Tattoo inks are largely unregulated by the FDA

Tattoos are made by injecting pigments into the skin

Tattoo ink is injected under the skin, which can leave the body open to infections and allergic reactions. While many tattoo artists are licensed professionals who follow sanitary guidelines, that’s not always the case.

Harvard and MIT researchers are developing life-saving tattoos

Tattoos aren’t just a fashion statement. Scientists are trying to find life-saving applications for them. Harvard and MIT researchers are developing tattoo inks that react to body chemicals, alerting diabetics to blood sugar fluctuations or athletes to dehydration. Someday, patients may observe their body chemistry with tattoos that change colors.

Removal of different color tattoo inks may require multiple lasers

Light needs to be absorbed by ink particles to break them down into small enough pieces for the immune system to eliminate. Color ink reflects, rather than absorbs, lasers of the same color, while black ink absorbs all colored lasers.

Tattoos remain visible thanks to immune cells called macrophages

Macrophages are a robust part of the human immune system. These large cells engulf invading particles, like viruses and bacteria, and use enzymes to break them apart. They perceive ink as a foreign body but can't digest them. Macrophages hold on to the ink, helping maintain the tattoo pattern.

Tattoos remain visible on your skin thanks to immune cells called macrophages

Around 32% of American adults have at least one tattoo

Tattoos have waxed and waned in popularity over the centuries, depending upon the social standing of their wearers. Throughout US history, they were often considered taboo. However, growing acceptance of tattoos means they’re more visible in the public eye.

Mycotoxins are toxic compounds produced by fungi—some show up in food

About a quarter of the world’s agricultural products are contaminated with mycotoxins. Some of these compounds can cause serious health problems, including cancer, so the US government has set up monitoring programs to detect them in our food and in animal feed. Humans can become ill if they eat contaminated food, but also if they ingest products from animals that had previously consumed these toxic compounds, such as milk from a cow that ate contaminated corn.

The federal government allowed toxic chemicals into alcohol during Prohibition

Industrial alcohol was still legal during Prohibition, and was often used by bootleggers. In an attempt to disrupt the black market, the government required toxic additives to be included in industrial alcohol, leading to more than one death.

Pollution from lead battery recycling has led to widespread contamination

Many small-scale operations worldwide remain unregulated, bypassing environmental regulations and causing increasing health threats, primarily to children. A 2020 report by UNICEF found that one-third of the world's children are being poisoned by lead from recycled batteries, among other sources.

The FDA claims microplastics have not yet been shown to pose a health risk

Although microplastics and nanoplastics are found in many foods and environments, their presence does not violate regulations. Additionally, as of 2025, the administration believes evidence does not confirm that detected levels harm humans.

The WHO labeled aspartame as 'possibly carcinogenic' but US regulators consider it safe

The International Agency for Research on Cancer, an arm of the World Health Organization, labeled aspartame—the artificial sweetener in Diet Coke—as one of several hundred possible cancer-causing substances in 2023. The determination was based on animal and human studies and "limited" evidence linking it to liver cancer. The WHO and US Food and Drug Administration both say the substance is safe at moderate levels. The FDA says a person weighing about 132 pounds would need to have 75 packets daily to reach an unsafe level.

Pigments in paint can come from rocks, plants, insects or synthetic sources

Paint's composition is varied through the combination of pigments with binding agents. In the past, artists created their own paints by mixing pigments with water, oils or egg yolks to bind the colors together.

Alpha-gal allergy is a problem for red meat lovers, and that same sugar is an issue for xenotransplants, too

In recent years, researchers have discovered ticks can induce spontaneous meat allergies in people they bite, a particularly problematic condition for previous meat lovers. This 18-minute podcast from RadioLab breaks down the cause.

The US FDA recently tried to regulate the expanded prenatal genetic tests

The agency proposed a new rule in 2023 to make it explicit that these types of tests are devices under existing law and clarify that that the agency could move to regulate them. They finalized a regulatory change in 2024 that added the words "including when the manufacturer of these products is a laboratory" to an existing law, but a federal district court vacated that edit in March 2025—returning the law to as it was before.

Scleroderma, which causes skin to harden and scar, has no FDA-approved treatment

It's an autoimmune disease that disproportionately causes worse complications in African American people for unknown reasons. It causes the body to overproduce collagen after the immune system attacks the body's own connective tissue, leading to excess collagen deposits and restricted blood circulation as small blood vessels are damaged. It can damage various organs, including the lungs.

'Barbie' drug melanotan II purportedly offers tanning without the sun—but it's very risky

The substance is not approved by the FDA and is illegal to sell in settings including the UK and Australia. Published case reports discuss serious side effects, including melanoma, a type of skin cancer.

Fertility treatments linked to increased risk of cancer among offspring

Recent research has explored potential links between increased childhood cancer occurrence, particularly leukemia, and assisted reproductive technology (ART). Though some studies have detected this type of association, researchers caution that it remains unclear if ART itself, fertility drugs, underlying infertility of the parents, or other unknown factors may explain any increased cancer numbers among ART-conceived children. Overall, the incidence of cancer in children, regardless of conception method, is very low.

