Sun protection accounts for about 80% of what you can influence in skin aging, so sunscreen by day, vitamin C in the morning and a retinoid at night beat any supplement, while acne, eczema and psoriasis often trace back to gut health, insulin and hormones.

• What to do: Wear sunscreen daily, use vitamin C in the morning and a retinoid at night, wash and moisturize, and add strength training, omega 3s and a whole food diet low in sugar and dairy.
• Why it matters: UV light is the number one extrinsic driver of skin aging, while sugar, insulin resistance, gut imbalance and falling estrogen add inflammation that breaks down collagen and worsens acne and psoriasis.
• How to apply it: Try a 2 to 3 week elimination of gluten, dairy, sugar and processed food for inflammatory skin problems, ask your doctor to check insulin, thyroid, vitamin D and gut health, and choose mineral sunscreen if chemical filters worry you.
• Metrics: Optimal fasting insulin is under 5, an omega 3 index above 8% is the goal, and the dermatologist says 65% of more than half a million Function Health members have high insulin.
• Tools: Retinol or tretinoin, topical vitamin C, niacinamide, copper peptides, urolithin A (Timeline Mitopure), omega 3s, collagen peptides and Function Health lab tests.
• Risks: Retinoids are not safe in pregnancy, lemon juice irritates skin, chemical sunscreens absorb more into the blood, and exosomes and injectable GHK Cu lack enough safety data.
• Exceptions: Gluten avoidance is strongest for people with positive gluten antibodies, and beef tallow is an overrated skincare trend.

When a weight loss shot cuts your meals from about 20 bites to 10 or 12, each bite has to carry more nutrition, and one or two bites of liver can match the nutrients in 20 or 30 bites of plant or grain foods.

• What to do: Start every meal with the densest foods first: eggs with the yolk, beef, sardines, salmon, liver, oysters or other shellfish, and plain full fat Greek yogurt or cottage cheese.
• Why it matters: The shots lower appetite and make food less enjoyable, so protein, vitamins, minerals and healthy fats are easy to undereat, which puts muscle, bone and brain function at risk.
• How to apply it: Eat 4 ounces of beef before touching anything else, start the day with one or two eggs, keep tinned sardines with the bones and skin on hand, and use unsweetened yogurt or cottage cheese when cooking smells make you nauseated.
• Tools: If you dislike liver, take 2, 4 or 6 Ancestral Supplements beef liver capsules a day, which the speaker compares to eating 1 to 3 ounces of liver.
• Risks: Filling a smaller stomach with bread, cookies, crackers and candy can lead to deficiencies and to losing muscle and bone along with fat.
• Exceptions: Chicken liver is the mildest option if beef liver is too strong, and goose or duck liver work as well.

Stress ages cells mainly when you read it as a threat, because the threat response constricts blood vessels and drives inflammation, while the challenge response raises cardiac output and is linked with longer telomeres and a slower pace of aging.

• What to do: Reframe stress as a challenge. Use a personal strength statement such as "I got this, I have what it takes" and remind yourself that a racing heart means your body is mobilizing to help you. Be the lion, not the gazelle.
• Why it matters: The stress response burns a lot of ATP, the energy made by mitochondria, so a vigilant nervous system all day leaves you exhausted. In caregivers, dampened mitochondrial activity matched lower positive mood at night.
• How to apply it: Use three bins: top down mindset tools, bottom up body tools that work stress out of the body, and change of scene with safety signals such as pets, pictures, smells and music. For unsolvable problems, practice radical acceptance and drop the rope.
• Metrics: Telomere length, epigenetic aging and mitochondrial enzyme activity were studied. A simple daily check is how positive you feel at night after a stressful day.
• Risks: Chronic, uncontrollable stress with constant rumination and wishing things were different predicts unhappiness and shorter telomeres.
• Exceptions: Some caregivers look biologically as young as controls, so the response to stress matters more than the stressor itself.

Mitochondria age like a power grid that stops being serviced: with age, mitophagy slows and up to 80 percent of mitochondria can end up damaged, but fasting, exercise and urolithin A restart the cleanup, and 500 milligrams to 1 gram a day of urolithin A shifted cells toward fat burning in trials.

