Most conversations about oestrogen are about quantity: too much, too little, or dropping. A blood test gives you a level and the conversation ends there.

Two women with the same oestrogen level can have completely different experiences. A large part of the difference lies in what happens next, once the body is finished with it.

Oestrogen has to go somewhere

Once oestrogen has done its job, the body breaks it down so it can be cleared. Research describes two major routes for this. One turns oestrogen into what are called catechol oestrogens, 2-OH and 4-OH. The other produces 16-OH.

Each route leads somewhere different, and the balance between them matters.

Three routes, three different outcomes

• 2-OH, the gentler route. This produces a milder form of oestrogen that researchers believe may even have anti-oestrogenic qualities. Ideally, most of your oestrogen goes this way.
• 16-OH, the stronger route. This form still binds to oestrogen receptors and keeps stimulating tissue. Some is normal, but the balance against 2-OH is worth knowing.
• 4-OH, the reactive route. If it is not neutralised, 4-OH can oxidise into compounds called quinones. In laboratory studies these damage DNA, while the 2-OH equivalents form far less harmful bonds. Ideally, this route stays small.
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Methylation, the step that makes it safe

After oestrogen is turned into 2-OH or 4-OH, the body neutralises it through a process called methylation. An enzyme called COMT converts these forms into stable versions that can be eliminated easily.

This step does real protective work. In a laboratory study on cells, blocking COMT led to a three- to fourfold increase in DNA-damaging oestrogen by-products.

What the research does and does not say

For years, the ratio of 2-OH to 16-OH was promoted as a predictor of breast cancer risk. A systematic review of the prospective studies found it could not be used as a predictive marker on its own. The researchers recommended looking at the wider profile of metabolites, including 4-OH, instead.

That is exactly why no single ratio is read in isolation. The value lies in the whole pattern.

What a DUTCH test shows that a blood test cannot

A standard blood test shows how much oestradiol is circulating. A DUTCH test measures the breakdown products in urine: 2-OH, 4-OH and 16-OH, plus the methylated forms that show how well that protective step is keeping up.

You see not just how much oestrogen you have, but where it goes and how well your body is clearing it.

From pathway to plan

When the data shows where the bottleneck sits, the plan can target it directly. That is a very different starting point from adding another supplement because it worked for someone else.

Your levels are only half the story. How you clear them is the other half.

Want a plain-language guide to each oestrogen pathway? Download The Dutch Dozen, my free guide.

Understand your hormones.

Sources:

• Cavalieri EL et al., Proceedings of the National Academy of Sciences, Molecular origin of cancer: Catechol estrogen-3,4-quinones as endogenous tumor initiators, 1997
• Cavalieri EL and Rogan EG, Review of estrogen metabolism and estrogen-DNA adducts
• Zahid M et al., Study of COMT inhibition and depurinating estrogen-DNA adducts
• Obi N et al., International Journal of Women's Health, Estrogen metabolite ratio: Is the 2-hydroxyestrone to 16α-hydroxyestrone ratio predictive for breast cancer?, 2011
• Precision Analytical, Using the DUTCH Test with Dr Carrie Jones