Mitochondrial Health · Longevity · Healthspan

Energy Is Manufactured: How to Keep Your Mitochondria Running Into the Second Half

Mitochondrial health sits underneath nearly every marker of how well you age, from strength and walking speed to blood sugar, brain function and survival itself. It is also one of the most trainable systems you own. Here is the physiology, the human data, and the full playbook for keeping the machinery young.

It is 3:15 in the afternoon and he is on his second coffee. He is fifty-two, runs a company, still lifts four days a week, and tells me something I have heard in some version for thirty-three years: "I'm not tired, exactly. I just run out earlier." The last set of the workout stopped happening. The afternoon meeting gets about sixty percent of him. His sleep is fine on paper. His labs are "normal."

Then he shows me what he has been doing about it. An NAD drip every couple of months. A longevity powder with fifteen ingredients. A cold plunge. What he has not done in roughly a decade is a single hard interval.

He is not lazy and he is not uninformed. He is doing exactly what the market trained him to do, which is to shop at the top of the pyramid while the foundation underneath runs short on the most basic parts. What he is describing is not a willpower problem or a caffeine deficiency. It is mitochondrial health, and it is the most important conversation in longevity that almost nobody frames correctly. So let's start where I start with every patient: with the machine itself.

The Factory Inside Every Cell

Most of your cells contain hundreds to thousands of mitochondria. Their job is unglamorous. They take the carbohydrate and fat you eat, strip the electrons off them, and use the flow of those electrons to pump protons across a membrane, which drives a molecular turbine called ATP synthase. The product is ATP, the molecule every heartbeat, muscle contraction, nerve impulse and thought spends.

The scale is hard to picture. You turn over roughly your own body weight in ATP every day, yet you store only seconds of it at any moment. Energy is not a reserve you draw down. It is a production line that has to run continuously, every second you are alive, and when the line slows you feel it long before any lab value flags it.

Think of it as an assembly line with five stations. Fat has to be carried inside the mitochondrion. Carbohydrate has to pass through a gateway enzyme. The Krebs cycle has to strip the fuel down to its electrons. Electron carriers, chiefly NAD+, have to ferry that harvest to the electron transport chain. And the finished ATP needs a buffer for moments of peak demand.

Every station runs on parts your body cannot make from scratch. Two of the cycle's gatekeeper enzymes, pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase, each need five cofactors present at the same time, and four of those five are built from B vitamins: thiamine, riboflavin, niacin and pantothenic acid.¹ Run short on any one of them and the whole line slows to the speed of its weakest station.

More than a power plant

Calling mitochondria the powerhouse of the cell undersells them. They also act as the cell's sensors and quality-control system. They signal when fuel is abundant or scarce, they help decide whether a damaged cell repairs itself or self-destructs, and they generate reactive oxygen species that are useful as signals in small amounts and damaging in large ones.

They are also constantly being rebuilt. When you train, a signaling cascade centered on a protein called PGC-1α tells the cell to build new mitochondria. This is called biogenesis. Meanwhile a cleanup process called mitophagy identifies worn-out mitochondria and recycles them. A healthy cell keeps both processes running, so the fleet stays young even as the person gets older. With age and inactivity, biogenesis slows and cleanup falls behind, and the cell fills with older, leakier mitochondria that produce less energy and more oxidative noise.⁴ That balance between building and clearing is the real target of everything in this article.

Why Mitochondria Are the Key to Healthspan

Lifespan is how long you live. Healthspan is how long you live well: strong, metabolically sound, mentally sharp and independent. Nearly every tissue that determines healthspan is a heavy mitochondrial user, which is why mitochondrial decline shows up everywhere at once. Your brain is about 2 percent of your body weight and consumes roughly 20 percent of your resting energy.² Your heart beats about a hundred thousand times a day without a single day off. Your skeletal muscle is the largest metabolic organ you have.

Mitochondrial capacity in human muscle declines across the adult lifespan, which the Mayo Clinic biopsy work led by Short and Nair documented two decades ago.³ Mitochondrial dysfunction now sits among the hallmarks of aging in the framework researchers use to organize the field, alongside chronic inflammation, loss of protein maintenance and impaired nutrient sensing, all of which it feeds.⁴ NAD+ follows the same trend. A 2022 study of human muscle biopsies found it among the metabolites most reduced in older adults.⁵

The Most Important Data Point in This Article

Here is the part that never makes it onto a supplement label. When researchers separate older adults who train from older adults who do not, much of what we call age-related mitochondrial decline turns out to be inactivity-related decline.

Most of these are small or cross-sectional studies, which limits how hard you can push any single number. The direction across all five is consistent.

In the Gries study, the lifelong exercisers did not stay twenty-five. Their VO2max still fell well below the young group's.¹² Lanza found trained older adults still carried less mitochondrial DNA than trained young adults.¹¹ Age is real. But the gap between a trained 74-year-old and an untrained 75-year-old was larger than most of what any pill on the market has ever been shown to close. The decline is real. A large share of it is also the decline of a machine that stopped being asked to work.

