https://synptide.com Evidence-based health optimization: peptides, GLP-1 medications, recovery, and longevity, without the hype. https://synptide.com/learn/electrolytes-and-fasting-keto-flu Why the keto flu hits when you start fasting or low-carb, and how sodium, potassium, and magnesium prevent it. Electrolytes while fasting, explained simply. Tue, 26 Jan 2027 00:00:00 GMT https://synptide.com/learn/electrolytes-and-fasting-keto-flu https://synptide.com/learn/when-does-fat-burning-start-fasting When does the body start burning fat when fasting? Why you're always oxidizing fat, what the ~12-hour metabolic switch means, and why hour counts mislead. Mon, 25 Jan 2027 00:00:00 GMT https://synptide.com/learn/when-does-fat-burning-start-fasting https://synptide.com/learn/what-breaks-a-fast What breaks a fast depends on your goal. How coffee, gum, sweeteners, and cream affect calories, insulin, and autophagy — plus the honest gray areas. Fri, 22 Jan 2027 00:00:00 GMT https://synptide.com/learn/what-breaks-a-fast https://synptide.com/learn/16-8-vs-omad-fasting-windows 16:8 vs OMAD compared: what the trials show on weight, muscle, and adherence, plus how to pick a fasting window you can actually stick to. Thu, 21 Jan 2027 00:00:00 GMT https://synptide.com/learn/16-8-vs-omad-fasting-windows https://synptide.com/learn/when-does-autophagy-start When does autophagy start when fasting? Honestly, there's no validated human clock — we separate the animal data from the sparse human evidence on timing. Tue, 19 Jan 2027 00:00:00 GMT https://synptide.com/learn/when-does-autophagy-start https://synptide.com/learn/when-does-ketosis-start-fasting When ketosis starts during a fast: why the metabolic switch lands in the 12-36 hour window, and why ketones climb gradually, not switching on at one hour. Mon, 18 Jan 2027 00:00:00 GMT https://synptide.com/learn/when-does-ketosis-start-fasting https://synptide.com/learn/fasting-stages-by-hour The fasting stages by hour — from digestion to glycogen depletion, the metabolic switch, and early ketosis — and why the hour marks are soft, not exact. Fri, 15 Jan 2027 00:00:00 GMT https://synptide.com/learn/fasting-stages-by-hour https://synptide.com/learn/hangover-timeline A hangover timeline: symptoms build overnight and peak when BAC hits zero. What drives them, how long they last, and why only time — not a cure — helps. Thu, 14 Jan 2027 00:00:00 GMT https://synptide.com/learn/hangover-timeline https://synptide.com/learn/what-is-a-standard-drink A US standard drink is 14 grams of pure alcohol — about a 12 oz beer, 5 oz wine, or 1.5 oz shot. How to count drinks and why real pours run bigger. Tue, 12 Jan 2027 00:00:00 GMT https://synptide.com/learn/what-is-a-standard-drink https://synptide.com/learn/does-anything-sober-you-up-faster Can you sober up fast? Coffee, cold showers, and food don't speed alcohol metabolism — only time does. What evidence shows, and why it's never OK to drive. Mon, 11 Jan 2027 00:00:00 GMT https://synptide.com/learn/does-anything-sober-you-up-faster https://synptide.com/learn/why-alcohol-affects-women-differently Why does alcohol affect women differently? How less body water raises BAC for the same drinks, what the Widmark r-factor captures, and the real risks. Fri, 08 Jan 2027 00:00:00 GMT https://synptide.com/learn/why-alcohol-affects-women-differently https://synptide.com/learn/how-long-to-wait-to-drive-after-drinking How long after drinking can you drive? The honest math on how BAC clears, why hour-based rules fail, and the one safe answer before driving: none. Thu, 07 Jan 2027 00:00:00 GMT https://synptide.com/learn/how-long-to-wait-to-drive-after-drinking https://synptide.com/learn/what-is-bac-blood-alcohol-levels-explained What does 0.08 BAC mean? A plain-English guide to blood alcohol concentration by the number, what happens at each level, and why no BAC is safe to drive. Tue, 05 Jan 2027 00:00:00 GMT https://synptide.com/learn/what-is-bac-blood-alcohol-levels-explained https://synptide.com/learn/how-long-does-it-take-to-fall-asleep How long does it take to fall asleep? A healthy sleep latency is about 10-20 minutes. Here's what faster or slower means and how to budget the time. Mon, 04 Jan 2027 00:00:00 GMT https://synptide.com/learn/how-long-does-it-take-to-fall-asleep https://synptide.com/learn/is-6-hours-of-sleep-enough Is 6 hours of sleep enough? For almost everyone, no — it sits below the 7+ hour adult recommendation. Here's the cycle math and the evidence on short sleep. Fri, 01 Jan 2027 00:00:00 GMT