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You may have heard recent news reports about a company that knowingly sold defective lead testing machines that tested tens of thousands of children between 2013 and 2017. Or wondered about lead in tap water after the widely reported problems with lead-contaminated water in Flint, Michigan. Reports like these are reminders that parents need to be aware of lead — and do everything they can to keep their children safe.

How is lead a danger to health?

Lead is poisonous to the brain and nervous system, even in small amounts. There really is no safe level of lead in the blood. We particularly worry about children under the age of 6. Not only are their brains actively developing, but young children commonly touch lots of things — and put their hands in their mouths. Children who are exposed to lead can have problems with learning, understanding, and behavior that may be permanent.

How do children get exposed to lead?

In the US, lead used to be far more ubiquitous than it is now, particularly in paint and gas. Yet children can be exposed to lead in many ways.

• Lead paint. In houses built before 1978, lead paint can sometimes be under other paint, and is most commonly found on windowsills or around doors. If there is peeling paint, children can sometimes ingest it. Dust from old paint can land on the floor or other surfaces that children touch with their hands (and then put their hands in their mouths). If there was ever lead paint on the outside of a house, it can sometimes be in the dirt around a house.
• Leaded gas. While leaded gas was outlawed in 1996, its use is still allowed in aircraft, farm equipment, racing cars, and marine engines.
• Water passing through lead pipes. Lead can be found in the water of older houses that have lead pipes.
• Other sources. Lead can also be found in some imported toys, candles, jewelry, and traditional medicines. Some parents may have exposure at work or through hobbies and bring it home on their hands or clothing. Examples include working in demolition of older houses, making things using lead solder, or having exposure to lead bullets at a firing range.

What can parents do to protect children from lead?

First, know about possible exposures.

• If you have an older home, get it inspected for lead if you haven’t done so already. (If you rent, federal law requires landlords to disclose known lead-based paint hazards when you sign a lease.) Inspection is particularly important if you are planning renovations, which often create dust and debris that increase the risk of exposure. Your local health department can give you information about how to do this testing. If there is lead in your home, don’t try to remove it yourself! It needs to be done carefully, by a qualified professional, to be safe.
• Talk to your local health department about getting the water in your house tested. Even if your house is new, there can sometimes be older pipes in the water system. Using a water filter and taking other steps can reduce or eliminate lead in tap water.
• If you have an older home and live in an urban area, there can be lead in the soil. You may want to have the soil around your house tested for lead. Don’t let your child play in bare soil, and be sure they take off their shoes before coming in the house and wash their hands after being outside.
• Learn about lead in foods, cosmetics, and traditional medications.
• Learn about lead in toys, jewelry, and plastics (yet another reason to limit your child’s exposure to plastic).

Second, talk to your pediatrician about whether your child should have a blood test to check for lead poisoning. The American Academy of Pediatrics recommends:

• Assessing young children for risk of exposure at all checkups between 6 months and 6 years of age, and
• Testing children if a risk is identified, particularly at 12 and 24 months. Living in an old home, or in a community with lots of older homes, counts as a risk. Given that low levels of lead exposure that can lead to lifelong problems do not cause symptoms, it’s always better to be safe than sorry. If there is any chance that your child might have an exposure, get them tested.

How is childhood lead exposure treated?

If your child is found to have lead in their blood, the most important next step is to figure out the exposure — and get rid of it. Once the child is no longer exposed, the lead level will go down, although it does so slowly.

Iron deficiency makes the body more vulnerable to lead poisoning. If your child has an iron deficiency it should be treated, but usually medications aren’t used unless lead levels are very high. In those cases, special medications called chelators are used to help pull the lead out of the blood.

For more information, visit the Centers for Disease Control and Prevention website on lead poisoning prevention.

About the Author

Claire McCarthy, MD, Senior Faculty Editor, Harvard Health Publishing

Claire McCarthy, MD, is a primary care pediatrician at Boston Children’s Hospital, and an assistant professor of pediatrics at Harvard Medical School. In addition to being a senior faculty editor for Harvard Health Publishing, Dr. McCarthy … See Full Bio View all posts by Claire McCarthy, MD

Online gambling — all those websites and apps that offer casino games, sports betting, poker, fantasy sports, and lotteries — can be exciting and entertaining. It’s an estimated $9.5 billion per year business, and growing. But for millions of Americans, what starts as occasional fun can lead to devastating gambling-related problems.