• What to do: Move regularly, train with some intensity or strength, sleep well, manage stress and consider fasting. Add targeted support such as urolithin A at 500 milligrams for maintenance or up to 1 gram if energy is very low.
• Why it matters: Damaged mitochondria appear in aging muscle, diabetes, frailty and cognitive dysfunction, and muscle strength depends on mitochondrial quality more than muscle mass.
• How to apply it: Build on sauna, fasting or intervals as a base, then use urolithin A as a small extra push. Singh suggests a high dose when starting, then a maintenance dose once you feel benefits.
• Metrics: Trials lasted about 4 months, with less fatigue in older adults and a shift from glucose to fatty acid use, but no big change in body composition. Doses studied: 500 milligrams to 1 gram.
• Tools: Urolithin A (Mitopure by Timeline), CoQ10, creatine, sauna, high intensity interval training, fasting, near infrared light, VO2 max testing and DEXA scans.
• Risks: Whether very high doses help people with insulin resistance is unknown, and avoid prolonged fasts if you worry about losing muscle as you age.
• Exceptions: Dose needs vary case by case, and evidence on body composition may need trials of 12 months or more.

Wall sits cut systolic blood pressure by 11 mmHg and diastolic by 5 in a review of 270 trials and 15,000 people, more than double what walking does, because holding the contraction triggers a nitric oxide surge and an insulin independent glucose uptake in the large leg muscles.

• What to do: Hold a wall sit with thighs parallel to the floor for as long as you can, building to 2 minutes. Do it two to three times per week for about a month, then once a week to maintain.
• Why it matters: Isometrics lowered systolic pressure by 8 mmHg as a category versus about 5 for cardio and resistance training and 4 for intervals. Total work time is only 10 to 12 minutes.
• How to apply it: Do a wall sit 15 to 30 minutes after your highest carbohydrate meal so AMPK pulls glucose into muscle without insulin, then add a walk. At a desk, hold a hand grip at 30% of max for 2 minutes and rest 1 minute.
• Metrics: Under 1 hour per week of isometrics dropped systolic by 10.4 and diastolic by 6.7. In 77 adults off medication, systolic fell 12.9 mmHg in one week, and a year long trial lowered resting heart rate by 4 beats per minute.
• Tools: A hand grip trainer costs 20 to 30 dollars, and a pull up bar allows dead hangs, starting at 15 seconds.
• Exceptions: Grip strength and dead hangs are proxies for whole body function and longevity, not proof that nothing else matters.

About half of men over 50 have low testosterone, and a simple morning blood test, repeated once, can show whether it is behind low energy, poor sleep, low libido or erectile problems that are often fixable.

• What to do: If you notice low energy, low sex drive, poor mood, sleep or concentration, or erectile problems, get a morning blood test for testosterone before 9 or 10 a.m. Repeat it if the first result is low. Consider screening from age 40 to 50, or earlier if you have symptoms.
• Why it matters: The normal range is wide, 300 to 900 ng/dL, and levels fall about 1% a year after 20 to 30. Low levels link with anemia, low bone density and mood. Erectile function is a check engine light for heart health.
• How to apply it: Sleep 7 to 9 hours, lose excess weight, lower stress and cut heavy drinking, because all of these suppress testosterone. If ED persists, ask a doctor about PDE5 pills, urethral gel, injections and other options. If you want children, test both partners.
• Metrics: Testosterone below about 300 ng/dL, 20 or more ejaculations a month linked with 20% lower prostate cancer risk, and PSA screening from your 50s.
• Tools: Gels, injections every two weeks, long acting shots, pellets and oral tablets for testosterone; sildenafil, tadalafil and vardenafil for ED.
• Risks: Testosterone therapy lowers sperm production in about 90% of men, and can cause acne, hair loss, breast growth and higher red blood cell counts. The TRAVERSE trial of about 5,000 men found no higher prostate cancer, heart attack or stroke risk.
• Exceptions: If testosterone is normal, therapy is unlikely to help performance, so do not take it for muscle or sexual performance.

A fasting insulin above 13 in a child signals hyperinsulinemia years before A1C rises, so a normal fasting glucose can hide type 2 diabetes that has already started, as incidence in ages 10 to 19 jumped from 2.37 to 22.3 per 100,000 between 2002 and 2023.

• What to do: Ask your pediatrician for an A1C and a fasting serum insulin if your child is overweight, has dark skin patches or has a family history of type 2 diabetes. Repeat the A1C at least once a year.
• Why it matters: Incidence grew 2.9% a year from 2002 to 2013 and 4.7% a year from 2014 to 2023. A child diagnosed young has decades to damage the heart, brain, kidneys and liver.
• How to apply it: Remove added sugar first, then slowly wean off cereal, bread, crackers, chips, cookies, pasta and fruit juice. Do not restrict portions or fast. Add meat, eggs and whole vegetables, and change the whole family's diet.
• Metrics: Healthy fasting insulin is about 3.9 in young children, about 5.0 before puberty, 7.2 in boys and 8.9 in girls near age 11, and never above 13. Treat an A1C rise of 0.1 or a fasting insulin of 15 to 17 as a red flag.
• Tools: Print the pediatric insulin studies from the show notes and bring your child's weight, glucose and family history to the visit.
• Risks: Prediabetes already harms small arteries, heart, brain, kidneys and liver, and normal fasting glucose can mislead the doctor.
• Exceptions: A very low fasting insulin can point to type 1 diabetes, which needs separate testing right away.

