Mitochondria are easy to dismiss as a high-school biology fact -- the powerhouse of the cell -- until something goes wrong with them. For people living with primary mitochondrial disease, something has gone wrong at the level of DNA itself. For many more people navigating unexplained fatigue, exercise intolerance, or accelerated aging, the question of how well their mitochondria are working is not abstract. It is the center of the problem.
A landmark 2025 review published through PubMed describes the field of primary mitochondrial disease as reaching a "translational inflection point" (https://pubmed.ncbi.nlm.nih.gov/42361626/) -- meaning that decades of basic science are now, finally, converting into real clinical trials and emerging treatment strategies. That is important news for patients with diagnosed disease. It is also worth understanding for anyone who wants an honest picture of how mitochondrial biology applies to everyday functional health.
This post unpacks what primary mitochondrial disease is, why the science is shifting now, what the evidence-based options look like, and where the honest limits of current knowledge sit.
What primary mitochondrial disease actually is
Mitochondria do more than generate ATP. They regulate calcium signaling, mediate cell death pathways, produce reactive oxygen species, and sit at the center of metabolic flexibility. But their most critical function -- the one that defines primary mitochondrial disease -- is oxidative phosphorylation: the process by which cells convert nutrients into usable energy.
Primary mitochondrial diseases are caused by pathogenic mutations in either mitochondrial DNA (mtDNA) or nuclear DNA (nDNA) that directly impair this energy-production machinery. The key word is "primary." These are not downstream effects of another disease. The genetic defect is the root cause (https://pubmed.ncbi.nlm.nih.gov/27775730/).
The clinical picture is heterogeneous -- which is part of what makes diagnosis so hard. Tissues with the highest energy demand suffer first and most severely: the brain, skeletal muscle, heart, and retina. Symptoms can include progressive muscle weakness, exercise intolerance, seizures, hearing loss, diabetes, and cardiomyopathy. Some people are diagnosed in infancy; others are not identified until adulthood, often after years of testing that pointed everywhere but the mitochondria (https://pubmed.ncbi.nlm.nih.gov/25503498/).
Prevalence estimates sit around 1 in 5,000 adults, making mitochondrial disease one of the most common inherited metabolic disorders -- and still one of the most underrecognized (https://pubmed.ncbi.nlm.nih.gov/25652200/).
Why primary and secondary mitochondrial dysfunction are not the same thing
This distinction matters because the internet has blurred it almost beyond recognition. Search "mitochondrial dysfunction" and you will find everything from rare genetic disease to jetlag to general fatigue, often presented as the same problem with the same fix.
Primary mitochondrial disease is a genetic diagnosis. Secondary mitochondrial dysfunction refers to impaired energy metabolism arising from something else -- aging, obesity, oxidative stress, nutrient depletion, sedentary behavior, toxin exposure, or any number of acquired conditions. The mechanisms can look similar at the cellular level. The clinical implications are not (https://pubmed.ncbi.nlm.nih.gov/27587988/).
Where the confusion creates real harm is in treatment. Someone with a confirmed mtDNA mutation may need a specialist-led protocol, gene therapy trials, and careful avoidance of certain drugs that further impair mitochondrial function. Someone with secondary mitochondrial dysfunction from years of poor sleep and low activity may respond meaningfully to exercise, targeted nutrition, and NAD+ precursor support. Treating both identically -- in either direction -- is a mistake.
At NoMi Beach Health, we draw this line clearly. Our role is to optimize the metabolic environment and to recognize when a picture points toward primary disease and a subspecialty referral. That is not a limitation; it is honest scope of practice.
What the translational inflection point means
For most of the history of mitochondrial medicine, the gap between bench science and bedside treatment was enormous. Researchers understood the biochemistry in exquisite detail; they had very few tools to change clinical outcomes.
That gap is narrowing. The 2025 review notes several converging developments: better natural history data from patient registries, improved biomarkers (including fibroblast growth factor 21 and GDF-15) that allow disease tracking without muscle biopsies, refined understanding of disease mechanisms at the complex I through complex V level, and a drug pipeline that now includes molecules targeting reactive oxygen species, NAD+ biosynthesis, mitochondrial biogenesis, and gene-level correction (https://pubmed.ncbi.nlm.nih.gov/42361626/).
None of this means there is a cure available today. There is not. But the scientific architecture needed to build one is now more solid than at any point in the field's history. And some of the mechanisms being targeted in primary disease -- particularly NAD+ metabolism and mitochondrial biogenesis -- are the same ones where lifestyle and supplementation strategies produce measurable effects in healthier populations (https://pubmed.ncbi.nlm.nih.gov/34706245/).
Mechanisms the evidence supports -- and where honest limits sit
NAD+ and energy metabolism
NAD+ is a coenzyme that mitochondria cannot function without. It accepts electrons during nutrient oxidation, fuels the electron transport chain, and acts as a substrate for sirtuins and PARP enzymes that regulate cellular repair and gene expression. NAD+ levels decline measurably with age and under conditions of metabolic stress (https://pubmed.ncbi.nlm.nih.gov/36699148/).
