NutriStack
Polyethylene Glycol and Vitamin C, a synergy.
Polyethylene glycol bowel-preparation products are sometimes formulated with gram-dose ascorbic acid to improve cleansing with a lower PEG volume. Randomized trials support PEG plus ascorbate regimens for colonoscopy preparation, but this evidence applies to medically directed bowel-prep dosing rather than routine daily vitamin C supplementation with OTC PEG for constipation.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
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At a glance
- Substances
- Polyethylene Glycol and Vitamin C
- Pair type
- Synergy
- Evidence (highest tier)
- Moderate
- Source citations
- 2 sources
- Stack Score effect
- +2 to your Stack Score (per scored synergy row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Synergy · Moderate evidence
Synergy
What is happening. Polyethylene glycol bowel-preparation products are sometimes formulated with gram-dose ascorbic acid to improve cleansing with a lower PEG volume. Randomized trials support PEG plus ascorbate regimens for colonoscopy preparation, but this evidence applies to medically directed bowel-prep dosing rather than routine daily vitamin C supplementation with OTC PEG for constipation.
Mechanism. PEG retains water osmotically in the intestinal lumen. Large bowel-prep doses of ascorbic acid add an additional osmotic load, allowing lower-volume PEG regimens while still producing catharsis; the same osmotic effect can worsen diarrhea, nausea, or dehydration if used outside directed bowel preparation.
Recommendation. Use PEG plus high-dose vitamin C only when it is part of a prescribed or procedure-directed bowel-prep regimen. Do not add large vitamin C doses to PEG laxative use on your own, especially if you have kidney disease, a history of oxalate kidney stones, dehydration risk, or electrolyte problems. Follow the prep instructions and hydration plan exactly.
Sources (2)
- Ell C, Fischbach W, Bronisch HJ et al.. Randomized trial of low-volume PEG solution versus standard PEG + electrolytes for bowel cleansing before colonoscopy. The American journal of gastroenterology. 2008 Apr;103(4):883-93. PMID 18190651
- Jung Y, Kang SB, Yoon HJ et al.. Improving the tolerability and safety of 1-L polyethylene glycol plus low-dose ascorbic acid for bowel preparation in a healthy population: a randomized multicenter clinical trial. Gastrointestinal endoscopy. 2022 Aug;96(2):341-350.e1. PMID 35288148
Stack Score
How this pair moves the number.
Effect on the composite score
If both Polyethylene Glycol and Vitamin C are in the same stack, this pair applies +2 to your Stack Score (per scored synergy row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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