The Methionine Cycle: Powering methylation and repair

Deep inside your cells, the Methionine Cycle is working around the clock. Its main product, SAMe (S-adenosylmethionine), is your body’s universal methyl donor, fuelling DNA repair, neurotransmitter production, detoxification, and even liver function.

Without enough SAMe, methylation slows down. And when methylation slows, energy, focus, and mood can all take a hit.

Why the Methionine Cycle matters

When this cycle is efficient, your biology hums along smoothly. DNA gets repaired, mood stays steady, and homocysteine is recycled.

But if it falters, the effects can ripple out as brain fog, low mood, fertility challenges, and raised homocysteine, a cardiovascular risk marker. At Stride, we’ve found that 87% of customers show some level of Methionine Cycle impairment, making it one of the most commonly affected pathways in our testing.

The DNA connection

Several genes help determine how well your Methionine Cycle performs:

• MTR & MTRR: recycle homocysteine back into methionine using folate and vitamin B12.
• BHMT: provides a “shortcut” pathway using betaine from foods like beetroot and spinach.
• PEMT: supports choline production, vital for liver and brain health.
• FUT2 & TCN2: influence how well your body absorbs and transports vitamin B12.

Variants in these genes can affect how efficiently you recycle homocysteine, produce SAMe, or generate choline, creating bottlenecks that impact everything from energy to fertility and cardiovascular health.

Explore each pathway in depth: BH4, Folate, Transsulfuration, Urea

Supporting your Methionine Cycle

• Prioritise B vitamins: especially folate, B6, and B12 (methylcobalamin is most effective if impaired).
• Eat betaine- and choline-rich foods: beetroot, spinach, quinoa, liver and eggs.
• Check your homocysteine: an important marker of methylation efficiency and cardiovascular health.
• Support gut health: probiotics and fibre improve nutrient absorption, including B12.

Why clarity matters

With 87% of StrideDNA customers showing impairment, the Methionine Cycle is a clear example of why personalisation matters.

DNA testing can reveal whether your cycle is efficient or needs support. With that knowledge, you can target what actually works for your biology — whether that’s boosting B vitamins, adding choline-rich foods, or keeping an eye on homocysteine levels.

Because when you understand your biology, you can finally focus on what moves the needle for you.

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