“You can experience harm from gambling, including addiction, just like you can with alcohol or other drugs,” says Debi LaPlante, director of the Division on Addiction at Harvard-affiliated Cambridge Health Alliance.

Who is being harmed?

In fact, the American Psychiatric Association’s classification of mental health disorders places gambling disorder in the section defining substance-related and addictive disorders, along with problems like opioid use disorder and alcohol use disorder.

In the US, about 1% of adults (two million) are estimated to have a severe gambling problem, and 2% to 3% (four to six million) are thought have a mild or moderate problem.

How can you recognize a possible gambling problem?

The Brief Biosocial Gambling Screen from the Cambridge Health Alliance’s Division on Addiction tests for gambling disorder risk by asking three questions:

• During the past 12 months, have you become restless, irritable, or anxious when trying to stop and/or cut down on gambling?
• During the past 12 months, have you tried to keep your family or friends from knowing how much you gambled?
• During the past 12 months, did you have such financial trouble due to gambling that you had to get help with living expenses from family, friends, or welfare?

“If you answer yes to any of these questions, you should evaluate your gambling and how it fits into your life, and seek out further assessment,” says LaPlante.

How do you know if you’re engaging in harmless or harmful gambling?

A gambling addiction often occurs gradually. The line between harmless and harmful is often blurred, so people don’t always recognize they have a problem until it becomes severe. Here is what is considered the threshold of low-risk gambling:

• You gamble no more than 1% of household income.
• You gamble no more than four days per month.
• You don’t gamble at more than two types of games.

What does gambling disorder share with other forms of addiction?

Gambling disorder shares certain risk factors with other types of addiction:

• genetics
• faulty thought patterns
• impulse control disorders
• availability in one’s community
• poverty.

Like other types of addiction, gambling-related problems can lead to disrupted romantic, social, and work relationships. Feelings of withdrawal when someone tries to cut back are similar, too.

Does online gambling affect the brain?

Gambling games can affect people at the neurobiological level. Many games have features that trick the brain into thinking a loss is actually a win. For example, a slot machine displays celebratory music, sounds, and lights for a $3 return on a $5 bet.

“Research has found that our sympathetic nervous system responds to losses celebrated as wins the same way it responds to actual wins,” says LaPlante. “This is a powerful reinforcer, and just one example of games affecting brains.”

How can you find help for problem gambling?

Finding help for gambling can be challenging because, unlike for other types of addiction, the number of professionals who treat gambling addiction is limited, according to LaPlante. “Also, because of shame and stigma, people are less likely to acknowledge that gambling can become a problem,” she says.

Still, resources such as Gamblers Anonymous, local and national crisis helplines like 1-800-GAMBLER, self-help books such as Your First Step to Change, and local departments of public health are available to connect people to help.

Addiction treatment is not an exact science, and success varies from person to person. Some treatments have shown promise for gambling disorders, such as cognitive behavioral therapy (CBT) and motivational interviewing.

With CBT, people work with a therapist to help identify faulty thoughts and behaviors, such as the feeling one is “due to win” after a string of losses, and then learn tools to reframe those harmful thought patterns and respond to them more appropriately. During motivational interviewing, a person works with a counselor to enhance their motivation to change by together examining their ambivalence about change.

“If the gambling addiction is a symptom of another mental or physical health problem, addressing those issues is essential,” says LaPlante.

What does recovery from a gambling problem look like?

Different people have different ideas about what it means to be recovered from gambling addiction. For some, this means completely cutting gambling out of their life; for others, it means cutting back.

“Ideally, the treatment experience will include plans to prevent lapses that take people away from maintaining their own goals,” says LaPlante.

