Supplement marketing is overwhelming. Most of it is noise. A short, evidence-supported stack for a lean endurance athlete past 40 — with specific doses, timing, and the rationale for each — looks like this.
The stack assumes a reasonable diet already in place (see Hardgainer Eating Strategy). Supplements fill specific gaps, not replace food.
The core stack — evidence-based and cheap
Vitamin D3 — 2000–4000 IU/day
What: Cholecalciferol (D3, not D2). Take with a fatty meal (it’s fat-soluble).
Why: Lean people splitting Korea (winter low-sun) and India (sunscreen-using urban life) are commonly deficient. Vitamin D is essential for:
- Bone mineralisation
- Immune function
- Muscle protein synthesis
- Mood regulation (deficiency correlates with depression)
Dose tuning: Start at 2000 IU. Get blood 25(OH)D tested. Target serum level: 50–80 ng/mL. If still below 40 after 2–3 months at 2000 IU, increase to 4000 IU. Anything above 5000 IU daily without monitoring is risky (hypercalcaemia at very high doses).
Brand notes: Any reputable D3. Now Foods, Thorne, Nordic Naturals all reliable. USD 5–15 per 6-month supply.
Vitamin K2 (MK-7) — 100–200 µg/day
What: Menaquinone-7 (MK-7 form, longer half-life than MK-4). Often sold combined with D3.
Why: This is the underrated paired supplement to D3. D3 increases calcium absorption from food. Without K2, that calcium doesn’t know where to go — it can deposit in arterial walls instead of bone. Long-term D3 supplementation alone may modestly increase arterial calcification.
K2 (specifically MK-7) activates the proteins that direct calcium to bone matrix and away from soft tissue.
Dose: 100–200 µg daily. Take with D3 in a fatty meal.
Brand notes: Look for “MK-7” specifically (not MK-4). NattoPharma MenaQ7 is the gold-standard ingredient brand; many supplements use it. USD 10–25 per 3–6 month supply.
Magnesium glycinate — 300–400 mg before bed
What: Magnesium bound to glycine. Highly bioavailable, non-laxative (unlike magnesium oxide).
Why:
- Endurance athletes deplete magnesium through sweat
- Cofactor for 300+ enzymatic reactions including ATP production
- Sleep quality improvement at night doses (glycine is itself mildly sedating)
- Supports cardiovascular and glucose regulation
Dose: 300–400 mg elemental magnesium, taken 30–60 minutes before bed.
Brand notes: Doctor’s Best, Pure Encapsulations, Now Foods. Avoid magnesium oxide (poor absorption, laxative). Magnesium threonate (300–400 mg) is an alternative for brain-specific benefits but is pricier with weaker general evidence than glycinate.
Omega-3 (EPA + DHA) — 2 g combined daily
What: Fish oil or algae oil. Look for the combined EPA + DHA number on the label, not “fish oil mg” (which includes fillers).
Why:
- Cardiovascular event reduction (strong evidence at 2 g+ EPA + DHA daily)
- Brain function and dementia risk reduction
- Anti-inflammatory effect helps with exercise recovery
- Most omnivores don’t eat enough fatty fish to hit therapeutic levels
Dose: ~2 g combined EPA + DHA daily. Some brands need 2–4 capsules to hit this.
Brand notes: Quality matters — fish oil oxidises easily and rancid fish oil is worse than no fish oil. Look for IFOS certification or third-party oxidation testing. Nordic Naturals, Carlson Labs, Thorne are reliable. Algae-based options (Nordic Naturals Algae Omega, Testa) are vegan and lower mercury but slightly more expensive per mg.
Storage: keep in the fridge after opening.
Creatine monohydrate — 3–5 g/day
What: Plain creatine monohydrate powder.
Why: Once “just for bodybuilders,” now well-supported for:
- Muscle mass and strength (modest but real, ~5–10% increase)
- Bone density support (when combined with resistance training)
- Cognitive function — emerging strong evidence for memory and mental endurance in older adults
- Endurance performance (slight; mostly a power-output booster)
Dose: 3–5 g daily, no need to “load” (loading just speeds up saturation by 2–3 weeks). Take with water; any time of day works.
Brand notes: Plain monohydrate is the most-studied and cheapest. Avoid HCl, ethyl ester, “buffered” variants — more marketing than benefit. Optimum Nutrition Micronized, MyProtein Creatine Monohydrate, Bulk Supplements all fine. USD 10–25 for 3–6 months supply.
