Browse the evidence

Hormonal markers, such as the testosterone/cortisol ratio, are not reliable for diagnosing Overtraining Syndrome because they reflect acute physiological strain rather than the syndrome itself, and no single hormonal test is generally accepted.

Do not rely on a single blood test, such as the testosterone/cortisol ratio, to diagnose overtraining. These markers reflect acute stress and vary widely. A comprehensive assessment including performance trends, mood, and exclusion of other health issues is required.

Rapamycin extends murine lifespan but does not slow the rate of aging, as its effects on most aging phenotypes are aging-independent rather than protective against age-related decline.

This study in mice shows that while rapamycin extends lifespan, it does not significantly improve most markers of physical or cognitive aging. The benefits seen in some areas (like exploratory activity or memory) appear to be direct drug effects rather than a slowing of the aging process. Therefore, relying on rapamycin for 'healthy aging' in humans is not supported by this evidence, as lifespan extension may be driven by cancer suppression rather than general anti-aging mechanisms.

A metabolic biomarker score derived from 14 circulating metabolites (including lipids, amino acids, and inflammatory markers) provides significantly better prediction of 5- and 10-year all-cause mortality than conventional clinical risk factors across all adult ages.

Standard blood tests (cholesterol, blood pressure) are not enough to accurately predict your risk of dying in the next 5-10 years, especially as you age. A specialized metabolic blood test (NMR metabolomics) that looks at 14 specific markers (lipids, amino acids, inflammation) provides a much more accurate risk score. This tool is currently best used by clinicians to make high-stakes decisions, such as determining if an elderly patient is too frail for surgery, rather than for self-management.

Female athletes with Anorexia Nervosa (BMI <16.5) or severe Bulimia Nervosa (purging >4 times/week) should be categorically restricted from sports participation due to high mortality and morbidity risks.

If you are a female athlete with a BMI under 16.5 or purging more than 4 times a week, you are not allowed to compete. This is a categorical restriction based on high mortality risk. Focus on getting help from a multidisciplinary team. Return to play is possible only after significant health improvement and clearance.

In normal, non-overfed humans, de novo hepatic lipogenesis (the conversion of carbohydrate to fat) is a quantitatively minor pathway, contributing less than 2% of circulating VLDL fatty acids even under high carbohydrate refeeding conditions.

You do not need to fear carbohydrates turning into body fat. In healthy individuals, even with high carbohydrate intake, the body converts less than 2% of those carbs into fat. Focus on total calorie balance and overall diet quality rather than avoiding carbs to prevent fat gain.

Positive airway pressure (PAP) therapy, including CPAP and ASV, does not reduce the risk of major adverse cardiovascular events (ACS, stroke, vascular death) or all-cause mortality in adults with sleep apnea compared to no treatment or sham.

If you have sleep apnea, use PAP to improve your sleep quality and daytime alertness, as it does provide symptomatic relief. However, do not rely on PAP alone to protect your heart or prevent death. You must still follow standard cardiovascular prevention guidelines, such as managing blood pressure, cholesterol, and using antiplatelet therapy if indicated.

Long-term vitamin D supplementation does not reduce the risk of major adverse cardiovascular events (MACE), myocardial infarction, stroke, or all-cause mortality compared to placebo.

Based on this large meta-analysis, taking vitamin D supplements will not protect you from heart attacks, strokes, or early death, even if you have low levels. It is not indicated for cardiovascular prevention.

Advanced maternal age (≥35 years) is a strong, non-modifiable risk factor for GDM, with risk increasing linearly with age.

If you are over 35, be aware your risk for GDM is higher. Prioritize the lifestyle interventions (diet and exercise) mentioned earlier, as they are even more critical for this age group.

Nocturnal supplemental oxygen does not reduce blood pressure in patients with obstructive sleep apnea, despite effectively reducing nocturnal hypoxemia.

If you have sleep apnea, using supplemental oxygen at night will not lower your blood pressure, even if it improves your oxygen levels. CPAP is required to reduce blood pressure. Oxygen might be used for other reasons, but it is not a substitute for CPAP for cardiovascular risk reduction.

Skeletal muscle-specific deficiency in mitochondrial OxPhos (via Crif1 knockout) activates the UPRmt, leading to elevated GDF15 secretion, which protects against obesity and insulin resistance.

Maintaining muscle mitochondrial health may naturally upregulate GDF15, a hormone that helps regulate body weight and blood sugar.

The current evidence is inadequate to establish a causal role of arsenic in diabetes due to methodological limitations in epidemiologic studies and the use of non-physiological concentrations in experimental studies.

While high arsenic exposure is linked to higher diabetes rates in some regions, scientists cannot yet say for sure that arsenic causes diabetes. The existing studies have significant flaws, such as not measuring individual exposure accurately or using unrealistic doses in lab experiments. More research is needed to confirm a cause-and-effect relationship.

Skeletal muscle contains a novel FBN1+ fibro-adipogenic progenitor (FAP) subtype in humans, which is also present in mice and may contribute to heterotopic ossification.

This is a basic science finding. The FBN1+ FAP subtype may play a role in bone formation within muscle (heterotopic ossification) after injury.

Prostaglandin D2 (PGD2) is a major sleep-promoting eicosanoid produced by leptomeninges and choroid plexus that stimulates sleep by eliciting adenosine release from arachnoid cells, which then acts on the ventrolateral preoptic area (VLPO).

