Precision Supplementation
Supplementation is a complex science that requires precision, quality, and personalization. What works for one person may be ineffective or toxic for another.
Bioactive taxonomy
Not all supplements are created equal. We must distinguish survival from optimization.
Essentials (nutritional needs)
Vitamins and minerals to compensate for modern deficits. Depleted soils, industrial food, and sedentary lifestyles create near-universal nutritional needs.
Geroprotectors (longevity)
Bioactives studied for their interactions with mechanisms associated with aging, without presuming their individual clinical relevance.
The universal formula myth
The average doesn't exist. What suits one person may not suit another. Your biology is unique — your supplementation must be too.
The U-Curve (hormesis)
Too little is bad, too much is toxic. Only a blood test defines your position on the curve.
Example: vitamin D
Two people taking 2000 IU will have radically different blood levels depending on their genetics (vitamin D receptor), body fat (D3 is fat-soluble), and sun exposure.
Variability factors: VDR genetics, body fat, skin pigmentation, latitude, season.
Scientific evidence: N=1
The Cell study (2015) on personalized glycemic response demonstrated that two people eating the same food can have radically different metabolic responses. Biology is unique. (lien)
Supplementation During Pregnancy
Avoid during pregnancy
Consider adding during pregnancy
- Methylated folate: up to 500 µg/day, the maximum authorised in a supplement (not synthetic folic acid)
- Vitamin B12 methylcobalamin: 2.6 µg/day
- Magnesium: up to 360 mg/day, the maximum authorised in a supplement
- Iron: up to 21 mg/day, the maximum authorised in a supplement
- Calcium: up to 800 mg/day, the maximum authorised in a supplement
- DHA/EPA: 1000-2000 mg/day (low heavy metal source)
Consult your doctor before any supplementation during pregnancy.
Possible Luteal Phase Adjustments
- Magnesium: up to 360 mg/day, the maximum authorised in a supplement (mood, cramps)
- Sodium: +200-400 mg/day (water retention)
- Potassium: +200-400 mg/day (water retention)
- Ashwagandha: 300-600 mg/day (stress, PMS)
- Rhodiola Rosea: 200-400 mg/day (fatigue, mood)
- Melatonin: 1-3 mg if sleep issues
Vitamin D: Singular's 20–50 ng/mL target
Singular uses 20–50 ng/mL as an internal target derived from nutritional reference points and observational associations. It is neither a universal medical consensus nor proof that raising a level into this range improves longevity.
Singular target
≥ 20 – ≤ 50 ng/mL
Range fetched dynamically from the biomarker page. Singular suggests a first check at around three months, then roughly every six months; season provides context without automatically changing the tier. View detail page
The VITAL 2025 trial
In a randomized VITAL ancillary study, 1,054 participants followed for four years showed a 0.14 kb difference in telomere attrition with 2,000 IU/day of D3. This was an intermediate endpoint measured in a small subsample, with no demonstrated clinical benefit.
Why no bolus
Singular uses daily intake with blood-level follow-up. Large boluses produce a different exposure and are not treated as equivalent to a daily dose; this formulation choice is not a longevity promise.
Complementary nutrients
- Magnesium. Cofactor of the hepatic and renal hydroxylases that convert D3 into 25(OH)D and then active 1,25(OH)2D. Magnesium may complement the formula under its own rules, but the 25(OH)D result does not trigger it.
- Vitamin K2 (MK-7). Vitamin K enables the carboxylation of proteins such as osteocalcin and matrix Gla protein. This mechanism explains possible complementarity in the formula without making K2 universally necessary with D3 or an action triggered by this biomarker.
Individual calibration
The current result sets the biological tier: 2,800 IU at 12 ng/mL or below, 2,000 IU above 12 and up to 20, 1,000 IU above 20 and up to 30, 600 IU above 30 and up to 40, then no D3 above 40; with no result, the base is 600 IU. Questionnaire responses, exclusions, and caps then apply. Age, season, skin type, BMI, and history do not automatically change this tier.
Read the full analysis : Vitamin D: Singular's 20–50 ng/mL target
Interaction chemistry
The stomach is a chemical reactor. Random mixing creates conflicts. The importance of precise timing and ratios is critical.
