✓ No active regulatory warningsFDA MedWatch, EMA EudraVigilance, WHO VigiBase, WADA Prohibited List · 2026-05-29
📰Read the full Uridine evidence review on GMJ News →Complete clinical article, references and updates on news.gmj.ge. This page is the structured safety summary.⚠ No standalone RCTs — only combination data (Souvenaid) [2]
⚠ 'Mr. Happy Stack' is popular but anecdotal [1]
⚠ Combine with DHA + choline for Kennedy pathway [1]
ℹ️ Not obtained from food. Not applicable — this is not obtained from food in meaningful amounts; supplementation is the practical route.
🔬 Lab interpreter
ℹ️ No validated blood test. There is no established laboratory test to assess status or guide dosing for this ingredient. Clinical response and symptoms are the practical guide.
⚕ For professionals — confirm ranges against your local laboratory.
Clinical verdict
Uridine is a nucleoside precursor to CDP-choline (brain membrane synthesis). Best combined with DHA + choline (Kennedy pathway substrates). Souvenaid combination showed benefit in early AD. The popular 'Mr. Happy Stack' is NOT validated by RCTs. Present in breast milk — likely important for infant brain development [1] [2].
1 How much do I need?
👤 Adults: Specific dosage data under clinical review
👴 Elderly: Specific dosage data under clinical review
🤰 Pregnancy: See guidance
In breast milk. Supplement: not studied [1].
👦 Pediatric: See guidance
Present in breast milk. Supplement: no data [1].
🏃 Athletes: Standard dose
⚖️ Obesity: Standard dose
Fat-soluble compounds may require dose adjustment in obesity.
🩺 Renal: Consult specialist
Dose adjustment may be needed in renal impairment.
🌱 Vegan: Standard dose
How to take
🍽 Timing: BID with meals [1].
💊 With food: With DHA-containing meal [1].
🚫 Avoid: No contraindications known [1].
2 Which form?
| Form | Bioavailability | Vegan | Cost |
|---|---|---|---|
| ['Uridine monophosphate (UMP)', 'preferred', 'Bioavailable form. 150–250 mg BID [1].'] | Standard | Check label | |
| ["Uridine 5'-triphosphate (UTP)", '', 'Less bioavailable orally [1].'] | Standard | Check label | |
| ['Triacetyluridine (TAU)', '', 'Prodrug form. May have better bioavailability [1].'] | Standard | Check label |
3 Common questions
What is the 'Mr. Happy Stack'? ▼
Uridine + DHA (fish oil) + choline source (citicoline or alpha-GPC). The theory: these three provide all substrates for the Kennedy pathway of brain membrane synthesis. Popular in nootropic communities. NOT validated by RCTs as a stack [1].
Is Souvenaid evidence for uridine? ▼
Souvenaid contains uridine + DHA + choline + B vitamins + other nutrients. SOUVENIR II showed benefit in early AD. You can't attribute the effect to uridine alone — it's a multi-nutrient intervention [2].
Why is uridine in breast milk? ▼
Likely important for infant brain development — rapid membrane synthesis during brain growth requires nucleotide precursors [1].
4 Clinical evidence
Strong
Kennedy pathway biochemistry: uridine → CDP-choline → phosphatidylcholine. Well-established [1]. BBB penetration: confirmed [1]. HIGH
Moderate
Souvenaid (uridine + DHA + choline + other nutrients): improved memory in early AD patients in SOUVENIR II trial [2]. Dopamine receptor expression: uridine increased D2 receptor expression in animal models [1]. MODERATE
Insufficient
5 Safety, toxicity & adverse events
Relative
⚠ Gout/hyperuricemia — theoretical purine-pathway concern
⚠ Limited long-term human data
⚠ Pregnancy and lactation — insufficient data
6 Interactions
Supplement synergies
Citicoline + DHA · 500 mg citicoline + 250 mg DHA
Complete Kennedy pathway: uridine → CDP-choline + DHA → phosphatidylcholine [1].
Complete Kennedy pathway: uridine → CDP-choline + DHA → phosphatidylcholine [1].
7 Regulatory
United States: Dietary supplement (UMP) [1].
European Union: Authorized in infant formula [1].
8 US supplement products
3
on-market products containing Uridine (NIH DSLD)
Brands carrying Uridine (3)
Click a brand to see its Uridine products.
9 Frequently paired with
10 Cite this page
Vancouver: Pkhakadze G. Uridine — safety profile [Internet]. Tbilisi: PHIG; 2026 [cited 2026 Aug 15]. Available from: https://supplement.ge/ingredients/uridine/
APA 7th: Pkhakadze, G. (2026). Uridine — Safety profile. Public Health Institute of Georgia. https://supplement.ge/ingredients/uridine/
📋 Editorial information
Author: Prof. G. Pkhakadze, MD, MPH, PhD
Institution: Public Health Institute of Georgia (PHIG)
Affiliation: David Tvildiani Medical University (DTMU)
First published: January 2026
Last reviewed: 2026-05-29
Next review: February 2027
References: 2 cited sources
COI: SupplementIndex receives no funding from supplement manufacturers. All content independently authored by PHIG.
Process: Systematic literature review
📄 License & reuse
Published under Creative Commons Attribution 4.0 International (CC BY 4.0). You may share and adapt for any purpose with attribution.
Pkhakadze G. "Uridine — Safety Profile." SupplementIndex, PHIG, 2026. https://supplement.ge/ingredients/uridine/ CC BY 4.0.
GP
Prof. G. Pkhakadze, MD, MPH, PhD
Professor of Public Health · Head of Department, DTMU
Editor-in-Chief, Georgian Medical Journal (ISSN 3088-4322)
Chair, Public Health Institute of Georgia · UEMS Public Health Section
Educational and public health purposes. CC BY 4.0. Consult your healthcare provider before starting any supplement. Corrections: info@accreditation.ge. Publisher: PHIG