Merrill Goodman

By Derrick Smith Published September 1, 2026 Apple cider vinegar is often discussed as a tool for metabolic health. However, direct clinical evidence in people with polycystic ovary syndrome (PCOS) is limited. One randomized controlled trial tested apple cider vinegar capsules in women with PCOS who were already taking metformin. The results were encouraging, but they apply to a specific group. They do not show that apple cider vinegar can replace standard treatment. Why Metabolic Health Matters in PCOS PCOS is a hormone-related disorder that affects women of reproductive age. It often occurs with insulin resistance, which means the body does not respond normally to insulin. PCOS may also occur with metabolic syndrome, a group of related metabolic risk factors. For more background, readers can explore how metabolic syndrome is understood and the basics of insulin resistance . The available trial focused on women who had PCOS, metabolic syndrome, and insulin resistance. This is importa...

The evidence points to a target range of roughly 30 to 50 ng/mL (75 to 125 nmol/L) of serum 25(OH)D for most adults, with anything below 20 ng/mL (50 nmol/L) considered inadequate for bone health. Don’t chase the highest number you can find. Levels above 50 ng/mL bring no proven extra benefit, and pushing past 125 nmol/L without your clinician watching your labs raises real safety concerns. TL;DR: Most adults should aim for serum vitamin D levels between 20 and 50 ng/mL, with levels below 12 ng/mL indicating deficiency that needs correction. Vitamin D measurements vary depending on assay methods and seasonality, so consistent testing and interpretation based on verified thresholds are essential. Testing is most recommended for older adults, those with limited sun exposure, fat absorption issues, obesity, darker skin, or chronic kidney conditions. Supplementation with vitamin D3 is more effective and sustainable than D2, especially at doses around 1,000 to 2,000 IU daily, tailored ...

Most people clear brain fog by restoring consistent sleep, steady meals and hydration, and regular movement, then correcting any documented deficiencies before reaching for a supplement shelf. If fog lingers two to four weeks despite those changes, ask your clinician for a B12, iron, and thyroid panel. Supplements help when a deficiency shows up on paper, not before. TL;DR: Addressing sleep quality, blood sugar stability, and hydration is essential before considering supplements for persistent brain fog. Most cases resolve within weeks through lifestyle changes, but ongoing symptoms may require lab testing for deficiencies like B12, iron, or thyroid issues. Environmental factors such as poor air quality and excessive screen time can exacerbate fog and should be managed alongside lifestyle adjustments. Supplements are only effective when correcting documented deficiencies; personalized testing and clinician oversight are crucial before adding them. Chronic illness-related fog fluctuates...

Yes, you can test for insulin resistance, and you have more options than most people realize. Clinicians typically build a picture using A1C, fasting plasma glucose, and surrogate insulin indices like HOMA‑IR, while the true research standard, the euglycemic hyperinsulinemic clamp, stays mostly locked inside university labs. The tests differ in what they actually measure, and that difference matters more than most lab reports let on. A1C of 5.7% to 6.4% and fasting plasma glucose of 100 to 125 mg/dL both flag prediabetes , but neither one directly measures insulin. HOMA‑IR does, by combining a fasting glucose and fasting insulin value into a single ratio that estimates how hard your pancreas is working to keep blood sugar in range. If you want early warning before glucose climbs, ask for fasting insulin alongside fasting glucose. If you want the standard diagnostic answer, A1C and fasting plasma glucose are what most guidelines are built around. Here’s how to act on th...