Health Claims

If young guys who haven’t worked out in a while switch up their strength exercises for the same muscles, they’ll likely build muscle more evenly across their thighs and arms over nine weeks compared to doing the same moves every time.

Measuring arm muscle thickness with ultrasound gives very consistent results when done the same way, so it’s good for tracking muscle growth over time.

For women who work out regularly, both preacher curls and inclined curls build arm muscle just about the same way — no matter where you look along the upper arm.

Doing a specific type of bicep curl on an incline with changing resistance doesn't seem to make certain parts of the upper arm muscles grow more in women who work out regularly — even after doing it consistently for 9 weeks.

For women who work out regularly, doing preacher curls that stretch the biceps a lot might help build more muscle in the lower part of the upper arm—about an 8.8% increase—compared to other curl types.

Your body uses a special chemical pathway to turn tryptophan from food into energy molecules, and this process might be linked to how we age and manage energy in our cells.

Turning off certain genes in mice changes their body chemistry in ways that depend on the tissue and whether they're male or female — and these changes are linked to how they age.

When mice are genetically changed so they don’t break down a certain nutrient (tryptophan) as much, it might help them live longer and healthier — and this could mean the same process matters for aging in other animals, including people.

After a 6-day water-only fast, a man’s metabolism resets certain chemicals in his body back to normal within a week of eating again—even if he hasn’t regained all his weight yet.

When healthy men go without eating for 6 days, their adrenaline spikes on day 4 — like the body’s stress system briefly kicking in during the fast.

If healthy guys stop eating for six days, their stress hormone levels don’t really go up — meaning their bodies don’t seem to treat it as a big stress event.

Fasting for six days with no calories may lower certain chemicals in the blood linked to brain health — one drops because you're not eating, and the other suggests your body is producing fewer harmful substances.

If healthy guys don't eat for six days, their bodies show higher levels of certain chemicals linked to how the body handles stress and metabolism, with the highest levels seen right at the end of the fast.

When the way tiny energy factories in cells split or merge goes out of balance, it can affect how long simple creatures like worms, flies, and yeast live — but sometimes too much splitting or merging helps, sometimes it hurts, depending on the situation.

As we age, levels of a molecule called NAD+ go down, and this might mess up how our cells' powerhouses work, especially in the brain and liver, possibly leading to diseases like Alzheimer's or diabetes.

Giving older mice supplements like NR or NMN might help their cells' energy factories work better and handle damage from aging.

Turning off a specific enzyme in worms makes them produce more NAD+ and live longer.

Blocking a specific enzyme in fruit flies and tiny worms helps them live longer, suggesting that changing how their bodies process a certain nutrient can slow aging in these animals.

When you fast or eat less, certain chemicals in your body from the kynurenine pathway help your body respond in ways that keep you healthier for longer.

If you're using diabetes or weight-loss drugs like semaglutide, adding personalized strength training can help you lose fat while keeping your muscle.

If you keep your muscle while losing weight with certain diabetes or weight-loss drugs like semaglutide, you might be less likely to gain the weight back after stopping the drug — muscle could help keep your metabolism healthy long-term.

If you lose weight on a low-calorie diet, you're more likely to keep it off if you combine liraglutide with aerobic exercise, rather than doing just one of those things — the exercise seems to boost how well the medication works over time.

If adults do guided strength training for over 10 weeks, they might gain around 3 kilograms of muscle and get 25% stronger — and this could help balance out muscle loss from weight-loss drugs.

Some newer weight-loss drugs help people lose a lot of weight—up to a quarter of their body weight—but they might also cause a big drop in muscle, about as much as people usually lose in 10 years of aging, which could make them weaker over time.