About the Author

Matthew Solan, Executive Editor, Harvard Men's Health Watch

Matthew Solan is the executive editor of Harvard Men’s Health Watch. He previously served as executive editor for UCLA Health’s Healthy Years and as a contributor to Duke Medicine’s Health News and Weill Cornell Medical College’s … See Full Bio View all posts by Matthew Solan

About the Reviewer

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Dr. Howard LeWine is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD

Nearly a century ago, surgeons developed what is still considered the gold-standard treatment for benign prostatic hyperplasia (BPH), an age-related affliction that occurs when an enlarged prostate obstructs the flow of urine.

Offered to men who don't respond to BPH medication, this procedure, called a transurethral resection of the prostate, or TURP, involves trimming excess prostate tissue with an electric loop. Roughly 90% of treated men achieve long-lasting relief, but they typically also have to spend a night recovering in the hospital, and many are left unable to ejaculate.

Newer, minimally-invasive BPH procedures offer faster recovery times and fewer risks of complications. Where a TURP cuts directly into the prostate, these alternate procedures treat BPH in other ways — for instance, by using steam, microwaves, or lasers to treat the obstructing tissues.

Minimally-invasive procedures are gaining in popularity, and earlier this year another won the FDA's approval. Called the Optilume BPH catheter system, it provided sustained relief from BPH symptoms that continued holding up after four years, according to study results presented at the 2023 Annual Meeting of the American Urological Association, in April.

The procedure and the study

During an Optilume procedure, doctors thread an inflatable catheter toward the prostate through the urethra, which is the tube that carries urine out of the bladder. The catheter splits the two halves of the prostate (which are called lobes), creating a V-shaped channel in the top of the gland that reduces pressure on the urethra, improving urinary flow rates. Importantly, the catheter is coated with a chemotherapy drug, paclitaxel, that helps to limit treatment-related inflammatory responses. After the catheter is removed, the channel in the prostate remains.

Dr. Steven Kaplan, professor of urology at the Icahn School of Medicine at Mount Sinai in New York, led the studies leading to the FDA's approval. He says symptom improvements with the new system rival those achieved with TURP. "We're pretty excited about it," he says. "This is a potential game changer."

During the research, Dr. Kaplan's team measured changes in the International Prostate Symptom Score (IPSS), which ranges from 0 to 35 and classifies BPH as either mild, moderate, or severe. According to results from the first clinical trial, called the PINNACLE study and limited to men with prostates ranging from 20 to 80 grams in size, Optilume treatment produced immediate benefits. At one year, IPSS scores among treated men were 11.5 points lower on average than those reported at baseline.

Follow-up and commentary

Follow-up evaluations for men enrolled in the second clinical trial, called the EVEREST study, are still ongoing. But results available so far — again for prostates no larger than 80 grams — show IPSS scores dropping from 22.5 at baseline to 11.5 four years after treatment, with no significant changes in ejaculatory functioning.

"Numerous innovative treatment alternatives for BPH have emerged over the years," says Dr. Heidi Rayala, a urologist affiliated with Beth Israel Deaconess Medical Center, an assistant professor at Harvard Medical School, and a member of the editorial board of the Harvard Medical School Annual Report on Prostate Diseases. "TURP still stands as the benchmark, given that many initially promising technologies have faltered due to loss of efficacy over time. Nonetheless, recent advancements like Optilume offer exciting prospects for enhanced durability with reduced side effects.

"It's essential to note that Optilume's efficacy varies based on prostate size and patient symptoms. Matching the appropriate surgical approach to the individual patient will remain crucial as patients and their urologists evaluate the optimal choice within the spectrum of minimally-invasive therapies."

About the Author

Charlie Schmidt, Editor, Harvard Medical School Annual Report on Prostate Diseases

Charlie Schmidt is an award-winning freelance science writer based in Portland, Maine. In addition to writing for Harvard Health Publishing, Charlie has written for Science magazine, the Journal of the National Cancer Institute, Environmental Health Perspectives, … See Full Bio View all posts by Charlie Schmidt

About the Reviewer

Marc B. Garnick, MD, Editor in Chief, Harvard Medical School Annual Report on Prostate Diseases; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Marc B. Garnick is an internationally renowned expert in medical oncology and urologic cancer. A clinical professor of medicine at Harvard Medical School, he also maintains an active clinical practice at Beth Israel Deaconess Medical … See Full Bio View all posts by Marc B. Garnick, MD

In today’s fast-paced world, our waking hours are filled with decisions — often surrounding what to eat. After a long day, dinner could well be fast food or takeout. While you may worry about the toll food choices take on your waistline or blood pressure, as a liver specialist, I also want to put fatty liver disease on your radar.

