Estrogen is a really important hormone for men, too

27% of US menopausal women used estrogen in 1999, but by 2020 that number was under 5%

The fallout of studies in the early 2000s linking hormone therapy for menopause and elevated cancer, stroke, and other health risks meant that even decades later—yet before the FDA removed its black box warning in 2025—use of HRT remained extremely uncommon. (Some users may experience a paywall.)

Testosterone therapy can cause infertility, and has been explored as a contraceptive

Augmenting testosterone with testosterone hormone therapy suppresses sperm production, and the resulting infertility is permanent in some men. Though a high level of testosterone inside the testicles is essential for fertility, testosterone supplements suppress the production of the pituitary hormones that leads to that natural testosterone production in the testicles—causing infertility.

Women experience heightened bone loss after menopause

Both women and men begin to lose some bone density after age 35, on average, but for the first decade after menopause women lose bone more rapidly due to the significantly decreased levels of estrogen, putting women at heightened risk of osteoporosis and related bone fractures.

Menopause can exacerbate anxiety

Some research shows that menopause can fuel anxiety and also that pre-existing anxiety can boost the chances of experiencing other menopause symptoms, including hot flashes, insomnia, and brain fog. But treatments including hormone replacement therapy, breathing exercises, and other forms of exercise can alleviate some of these symptoms.

Gender-affirming hormone therapy cues changes similar to puberty

When HRT is part of gender affirmation care, people receive regular doses of estrogen or testosterone to alter hormone levels to more closely align with those of cis individuals of that biological sex. HRT may affect voice pitch, body hair, bone density, and more. Many of those changes are not reversible with the cessation of therapy, though the effects may diminish.

Less than 1% of aging studies consider menopause and its effects

Nearly all studies researching the biology of aging don't consider menopause in their setup, in part because menopause is difficult to emulate in animal models. Menopause is uncommon in the animal world beyond humans and whales. This presents a problem for medicine and science because about 75% of aging-related diseases are likely influenced by menopause.

'Menobelly' is real, with more fat stored around the abdomen as estrogen levels drop

The way fat is carried in the body shifts with menopause, with those pounds increasingly settling around the abdomen instead of the hips and thighs. Exacerbating this phenomenon, muscle mass also begins to decline, so calories stick around longer than usual. Resistance training, including push-ups and planks, alongside a heavier protein diet can help.

The word allergy is partly derived from the Greek word 'allos' for 'other'

For people with allergies, their immune systems recognize substances as a harmful "other"—cuing an inflammatory response. This podcast explores allergy details and related topics, including how scientists are interested in if the same allergic response mechanisms could underpin other health issues, including severe, painful symptoms around the time of menstrual cycles. Since estrogen acts on white blood cells called mast cells, which leads to the release of histamines—similar to what happens during allergic responses—an understudied question is whether the same process is fueling some of the uncomfortable symptoms around menstruation. An allergist guest notes this raises questions about if antihistamine medications like Pepsid might alleviate them, something that hasn't yet been explored in clinical trials.

Men are flocking to hundreds of new online testosterone clinics for low T prescriptions

Many primary care clinicians may not be familiar with testosterone testing protocols and treatments, but online testosterone clinics are proliferating, with names like DudeMeds. COVID-era restrictions loosened remote prescribing rules, allowing them to expand online widely, though those more lenient prescribing policies are slated to expire in December 2026 unless they're renewed. (Some users may experience a paywall.)

Menopause is a hormonal transition point, like puberty

Yet menopause isn't talked about as much. In this podcast episode by Houston Methodist, a Texas-based hospital, the host speaks with a gynecologist with a specialization in menopausal medicine about what menopause really is, and how women and the people in their lives can navigate this next life stage.

The number and quality of sperm in men's semen is down, giving rise to various movements to avoid 'spermpocalypse'

A typical fertile, healthy young man produces over 100 million spermatozoa, or sperm cells, in his testicles every day. Scientists agree sperm figures are generally moving in the wrong direction, but also emphasize there's still a lot to learn about sperm.

Too little stress can be as problematic as too much stress

Hormesis—mild or moderate stress followed by recovery—helps make us more resilient. A stress expert speaking during this roughly 30-minute CNN special explains that our bodies depend on periodic mental and physical challenges to activate our innate defense mechanisms, spurring cellular repair and regeneration.

Women are four times as likely to be diagnosed with seasonal depression

This prevalence trend mirrors the broader incidence of depression among women and is well-documented. Researchers suggest the disparity stems from differences in hormones, social role expectations, coping mechanisms, and more. Men may also present with depression differently, and seek help less.

Diabetes is a hormonal disorder

Hormones are naturally produced in the body in concert with cell receptors, influencing how cells behave, but diseases that affect hormonal production, including those produced by the pancreas or the thyroid, can upend those processes.

Why are there as many males as females?

