High weekly bolus doses of vitamin D (20,000 to 50,000 IU) exhibit higher absorption efficiency and less supplement concentration variability than daily dosing.
"if you're doing a weekly dose that's really, really high, so if you're doing like 20,000, 50,000 IU a week, um you're much less likely to have that huge variation in the concentration of the vitamin D supplement, like for some reason, and it seems to be absorbed a little bit better, too." (said at 1:05:59)
Clinical studies and randomized controlled trials comparing daily versus weekly or monthly vitamin D supplementation show that daily dosing leads to equal or superior steady-state serum 25-hydroxyvitamin D [25(OH)D] concentrations compared to bolus or weekly dosing. High intermittent bolus doses do not improve absorption efficiency; in fact, daily dosing maintains more consistent circulating concentrations and avoids the larger peak-to-trough fluctuations in serum 25(OH)D levels seen with high intermittent doses. A randomized trial directly evaluating low dose-high frequency (daily), medium dose-medium frequency (weekly, 50,000 IU), and high dose-low frequency (every other week, 100,000 IU) supplementation found that daily administration achieved equivalent or higher 25(OH)D levels at steady state compared to weekly dosing (PMID 41369768). Therefore, the host's claim that high weekly bolus doses have higher absorption efficiency and less concentration variability than daily dosing is contradicted by the available trial evidence.
- contradicts: Kinetics and concentrations of circulating 25-hydroxyvitamin D using different vitamin D r… (Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA 2026)
"At baseline, group A had a slightly higher mean 25(OH)D level than group B (21.0 vs 16.9 ng/mL, p-value 0.03) as well as at week 36 (47.7 vs 40.2 ng/mL, p-value 0.007); otherwise, there were no significant differences between the groups at any other time points." (abstract, results, passage verified)
pubmedfull study (doi)