One variant, officially called nonalcoholic fatty liver disease (NAFLD), now affects one in four adults globally. Sometimes it progresses to extensive scarring known as cirrhosis, liver failure, and higher risk for liver cancer. The good news? Fatty liver disease can be prevented or reversed.

What is fatty liver disease?

Fatty liver disease is a condition caused by irritation to the liver. Liver tissue accumulates abnormal amounts of fat in response to that injury. Viral hepatitis, certain medicines (like tamoxifen or steroids, for example), or ingesting too much alcohol can all cause fatty liver disease.

However, NAFLD has a different trigger for fat deposits in the liver: a group of metabolic risk factors. NAFLD is most common in people who have high blood pressure, high cholesterol, insulin resistance (prediabetes), or type 2 diabetes. It is also common among people who are overweight or obese, though it is possible to develop NAFLD even if your body mass index (BMI) is normal.

What helps prevent or reverse NAFLD?

Diet can play a huge role. Because NAFLD is so closely tied to metabolic health, eating more healthfully can help prevent or possibly even reverse it. A good example of a healthful eating pattern is the Mediterranean diet.

Overweight or obesity is a common cause of NAFLD. A weight loss program that includes activity and healthy eating can help control blood pressure, cholesterol, and blood sugar. Among the many healthful diet plans that help are the DASH diet and the Mediterranean diet. Talk to your doctor or a nutritionist if you need help choosing a plan.

To vigorously study any diet as a treatment for fatty liver disease, researchers must control many factors. Currently, no strong evidence supports one particular diet over another. However, the research below highlights choices to promote a healthy liver.

Avoid fast food

A recent study in Clinical Gastroenterology and Hepatology linked regular fast-food consumption (20% or more of total daily calories) with fatty liver disease — especially in people who had type 2 diabetes or obesity. Fast foods tend to be high in saturated fats, added sugar, and other ingredients that affect metabolic health.

Steer clear of soft drinks and added sugars

Soft drinks with high-fructose corn syrup, or other sugar-sweetened beverages, lead directly to large increases in liver fat deposits, independent of the total calories consumed. Read labels closely for added sugars, including corn syrup, dextrose, honey, and agave.

Instead of sugary drinks, sip plain water. Black coffee or with a splash of cream is also a good pick; research suggests coffee has the potential to decrease liver scarring.

Avoid alcohol

Alcohol directly damages the liver, lacks nutritional value, and may affect a healthy microbiome. If you have NAFLD, it’s best to avoid any extra cause for liver injury. We simply do not know what amount of alcohol is safe for those with fatty liver disease — even social drinking may be too much.

Eat mostly whole foods

Vegetables, berries, eggs, poultry, grass-fed meats, nuts, and whole grains all qualify, but cutting out red meat may be wise. An 18-month trial enrolled 294 people with abdominal obesity and lipid imbalances such as high triglycerides. Regular activity was encouraged, and participants were randomly assigned to one of three diets: standard healthy dietary guidelines, a traditional Mediterranean diet, or a green-Mediterranean diet. (The green-Med diet nixed red and processed meats and added green tea and a dinner replacement shake rich in antioxidants called polyphenols.)

All three groups lost some weight, although the Mediterranean diet groups lost more weight and kept it off for a longer period. Both Mediterranean diet groups also showed reduced liver fat at the end of 18 months, but liver fat decreased twice as much in the green-Med group as in the traditional Mediterranean diet group.

Healthy fats are part of a healthy diet

We all need fat. Dietary fats help your body absorb vitamins and are vital in the protection of nerves and cells. Fats also help you feel satisfied and full, so you’re less likely to overeat. Low-fat foods often substitute sugars and starches, which affect blood sugar regulation in our bodies. But all fat is not created equal.