Pretty much every species breaks down with an equal sex-ratio, with roughly the same number of males as females. But on the surface, it appears that most species wouldn't need many males to keep the population growing, with their energy-efficient, abundant sex cell production. So why is it equal? Scientists argue an equal ratio is the most evolutionarily stable. Learn about this quirk of biology here.

Prostate cancer is both manageable and the second-deadliest cancer for men

One in 44 men in the US will die from prostate cancer, while one in eight will be diagnosed with it. Commonly viewed as the safest cancer to have, screenings can save lives—but they can also cause complications for otherwise benign cases of the disease.

The hidden effects of March Madness

March Madness isn’t just a major sporting event—it’s also peak season for vasectomies. Urologists report a 50% increase during the tournament, as patients use recovery time as an excuse to watch nonstop basketball. Meanwhile, workplace distractions from bracket pools and game streaming are estimated to cost US businesses $17 billion.

The university system has an enrollment problem

Enrollment has dropped over the past few years—especially for men. In this Freakonomics podcast episode, educators and economists explain why they think college enrollment has been on the decline. They also offer solutions and make predictions for the future of college.

The halting of human bone growth helps manage heat produced from metabolism

While fish, amphibians and reptiles get bigger throughout their lives until they die, their slower metabolisms allow their bodies to regulate the resulting smaller temperature increases. In humans, hormones triggered during puberty harden growth plates, ending bone lengthening.

What causes high cholesterol?

Cholesterol is a complex health issue, and for a long time, the American Health Association recommended Americans not eat more than three eggs a week to avoid it. But scientific advancements on the impact of different types of cholesterol revealed eggs aren't so bad. So what is it, and how does it effect us? Dive into the digestive tract here.

Overuse of antibiotics gives bacteria more opportunity to evolve their defenses

The overuse and misuse of antibiotics are significant contributors to the rise of antibiotic resistant bacteria. Experts say antibiotics should only be used for specific medical problems, and patients need to be sure to take antibiotics exactly as prescribed in order to reduce the risk of antibiotic resistance.

The hormone that spreads love and helps fish share fear

Scientists consider emotions like fear and empathy to be among the oldest evolutionary behaviors observed in mammals. Yet to date, how these reactions are processed in the brain, regardless of species, is not well understood. A new study reveals how the chemical oxytocin—known as the "love hormone" in humans—helps let fish know when their friends are in danger.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

Temperature and certain medications can also affect your circadian rhythms

Although light and dark have the largest influence on circadian rhythms, temperature, stress, and certain medications are among the factors that also play a role. Persistent trouble sleeping or staying asleep may signal it’s time to see your doctor to get a better sleep-wake schedule.

Sex determination isn’t all XX and XY

We’re generally taught that chromosomes determine an animal’s sex, but it is way more nuanced than that. Watch this 12-minute video to find out how.

Yes, you can take too many vitamins and they can make you sick

Too much of vitamins A, D, E, and K (which are fat-soluble) can build up in the body and cause serious health problems, including liver damage, kidney stones, and blood clotting irregularities. Excess iron and calcium can also make it harder for the body to absorb other needed nutrients.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

Doctors differentiate between a phobia and fear by asking patients whether their fear interferes with their day-to-day activities.

Ebola infects and disables immune cells, triggering a cascade of events that leads to small blood clots throughout the body, weakening blood vessels and interrupting blood flow to key organs.

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Georgia O'Keeffe's flower paintings are often assumed to be sexual, though the artist claimed she was simply interested in highlighting the beauty of flowers that most people neglect

20,000 letters to the advice columnist 'Dear Abby' provide insight into prevailing sex, religion, and LGBTQ fears, anxieties, and concerns from the 1950s onward.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

Learn how to read a prospectus, the juicy document that any company must file with the SEC before going public.

The US dollar is the most widely circulated currency in the world, and is involved in nearly 90% of global transactions

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

Fireworks-related ER visits are on the rise—in 2024, they increased by 52% as compared to the prior year.

Poison ivy can cause rashes year-round since all parts of the plant contain urushiol, the oil that triggers our allergic response.

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

The price of gas is a composite made up of several different factors, with the federal gas tax making up less than 20% of what drivers pay at the pump.

The Dracula character, now seen as the vampire archetype, was inspired by a seafood-induced nightmare its creator experienced.

Play the role of a student in a game where you try to navigate college and remain debt-free, selecting different income levels, high school experience, race, ethnicity, and more.

When a Paris department store hesitated to sell Estée Lauder's perfume, she 'accidentally' broke a bottle, causing the smell to spread throughout the store and shoppers to start asking to buy the scent.

Iran's Revolutionary Guard Corps is independent of Iran's regular army and is one of the most powerful and influential military-political organizations in the Middle East.

The Russia-Ukraine conflict is the largest ground war in Europe since World War II in terms of casualties, forces mobilized, and displacement of civilians.

The rivalry between Alexander Hamilton and Thomas Jefferson centered on federalism—the question of how much power the federal government should hold relative to the states.