Stainless steel and cast-iron pans should be used over older nonstick cookware

Although modern nonstick pans avoid forever chemicals like PFOA, they were previously used in the manufacturing of Teflon coatings and have been linked with certain types of cancer, infertility, and other adverse health outcomes. Vintage plastic utensils should also be avoided due to the leeching of contaminants in early formulations of plastic.

Trader Joe's isn't a public company, so it doesn't have to disclose its suppliers

However, when a product is recalled, the US FDA reveals the manufacturer. Business Insider dug into Trader Joe's recalled product history to figure out who is making its food. As it turns out, it's a multitude of suppliers, including big companies that make food for other grocers, such as PepsiCo's Naked Juice and Conagra.

There's no definitive test for inflammation, or a baseline for what's considered normal

Existing tests can pick up proteins that indicate an immune response—in particular C-reactive protein, which the liver produces when the body's stressed—but that won't tell you why there's inflammation nor if it's chronic or acute inflammation. (Some users may experience a paywall.)

See images of medical cases of firework injuries shared on this 'Instagram for doctors.' (Warning: Graphic content)

The fish in sushi is usually frozen to eliminate parasites

Most raw fish contain parasites, but sushi restaurants and fish markets use “super freezers” to make the food safe for consumption. The United States Food and Drug Administration warns that frozen raw seafood can still contain parasites, depending on the type of fish and the conditions of the “super freezer.”

Chromium contaminants in a ruby crystal gave the world's first laser its red color

The red light originates from a long-lasting excited electron state in the element's atomic structure. The brittle gray metal has historically been used in pigment production, the manufacturing of rust-resistant stainless steel, and the creation of durable coatings with long-lasting shine for metals, wood, and leather.

Explore some of the trademarked scents in the US

Scents, when they are truly unique and identifiable to a particular brand, can be trademarked. Any trademark on a scent must pass two tests: distinctiveness and non-functionality. In order to be trademarked, the scent of a product can't be the primary purpose of that product (like a candle or a perfume), and the scent has to be distinct. Some of the trademarked scents include Play-Doh and the pain-relief patch Salonpas.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

Certain medications can make tinnitus worse

Certain antidepressants, antimalarial medications, antibiotics, ibuprofen, and cancer drugs have been linked with the condition. At higher doses, particularly, it seems they can trigger or worsen tinnitus in some individuals.

Find fracking wells where you live and what chemicals operators are using

Fracturing fluid recipes are largely proprietary, but FracFocus has maintained a database of chemical disclosures since 2011. Today, the Department of Energy-affiliated nonprofit has more than 240,000 disclosures, along with a searchable database of fracking wells by state, county, and city.

11 people died from firework injuries in the US in 2024

Most of those deaths involved misuse of the explosives and device malfunctions or misfires. That fatality count doesn't include the almost 15,000 people who received treatment in the emergency room due to firework-related injuries. More than a third of all the injuries in 2024 were burns, underscoring the risks of using these explosive devices.

Louisiana's 'Cancer Alley' is infamous for having some of the highest industrial pollution, toxic air emissions, and cancer risks in the US.

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

An investigation suggests a Scottish island became awash in forever chemicals via seafoam and seaspray—raising questions about what that means for the safety of other coastal areas.

Poison ivy's rash-causing compound is found in the plant's roots, stem, and leaves—so coming into contact with any part of the plant can lead to rashes for the 85% of people who are allergic to it.

See this overview of the firework rules across all 50 states, ranging from a complete ban on non-professional fireworks in Massachusetts to states with more lax rules like Indiana.

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

See these 16 pieces of art evoking phobias of snakes, flying, spiders, and more. 

When caught in the mouths of cardinal fish, seed shrimp release glowing, bioluminescent chemicals, which alert predators of the cardinal fish, prompting the shrimp's ejection.

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.

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

The original copy of the Declaration of Independence is not a pristine document, and even features a smudged anonymous handprint in the bottom left corner.

Prince's sexually explicit 1984 track 'Darling Nikki' attracted the ire of the Parents Music Resource Center, an advocacy group that inspired the Parental Advisory sticker, even though the song ends with a Christian message.

Art theft is the third-largest source of criminal revenues worldwide, thanks in part to the subjective nature of valuing a work of art.

Telehealth demand for GLP-1s for weight loss is booming as consumers seek easier access.

Mid-century modern graphic designers, known for their bright colors and bold lines in advertising, also found success with children's books.

Power lines are dotted with large, brightly colored balls to improve the visibility of these thin wires to helicopters and small planes and help prevent potential crashes.

Despite being favored by 87% of Americans, Congress does not have term limits.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

While the first exchange-traded fund (a 'basket' of different assets that can be bought and sold on a stock exchange) in the US only launched in 1993, the global ETF market has grown to more than $10T in the short time since.

Abraham Lincoln was almost assassinated weeks before his inauguration as he traveled from Illinois to DC through Baltimore in 1861; it took two independent claims for Lincoln to be convinced the threat was real

Massive 3D printers have been used to build homes by stacking layers of 'concrete toothpaste,' a fire-resistant material that effectively insulates against outside noise.

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