It’s clear that Mediterranean-style diets can help decrease liver fat, thus helping to prevent or possibly reverse NAFLD. These diets are high in healthful fats, such as monounsaturated fats found in olive oil and avocados and omega-3 fats found in walnuts and oily fish like salmon and sardines.

With so many choices, it’s hard to know where to start in the healthy eating journey. Let’s strive to eat whole foods in their natural state. Our livers will thank us for it.

About the Author

Kathleen Viveiros, MD, Contributor

Dr. Kathleen Viveiros is a clinical hepatologist at Brigham and Women’s Hospital who sees patients in Boston and in Foxborough and Westwood, MA. She is an instructor in medicine at Harvard Medical School. Her professional interests … See Full Bio View all posts by Kathleen Viveiros, MD

One of the many underappreciated things about the human body is that it has a lot of excess capacity. That is, our organs have more reserve than most of us will ever need.

It’s as if our bodies were designed with the idea that we might need backups in case of illness or injury. And voila: when all goes well, we arrive at birth with two kidneys, not just one!

Of course, the kidneys are not the only example. So, why are we built with natural redundancy? And which of your body parts can safely fail or be removed without impairing your health?

Why do our organs have so much reserve?

The likely answer is evolution: early humans with a genetic makeup that produced organs with functional space to spare were better able to survive, thrive, and reproduce than others without such a genetic makeup. As a result, genes associated with excess organ capacity — remember: two kidneys, not one — were more likely to be passed down to future generations.

Meanwhile, evolutionary ancestors without as much reserve may not have survived long enough to reproduce, and so weren’t as successful at passing their genes along. Over thousands of years, this power of natural selection has led to modern-day humans having organs with plenty of reserve.

Eyes, liver, lungs, and more

Here’s just a partial list of body parts with plenty of reserve:

• Eyes: You can be perfectly healthy with one eye, although you may miss the depth perception and larger field of vision provided by having two. Even losing both eyes does not directly lead to poor health, though obviously blindness can pose challenges and impact quality of life. Additionally, studies suggest that significant vision impairment may raise the risk of Alzheimer’s disease.
• Ears: Although having two ears allows us to locate sounds from all directions, losing hearing in one or both ears doesn’t immediately impact overall health. But as with vision loss, quality of life can be diminished by hearing loss. And as with vision loss, recent studies suggest that people with hearing impairment are at an increased risk of developing cognitive problems.
• Gut: Relatively large portions of the small and large intestines can be removed without having a major impact on your health. In fact, the entire colon can be removed (an operation called pancolectomy) without shortening a person's life, although diarrhea or other digestive symptoms may follow. Removing a section of bowel is a relatively common operation (for colon cancer, for example), but the removal of part of the bowel doesn’t itself impair health or shorten lifespan.
• Kidneys: Most people can live perfectly well with only one kidney. That's why people can donate a kidney to someone in need. However, the remaining kidney must work harder, and the risk of future kidney failure does increase somewhat. In addition, an injury, infection, or other disease affecting the remaining kidney can lead to kidney failure more quickly than usual.
• Lungs: When necessary, an entire lung can be removed, and you can rely on the other lung and function quite well. A lung may be removed due to a tumor, but occasionally it's done because of infection or emphysema.
• Liver: A relatively large portion of the liver can be removed (assuming the rest of the liver is healthy) because there is so much “reserve” liver tissue, and because the liver has an ability to regenerate.

Does this mean many parts of our bodies are truly expendable?

Maybe. If you’re only considering survival, you could view many of our body parts as expendable. Indeed, you could survive without your spleen, much of your liver, your eyes, your ears, a lung, a kidney, and other parts.

But clearly, there are factors to consider other than survival, especially quality of life. So, no one would suggest parting with even the least useful organs without a good reason.

The bottom line

It’s fortunate that our organs have so much reserve: millions of people worldwide owe their very survival to the fact that our organs have so much redundancy. And living organ donors can give up a kidney or a portion of another organ to help others live well and still be healthy.

So, even if some parts aren’t absolutely necessary, it’s good to know there’s so much reserve available. You never know when it might come in handy.

