The question isn’t whether to supplement. For most high performers living modern lives — indoors, under artificial light, eating convenient food, running on compressed sleep — targeted supplementation addresses genuine gaps that diet and lifestyle don’t fully cover.
The question is which supplements are backed by real evidence, at what doses, and for whom.
This is not a guide to cognitive optimization specifically — that’s covered separately. This is a guide to the foundational compounds with genuine scientific support for overall health, longevity, immune function, metabolic health, and physical resilience.
It is also an honest accounting of what doesn’t hold up under scrutiny.
The Evidence Framework
As with any evidence review, quality matters. The bar here is human randomized controlled trial data — not animal studies, not mechanistic speculation, not epidemiological association (which is useful for generating hypotheses but cannot establish causation). Where evidence is strong, it’s noted. Where it’s preliminary, that’s noted too.
A pre-read note on deficiency vs. optimization:
There is an important distinction between supplementing to correct a genuine deficiency and supplementing to optimize beyond a normal range. The former produces large, reliable effects. The latter typically produces small or negligible ones. Most people don’t know which situation they’re in — which is why testing, not guessing, is the correct starting point.
The Short List: Compounds with Genuine Evidence
Vitamin D3 (with K2)
The situation: Vitamin D deficiency is one of the most prevalent nutritional deficiencies in the developed world. Estimates suggest 40–50% of US adults have insufficient vitamin D levels (below 30 ng/mL), with rates higher in northern latitudes, darker skin tones, people who work indoors, and those who avoid sun exposure.
The evidence: Vitamin D functions more like a hormone than a vitamin, binding to receptors in virtually every tissue in the body. It plays roles in immune regulation, bone metabolism, muscle function, cardiovascular health, and increasingly, metabolic function. A landmark 2022 meta-analysis of the VITAL trial in NEJM Evidence found that vitamin D supplementation (2,000 IU/day) significantly reduced cancer mortality (17%) and autoimmune disease risk (22%) in adults over 5 years. Effects on cardiovascular disease were neutral in the primary analysis.
For bone health, the evidence combining vitamin D and calcium is well-established across decades of research.
Why K2 matters: Vitamin D increases calcium absorption. Vitamin K2 (specifically MK-7 form) directs calcium into bones and teeth rather than arterial walls. Pairing D3 with K2 is increasingly standard practice — the two work synergistically.
The practical application: 2,000–4,000 IU vitamin D3 daily with 100–200mcg vitamin K2 (MK-7 form), taken with a fat-containing meal for absorption. Test your 25(OH)D level first — target maintenance range is 40–60 ng/mL. Don’t guess.
Magnesium
The situation: Up to 50% of Americans don’t meet the RDA for magnesium through diet alone. Modern agricultural soil depletion, high-stress lifestyles (cortisol depletes magnesium), and high caffeine intake all contribute. Subclinical deficiency is common and rarely diagnosed.
The evidence: Magnesium is a cofactor in over 300 enzymatic reactions including energy metabolism (ATP synthesis), protein synthesis, DNA repair, and regulation of the nervous system. Clinical evidence supports supplementation for:
- Sleep quality: Multiple RCTs demonstrate improved sleep onset, duration, and quality, particularly in older adults and those with suboptimal magnesium status
- Blood pressure: A 2016 meta-analysis in Hypertension found that magnesium supplementation significantly reduced systolic and diastolic blood pressure
- Insulin sensitivity: Research consistently shows associations between higher magnesium intake and better glycemic control; supplementation studies in insulin-resistant individuals show modest but meaningful improvements
- Anxiety and stress resilience: Magnesium modulates HPA axis activity; deficiency is associated with heightened stress reactivity and anxiety
Forms matter: Magnesium oxide (the cheapest and most common form) has poor bioavailability (~4%). Magnesium glycinate and malate have high bioavailability and are well-tolerated. Magnesium citrate is effective but has a laxative effect at higher doses.
The practical application: 200–400mg elemental magnesium glycinate, before bed. If you experience muscle cramps, poor sleep, or high stress, this is the first thing to add.
Omega-3 Fatty Acids (EPA + DHA)
The situation: The modern Western diet has inverted the omega-6:omega-3 ratio from an ancestral approximate 4:1 to something closer to 20:1 in many individuals. This imbalance drives chronic low-grade inflammation — a foundational mechanism in cardiovascular disease, metabolic dysfunction, and accelerated aging.
The evidence: The evidence base for omega-3s is among the broadest of any supplement:
- Cardiovascular health: The REDUCE-IT trial (2018, NEJM) found that high-dose EPA (4g/day icosapentaenoic acid) reduced major adverse cardiovascular events by 25% in high-risk patients with elevated triglycerides. At standard doses, consistent evidence for triglyceride reduction (by 20–30%) at 2–4g/day.