Precursor supplementation -- primarily with NMN (nicotinamide mononucleotide) or NR (nicotinamide riboside) -- raises intracellular NAD+ levels in human subjects. A well-designed trial in healthy middle-aged and older adults confirmed that NR supplementation is well-tolerated and raises blood NAD+ metabolites dose-dependently (https://pubmed.ncbi.nlm.nih.gov/29581452/). What the evidence does not yet show is whether raising NAD+ in healthy people translates to clinical outcomes like longer lifespan or reduced disease incidence. We tell patients that directly. For people with primary mitochondrial disease, NAD+-boosting approaches are an active area of trial investigation -- the results are not in yet.
For a deeper look at how we use NAD+ therapeutically at NBH, see our post on NAD therapy and cellular rejuvenation.
Mitochondrial biogenesis through exercise
Exercise is the most robustly evidence-based intervention for mitochondrial health in the general population, and it retains a meaningful role even in some forms of primary mitochondrial disease. Aerobic exercise activates PGC-1 alpha, the master regulator of mitochondrial biogenesis, increasing both mitochondrial number and efficiency in skeletal muscle (https://pubmed.ncbi.nlm.nih.gov/31778608/).
In people with mitochondrial myopathy, endurance exercise has been shown to increase the proportion of wild-type (healthy) mtDNA relative to mutant mtDNA in muscle -- a phenomenon called "mutant shifting" -- and to improve exercise capacity and quality of life (https://pubmed.ncbi.nlm.nih.gov/24820351/). This does not cure the disease, but it is a real, mechanism-driven clinical benefit.
A 2025 systematic review of healthspan interventions reinforced that structured physical activity remains among the highest-evidence strategies for improving multi-system biological function across the lifespan (https://pubmed.ncbi.nlm.nih.gov/42172592/).
Reactive oxygen species and antioxidant strategy
Dysfunctional mitochondria overproduce reactive oxygen species (ROS), which damage cellular components and accelerate disease progression (https://pubmed.ncbi.nlm.nih.gov/19336460/). This has driven interest in mitochondria-targeted antioxidants -- compounds engineered to concentrate inside the mitochondrial matrix rather than circulating diffusely.
Coenzyme Q10 (CoQ10) has been used for decades in clinical practice for mitochondrial disease, with a reasonable safety profile and some signal for benefit in specific mutations, though robust randomized trial data remain limited (https://pubmed.ncbi.nlm.nih.gov/32386303/). MitoQ, a mitochondria-targeted CoQ10 derivative, and other targeted antioxidants are in earlier stages of investigation.
The honest position here: targeted antioxidant strategies are scientifically rational, modest in proven benefit, and safe at established doses. They are not cures, and they should not be sold as such.
What a real evaluation looks like
If you are coming to us with significant, unexplained fatigue -- the kind that does not improve with a week of good sleep, that limits your exercise capacity, that has been dismissed as stress -- we do not start by ordering a mitochondrial gene panel. We start where good medicine starts: a thorough history, a physical exam, and a systematic workup for common and reversible causes.
Thyroid dysfunction, iron deficiency, sleep apnea, vitamin D deficiency, depression, and deconditioning all look like mitochondrial problems from the outside. They are far more common and far more treatable. We rule those out or in first.
If the picture after that workup still points toward a primary metabolic problem -- particularly if there is a family history, multi-organ involvement, elevated lactate, or exercise intolerance out of proportion to conditioning -- we discuss subspecialty referral. Mitochondrial disease is diagnosed and managed by neurologists and metabolic disease specialists with access to muscle biopsy, respiratory chain enzyme testing, and full genetic sequencing. We support that process; we do not replace it.
What we do manage directly is the optimization layer: structured exercise programming, nutritional gaps, targeted supplementation with an honest evidence tier attached to each recommendation, and monitoring labs at intervals that actually mean something. That is the work described in our functional wellness approach, and it is grounded in the same mechanistic biology being studied in the primary disease trials.
For context on how mitochondrial support fits into a broader metabolic picture, our post on HM568 and NAD biosynthesis in mitochondrial dysfunction covers the preclinical pathway in more detail.
Where the science is heading
The drug pipeline for primary mitochondrial disease now includes gene therapy approaches, small molecules that modulate the NAD+ axis, mitochondria-targeted antioxidants, and compounds designed to shift the ratio of healthy to mutant mtDNA. Several are in phase II and III trials. Natural history registries like the NAMDC and NorthStar are providing the outcome data that earlier trials lacked.
The field is also learning from its failures. Multiple compounds that showed strong preclinical signals failed to replicate in human trials -- a reminder that mitochondrial biology in a living person is far more complex than in a cell line. The translational inflection point is real, but it is also humbling. The science says "we are getting closer." It does not yet say "we have arrived."