About the Author

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. … See Full Bio View all posts by Robert H. Shmerling, MD

Colon cancer is the second-deadliest form of cancer after lung cancer. If recent messages about colon cancer screening have left you a little confused, that's understandable. In August, the American College of Physicians (ACP) released updated guidance for colon cancer screening that differs from other major organizations, including recommendations from the American Cancer Society (ACS) and the US Preventive Services Task force (USPSTF).

So, what do you need to know?

How does the advice differ?

First, please note that this advice applies only to people at average risk without a family history of colon cancer. If you have family history, or if other health issues put you at higher-than-average risk for colorectal cancer, talk to your doctor about the best course of action for you.

The main point of disagreement relates to the age at which people should start getting screened. The new ACP guidance says 50, while the other two organizations recommend 45. That earlier age is endorsed by the U.S. Multisociety Task Force on Colorectal Cancer. It's also endorsed by many physicians, including Harvard Medical School professor Dr. Andrew T. Chan, a gastroenterologist and director of epidemiology at Massachusetts General Hospital Cancer Center, who helps explain key facts below.

Why do experts suggest starting screening earlier?

"We're facing an unexplained and alarming increase in the incidence of colon cancer in people younger than 50," says Dr. Chan.

Overall, deaths from colon cancer dropped by 2% per year from 2011 to 2020. But that's not the case among people younger than 50. In that age group, deaths from colon cancer rose between 0.5% and 3% during the same time period, according to statistics published in 2023.

The rising rates of colon cancer in younger people are occurring in all racial and ethnic groups, with the steepest rises seen among Alaskan Natives and Native Americans. Overall, Blacks and African Americans are more likely to get and die from colon cancer than whites, and early-onset cases are higher in Black individuals than whites.

Efforts to encourage colon cancer screening began in the mid-1990s. Today, about 60% of adults over 50 follow the advice to receive a colonoscopy (described below) on a regular basis. This track record, while not perfect, likely explains the decline in deaths from colon cancer in older adults.

"I think that promoting earlier screening will help stem the rise in early-onset cases, at least for those in their 40s. We've also seen that earlier colonoscopies may be associated with lowering incidence of colon cancer even later in life, "says Dr. Chan.

What are the different screening tests for colon cancer?

The two most widely used screening tests are a standard colonoscopy and various stool-based tests.

Colonoscopy. For this test, a gastroenterologist or surgeon snakes a long, flexible tube with a camera on the end through your rectum and beyond to inspect the entire length of your colon. Considered the gold-standard test, this procedure can detect precancerous polyps called adenomas, and allow for their removal.

The test requires taking laxatives and drinking lots of fluids beforehand to clean all the fecal material (stool) out of your colon. Serious complications, which include perforation or bleeding, are rare, occurring in about three in 1,000 procedures. If no polyps are found, a repeat colonoscopy isn't recommended for another 10 years. If you have polyps, or your risk or symptoms change, this interval will be shorter.

Stool tests. The more worrisome colon polyps (adenomas) often shed tiny amounts of blood and abnormal DNA into the stool. This can be detected from samples you collect yourself at home.

• Two tests, the fecal occult blood test (FOBT) and fecal immunochemical test (FIT), check for blood. They require small stool samples that you put on a card or in a tube that's then mailed to a lab. These tests should be done every year.
• A third option, the FIT-DNA test, checks for both blood and abnormal DNA; it's usually repeated every three years.

Additionally, the guidelines from the American College of Physicians suggest another option: flexible sigmoidoscopy, which inspects only the lower part of the colon, once every 10 years, combined with a fecal FIT testing every two years. However, doctors in the United States rarely order sigmoidoscopy today.

If flexible sigmoidoscopy or any of these stool tests show evidence of a problem, a colonoscopy is needed to check for adenomas or cancer.

Why might stool-based screening make sense for younger adults?

Colonoscopy isn't necessarily the best initial screening test for everyone, says Dr. Chan. That's especially true for younger people, mainly because it's time-consuming and inconvenient.

"Maybe you just can't find time in your schedule or are worried about having a colonoscopy," he says. If that's the case, a stool-based test — which is noninvasive and takes very little time — is an appropriate option.

"The worst option is not doing anything, because early detection and treatment can prevent deaths," he says.