- Inflammation: EPA and DHA are precursors to resolvins and protectins — compounds that actively resolve inflammatory processes rather than simply blocking them
- Metabolic health: Omega-3s improve insulin sensitivity and reduce hepatic fat accumulation (non-alcoholic fatty liver disease)
- All-cause mortality: A 2021 meta-analysis covering over 150,000 participants found omega-3 supplementation associated with reduced risk of fatal myocardial infarction
The practical application: 1–2g combined EPA+DHA daily for general health maintenance. Triglyceride-form fish oil or algae-based omega-3 (for those avoiding fish products). As with vitamin D: test your omega-3 index. Target above 8%.
Creatine Monohydrate
The evidence beyond cognition: Creatine is one of the most studied supplements in existence — and its benefits extend well beyond cognitive performance and muscle building.
- Muscle mass and strength: The evidence is unambiguous and spans decades. Creatine supplementation consistently improves strength, power output, and lean mass gains when combined with resistance training, across all age groups
- Bone health: Emerging evidence suggests creatine supports bone mineral density, particularly when combined with resistance training — relevant for long-term skeletal health
- Healthy aging: A growing body of research suggests creatine has neuroprotective and cardioprotective properties. A 2022 review noted benefits in sarcopenia prevention (age-related muscle loss) and metabolic health in older adults
- Glucose metabolism: Creatine improves glycogen synthesis and appears to enhance insulin sensitivity in some populations
The practical application: 3–5g creatine monohydrate daily. This is the most cost-effective supplement on this list by a significant margin — approximately $15–20 per month for a clinically dosed supply. The “loading phase” (20g/day for 5–7 days) is optional; daily maintenance dosing reaches saturation within 3–4 weeks.
Vitamin K2 (MK-7)
Beyond its role with vitamin D, K2 has standalone evidence worth noting:
- Arterial health: K2 activates matrix Gla protein (MGP), which inhibits arterial calcification. Observational data from the Rotterdam Study found that high K2 intake was associated with a 57% reduction in risk of dying from heart disease
- Bone density: K2 activates osteocalcin, a protein required for calcium binding in bone matrix. Multiple RCTs demonstrate meaningful bone density preservation with MK-7 supplementation
- Most people are deficient: Dietary K2 is found primarily in fermented foods (natto, aged cheese) — foods most Western diets contain very little of
The practical application: 100–200mcg MK-7 form daily, with a fat-containing meal. Inexpensive, often formulated with D3, and widely underused.
Zinc
The situation: Zinc is an essential mineral involved in immune function, DNA synthesis, wound healing, protein metabolism, and testosterone production. Deficiency is common in athletes (lost through sweat), vegetarians (lower bioavailability from plant sources), and older adults.
The evidence:
- Immune function: Zinc is one of the most evidence-backed interventions for immune support. A Cochrane review found that zinc supplementation within 24 hours of cold onset reduced duration and severity of symptoms
- Testosterone: Zinc deficiency is associated with reduced testosterone levels; correction of deficiency restores them. Note: supplementing beyond repletion does not further elevate testosterone in individuals with adequate zinc
- Wound healing and skin: Strong mechanistic and clinical evidence for wound healing and skin barrier integrity
The practical application: 15–30mg elemental zinc daily (zinc glycinate or picolinate for best absorption). Zinc and copper compete for absorption — if supplementing zinc long-term above 25mg/day, consider adding 1–2mg copper to prevent depletion.
Berberine
The mechanism: Berberine is a plant alkaloid that activates AMPK (AMP-activated protein kinase) — often called the “metabolic master switch.” AMPK activation mimics some of the metabolic effects of exercise and caloric restriction at the cellular level.
The evidence: The evidence for berberine in metabolic health is genuinely compelling:
- Blood glucose: Multiple RCTs demonstrate reductions in fasting glucose and HbA1c comparable to metformin in type 2 diabetic patients. A 2008 RCT in Metabolism found berberine reduced fasting blood glucose by 20% and HbA1c by 12% over 3 months
- Lipids: Berberine consistently reduces LDL cholesterol (by 15–25%) and triglycerides in clinical trials
- Insulin sensitivity: Significant improvements across multiple studies
Who this is for: Not everyone. For individuals with normal metabolic function, the glucose-lowering effect is modest. For those with pre-diabetes, metabolic syndrome, or elevated triglycerides/LDL, the evidence is strong enough that a physician conversation about berberine is warranted.
The practical application: 500mg, two to three times daily with meals (to blunt postprandial glucose spikes). Can cause gastrointestinal discomfort initially — start low and increase gradually.
NMN / NR (Nicotinamide Mononucleotide / Nicotinamide Riboside)
The mechanism: Both NMN and NR are precursors to NAD+ (nicotinamide adenine dinucleotide), a coenzyme essential for energy metabolism and DNA repair. NAD+ levels decline significantly with age — by approximately 50% between age 40 and 60. This decline is implicated in reduced mitochondrial function, impaired DNA repair, and various aging-related processes.