Training builds the factory. Nutrition keeps it from sitting idle, waiting on parts.

Where the Longevity Story Gets Oversold, Including by My Side

The people selling mitochondrial products are not wrong about the biology. The decline is documented and the cofactor chemistry is textbook. Where it goes wrong is in the numbers, and in what gets left out.

The "eight years younger" claim

Take the most-shared figure in this space: an alpha-ketoglutarate formula that "reversed biological age by eight years." That comes from a real paper.¹⁵ It was also a retrospective review of 42 people who chose to take the product, with no placebo group, measured with a saliva DNA methylation test, and the author list included people from the company that sells the test and the company that sells the formula. The authors themselves wrote that a placebo-controlled study is still needed. The lifespan data on AKG is real too, but it is mouse data.¹⁶ I cannot trace "eight years younger" to a controlled human trial, so I am not going to repeat it as one. The honest version is that AKG is a Krebs cycle intermediate with interesting animal data and no controlled human longevity result yet.

NAD: solid biochemistry, unsettled payoff

NAD precursors have the opposite problem. Oral nicotinamide riboside raises whole-blood NAD+ in a clean dose-response: 22 percent at 100 mg, 51 percent at 300 mg and 142 percent at 1,000 mg daily in an eight-week placebo-controlled trial of 140 adults.¹⁷ That part is not in dispute. But blood is not muscle. In a small trial in men in their seventies, three weeks of 1,000 mg shifted the muscle NAD metabolome and lowered inflammatory signaling without significantly raising muscle NAD+ itself.¹⁸ In healthy adults aged 55 to 79, NAD+ rose with no change in exercise capacity.¹⁹ In obese men, two grams a day did not improve insulin sensitivity.²⁰ Raising the number in the blood is reliable. Turning that into something you can feel or measure in performance is still being worked out.

The false choice: exercise or NAD

Here is the framing I want to retire. Training raised NAMPT, the enzyme that recycles NAD in muscle, by 28 to 30 percent in adults over 55.¹⁴ A precursor supplies raw material. Training expands recycling capacity. Those are different jobs. A man who trains and supplies the raw material is not doing the same thing twice. He is working both ends of the same pathway.

Popular habits with thin human data

Cold plunges, sauna protocols, extended fasting and red light all have enthusiastic followings and some plausible mechanisms. Much of the mitochondrial evidence behind them comes from animals, cell cultures or short-term markers. I cannot point you to controlled human data showing any of them improves muscle mitochondrial capacity the way interval training does. If you enjoy them, keep them. Just do not let them take the place of the work that has the data.

How to measure your mitochondria without a biopsy

Nobody needs a muscle biopsy to track this. These four numbers move with mitochondrial health and are easy to retest every three to six months.

• VO2max. A cardiopulmonary exercise test gives the direct number, and many fitness centers and sports medicine clinics offer one. It is the single best mitochondrial proxy you can buy.
• Walking speed. Time yourself over a fixed distance at your normal pace. It is crude, free, and tied to both mitochondrial function and survival.^7,8
• Grip strength. A hand dynamometer is inexpensive and tracks overall muscle function.⁶
• Resting heart rate and recovery. How fast your heart rate falls in the minute after a hard effort improves as aerobic fitness improves.

The Free Levers: Start Here

Every one of these costs nothing, and every one acts on the machinery directly. They are listed in order of the strength of the human evidence.

1. Two to three interval sessions a week. In the Mayo Clinic trial, twelve weeks of high-intensity cycling intervals raised mitochondrial capacity 49 percent in adults 18 to 30 and 69 percent in adults 65 to 80, the largest gain of any training mode they tested.¹³ No supplement has produced a muscle number like that. The format is simple: hard efforts of two to four minutes, near the top of what you can sustain, with equal or slightly shorter recovery. Start with four rounds.
2. Build an aerobic base. Two or three sessions a week of steady work at a pace where you can still speak in sentences, 30 to 60 minutes. This is the training behind the Lanza and Gries findings, where endurance-trained older adults kept mitochondrial capacity, capillaries and aerobic enzymes close to young levels.^11,12 Intervals build the ceiling. Steady work builds the foundation underneath it.
3. Lift two or three days a week. Resistance training raised the NAD recycling enzyme as much as aerobic work did in older adults.¹⁴ It also builds the muscle that houses your mitochondria in the first place. More muscle means more factory floor.
4. Walk more than you think you need to. Daily step count tracked with muscle NAD+ in older adults.⁵ Walking after meals also blunts the blood sugar spike that strains the whole system.
5. Stop flooding the line. Chronic caloric excess forces fuel into muscle faster than the mitochondria can burn it, which is exactly the fat-in-muscle pattern linked to insulin resistance.⁹ Losing visceral fat and fixing insulin resistance takes pressure off the entire system.
6. Eat the parts. Protein at every meal. Meat, fish, eggs, dairy, legumes and whole grains supply the B vitamins. Red meat is the richest dietary source of carnitine. Colorful plants supply the antioxidants that buffer the oxidative byproducts of energy production.
7. Treat alcohol as a mitochondrial tax. Alcohol raises thiamine demand and its metabolism competes directly for NAD+ in the liver. Less is better. None on most nights is better still.
8. Protect seven to nine hours of sleep. Repair, hormone signaling and appetite regulation all depend on it, and training adaptations happen during recovery, not during the session.