https://synptide.com/learn/is-6-hours-of-sleep-enough https://synptide.com/learn/how-much-sleep-do-you-need-by-age How much sleep do you need? The evidence-based hour ranges by age from the NSF and AASM — newborns to older adults — and why they're ranges, not rules. Thu, 31 Dec 2026 00:00:00 GMT https://synptide.com/learn/how-much-sleep-do-you-need-by-age https://synptide.com/learn/best-time-to-wake-up-sleep-inertia The best time to wake is at the end of a sleep cycle, not mid-cycle — waking from deep sleep drives sleep inertia. Here's what the research shows. Tue, 29 Dec 2026 00:00:00 GMT https://synptide.com/learn/best-time-to-wake-up-sleep-inertia https://synptide.com/learn/what-time-should-i-go-to-bed Want to wake at 6am feeling clear? Count back in ~90-minute sleep cycles, add time to fall asleep, and aim to wake between cycles. Here's the bedtime math. Mon, 28 Dec 2026 00:00:00 GMT https://synptide.com/learn/what-time-should-i-go-to-bed https://synptide.com/learn/the-90-minute-sleep-cycle The 90-minute sleep cycle is an average, not a fixed clock — real cycles run 70-120 minutes and shift across the night. Here's what the science shows. Fri, 25 Dec 2026 00:00:00 GMT https://synptide.com/learn/the-90-minute-sleep-cycle https://synptide.com/learn/does-decaf-have-caffeine Does decaf have caffeine? Yes, about 2 to 15 mg per cup. What "decaffeinated" legally means, how caffeine is removed, and when the leftover amount matters. Thu, 24 Dec 2026 00:00:00 GMT https://synptide.com/learn/does-decaf-have-caffeine https://synptide.com/learn/caffeine-content-chart-by-drink A caffeine content chart by drink: coffee, espresso, black and green tea, soda, and energy drinks, with mg ranges from FDA and USDA data and why they vary. Tue, 22 Dec 2026 00:00:00 GMT https://synptide.com/learn/caffeine-content-chart-by-drink https://synptide.com/learn/caffeine-sensitivity-why-it-varies Why caffeine sensitivity varies so much between people: the CYP1A2 metabolism gene, the ADORA2A receptor, sleep, smoking, pregnancy, and how much you drink. Mon, 21 Dec 2026 00:00:00 GMT https://synptide.com/learn/caffeine-sensitivity-why-it-varies https://synptide.com/learn/how-much-caffeine-is-too-much How much caffeine is too much? The FDA puts the safe daily ceiling at 400 mg for healthy adults, roughly 4 cups of coffee. See the numbers by drink and dose. Fri, 18 Dec 2026 00:00:00 GMT https://synptide.com/learn/how-much-caffeine-is-too-much https://synptide.com/learn/what-time-should-you-stop-drinking-coffee What time to stop drinking coffee: work back from bedtime using caffeine's ~5-hour half-life. A cutoff of about 8-10 hours before bed protects deep sleep. Thu, 17 Dec 2026 00:00:00 GMT https://synptide.com/learn/what-time-should-you-stop-drinking-coffee https://synptide.com/learn/how-long-does-caffeine-last-half-life How long does caffeine last? Its half-life is about 5 hours, so a quarter of your afternoon coffee is still in your blood at bedtime — and what changes that. Tue, 15 Dec 2026 00:00:00 GMT https://synptide.com/learn/how-long-does-caffeine-last-half-life https://synptide.com/learn/cardiovascular-risk-in-your-40s In your 40s your 10-year heart risk looks low even when lifetime risk is high. Why lifetime and 30-year cardiovascular risk matter more at this age. Mon, 14 Dec 2026 00:00:00 GMT https://synptide.com/learn/cardiovascular-risk-in-your-40s https://synptide.com/learn/lipoprotein-a-inherited-risk Lipoprotein(a) is an inherited cardiovascular risk factor standard cholesterol panels and ASCVD scores miss. What Lp(a) is, its thresholds, and why to test. Fri, 11 Dec 2026 00:00:00 GMT https://synptide.com/learn/lipoprotein-a-inherited-risk https://synptide.com/learn/prevent-vs-pooled-cohort-equations How the AHA PREVENT risk calculator differs from the older Pooled Cohort Equations: new outcomes, ages 30-79, 10- and 30-year risk, and why estimates fell. Thu, 10 Dec 2026 00:00:00 GMT https://synptide.com/learn/prevent-vs-pooled-cohort-equations https://synptide.com/learn/coronary-artery-calcium-score What a coronary artery calcium (CAC) score measures, how the Agatston scale reads, and how a CAC of 0 or 100+ can reclassify statin decisions. Tue, 08 Dec 2026 00:00:00 GMT https://synptide.com/learn/coronary-artery-calcium-score https://synptide.com/learn/ascvd-risk-enhancers ASCVD risk enhancers like Lp(a), hs-CRP, family history, and CKD refine borderline and intermediate risk when the 10-year score alone isn't enough. Mon, 07 Dec 2026 00:00:00 GMT https://synptide.com/learn/ascvd-risk-enhancers