The honest evidence assessment: This is the most hyped category in longevity supplementation, and also one of the most scientifically interesting. The animal data is striking — NAD+ precursor supplementation consistently extends lifespan and healthspan in multiple model organisms. The human data is newer and more limited.
A 2022 clinical trial published in Nature Aging found that NMN supplementation in healthy middle-aged adults significantly raised NAD+ levels in blood and skeletal muscle, improved muscle insulin sensitivity, and showed trends toward improved physical performance. Studies on NR have shown similar NAD+ elevation.
What we don’t yet know: Whether the impressive animal data translates to meaningful human longevity effects. The trials are short, the sample sizes are small, and “raises NAD+ levels” is a biomarker endpoint, not a health outcome.
The practical application: If you choose to supplement, NMN at 500mg–1g daily or NR at 300–500mg daily. Given the cost ($60–150/month for quality products) and the still-developing evidence base, this is an informed personal choice rather than a clear evidence-based recommendation. Many longevity researchers take it; most acknowledge they’re making a bet on incomplete evidence.
What Doesn’t Hold Up
Multivitamins (for generally healthy adults): Multiple large, well-designed trials including the Physicians’ Health Study II found no significant benefit for cardiovascular disease, cancer, or cognitive decline in well-nourished adults. The exception: individuals with confirmed deficiencies or poor dietary variety. Targeted supplementation based on testing outperforms broad-spectrum multivitamins.
Collagen supplements: Collagen is digested into amino acids before absorption — it doesn’t arrive at target tissues as intact collagen. There is modest evidence for joint-specific benefits from hydrolyzed collagen, but the mechanism likely involves amino acid supply (glycine, proline, hydroxyproline) rather than delivered collagen peptides. Not a priority.
Antioxidant megadosing (high-dose vitamin C and E): High-dose antioxidant supplementation has not only failed to reduce disease risk in large trials — it has in some cases shown harm. High-dose vitamin E supplementation was associated with increased all-cause mortality in a meta-analysis of 19 trials. The hormetic stress of mild oxidative signaling is important for cellular adaptation; blocking it entirely is not beneficial.
Probiotics (as a general supplement): The evidence for specific probiotic strains in specific conditions (IBS, antibiotic-associated diarrhea) is solid. The evidence for general probiotic supplementation in healthy individuals producing meaningful health benefits is much weaker. Dietary sources of fermented foods and dietary fiber are more reliably beneficial for the microbiome than generic probiotic capsules.
The Right Starting Protocol
Rather than a comprehensive stack, here is what the evidence supports as a rational starting point for a health-oriented adult:
First: Test, don’t guess
- 25(OH)D (vitamin D)
- Omega-3 index
- Magnesium RBC
- Ferritin, B12 (particularly relevant for those with restricted diets)
- HbA1c and fasting glucose (metabolic baseline)
Then: Correct what’s actually deficient
For most people, that will include some combination of:
| Supplement | Who | Dose |
|---|---|---|
| Vitamin D3 + K2 | Most people (test first) | 2,000–4,000 IU D3 + 100–200mcg K2 |
| Magnesium glycinate | Most people | 200–400mg before bed |
| Omega-3 (EPA+DHA) | Most people eating Western diet | 1–2g combined daily |
| Creatine monohydrate | Adults of all ages | 3–5g daily |
| Zinc | Athletes, vegetarians, older adults | 15–30mg daily with food |
| Berberine | Metabolic health concerns | 500mg 2–3x daily with meals |
Then: Layer intelligently based on goals
Longevity focus → consider NMN/NR on current evidence Immune resilience → zinc is already on the list; elderberry extract has modest evidence for cold duration Cardiovascular risk → omega-3 dose may warrant increasing to 2–4g under physician guidance
The Foundational Principle
The supplements on this list work best when they’re not doing the heavy lifting. Vitamin D won’t compensate for a sedentary life spent entirely indoors. Magnesium can’t overcome the cortisol load of 60-hour stress-saturated weeks indefinitely. Omega-3s don’t override a diet built on processed food.
The value of evidence-based supplementation is in addressing genuine gaps in an otherwise solid foundation — not in circumventing the hard work of building that foundation.
Test first. Correct what’s deficient. Keep the stack small and evidence-informed. And remember that the most powerful interventions for long-term health are still free: sleep, movement, stress regulation, and real food.
Eathan Janney, PhD, is the founder of NeuroGenerative Dynamics — an evidence-based performance coaching system for entrepreneurs, executives, and high performers. Nothing in this article constitutes medical advice. Consult a qualified physician before beginning any supplementation protocol, particularly if you have existing health conditions or take prescription medications.