Cannabis & CBD and Your DNA — How Your Genes Affect THC and CBD

What Decode+ Does

Decode+ analyzes your CYP2C9, CYP2C19, CYP3A5, and CYP1A2 genotypes and interprets them specifically for cannabis and CBD metabolism. These enzymes determine how fast you clear THC, how you process CBD, whether you're at elevated risk for CBD side effects, and whether smoked cannabis may interact with other medications you take.

Decode+ uses the same DNA data already uploaded and analyzed for your other DecodeMyBio results. No new sample or upload is needed.

Genes Analyzed

• CYP2C9 — Primary THC metabolism (~70% of clearance). Poor metabolizers can experience up to 3x higher THC exposure.
• CYP2C19 — Primary CBD metabolism via 7-hydroxylation. Metabolizer status affects CBD-to-metabolite ratios and efficacy.
• CYP3A5 — Gene-gene interaction with CYP2C19: poor CYP3A5 metabolizers may experience 5.6x higher rate of CBD side effects.
• CYP1A2 — Smoked cannabis (not vaped/edible) induces CYP1A2 through combustion byproducts, affecting caffeine, clozapine, and olanzapine levels.

What You'll See

1. THC Metabolism Profile — Your CYP2C9 diplotype, phenotype, and what it means for THC clearance speed and effect duration.
2. CBD Metabolism Profile — Your CYP2C19 result and how it affects CBD processing and active metabolite production.
3. CBD Side Effect Risk — CYP3A5 + CYP2C19 gene-gene interaction analysis (shown only when the elevated-risk combination is present).
4. Smoked Cannabis Interactions — CYP1A2 inducibility and which medications are affected by cannabis smoking.
5. Limitations & Disclaimers — Transparent scope boundaries and legal context.

How It Works

1. Upload your DNA data from 23andMe, AncestryDNA, MyHeritage, or FamilyTreeDNA (or use data you've already uploaded).
2. Your existing genotype results for CYP2C9, CYP2C19, CYP3A5, and CYP1A2 are interpreted specifically for cannabis pharmacogenomics.
3. See your results in-app with personalized findings, clinical context, and published research citations.

Key Clinical Evidence

• CYP2C9 and THC: CYP2C9 *3/*3 poor metabolizers showed 3-fold higher THC exposure (AUC) and increased sedation in clinical studies (Sachse-Seeboth et al., 2009).
• CYP2C19 and CBD: Primary enzyme for CBD 7-hydroxylation. Metabolizer status significantly affects CBD parent-to-metabolite ratios (Drug Metabolism & Disposition, 2024).
• CYP3A5 + CYP2C19 Interaction: 39% vs 7% diarrhea rate based on genotype combination — a 5.6-fold difference in CBD side effects (Etkins et al., 2026).
• CYP1A2 and Smoking: Smoked cannabis induces CYP1A2 via combustion byproducts, lowering clozapine levels by up to 2.5x (Zullino et al., 2002).

Learn More

• See a sample — preview what Decode+ shows before you start
• Cannabis genetics from 23andMe or AncestryDNA data — what your raw data contains and how to use it

Limitations

• Cannabis pharmacogenomics is an evolving field with fewer clinical trials than pharmaceutical PGx. Findings are based on the best available published evidence.
• Consumer genotyping chips test a limited set of variants per gene. Rare or novel variants not on the chip will be missed.
• Individual response to cannabis depends on many factors beyond genetics: dose, frequency, consumption method, other substances, and tolerance.
• Decode+ does not predict subjective experience (euphoria, anxiety, paranoia), cannabis dependence risk, or tolerance effects.

Important Disclaimer

Decode+ is for educational and informational purposes only. It does not constitute medical advice, diagnosis, or treatment. It does not recommend or endorse cannabis use. Cannabis laws vary by jurisdiction — verify legality in your area before making any decisions. Consult a healthcare provider before making decisions about cannabis or CBD use, especially if you take other medications.

Related

• Pain & Anesthesia — Your CYP enzymes also affect opioid and pain medication response. Find out if codeine, tramadol, or other pain medications work differently for you.
• Psychiatric Medication — CYP2C19 also metabolizes SSRIs and other antidepressants. See how your genetics affect psychiatric medications.
• Celiac & Gluten Screening — Rule out celiac disease from your existing DNA data.

References

1. Sachse-Seeboth C et al. Interindividual variation in the pharmacokinetics of Delta9-tetrahydrocannabinol as related to genetic polymorphisms in CYP2C9. Clin Pharmacol Ther. 2009;85(3):273-6. PMID: 19005461.
2. Etkins AE et al. CYP3A and CYP2C19 genotypes impact cannabidiol safety and steady-state pharmacokinetics. Clin Transl Sci. 2026;19:e70455. PMID: 41451876.
3. Nasrin S et al. Cannabinoid metabolites as inhibitors of major hepatic CYP450 enzymes. Drug Metab Dispos. 2024. PMC11025033.
4. Zullino DF et al. Cannabis and cytochrome P450. Pharmacopsychiatry. 2002;35(2):50-2. PMID: 11981356.
5. Dronabinol and CYP2C9: Pharmacogenomics. NCBI Bookshelf. NBK564166.