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Absorption and delivery, explained

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Short, sourced answers to the questions people ask about how supplements and active compounds are absorbed: what bioavailability means, what liposomal and phytosome labels describe, and why some compounds barely reach the bloodstream. Each guide states the answer first and cites peer-reviewed research or regulators such as the FDA and EFSA. Browse by topic below, or go to the Compound Library for single-compound pages.

Absorption and delivery

  • Do transdermal supplement patches work?Do vitamin patches work? What the skin barrier lets through, what studies of multivitamin, vitamin D and berberine patches show, and how US law treats them.
  • How does nanoparticle drug delivery work?How nanoparticle drug delivery works: what the carriers are made of, how a liposome differs from a lipid nanoparticle, and why so little reaches its target.
  • Liposomal vitamin C vs regular vitamin CLiposomal vs regular vitamin C: how much more reaches the blood in trials, why results vary so widely, and how buffered vitamin C forms differ from both.
  • NMN vs NR vs NAD+NMN vs NR vs NAD+: how each becomes NAD+ in the body, what the first head-to-head human trial of NMN and NR found, and why intact NAD+ is broken down.
  • Ubiquinol vs ubiquinoneUbiquinol vs ubiquinone: how the two forms of CoQ10 differ, what absorption studies found, and why formulation drives CoQ10 absorption as much as the form.
  • What does liposomal mean?What liposomal means: what a liposome is made of, how liposomal delivery works in the gut, what liposomal glutathione is, and liposomal vs non-liposomal.
  • What is a phytosome?What a phytosome is, how it differs from a liposome, and what human studies of berberine phytosome and curcumin phytosome report about absorption.
  • What is bioavailability?What is bioavailability? How it is measured, why absorption differs between compounds and supplements, and which factors raise or lower it in published studies.
  • Why are most peptides injected rather than swallowed?Why most peptides are injected, which oral peptides already work and how they get through the gut, and how oral semaglutide compares with the injection.
  • Why is curcumin poorly absorbed?Why curcumin is poorly absorbed, whether piperine raises curcumin bioavailability, and how phytosome, micellar and other curcumin formulations compare.

Knowledge