The spermidine supplement market has consolidated around wheat germ extract as the primary source, with products typically providing 0.5–4 mg spermidine per daily serving. Synthetic spermidine (diaminopropane-based) is also available but more expensive. Both forms appear to elevate blood spermidine levels effectively; natural wheat germ extract provides complementary polyamines (putrescine, spermine) alongside spermidine.

Is 0.9 mg/day enough or should I take more?

0.9 mg/day is the SmartAge trial dose showing cognitive benefits. More aggressive longevity protocols use 2–4 mg/day. No significant safety concerns have been identified up to 10 mg/day. Dose selection depends on individual goals and budget.

Should spermidine be cycled like senolytics?

No. Spermidine works through continuous daily elevation of autophagy flux, not through burst-dose cellular clearance like senolytics. Daily continuous use without cycling is the evidence-aligned approach.