About the Author

Julie Corliss, Executive Editor, Harvard Heart Letter

Julie Corliss is the executive editor of the Harvard Heart Letter. Before working at Harvard, she was a medical writer and editor at HealthNews, a consumer newsletter affiliated with The New England Journal of Medicine. She … See Full Bio View all posts by Julie Corliss

About the Reviewer

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Dr. Howard LeWine is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD

A tremendous buzz surrounds collagen drinks and supplements, as celebrities and influencers tout miraculous benefits for skin, hair, and nails. Since the collagen in our bodies provides crucial support for these tissues, it seems plausible that consuming collagen might lead to lush locks and a youthful glow. But what does the science say?

What is collagen?

Collagen is a major structural protein in our tissues. It’s found in skin, hair, nails, tendons, cartilage, and bones. Collagen works with other substances, such as hyaluronic acid and elastin, to maintain skin elasticity, volume, and moisture. It also helps make up proteins such as keratin that form skin, hair, and nails.

Our bodies naturally produce collagen using the amino acids from protein-rich or collagen-rich foods like bone broth, meat, and fish. But aging, sun damage, smoking, and alcohol consumption all decrease collagen production.

Collagen drinks and supplements often contain collagen from many different sources, such as fish, cattle, pigs, or chicken. Typically, they contain peptides, short chains of amino acids that help make up essential proteins in the body, including collagen itself and keratin.

What does the science say about collagen drinks and supplements?

Research on skin includes:

• A review and analysis of 19 studies, published in the International Journal of Dermatology, that had a total of 1,125 participants. Those who used collagen supplements saw an improvement in the firmness, suppleness, and moisture content of the skin, with wrinkles appearing less noticeable. That sounds promising, but it’s unclear if these skin improvements were actually due to collagen. Most of the trials used commercially available supplements that contained more than collagen: vitamins, minerals, antioxidants, coenzyme Q10, hyaluronic acid, and chondroitin sulfate were among the additional ingredients.
• A few randomized, controlled trials (see here and here) show that drinking collagen supplements with high amounts of the peptides prolylhydroxyproline and hydroxyprolylglycine can improve skin moisture, elasticity, wrinkles, and roughness. But large, high-quality studies are needed to learn whether commercially available products are helpful and safe to use long-term.

Hardly any evidence supports the use of collagen to enhance hair and nails. One small 2017 study of 25 people with brittle nails found that taking 2.5 grams of collagen daily for 24 weeks improved brittleness and nail growth. However, this small study had no control group taking a placebo to compare with the group receiving collagen supplements.

There haven’t been any studies in humans examining the benefits of collagen supplementation for hair. Currently, no medical evidence supports marketing claims that collagen supplements or drinks can improve hair growth, shine, volume, and thickness.

Should you try collagen supplements or drinks?

At this time, there isn’t enough proof that taking collagen pills or consuming collagen drinks will make a difference in skin, hair, or nails. Our bodies cannot absorb collagen in its whole form. To enter the bloodstream, it must be broken down into peptides so it can be absorbed through the gut.

These peptides may be broken down further into the building blocks that make proteins like keratin that help form skin, hair, and nails. Or the peptides may form collagen that gets deposited in other parts of the body, such as cartilage, bone, muscles, or tendons. Thus far, no human studies have clearly proven that collagen you take orally will end up in your skin, hair, or nails.

If your goal is to improve skin texture and elasticity and minimize wrinkles, you’re better off focusing on sun protection and using topical retinoids. Extensive research has already demonstrated that these measures are effective.

If you choose to try collagen supplements or drinks, review the list of ingredients and the protein profile. Avoid supplements with too many additives or fillers. Products containing high quantities of prolylhydroxyproline and hydroxyprolylglycine are better at reducing wrinkles and improving the moisture content of skin.

Consult your doctor before starting any new supplements. People who are prone to gout or have other medical conditions that require them to limit protein should not use collagen supplements or drinks.

The bottom line

Large-scale trials evaluating the benefits of oral collagen supplements for skin and hair health are not available. If you’re concerned about thinning or lackluster hair, brittle nails, or keeping skin smooth and healthy, talk to your doctor or a dermatologist for advice on the range of options.