For anyone with a confirmed diagnosis, that pipeline is worth watching closely and worth discussing with a specialist who tracks trial enrollment. For people without a confirmed diagnosis, the practical message is simpler: the mechanisms being targeted in the most serious mitochondrial diseases -- NAD+ metabolism, mitochondrial biogenesis, oxidative stress management -- respond to lifestyle and evidence-based supplementation in ways that are measurable and meaningful, even if they fall short of "cure."
The goal is not to sell you a mitochondrial wellness program. The goal is to be honest about what the evidence supports, where the limits are, and what a real clinical evaluation looks like when you are tired of being tired.
If unexplained fatigue, exercise intolerance, or multi-system symptoms have been following you without a clear answer, a structured evaluation is the right next step -- not a supplement stack, not a gene panel ordered online. We draw real labs, ask the right questions, and tell you what we find. Visit our functional medicine services page to book a new-patient visit, or call us at (786) 744-5152.
Frequently Asked Questions
- What are primary mitochondrial diseases?
- Primary mitochondrial diseases are genetic disorders that impair the mitochondria's ability to produce energy in the form of ATP. They can affect nearly every organ system, though the brain, muscles, and heart -- which have the highest energy demands -- are most often involved. Symptoms vary widely depending on which gene is mutated and which tissues are affected.
- How are mitochondrial diseases different from mitochondrial dysfunction?
- Primary mitochondrial disease is caused by a pathogenic mutation in mitochondrial or nuclear DNA, and it is a diagnosable medical condition. Mitochondrial dysfunction is a broader, functional term describing suboptimal energy production that can arise from aging, nutrient deficiencies, oxidative stress, or lifestyle factors. The two can overlap, but they are not the same diagnosis.
- Is there an approved treatment for primary mitochondrial disease?
- As of 2025, no disease-modifying therapy has broad regulatory approval for primary mitochondrial diseases, though several compounds are in late-stage trials. Symptomatic and supportive care -- including targeted supplementation, exercise protocols, and metabolic support -- remain the clinical standard while the drug pipeline matures.
- Can lifestyle changes actually improve mitochondrial function?
- Robust evidence shows that aerobic exercise stimulates mitochondrial biogenesis through pathways including PGC-1 alpha, and that resistance training preserves mitochondrial density in aging muscle. These effects are real and clinically meaningful, even though they do not reverse a genetic mutation in someone with a primary disease.
- What role does NAD+ play in mitochondrial health?
- NAD+ (nicotinamide adenine dinucleotide) is a coenzyme that sits at the center of mitochondrial energy metabolism and serves as a substrate for sirtuins and PARP enzymes that regulate cellular repair. NAD+ levels decline with age, and precursor supplementation with NMN or NR has shown early promise in human trials, though large-scale outcome data are still limited.
- Who should consider a mitochondrial health evaluation?
- Anyone with unexplained fatigue that does not resolve with adequate sleep, progressive exercise intolerance, multi-system symptoms without a clear diagnosis, or a known family history of mitochondrial disease may benefit from evaluation. A clinician-led workup -- not a direct-to-consumer test -- is the right starting point.
- Does a concierge primary care practice manage primary mitochondrial disease?
- A concierge integrative practice like NoMi Beach Health works best in partnership with a neurologist or metabolic disease specialist for confirmed primary mitochondrial disease. Where we add value is in optimizing the metabolic environment -- nutrition, targeted supplementation, exercise programming, and labs -- and in coordinating referrals when the picture calls for subspecialty expertise.
Sources
- Gorman GS, et al. Primary mitochondrial diseases. Nat Rev Dis Primers (2016).
- Parikh S, et al. Diagnosis and management of mitochondrial disease: a consensus statement from the Mitochondrial Medicine Society. Genet Med (2015).
- Niyazov DM, et al. Primary mitochondrial disease and secondary mitochondrial dysfunction: importance of distinction for diagnosis and treatment. Mol Syndromol (2016).
- Halling JF, Pilegaard H. PGC-1alpha-mediated regulation of mitochondrial function and physiological implications. Appl Physiol Nutr Metab (2020).
- Abdellatif M, et al. Interventions that prolong multidimensional healthspan in humans: a systematic review of randomized controlled trials. Nat Aging (2025).
- Martens CR, et al. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults. Nat Commun (2018).
- Stocks B, et al. NAD+ precursor supplementation prevents NAD+ decline in aging and improves muscle function. Cell Metab (2021).
- Viscomi C, Zeviani M. Strategies for fighting mitochondrial diseases. J Intern Med (2020).
- Distelmaier F, et al. Mitochondrial complex I deficiency: from organelle dysfunction to clinical disease. Brain (2009).
- Tarnopolsky MA. Exercise as a therapeutic strategy for primary mitochondrial cytopathies. J Child Neurol (2014).
- Fang M, et al. New insights into NAD+ biology and its roles in the cardiovascular system. JACC Basic Transl Sci (2023).
- Gorman GS, et al. Prevalence of nuclear and mitochondrial DNA mutations related to adult mitochondrial disease. Ann Neurol (2015).
