Spermidine supplements raise spermidine levels in your body
Mostly falseThe Claim
Because spermidine declines with age, taking a spermidine supplement is assumed to directly top up the body's spermidine levels.
Origin
Marketing links age-related spermidine decline to supplementation, assuming oral spermidine is absorbed and circulates unchanged.
What Science Says
In a randomized, placebo-controlled pharmacokinetic study, 15 mg/day spermidine did not increase spermidine in blood plasma or saliva; instead plasma spermine rose, suggesting spermidine is converted before reaching circulation. A separate RCT in older men found that even 40 mg/day of high-purity spermidine for 28 days produced no substantial changes in serum or urine polyamine concentrations.
Verdict
Mostly False
Sources
- PMID:37111071 High-Dose Spermidine Supplementation Does Not Increase Spermidine Levels in Blood Plasma and Saliva of Healthy Adults: A Randomized Placebo-Controlled Pharmacokinetic and Metabolomic Study.
- PMID:39405978 Supplementation of spermidine at 40 mg/day has minimal effects on circulating polyamines: An exploratory double-blind randomized controlled trial in older men.