Dr. Mark Hyman says the single most important immune step is raising vitamin D to about 45 to 60 instead of the lab cutoff of 30, citing a COVID study where people with low levels had 75% higher risk of hospitalization or death and those above 50 had zero deaths.

• What to do: Build the foundations first: whole foods, little sugar and ultraprocessed food, regular sleep, daily stress reduction, moderate exercise, and test your nutrient levels, especially vitamin D, instead of guessing.
• Why it matters: Sugar suppresses immune cell function and drives insulin resistance, and poor sleep, chronic stress and a troubled gut all weaken the immune system, so supplements cannot compensate for them.
• How to apply it: Take vitamin D after measuring your level (some people need 1,000 units, others 10,000), keep zinc and vitamin C adequate, cook chicken soup with ginger, garlic and astragalus, and at the first sign of illness rest, sauna, walk and take your stack.
• Metrics: Vitamin D target of 45 to 60 or 70, 60 to 80% of people are insufficient or deficient, and his own routine is 50,000 units each of vitamin A and D for 3 to 5 days at symptom onset.
• Tools: Function Health testing, Host Defense mushroom formulas, Transfer Factor Multi Immune, echinacea, zinc lozenges and a garlic, ginger, honey, lemon and red pepper drink.
• Risks: The 50,000 unit protocol and his use of thymosin alpha 1 and LL-37 peptides are personal choices he does not recommend to others.
• Exceptions: He skips the flu vaccine himself but recommends it for people with lung disease, heart failure, diabetes or higher risk, and asks for single dose vials to avoid thimerosal.

Three platforms analyzed the same two coronary CT scans and reported plaque changes of minus 48%, plus 20% and nearly flat (10.4 to 11.5 cubic millimeters), because with very little plaque and only 16.5 months between scans, measurement noise looks like a result.

• What to do: If you track plaque with coronary CT angiography, use the same provider, the same scanner and the same settings every time, and wait at least 2 to 5 years between scans, as the American College of Cardiology statement suggests.
• Why it matters: Plaque depends on cumulative exposure to ApoB, the protein on each atherogenic particle, so years at an LDL of about 125 matter even after a diet change, and no platform showed rapid progression (1 percentage point or more per year).
• How to apply it: Ask your doctor about your ApoB target, since he is aiming for 40 mg/dL or lower with Repatha (evolocumab) after sitting at 70 to 80 on a plant based diet, and keep training, sleep and diet in place.
• Metrics: ApoB 70 to 80 mg/dL, LDL 125 before diet change, calcium score 4, soft plaque down about 40% on Qangio, and a reading near the 55th percentile on Clearly versus the 80th on HeartFlow.
• Tools: Qangio, Clearly and HeartFlow for plaque analysis, aged garlic extract at 2,400 mg a day, and Eight Sleep for sleep temperature.
• Risks: AI platforms may overestimate small plaque amounts, and this is one person's plan, not a recommendation.
• Exceptions: Statins remain first line therapy and may fit you better, and some people need two drugs to reach target.

Weight regain after a GLP-1 drug is not inevitable, because the hunger that returns is best met by a nutrient dense, animal based diet and strength training started while you are still on the drug, ideally within a 3 to 6 month window at a low dose.

• What to do: Start shifting to a proper human diet now: fatty meat, eggs with the yolk, fish, avocado and broccoli, instead of ultra processed food made of wheat, rice, oats, corn, added sugar and seed oils. Lift heavy things and protect your protein intake.
• Why it matters: These drugs help you lose fat but also muscle, and most regain after stopping is fat tissue. If you ate the same junk food in smaller amounts, the old appetite returns and the weight comes back.
• How to apply it: Treat the medication as a tool for 3 to 6 months at a low dose, especially if BMI is above 35 or A1C is above 10. Use that window to build habits that you can keep for 30 to 60 years, not a temporary hack.
• Risks: No research shows higher doses or long term use are safe in humans. Coaches also warn about a blunted desire for food and other pleasures, and about the drugs masking an unhealthy relationship with food.
• Exceptions: Some people have a real medical reason to use these drugs, so the goal is to ask whether the drug is helping or hurting your long term health goals.