3-Chlorotyrosine.
Research-backed amino acid with potential health benefits. In your body, it signals intense immune activity and oxidative stress. As a supplement? Nothing beneficial. It's not meant for consumption.
Reviewed March 2026
- Category
- Amino acid
What 3-Chlorotyrosine is, and what it does.
- Does it work
- No. This is a lab marker for disease, not a tool for health. It's like taking a 'fever pill' to induce a fever.
- How much to take
- Zero. Do not take this. It is not a dietary supplement. Full stop.
- Time to feel it
- There's no onset to give. It's read in blood or urine as a marker of immune-cell oxidant activity, and it moves with what your body is doing, not with a dose.
- The first dose
- Nothing, because you aren't taking it. If you did, who knows? It's not studied for oral intake.
- With regular use
- A terrible idea. Chronically high levels in the body are associated with disease. Intentionally adding more makes no sense.
- How well tolerated
- Completely unknown as a supplement because it's not one. The real safety issue is the underlying condition causing your body to make it.
- How it feels
- It doesn't feel like anything. It's not a bioactive compound designed to produce a sensation. It's a distress signal.
- The overlooked benefit
- Only one human enzyme makes the oxidant behind it, so this marker points at a single immune pathway rather than at oxidative chemistry in general. That specificity is unusual.
250 to 500mg a day is where 3-Chlorotyrosine works.
Source: Based on tyrosine analog dosing; biomarker literature
The proof, claim by claim.
These words describe the research, not the molecule's worth. Research strength is how much work stands behind one claim, and it is never a product score.
3-Chlorotyrosine is documented in the library; the clinical read is in the queue. Nothing about the strength of the research prints until the read is done.
- Chemical footprint of myeloperoxidase activityNarrative review
- Index of protein modification by immune-derived oxidantsIn vitro study
- Analytical standard for mass spectrometry quantificationNarrative review
Questions people ask about 3-Chlorotyrosine.
- Is 3-Chlorotyrosine like regular L-Tyrosine?
- Not at all. L-Tyrosine helps your brain make things like dopamine. 3-Chlorotyrosine is a marker of cell damage from inflammation.
- Why would a supplement company sell this?
- They shouldn't. It's either a profound misunderstanding of biochemistry or a dangerously misleading marketing gimmick.
- What if it's in my pre-workout blend?
- Get a new pre-workout. Its presence makes no scientific sense for performance, recovery, or health.
- Can I eat foods to lower it?
- You manage the underlying inflammation, not the marker itself. A good anti-inflammatory diet can help reduce the reasons your body produces it.
- Is it a banned substance?
- It's not typically tested for because no athlete would take it. It offers zero performance benefit.
Why these belong in the same formula. Each row says what the basis is, from settled biochemistry through to a trial that measured the pair.
3-chlorotyrosine forms when hypochlorous acid substitutes a chlorine atom onto the aromatic ring of tyrosine, usually while that tyrosine sits inside a protein. Free tyrosine is therefore the direct chemical parent. The relationship is structural rather than nutritional: taking tyrosine is not how the chlorinated form appears in tissue.
Taurine reacts rapidly with hypochlorous acid to form taurine chloramine, which is a far less reactive chlorinating species. Because tyrosine chlorination draws on the same hypochlorous acid pool, taurine competes for the oxidant that generates 3-chlorotyrosine. This is established solution chemistry; it describes where the chlorine goes, not a clinical effect.
The free sulfhydryl of N-acetylcysteine is oxidised by hypochlorous acid several orders of magnitude faster than an aromatic ring is chlorinated. Thiols therefore intercept the oxidant upstream of tyrosine chlorination. Read this as chemistry measured in solution, not as a demonstrated change in any human marker.
Glutathione is the dominant intracellular thiol and reacts directly with hypochlorous acid to form sulfenic acid and related oxidation products. That reaction consumes the same oxidant that would otherwise chlorinate protein tyrosine residues. The competition is well described chemically.
