Browse the evidence

Menstrual cycle phase has a trivial effect on exercise performance in eumenorrheic women, with no evidence supporting general guidelines for modulating training across phases.

Stop tracking your menstrual cycle to schedule workouts. The science shows that performance differences across phases are trivial and inconsistent. Instead of trying to align your training with your hormones, focus on consistent training habits. If you notice a personal pattern where you feel weaker or stronger in a specific phase, adjust your expectations for that specific session, but do not change your overall training plan based on the calendar.

SGLT-2 inhibitors increase the risk of genital infections, while GLP-1 receptor agonists may increase the risk of severe gastrointestinal events.

Be aware of potential side effects: SGLT-2 inhibitors can increase genital yeast infections, and GLP-1 agonists can cause nausea or GI issues. These are common and manageable, but you should discuss prevention strategies (like hygiene for SGLT-2 or slow dose titration for GLP-1) with your doctor before starting.

Blue wavelength light is the most efficient stimulus for shifting the circadian system and suppressing melatonin due to its sensitivity in non-rod, non-cone photoreceptors.

Blue light is the most efficient wavelength for shifting your circadian clock. Light therapy devices enriched with blue light are being tested for this purpose, though sufficient intensity white light can also be effective.

Modafinil is indicated to enhance alertness during the night shift for patients with Shift Work Disorder (SWD).

If you work night shifts and struggle with alertness, ask your doctor about modafinil. It is a guideline-recommended treatment to help you stay awake and perform better during your shift, with a known safety profile.

Gut microbiota composition influences bile acid pool size and signaling, where germ-free mice are resistant to high-fat diet-induced obesity and NASH due to altered FXR signaling and larger bile acid pools.

Your gut bacteria affect how your body processes fats and sugars. While animal studies show that a healthy microbiome can protect against obesity, we don't yet know exactly how to manipulate this in humans to treat fatty liver disease.

Vitamin D supplementation may reduce the severity and risk of COVID-19 infection, particularly in individuals with vitamin D deficiency, by modulating immune response and reducing pro-inflammatory cytokines.

Consider Vitamin D supplementation, especially if you have limited sun exposure or are elderly. Aim for a daily intake of up to 2000 IU, and ensure adequate magnesium intake to support Vitamin D metabolism. Consult a healthcare provider for personalized advice.

Consumption of non-digestible oligosaccharides (NDO) may interact with lipid metabolism, potentially lowering serum triacylglycerols and cholesterol in hyperlipidaemic individuals.

If you have slightly high blood fats, consuming 10-18g of inulin or oligofructose daily for 8+ weeks may help lower triglycerides and insulin levels. Effects on cholesterol are less consistent and may require longer consumption.

Orthorexia is independently associated with executive dysfunction, specifically deficits in set-shifting, external attention, and working memory, which overlap with but are distinct from anorexia and OCD profiles.

If you feel unable to deviate from your strict diet even when it causes problems, you may be experiencing cognitive rigidity. This is a treatable cognitive pattern, not a moral failing. Cognitive-behavioral therapy can help improve mental flexibility.

Computer and Internet use may be favorably associated with cognitive function in older adults.

For older adults, using computers and the Internet may support cognitive function, unlike passive TV viewing. Engaging with technology can be a beneficial sedentary activity.

Testosterone therapy does not increase the risk of prostate cancer or benign prostatic hyperplasia (BPH) in men without existing prostate disease, but it can aggravate symptoms in men with locally advanced or metastatic prostate cancer.

Do not let the fear of prostate cancer stop you from seeking treatment for low testosterone if you are otherwise healthy. Current guidelines show no link between TRT and developing prostate cancer. However, if you already have advanced prostate cancer, TRT is contraindicated. Regular prostate checks (PSA and DRE) are essential before and during treatment.

Islamic Ramadan fasting results in heterogeneous health outcomes, with no consensus on changes to body mass index, blood lipids, or blood pressure, largely due to confounding variables like dietary choices, smoking cessation, and fasting duration.

Ramadan fasting does not guarantee health improvements; outcomes depend heavily on what and how much you eat during non-fasting hours, as well as other lifestyle factors like smoking.

Moderate consumption of red wine (and beer) is associated with a lower prevalence of metabolic syndrome compared to abstainers or heavy drinkers, whereas liquor/spirit intake increases risk.

If you drink alcohol, moderate wine consumption (up to 1 drink/day for women, 2 for men) is associated with better metabolic health than abstaining or drinking spirits. Do not start drinking if you don't already.

