the body is already shifting in ways that can significantly affect how they feel.
One of the earliest changes is a decline in progesterone, which Yoo says is tied to less consistent ovulation. At the same time, estrogen becomes increasingly unpredictable, spiking one week and crashing the next. “That imbalance alone can cause disrupted sleep, anxiety, mood swings, heavier periods, brain fog and fatigue,” she says. “Women often tell me they just don’t feel like themselves anymore.”
Testosterone, often excluded from women’s health conversations, plays a major role as well. Levels begin declining in a woman’s 30s, affecting energy, motivation, muscle tone, metabolism, mental clarity and libido. “When testosterone gets low, women describe feeling ‘blah’ or like they’ve lost their edge,” Yoo says.
Lifestyle factors can accelerate these changes. Poor sleep, chronic stress, under eating, overtraining, alcohol use and even common medications such as antidepressants or hormonal birth control can further disrupt hormonal balance.
“That’s why two women the same age can have completely different experiences,” Yoo says. “It’s not just about age. It’s about how your body is responding to stress, recovery and daily habits.”
Historically, perimenopause has been framed as something that happens much later in life, largely because women’s health has long focused on fertility and pregnancy. The years between those stages and menopause were often overlooked. As a result, many women in their late 30s and 40s are told they’re “too young” for hormone changes, even when symptoms are obvious.
“The impact of that misunderstanding is huge,” Yoo says “Women are dismissed, told it’s just stress or depression, and often given bandage solutions like sleep medications or antidepressants, while missing a critical window to protect long-term health.”
Hormones play a significant role in brain health, heart health, bone density and metabolism, all of which begin to shift during perimenopause.
Mental and emotional changes are often among the first red flags. Estrogen supports serotonin and dopamine, while progesterone influences GABA, the brain’s calming neurotransmitter. When those hormones fluctuate, anxiety, irritability, low mood and emotional disconnection can follow.
“These symptoms are real and physiological,” Yoo says. “You’re not imagining them.”
Metabolically, perimenopause can feel especially frustrating. Declining progesterone, fluctuating estrogen and falling testosterone create what Yoo calls a “perfect storm” for weight gain, insulin resistance, inflammation and fatigue — often without any changes in diet or exercise.
“Your metabolism isn’t broken,” she says. “It’s responding to a new hormonal rhythm.”
Modern hormone therapy has evolved dramatically, and Yoo says fear surrounding HRT is often based on outdated information. Today’s approach focuses on bioidentical hormones, individualized dosing and appropriate timing — tools that can protect brain, bone and cardiovascular health while improving quality of life.
Emerging therapies, including peptide therapy, are also reshaping women’s health. These compounds work with the body’s natural signaling systems to support sleep, muscle maintenance, gut health, inflammation control and metabolic resilience.
“This is precision-based care,” Yoo says. “We’re no longer guessing. We’re optimizing.”
Ultimately, Yoo believes perimenopause should be viewed not as a decline, but as an opportunity.
“This is a window into your future health,” she says. “When women shift from just managing symptoms to investing in their health span, everything changes.”
And for women who’ve been told, “This is just part of aging”? Yoo is unequivocal: “Just because something is common doesn’t mean it’s normal. You have options. You deserve to feel strong, clear and vibrant — at every stage of life.”