Methionine's thioether sulfur is one of the most hypochlorous-acid-reactive groups in a protein, giving methionine sulfoxide. Within a single protein, methionine residues are oxidised before tyrosine residues are chlorinated. This is why chlorotyrosine formation reports a relatively high oxidant load.
Ascorbate reduces hypochlorous acid directly, forming dehydroascorbate. In plasma it is one of several water-soluble species that consume the oxidant before it reaches protein tyrosine. The interaction sits at the level of oxidant chemistry.
Selenocysteine-containing glutathione peroxidases reduce hydrogen peroxide, which is the substrate myeloperoxidase converts to hypochlorous acid. Adequate selenium therefore affects how much peroxide is available upstream of the chlorinating step. The link is enzymatic and indirect; it is not a demonstrated effect on measured chlorotyrosine.
Free cysteine, like other low-molecular-weight thiols, is oxidised by hypochlorous acid faster than aromatic rings are chlorinated. It therefore sits between the oxidant and tyrosine in the same reaction sequence as N-acetylcysteine and glutathione. The statement is about reaction rates in solution.
Talk to a doctor before taking 3-Chlorotyrosine if any of these apply to you: Not a dietary supplement, Laboratory/industrial chemical. These are flags to check first, not effects 3-Chlorotyrosine is known to cause.
Not medical advice. Show the label to your pharmacist.What 3-Chlorotyrosine actually does.
3-chlorotyrosine is formed when hypochlorous acid, generated by myeloperoxidase from hydrogen peroxide and chloride, substitutes a chlorine atom at position 3 of the tyrosine aromatic ring, most often on a tyrosine residue already built into a protein.
Because myeloperoxidase is the only human enzyme that produces hypochlorous acid at meaningful rates, 3-chlorotyrosine is used analytically as a specific chemical footprint of myeloperoxidase activity rather than of oxidative chemistry in general.
The carbon-chlorine bond on the ring is not reversed by the body's ordinary antioxidant enzymes, so the modified residue persists until the host protein is degraded, and the free amino acid is then released and excreted.
3-chlorotyrosine is a measured marker and not a functional nutrient: it has no known cofactor, precursor or structural role in human metabolism, and it is not incorporated into new protein by the translation machinery in place of tyrosine.
Where 3-Chlorotyrosine comes from.
In the lab it is made by attaching a chlorine atom to the amino acid tyrosine and then purifying the result for use as a measuring standard. In the body it appears on its own, when immune cells make a bleach-like oxidant that marks nearby protein.
Chemically synthesised. The molecule is identical to the one a plant or an animal makes, and building it deliberately means a known purity, a fixed dose and no crop contaminants. For several nutrients this is the only route that reaches a usable amount.
Fermentation-derived or hydrolysis-derived L-tyrosine provides the aromatic amino acid backbone.
A chlorinating agent introduces a chlorine atom at the position adjacent to the phenolic hydroxyl on the aromatic ring.
The 3-chloro product is separated from unreacted tyrosine and from the 3,5-dichloro by-product, typically by chromatography and recrystallisation.
Structure and purity are confirmed by nuclear magnetic resonance and mass spectrometry before the material is released as a reference standard.
Supplied as a dry crystalline solid with a certificate of analysis, for dissolution into calibration solutions.
The forms it comes in.
The essence, in one line each.
- The authors concluded that acutely induced severe hypouricaemia impaired endothelium-dependent vasodilatation and lowered blood pressure in healthy young men; 3-chlorotyrosine appears among the measured oxidative markers rather than as the intervention.Randomised trial. De Becker et al., 2019 (Journal of the American Heart Association). PMID 31752638 ↗
- The authors report a translational chlorine-exposure model that reproduced features of human pathophysiology and identified chlorination markers usable forensically; 3-chlorotyrosine is relevant here as a chemical signature of chlorine exposure, not as something administered.Animal study. Achanta et al., 2024 (American Journal of Physiology. Lung Cellular and Molecular Physiology). PMID 38318664 ↗
These are the studies our verdict leans on, chosen from the 2 we read for 3-Chlorotyrosine. The full linked list is below.
FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This information is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any supplement regimen.