It will also help to:

• Follow a healthy lifestyle and eat a balanced diet that includes protein-rich foods.
• If you smoke, quit.
• Limit alcohol to two drinks or less in a day for men or one drink or less in a day for women.
• Apply sunscreen daily and remember to reapply every two hours.
• Wear wide-brimmed or UV-protective hats and clothing when you’re spending a lot of time in the sun.

Follow Payal Patel on Twitter @PayalPatelMD

Follow Maryanne Makredes Senna on Twitter @HairWithDrMare

About the Authors

Payal Patel, MD, Contributor

Dr. Payal Patel is a dermatology research fellow at Massachusetts General Hospital. Her clinical and research interests include autoimmune disease and procedural dermatology. She is part of the Cutaneous Biology Research Center, where she investigates medical … See Full Bio View all posts by Payal Patel, MD

Maryanne Makredes Senna, MD, Contributor

Dr. Maryanne Makredes Senna is a board-certified dermatologist at at Beth Israel Lahey Health, and assistant professor of dermatology at Harvard Medical School. Dr. Senna founded and directs the Lahey Hair Loss Center of Excellence and … See Full Bio View all posts by Maryanne Makredes Senna, MD

Quick, point to your thymus gland.

If you pointed to the front of your upper chest, well done! The thymus gland sits just behind the upper part of the breastbone, between the tops of the lungs and in front of and above the heart. In newborns, the thymus gland may be 2.5 inches long and weigh 1 ounce, but it shrinks over time beginning in the first year of life.

If you pointed elsewhere or had no idea, don’t feel bad. For most people, the thymus is unfamiliar and so is its whereabouts. And, for good reason: in most adults, the thymus gland is a tiny gland that’s been largely replaced by fat. But it wasn’t always that way.

How does the thymus gland help the immune system?

During fetal development, infancy, and early childhood, the thymus gland is quite important for the developing immune system. That’s when the thymus produces a special type of immune cells called T-cells (named for the thymus gland).

T-cells are essential to healthy immune function because they can kill cells infected by bacteria or viruses. They also attack tumor cells and help regulate other parts of the immune system.

Do you actually need your thymus gland?

The answer to this question depends on whether you are a developing fetus, young child, or adult. For the fetus and young child it’s quite essential, as noted above.

But there’s been uncertainty regarding the role of the thymus gland among adults. One reason is that over time it becomes a shrunken vestige of its former self, weighing in at a fraction of an ounce and shrinking to just one inch.

In addition, adults seem to do just fine without a thymus gland if it needs to be removed as a treatment for certain diseases, such as cancerous or benign tumors. Along with medications, thymus removal (thymectomy) may be part of treatment for myasthenia gravis, an autoimmune disease that causes muscle weakness, droopy eyelids, and double vision. The thymus gland seems to be the source of abnormal immune cells that cause this disease.

Rethinking the importance of the thymus gland in adulthood

Growing evidence suggests the thymus gland might play a role in the health of the immune system, and overall health in adults, for much longer than previously thought. For example:

• The thymus gland continues to produce T-cells well into adulthood, though at a slower pace. In addition, newer scanning technology suggests less shrinkage of the organ than had been reported in the past. 
• Even though the thymus gland’s function declines over time, it may help adults fight off infections, such as HIV and COVID-19.
• A 2023 study concluded that people who had their thymus removed during adulthood had higher rates of cancer, autoimmune disease, and death than people who had other types of surgery.

Along with other research, this suggests that we may have underestimated this gland’s function and importance in adults.

The bottom line

There is much we don’t know about the thymus gland, but one thing seems certain: most people are unaware of its major contributions to immune function and overall health.

Future research may change how we think about the importance of this gland, especially its role among aging adults. But well before that happens, I think the thymus gland deserves more recognition and respect. Without the thymus gland, we’d be prone to childhood infections and shorter lifespans. By the time we’re old enough to appreciate it, this amazing gland has already helped create a well-functioning immune system that protects us from health threats we face throughout our lives.

It’s truly amazing what a small, shrunken gland can do — or has already done — for you.

About the Author

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. … See Full Bio View all posts by Robert H. Shmerling, MD