Review Maps CBD Absorption Across All Administration Routes, Highlighting Transdermal Potential | Research

The takeaway

A comprehensive review of CBD administration routes found oral bioavailability ranges from 6-19% with significant hepatic degradation, while transdermal delivery offers improved bioavailability and targeted effects as a promising alternative.

CBD consumers, pharmacists, dermatologists, pharmaceutical formulators

What the researchers found

Oral CBD has 6-19% bioavailability due to hepatic first-pass metabolism and gastric instability. Inhaled routes provide rapid onset but raise pulmonary concerns. Transdermal delivery bypasses hepatic degradation, offers improved bioavailability and targeted effects. The review compiled a literature-based ADME profile highlighting that individual responses to CBD vary significantly.

Why it matters

Most CBD consumers use oral products without understanding that only 6-19% of their dose reaches the bloodstream. Understanding bioavailability across routes helps consumers and clinicians choose the most effective and efficient delivery method.

The numbers in context

Oral bioavailability: 6-19%. Transdermal delivery bypasses first-pass hepatic metabolism. CBD regulatory landscape reviewed across Europe, UK, USA, Australia. Individual ADME variability documented.

How the study worked

Narrative review examining transdermal CBD administration, skin barrier strategies, and bioavailability across different routes. Compiled literature-based ADME study. Reviewed endocannabinoid system function and CBD regulatory landscape across Europe, UK, USA, and Australia.

What this study cannot tell us

Narrative review without systematic methodology. Transdermal CBD clinical data is limited. Individual variability makes generalizations difficult. Regulatory landscape changes rapidly and review may not reflect current status.

How to read the evidence

Comprehensive narrative review of ADME data, but largely preclinical evidence for transdermal approaches and significant individual variability.

When this study was published

2025 publication.

The bigger picture

As CBD products proliferate worldwide with inconsistent regulation, understanding pharmacokinetics becomes essential for both consumers and healthcare providers. Transdermal delivery could solve the fundamental problem of poor oral bioavailability that limits CBD efficacy.

Questions still open

What transdermal technologies best enhance CBD skin penetration?
Could standardized transdermal CBD formulations improve clinical trial outcomes?

Common questions

How much CBD actually gets absorbed when you take it orally?

Only about 6-19% of oral CBD reaches the bloodstream due to breakdown in the liver and stomach. This review found transdermal (skin-applied) CBD may offer better absorption by bypassing the digestive system.

What is the best way to take CBD?

This review found each route has trade-offs: oral has low bioavailability (6-19%), inhaled is fast but may affect lungs, and transdermal bypasses the liver for better absorption. The best route depends on the condition being treated and individual factors.

Read the original research

Cannabidiol-A friend or a foe?

European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, 208, 107036

View on PubMed ↗Publisher’s paper ↗

Citation

Tihăuan, Bianca-Maria; Onisei, Tatiana; Slootweg, Walter; Gună, Daniel; Iliescu, Ciprian; Chifiriuc, Mariana-Carmen. (2025). Cannabidiol-A friend or a foe?. European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, 208, 107036. https://doi.org/10.1016/j.ejps.2025.107036