Smoking increases the risk of metabolic syndrome, and smoking cessation is associated with an increased risk of MetS in the short-to-medium term (up to 10 years) due to weight gain and metabolic changes.

Quit smoking to prevent metabolic syndrome. Be aware that you may gain weight and have a higher MetS risk for up to 10 years after quitting. Counter this by adopting a calorie-restricted diet and increasing physical activity immediately.

Selenium status has a complex, non-linear relationship with diabetes risk, where both deficiency and excess (high serum levels) may be associated with adverse metabolic outcomes depending on geographic and baseline status.

Do not supplement with selenium unless you live in a selenium-deficient area or have a confirmed deficiency. High selenium levels may actually increase diabetes risk. Focus on getting selenium from a varied diet, and consult a doctor for testing if you are considering supplementation.

Natural plant-derived antioxidants (polyphenols, carotenoids, etc.) may mitigate obesity and metabolic complications by reducing intracellular oxidative stress, scavenging reactive oxygen species (ROS), and preventing NF-κB activation.

Focus on consuming a diet rich in plant-based antioxidants (polyphenols, flavonoids, carotenoids) as part of a broader lifestyle strategy. While these compounds show promise in reducing oxidative stress and inflammation linked to obesity, they are not a standalone cure. Prioritize lifestyle modifications like diet changes and reduced sedentarism, using plant-derived foods as a supportive component rather than a primary intervention.

Lifestyle interventions may improve the Free Androgen Index (FAI) in women with PCOS, but evidence quality is low.

Lifestyle changes may help lower male hormone levels (FAI) in women with PCOS. However, the evidence is not strong enough to be certain, so this should be viewed as a potential benefit rather than a guaranteed outcome.

Zinc deficiency is associated with increased body fat and reduced lean mass in children, and may influence leptin secretion, though human intervention studies show mixed results.

Ensure adequate zinc intake, especially if you are a child or adolescent in a region with potential malnutrition. While zinc supports metabolic health, it is not a standalone weight loss solution.

Faecal Microbiota Transplantation (FMT) from lean donors shows promise for improving insulin sensitivity in metabolic syndrome, but current human evidence is limited, small, and unreplicated.

FMT from lean donors may improve insulin sensitivity, but it is not yet a standard or proven treatment for diabetes due to limited and unreplicated human data. Do not pursue this outside of clinical trials.

Testosterone therapy is conditionally recommended for postmenopausal women with properly diagnosed hypoactive sexual desire disorder (HSDD) to achieve midnormal premenopausal levels, with monitoring for androgen excess.

If you are postmenopausal and have been diagnosed with HSDD, a trial of physiological testosterone may be considered. The goal is to reach midnormal premenopausal levels, not supraphysiological ones. You must be monitored closely for signs of androgen excess, and therapy should be stopped if there is no response within 6 months.

Prunes contain phenolic compounds that inhibit human LDL oxidation in vitro, potentially serving as preventive agents against chronic diseases like heart disease and cancer.

Prunes contain phenolic compounds that may help prevent chronic diseases by inhibiting LDL oxidation, but this is based on lab studies, not clinical trials.

Plant-based diets modulate the gut microbiome towards a favorable diversity of bacteria species, but the functional 'bottom up' signaling from these microbial changes to host health remains highly speculative.

While plant-based diets likely increase gut microbiome diversity, the direct health benefits of these changes are not yet fully understood or proven.

Exercise-based rehabilitation may reduce long-term mortality (greater than 12 months) in heart failure patients, although the evidence is less certain than for short-term outcomes.

While short-term mortality is not significantly affected, engaging in exercise may offer a survival benefit over the long term (beyond one year). This supports the value of maintaining an exercise routine as a long-term health strategy for heart failure.

Propionate metabolism in the liver stimulates hepatic gluconeogenesis, which activates hepatic vagal afferents to signal satiety to the brainstem, a mechanism well-established in ruminants but less defined in humans.

Propionate from fiber fermentation may contribute to satiety via liver signaling, but this is likely a secondary effect compared to direct gut hormone release in humans.

The negative effects of isolation on energy intake (in females) and physical activity levels persisted for 6-8 weeks even as government restrictions began to ease, suggesting long-term behavioral shifts.

Do not assume that lifting restrictions will automatically restore your previous healthy habits. The study shows that negative behavioral changes (higher intake, lower activity) can persist for weeks even when the external constraints are removed. Proactive effort is needed to reverse these entrenched habits.