Antagonisms
Excess zinc inhibits the intestinal absorption of copper: the wall retains copper instead of letting it through, and the copper-to-zinc ratio, which Singular calculates from your blood test, falls accordingly. The Singular blood panel calculates this ratio from your two measurements: it situates one relative to the other, where each value taken alone would not show it. (lien)
An imbalanced ratio creates secondary imbalances.
Synergies
Vitamin D3 + K2
Vitamin D increases calcium absorption and osteocalcin production. K2 then helps that protein in bone bind calcium there.
Reference table of major interactions
Beyond the two illustrated examples above, these are the antagonistic and synergistic pairs most worth integrating into daily planning.
| Type | Pair | Documented effect | Action |
|---|---|---|---|
| Antagonism | Calcium / Iron | −50 to −60% iron absorption | Separate by 2 h |
| Antagonism | Iron / Polyphenols (tea, coffee) | −60 to −90% absorption | No tea/coffee within 1 h |
| Antagonism | Calcium / Magnesium | Transport competition | Spread across the day |
| Synergy | Vitamin C / Non-heme iron | ×2 to ×6 absorption | Co-administer with meal |
| Synergy | Vitamin D / Fatty meal | +50% absorption | Take with the day's fattiest meal |
Read the full analysis : Supplement interactions no one explains
Purity & bioavailability
What's written on the label isn't what reaches your cells. The chemical form determines actual absorption.
The forms deception: magnesium
Why does the industry use oxide? Because it costs 10x less. What isn't absorbed stays in the gut, draws water into it, and that is where the laxative effect of cheap magnesium comes from. (lien)
To avoid (industry)
- Titanium dioxide (E171)
- Excessive magnesium stearate
- Talc (E553b)
- Artificial colorings
Ideal standard
- 100% active, 0% filler
- Forms and processes selected using documented criteria
- Third-party testing (heavy metals, contaminants)
- Transparent certifications
The feedback loop
A formula is never final. Your needs change, science advances. A static approach quickly becomes obsolete.
Biological adaptation
Your needs constantly evolve. What worked 6 months ago may no longer be optimal today.
Scientific obsolescence
Longevity science advances rapidly. Example: the recent questioning of Resveratrol. What was recommended yesterday may be outdated tomorrow.
What Singular excludes, and why
Three filters systematically rule out certain popular molecules: insufficient real-world bioavailability, lack of convincing human clinical evidence, or unfavorable benefit/risk ratio. A formula's rigor is measured as much by what you take out as by what you put in.
- Resveratrol and stilbenes. Plasma bioavailability below 5 ng/mL in free form despite over 70% intestinal absorption (massive hepatic first-pass). The SIRT1 hypothesis was invalidated in 2010 (peptide-fluorescein artifact). 84 oral administrations analyzed in a 2025 meta-analysis: no robust clinical evidence of longevity benefit in humans.
- EGCG, quercetin, fisetin. EGCG: 2 to 13% absorption, too variable for precision calibration. Quercetin and fisetin: their senolytic value rests on intermittent dosing, incompatible with a daily formula. Quercetin also warrants interaction vigilance (CYP3A4 inhibition).
- Antioxidants at pharmacological doses. β-carotene: the ATBC and CARET trials showed +18 to +28% lung cancer in supplemented smokers. Vitamin A above 10,000 IU/day: hepatotoxic, increases fracture risk. Vitamin E at 400 IU/day or more: SELECT trial — increased prostate cancer risk. The U-curve applies strictly to fat-soluble vitamins.
- Traditional adaptogens. Ashwagandha and rhodiola: clinical data limited to 4 to 12 weeks, no longevity evidence, with reported hepatotoxic profiles. Reserved for occasional supervised use — never a continuous formula.
- Oral glutathione and orphan precursors. Oral glutathione: degraded in the stomach. Astragaloside IV / TA-65: evidence limited to a single commercial research group. Ergothioneine, apigenin, ALCAR: insufficient bioavailability or human clinical evidence to date.
- CoQ10, ALA, spermidine. CoQ10: mitohormesis suggests that chronic supplementation may inhibit endogenous mitochondrial biogenesis in non-deficient subjects. Alpha-lipoic acid (ALA) and spermidine: converging data missing beyond animal models.
- Nicotinamide riboside (NR). At 100 and 300 mg per day, NR raises whole-blood NAD+. No human clinical benefit has been demonstrated for the intended general population, however, and this marker is not a validated surrogate. NR therefore fails the human clinical evidence filter.