Side notes: May cause 0.5–1 kg of water weight in the first 2 weeks (intramuscular water retention). This is normal and is desirable for a lean person trying to build mass.
The maybe-stack — evidence supports it but less universal
Whey protein or plant protein — 25–30 g/serving as needed
Why: Not really a “supplement” — it’s just food in powder form. The use case is hitting 100–140 g/day protein target without overeating. See Hardgainer Eating Strategy for the high-calorie shake recipe.
Brand notes: Whey isolate or whey concentrate both fine. For plant-based: pea + rice blend (complete amino acid profile). Avoid soy protein isolate if oestrogen-sensitive (mild phytoestrogen effect; controversial but easy to sidestep).
Beetroot juice or powder — 500 mg dietary nitrate before workouts
Why: Direct nitric oxide pathway booster. Improves running and cycling economy 1–3% in trained athletes.
Dose: 500 mg nitrate (equivalent to a typical Beet It Sport shot, or 1 tbsp concentrated beetroot powder), taken 2–3 hours before exercise.
Critical pairing: This doesn’t work if you use antibacterial mouthwash. See Oral Microbiome and Mouthwash Paradox.
Caffeine — context-dependent
Why: Performance booster for endurance, mild cognitive enhancement, well-tolerated.
Dose: 3–6 mg/kg bodyweight, 30–60 min before exercise. For a 64 kg person: 200–400 mg (1–2 strong coffees).
Cautions: Tolerance builds; cycling off helps. Heavy daily caffeine (>400 mg) can elevate cortisol and disrupt sleep, undermining HRV.
Curcumin (turmeric extract with piperine) — 500–1000 mg/day
Why: Anti-inflammatory. Some evidence for joint health and cardiovascular markers. Plain turmeric powder in food has very poor bioavailability — needs the piperine pairing or a liposomal formulation.
Dose: 500–1000 mg curcumin with 5–10 mg piperine.
Brand notes: Doctor’s Best High Absorption Curcumin, Thorne Meriva, NOW Curcumin. USD 15–30 for 2–3 month supply.
The skeptical pile
Things commonly sold as longevity supplements that the evidence doesn’t really support, or where the evidence is mouse-only:
- NMN, NR (NAD+ precursors) — popular, expensive, evidence in humans is weak. Save the money.
- Resveratrol — failed to replicate in humans the way it did in mice. Skip.
- Collagen peptides — modest evidence for skin and joint markers; works if you don’t already eat enough protein. Just hit the protein target.
- Glutathione, NAC — situational; not universally indicated
- Adaptogens (ashwagandha, rhodiola) — adaptogens are inconsistently studied; ashwagandha has the best evidence (sleep, cortisol) but lower-priority
Specifically dangerous if overdone
- Iron — supplementing without ferritin testing is a bad idea. Excess iron is pro-oxidant and pro-cancer.
- Vitamin A (retinol) — fat-soluble, accumulates; toxicity at high doses
- Calcium isolated supplementation — mixed cardiovascular evidence; prefer dietary calcium
- High-dose D3 (>5000 IU/day) without blood monitoring — risk of hypercalcaemia
Timing summary
| Time | What |
|---|---|
| Morning, with first meal | D3 + K2, fish oil, curcumin |
| Pre-workout | Beetroot juice (if applicable), caffeine, creatine (anytime works) |
| Post-workout | Whey or plant protein (with the high-cal shake) |
| Evening, with dinner | Second fish oil dose if splitting |
| 30–60 min before bed | Magnesium glycinate |
Monthly cost estimate
For the core stack:
| Item | Monthly cost (USD) |
|---|---|
| D3 + K2 (combined) | 5–10 |
| Magnesium glycinate | 10–15 |
| Omega-3 | 20–35 |
| Creatine monohydrate | 5–10 |
| Total | 40–70 |
A USD ~50/month spend on the core stack is roughly the cost of one fancy dinner. Risk-adjusted, this is among the better-yielding longevity expenses available.
When to reassess
Re-evaluate the stack annually based on:
- Blood panel results (see Preventative Health Panel at 40)
- Body composition changes
- Training load
- Any new research that genuinely changes the picture (resist the every-podcast new-supplement-of-the-week temptation)