NutriStack
BCAAs and Levodopa/Carbidopa, timing-sensitive.
BCAA supplements can reduce or delay levodopa's benefit because branched-chain amino acids compete with levodopa for the same intestinal and blood-brain barrier transport pathways. This can make Parkinson's symptoms break through sooner, especially in people who already notice protein-sensitive wearing off. The risk is highest when BCAAs are taken close to a levodopa dose or repeatedly during the daytime dosing window.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- BCAAs and Levodopa/Carbidopa
- Pair type
- Timing Sensitive
- Evidence (highest tier)
- Strong
- Source citations
- 3 sources
- Stack Score effect
- −5 to your Stack Score (per scored timing-sensitive row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Timing Sensitive · Strong evidence
Timing Sensitive
What is happening. BCAA supplements can reduce or delay levodopa's benefit because branched-chain amino acids compete with levodopa for the same intestinal and blood-brain barrier transport pathways. This can make Parkinson's symptoms break through sooner, especially in people who already notice protein-sensitive wearing off. The risk is highest when BCAAs are taken close to a levodopa dose or repeatedly during the daytime dosing window.
Mechanism. Levodopa is transported across the gut wall and blood-brain barrier by large neutral amino acid transporters, including LAT systems. Leucine, isoleucine, and valine compete for these transporters, lowering levodopa absorption and central nervous system entry.
Recommendation. Do not take BCAAs with levodopa/carbidopa doses. Take levodopa at least 30-60 minutes before amino acid or protein supplements, and keep BCAAs at least 2 hours away from levodopa when possible. If your mobility worsens after starting BCAAs, stop the supplement and review your levodopa schedule with your prescriber.
Minimum separation. 120
Sources (3)
- Nutt JG, Woodward WR, Hammerstad JP, Carter JH, Anderson JL. The "on-off" phenomenon in Parkinson's disease. Relation to levodopa absorption and transport. N Engl J Med. 1984;310(8):483-488. PMID 6694694
- Cereda E, Barichella M, Pedrolli C, Pezzoli G. Low-protein and protein-redistribution diets for Parkinson's disease patients with motor fluctuations: a systematic review. Mov Disord. 2010;25(13):2021-2034. PMID 20669318
- Camargo SM, Vuille-dit-Bille RN, Mariotta L, Ramadan T, Huggel K, Singer D, et al. The molecular mechanism of intestinal levodopa absorption and its possible implications for the treatment of Parkinson's disease. J Pharmacol Exp Ther. 2014;351(1):114-123. PMID 25073474
Stack Score
How this pair moves the number.
Effect on the composite score
If both BCAAs and Levodopa/Carbidopa are in the same stack, this pair applies −5 to your Stack Score (per scored timing-sensitive row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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