For people who already have adequate vitamin D, taking supplements for 5 years yields identical rates of cancer, cardiovascular disease, and death as …
Cost
Roughly 0.2 to 0.5 yuan per day, or 100 to 200 yuan per year. That’s not much money, but t…
Benefit
The VITAL trial followed 25,871 participants who took 2,000 IU of vitamin D daily for a me…
This isn’t just ineffective — it’s actually harmful. A review of 78 randomized controlled trials involving nearly 300000 people found that those takin…
Cost
Roughly 0.5 to 2 yuan per day. For smokers, the real cost is a higher risk of lung cancer.
In a major clinical trial for knee osteoarthritis over 24 weeks, dummy pills alone produced pain relief in 60.1% of patients. Adding glucosamine or ch…
Cost
Roughly 2–5 RMB per day, or 700–1800 RMB per year.
Benefit
As noted above, glucosamine and chondroitin showed minimal benefits compared to placebo. T…
A combined analysis of 29 controlled trials shows that daily vitamin C intake hardly reduces the likelihood of catching a cold. Taking it after sympto…
Cost
Each effervescent tablet costs roughly 1–2 yuan; annual expense ranges from 300 to 700 yua…
Benefit
Cochrane’s pooled analysis of 29 trials with 11306 participants indicates that regular vit…
Screening completely healthy people most often yields false alarms. In one study, 86% of 1192 symptom-free individuals had at least one “abnormality” …
Cost
A whole-body PET-CT costs roughly $7000–$10000 per scan and exposes you to ionizing radiat…
Benefit
The USPSTF, which evaluates preventive measures in the U.S., assigned a D rating to CA-125…
471 overweight adults followed the same diet and exercise plans. The group wearing fitness trackers lost just 3.5 kilograms over two years, while the …
Cost
Devices cost between 200 and 2000 RMB. Plus, you have to constantly pay attention to the d…
Benefit
The IDEA trial involved 471 overweight or obese adults and lasted 24 months. All participa…
When we combine 17 studies done on humans with 223 studies analyzing food composition, there’s no solid evidence that organic food is significantly mo…
Cost
Typically 1 to 3 times the price of regular versions of the same foods.
Benefit
One systematic review brought together 17 human studies and 223 studies on food compositio…
Multivitamins, fish oil, and vitamin D — common ingredients found in many supplements — have all been evaluated in the first six sections of this chap…
Cost
Prices range from a few hundred to tens of thousands of yuan. Once packaged as gifts, the …
Benefit
The real benefit comes from saving that money instead. The reasons are explained in the fi…
A review of clinical trials conducted on healthy adults shows that probiotics don’t bring about lasting changes in gut bacteria; once you stop taking …
Cost
Roughly 2–5 RMB per day, or 700–1800 RMB per year.
Benefit
This review concludes that there’s no solid proof that probiotics can produce lasting alte…
In a large clinical trial, individuals who took cold showers reported 29% fewer sick days, yet their total days missed due to illness remained unchang…
Cost
No cost at all. It requires enduring discomfort for 30 to 90 seconds each day; staying con…
Benefit
A randomized controlled trial conducted in the Netherlands enrolled 3018 participants. Aft…
One review examined whether there is any evidence supporting detox diets. It concluded that while the detox industry is huge, there is very little cli…
Cost
Several hundred to several thousand yuan. Fasting as a way to “detox” can even lower blood…
Benefit
That same review reiterated that despite the rapid growth of the detox market, there is al…
Some people have tried to trace the origin of the “8 glasses a day” rule, but no studies supporting it have ever been found. On the contrary, surveys …
Cost
No cost at all. It does require some time and effort to remember to drink, and you’ll like…
Benefit
One literature review specifically examined the “8×8” rule — that is, 8 glasses a day, eac…
There’s a classic classroom experiment: students receive a “personality analysis” that is identical for everyone, yet most find it very accurate. This…
Cost
It costs nothing. The hard part is giving up a quick shortcut for making choices and havin…
Benefit
In that same experiment, students rated the generic personality analysis they received aft…
Blue-light-blocking lenses provide no real benefit. Skipping them saves you money, and there’s no evidence they reduce eye strain or protect the retin…
Cost
These glasses cost nothing, and you’ll also avoid paying the extra few hundred to a few th…
Benefit
A 2023 Cochrane systematic review analyzed 17 randomized controlled trials, each enrolling…
The idea that donating blood helps “detoxify,” lowers cholesterol, or prevents heart attacks is not reliable. Those conclusions stem from observationa…
Cost
There is no monetary cost. A single donation — including registration, drawing blood, and …
Benefit
The Kuopio study in Finland followed 2862 men aged 42–60 for nearly nine years. In the 24 …
People who regularly undergo generic health checks have the same mortality rates as those who don’t, including deaths from cardiovascular disease and …
Cost
There’s no cost at all; you even save hundreds to thousands of yuan each year by avoiding …
Benefit
The 2019 update of a Cochrane systematic review included 17 randomized controlled trials. …
People whose uric acid levels are high but who’ve never had gout attacks or tophus deposits mainly gain peace of mind from taking uric‑acid‑lowering d…
Cost
There’s no cost at all; you also avoid long‑term medication expenses, regular follow‑ups, …
Benefit
The 2020 gout guidelines from the American College of Rheumatology address asymptomatic hy…
For people with gallstones but no pain, roughly 80% remained symptom-free over the next nine years. Without any intervention, only about 0.1% to 0.3% …
Cost
There’s no cost at all — you even avoid the expense of general anesthesia and a hospital s…
Benefit
In Italy, the MICOL study followed 11,229 people aged 29 to 69 using ultrasound screening.…
People who’ve had calcium oxalate stones are often advised to limit calcium intake, but randomized trials show the opposite. A study with 120 men who …
Cost
No cost at all. In fact, it’s easier — no need to constantly watch what foods contain calc…
Benefit
This five‑year randomized trial enrolled 120 men with recurrent calcium oxalate stones and…
There is absolutely no verifiable evidence supporting claims that wearing such items can change one’s fate, attract wealth, or improve health. These a…
Cost
There is no monetary cost involved. The only requirement is to avoid listing “good luck,” …
Benefit
Classic classroom experiments demonstrate that when participants receive the same generic …
On average, people who place a higher value on money and material possessions report lower levels of happiness. This conclusion comes from pooled anal…
Cost
No cost at all. The hard part is resisting the urge to buy things when you’re feeling down…
Benefit
This meta-analysis combined data from 259 independent studies, covering a total of 753 eff…
When comparing people with similar incomes, those whose neighbors earn more report lower happiness levels. This effect appears only among neighbors wi…
Cost
No cost at all. All you need to do is ask one extra question before increasing your budget…
Benefit
The National Survey of Family and Households (NSFH) in the U.S. surveyed the same individu…
The popular idea is that after doing something that requires self‑control, it becomes easier to give in to temptation later on, so we should “save” ou…
Cost
No cost at all. All that needs changing is the way we talk about it.
Benefit
In a multi‑lab preregistered replication study, 23 labs with 2,141 participants followed S…
Popular belief holds that skipping breakfast leads to overeating at lunch and dinner, ultimately increasing total daily calorie intake. Research does …
Cost
There’s no monetary cost. What you save is the mental energy you’d otherwise spend worryin…
Benefit
Let’s first address the claim that skipping breakfast causes people to eat more later in t…