PGD2, produced in the membranes surrounding the brain, promotes sleep by triggering the release of adenosine, which then acts on sleep-active neurons. This highlights a complex interaction between brain structures and biochemical signals in regulating sleep.

Tirzepatide treatment does not increase the risk of major adverse cardiovascular events (MACE-4) in patients with type 2 diabetes compared to control groups.

If you have type 2 diabetes, taking tirzepatide once a week does not increase your risk of heart attacks, strokes, or cardiovascular death compared to other standard treatments. This holds true for patients with both low and high existing heart risk, providing a safe option for cardiovascular protection while managing blood sugar.

High-dose vitamin D supplementation (4000-10,000 IU/day) does not improve bone health and is associated with a significant decrease in volumetric bone mineral density (BMD) at the radius and tibia compared to a low dose (400 IU/day).

If you are a healthy adult over 55 with normal vitamin D levels, taking high-dose vitamin D (4000-10,000 IU daily) will not strengthen your bones and may actually weaken them over time. Stick to standard recommended doses (around 400-800 IU) unless you have a diagnosed deficiency, as high doses can disrupt the hormones that regulate bone density.

Hormone replacement therapy (HRT) with estrogen plus progestin in postmenopausal women increases the risk of coronary heart disease, stroke, and pulmonary embolism without improving cardiovascular outcomes.

If you are a postmenopausal woman considering hormone replacement therapy, understand that current evidence suggests it does not prevent heart disease and may actually increase the risk of heart attacks, strokes, and blood clots. It should only be used to manage severe menopausal symptoms for the shortest duration possible, after a thorough discussion of risks with your doctor.

In critically ill ICU patients, early parenteral nutrition (PN) combined with enteral nutrition delays recovery and increases infection risk compared to withholding PN for the first week (late PN), regardless of illness severity.

For critically ill patients in the ICU, current guidelines recommending early, full-calorie parenteral nutrition when enteral feeding is insufficient should be reconsidered. Evidence suggests that withholding parenteral nutrition for the first week (allowing a caloric deficit) leads to faster recovery, fewer infections, and shorter ICU stays, regardless of how sick the patient is. The focus should be on tolerating hypocaloric enteral feeding rather than aggressively reaching caloric targets via IV nutrition early on.

The Sugar Research Foundation (SRF) sponsored a 1967 literature review that selectively discounted evidence linking sucrose to coronary heart disease (CHD) while promoting fat and cholesterol as the primary dietary causes, thereby successfully shifting public health policy and scientific consensus away from sugar risks.

Be skeptical of nutrition research funded by the food industry, particularly regarding sugar and heart health. Look for independent studies that examine multiple biomarkers, not just cholesterol, and consider mechanistic evidence linking sugar to metabolic issues.

NCL-1 (TRIM2/Brat) mediates lifespan extension in major longevity pathways by limiting nucleolar size and reducing fibrillarin expression.

In C. elegans, the protein NCL-1 is essential for the lifespan benefits of various longevity pathways. It works by reducing the size of the nucleolus and lowering fibrillarin levels. This suggests that regulating nucleolar function is a critical step in extending life in these genetic models.

Reducing brain-specific IGF-1 receptor signaling lowers somatotropic hormone output (GH/IGF-I), which extends mean lifespan and delays mortality in mammals.

This research suggests that lower levels of Growth Hormone and IGF-1 signaling are associated with a longer life in mammals. While this is a genetic study in mice, it challenges the common practice of using GH to combat aging in humans, implying that high levels of these hormones might carry a risk of shortened lifespan.

Metchnikoff's historical theory that consuming yogurt (Lactobacillus bulgaricus) delays senility and extends life is scientifically unvalidated and based on a mechanism (L. bulgaricus surviving in the human intestine) that subsequent research disproved.

Do not rely on Lactobacillus bulgaricus (found in traditional yogurt) to extend your lifespan or delay aging. While a healthy lifestyle is important, this specific probiotic does not survive in the human gut, and Metchnikoff's longevity claims were never scientifically validated. Focus on evidence-based health practices instead.

Perilipin 1 (PLIN1) acts as a gatekeeper for lipid storage by sequestering lipases (ATGL and HSL) from cytosolic lipid droplets in the basal state, thereby suppressing lipolysis until hormonal stimulation triggers phosphorylation and enzyme recruitment.

In fat cells, a protein called PLIN1 acts as a protective coat that keeps fat-burning enzymes away from stored fat when you are at rest or fed. This prevents unnecessary fat loss. Only when your body signals a need for energy (via hormones like adrenaline) does this coat get modified to allow enzymes access. This highlights that fat storage is an active, regulated process, not just passive accumulation.

AMPK acts as a cellular energy sensor that restores homeostasis by activating catabolic pathways (ATP generation) and inhibiting anabolic pathways (ATP consumption) in response to energy stress.

Your cells have a built-in energy sensor (AMPK) that switches on fat burning and turns off fat storage when energy is low. This happens naturally during fasting or exercise.

GrimAge version 2 (GrimAge2), an epigenetic clock based on DNA methylation, is a superior predictor of all-cause mortality and age-related morbidity compared to the original GrimAge and other epigenetic clocks.

GrimAge2 is a blood test that measures your biological age based on DNA methylation patterns. It is a more accurate predictor of your risk for death and age-related diseases (like heart disease and diabetes) than your actual age or other aging clocks. While you cannot change your chronological age, your biological age can be influenced by lifestyle factors such as smoking, diet, and physical activity. Monitoring this metric can provide early warning signs of health decline, allowing for proactive lifestyle interventions.