The mitochondrial week

Here is what that looks like on a calendar. It is a template, not a prescription, and it assumes you have medical clearance for vigorous exercise.

Daily walking after meals on every day. Add a third lifting session or third interval session only once recovery is solid.

You can act on this entire section without buying anything from me. Do only this, and you will be ahead of most men your age.

Where Targeted Support Earns Its Place

On a good day, food covers the parts. The trouble is that men over forty who train hard, travel and carry real cognitive load do not live on good days. Training also raises demand for exactly the cofactors the line runs on. That is who I built MitoHealth for: the daily layer that keeps every station stocked so the training you are already doing can pay off.

The core is the cofactor set from stations two and three, all at or above 100 percent of the daily value: thiamine 2 mg, riboflavin 2 mg with half supplied as already-activated riboflavin-5-phosphate, niacinamide 20 mg NE, pantothenic acid 5 mg and biotin 500 mcg, with vitamin A at 1,500 mcg RAE. Alongside them sit acetyl-L-carnitine 500 mg for the fuel shuttle at station one, AKG 100 mg as a Krebs cycle intermediate, creatine HCl 500 mg, nicotinamide riboside 20 mg, ATP 30 mg, mixed tocopherols 20 mg for the lipid membranes surrounding the mitochondria, and alpha-GPC 5 mg. No stimulants, every dose printed on the label, stevia-sweetened, one scoop of orange fruit punch in cold water.

The pairing: MitoHealth and NAD Catalyst

MitoHealth contains 20 mg of nicotinamide riboside. NAD Catalyst contains 500 mg per capsule, or 1,000 mg at the two-capsule serving, which is the top arm of the dose-response trial above. That is fifty times the amount, and I would rather you hear it from me than find it on the panel.

They are not competing for the same job. MitoHealth supplies the cofactors the entire line depends on, from the carnitine shuttle through the Krebs cycle. NAD Catalyst loads station four, the single carrier pool every station upstream feeds into, at the dose the research actually used. One keeps the factory supplied. The other targets its main conveyor belt. Add the training that expands NAD recycling, and you are working the pathway from all three directions: supply, cofactors and capacity.

My routine is one scoop of MitoHealth in the morning, one NAD Catalyst capsule with breakfast and the second with dinner, which is the split the six-week trial used.¹⁹

Station five has its own product. The 500 mg of creatine in MitoHealth is a contributing amount, while the researched daily dose is 3 to 5 grams.²² Creatine is also one of the few supplements with randomized trial data on cognition in healthy adults, though the effects are modest and the clearest signal was for short-term memory, particularly in older adults.²³ Pure Creatine does that job, and it layers under both.

Honest Expectations

Here is what this stack will not do, stated plainly.

• MitoHealth will not give you a jolt. There is no stimulant in it. Cofactor repletion is a filling-the-tank process measured in weeks.
• It does not deliver a research dose of its specialty ingredients. Controlled trials of acetyl-L-carnitine in older adults generally used 1.5 to 3 grams a day,²⁴ so 500 mg is the low end. Swallowed ATP is not absorbed intact,²⁵ so the 30 mg is formulation support. The alpha-GPC is not the reason to buy it, and the 100 mg of AKG is not the "eight years."
• NAD Catalyst reliably raises blood NAD+. Whether that translates into how you feel, train or age is still being worked out, and some trials found nothing.
• Neither product builds new mitochondria. Intervals and aerobic training do that.
• Add up your vitamin A and B3 across products. MitoHealth carries 1,500 mcg RAE of preformed vitamin A against an adult upper limit of 3,000. Run with NAD Catalyst, total niacinamide is 36 mg NE, just over the 35 mg upper limit, which was set on the flushing caused by nicotinic acid. Niacinamide does not flush, but if you also take a multivitamin, count it.

What MitoHealth will do is supply the cofactors your mitochondria physically require, at full daily value, in a form you will actually take every morning. Give it eight to twelve weeks alongside the training, retest your VO2max or walking speed, then judge it honestly.

The Second Half Runs on What You Supply

Back to the man with the second coffee. He did not need a more exotic molecule. He needed his assembly line asked to work again: two interval sessions, two steady aerobic days, three lifting days, and every station kept stocked while it adapted. The drip was turning up the volume in a body that could not hear it.

Mitochondria are where longevity stops being an abstraction. They decide whether your legs carry you at eighty, whether your blood sugar holds, whether your brain gets the energy it asks for. And unlike your genes, they answer to what you do this week.

In the first half of life, the machine runs on youth. In the second half, it runs on what you demand of it and what you supply it with. Demand comes first, and it is free. Supply is where a daily scoop of MitoHealth earns its spot on the counter. It's only halftime, and the second half is where the game gets decided.