What is 2-Hydroxyestrone (2-OH E1) And Why Does the Hormone Zoomer Test for It?

Estrogen phase I metabolite

2-Hydroxyestrone (2-OH E1) is a primary Phase I metabolite produced when the body modifies estrone. Measuring it shows how much estrogen is routed through the 2‑hydroxylation pathway, offering a window into metabolism and clearance patterns that affect hormonal balance.

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2-Hydroxyestrone (2-OH E1)

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About 2-Hydroxyestrone (2-OH E1)

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About 2-Hydroxyestrone (2-OH E1)

Overview and History

2‑Hydroxyestrone is a catechol estrogen formed by enzymatic 2‑hydroxylation of estrone and, to a lesser extent, estradiol. This reaction is carried out by liver and extra‑hepatic cytochrome P450 enzymes and represents a Phase I biotransformation step in estrogen metabolism. After formation, 2‑hydroxyestrone can be further processed by conjugation and by COMT‑mediated methylation to 2‑methoxyestrone for clearance. Because 2‑hydroxy metabolites generally have lower affinity for estrogen receptors than some other metabolites, the balance among estrogen pathways (for example, 2‑hydroxylation versus 16α‑hydroxylation) has been studied as a marker of how the body handles estrogenic compounds.

Interpreting Highs and Lows

Higher 2‑OH E1 levels may reflect relatively strong 2‑hydroxylation pathway activity or increased Phase I metabolism and subsequent clearance. Environmental or lifestyle factors that affect P450 enzyme activity can also be associated with elevated 2‑hydroxylation. Low 2‑OH E1 levels may suggest reduced 2‑hydroxylation activity or a relative shift toward other estrogen metabolic routes, and may occur alongside changes in downstream methylation or conjugation capacity. Interpretation depends on the pattern of other estrogen metabolites, methylation markers, and overall panel context rather than a single value alone.

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The Hormone Zoomer includes 2‑OH E1 to map estrogen metabolism pathways and clearance. As one node in a network of estrogen metabolites, methylation markers, adrenal hormones, and toxin screens, it helps clinicians see whether estrogen is being routed, cleared, or processed differently—information that supports more precise evaluation of hormonal patterns and individualized care planning.

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2-Hydroxyestrone (2-OH E1) FAQs

What is 2‑Hydroxyestrone (2‑OH E1) and why is it important?

2‑Hydroxyestrone is an estrogen metabolite produced when the body modifies estrone via the 2‑hydroxylation pathway. It is part of the body’s normal process for processing and clearing estrogens. Measuring it helps show which metabolic routes are active and how estrogen is being handled in the body.

What does it mean if my 2‑Hydroxyestrone (2‑OH E1) levels are low?

Low 2‑OH E1 can suggest relatively less activity in the 2‑hydroxylation pathway or a shift toward other estrogen metabolites. It may also point to downstream processing differences, such as methylation or conjugation capacity. A low value is best interpreted alongside other estrogen metabolites and lab measures to understand the overall metabolic pattern.

What does it mean if my 2‑Hydroxyestrone (2‑OH E1) levels are high?

Higher 2‑OH E1 levels often reflect increased 2‑hydroxylation and Phase I processing of estrone, which can occur with changes in liver enzyme activity or exposure that influences P450 enzymes. Elevated results should be reviewed together with other metabolites, methylation markers, and clinical context to clarify what the pattern indicates.

Why is 2‑Hydroxyestrone included in the Hormone Zoomer?

2‑OH E1 is measured to define estrogen metabolic routing and clearance as part of the panel’s broader view of sex hormone production and detoxification. Paired with other metabolites, methylation markers, adrenal measures, and toxin screens, it helps providers detect metabolic patterns and tailor testing interpretation for each person.

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