Key Insights

• See your current level of tiglylglycine — a urinary metabolite that reflects recent mitochondrial and isoleucine-processing stress — and how it compares with typical levels.
• Identify meaningful patterns and potential contributors, like fasting, strenuous workouts, intercurrent illness, certain medications, or environmental stressors that can strain energy metabolism.
• Clarify whether this signal could be part of a symptom cluster such as low energy, exercise intolerance, brain fog, or liver–kidney processing stress that warrants clinical follow up.
• Support reproductive planning or pregnancy safety by checking for elevations during life stages when energy metabolism and renal handling change.
• Track trends over time after changing diet, routines, products, work conditions, or medications to distinguish transient spikes from persistent patterns.
• Inform conversations with your clinician about when additional evaluations — like broader organic acids, acylcarnitines, or liver–kidney panels — may be useful.

What is Tiglylglycine (TG)?

Tiglylglycine (often abbreviated TG) is an acylglycine — a small molecule your body produces when it couples glycine to tiglyl‑CoA, an intermediate in the breakdown of the amino acid isoleucine. In practical terms, it’s a “metabolic breadcrumb” that shows up in urine when certain energy pathways run faster, get backed up, or are stressed. Clinical laboratories typically measure tiglylglycine in urine using mass spectrometry and report it relative to creatinine to account for hydration. Because urine reflects what your body has been processing recently, tiglylglycine is best viewed as a near‑term snapshot of metabolic state rather than a long‑term body burden.

Why it matters: tiglylglycine can rise when mitochondria — the cell’s power plants — are under strain, when isoleucine catabolism is impaired, or in some inborn errors of metabolism. Short‑term spikes may also appear with catabolic states like fasting, fever, or very intense exercise. Certain medications and toxins can influence these pathways indirectly by altering mitochondrial enzymes or liver handling, though human data vary by exposure and more research is needed. In healthy conditions, tiglylglycine tends to be low or near trace levels; persistent elevations can be a clue to look more broadly at energy metabolism, liver–kidney function, and potential contributors in the diet and environment.

Why Is It Important to Test For Tiglylglycine (TG)?

Mitochondria power everything from brain work to workout recovery. When the pathways that burn amino acids and fats run smoothly, intermediates like tiglyl‑CoA move along quietly. When there’s a bottleneck, your body offloads some of that traffic as acylglycines that spill into urine — tiglylglycine among them. Measuring TG helps separate incidental, short‑lived shifts (a tough interval session, a missed meal, a viral bug) from a sustained pattern that could align with symptoms such as fatigue, reduced exercise tolerance, or nonspecific brain fog. It can also complement occupational or environmental assessments, because some stressors are mitochondria‑active and may nudge these pathways, even if they aren’t the sole cause of symptoms.

Big picture: no single molecule tells the whole story. Tiglylglycine finds its best footing alongside related organic acids, acylcarnitines, liver and kidney markers, and your lived context. Patterns — not one‑off values — guide risk over time. Tracking TG with other data helps distinguish transient spikes from persistent metabolic stress and supports smarter decisions with your clinician about whether additional testing or environmental changes are warranted.

What Insights Will I Get From a Tiglylglycine (TG) Test?

Laboratories usually report tiglylglycine as a urine value indexed to creatinine and compared with a population‑based reference interval. For metabolites linked to energy stress, lower values are generally preferable when feasible. Because TG reflects recent physiology, interpretation improves with timing notes (meals, workouts, illness) and, when needed, repeat testing.

When tiglylglycine is relatively lower or within the lab’s typical range, it suggests limited recent buildup of isoleucine‑related intermediates and a lower likelihood of short‑term mitochondrial strain. Many healthy people have TG at low or near‑trace levels. In pregnancy and early childhood, renal handling and growth demands shift metabolism; values can differ modestly and merit clinician context rather than strict one‑size‑fits‑all cutoffs.

When tiglylglycine is relatively higher, it can indicate recent or ongoing metabolic stress — for example, catabolic states from fasting or illness, very intense training, or impaired processing along the isoleucine pathway. The liver and kidneys help clear these metabolites, so elevations may travel with other signs of detoxification and clearance workload. Depending on the whole pattern, symptoms may surface in energy systems (fatigue, exercise intolerance), neurologic performance (concentration dips), or recovery capacity. A single result shouldn’t carry all the weight; trends over weeks to months, plus related biomarkers, provide the signal from the noise.

The take‑home: tiglylglycine is most meaningful when combined with other environmental and metabolic markers, general health indicators, and what’s happening in your life. Over time, that integrated view helps separate transient blips from persistent patterns and supports safer, more effective next steps with your clinician.

How the Test Works

This is a urine test analyzed by mass spectrometry and typically normalized to creatinine to adjust for hydration. First‑morning or timed collections reduce variability from recent meals and activity. Results generally reflect the prior 24–48 hours. If you’re tracking a change — like a new training block, a period of fasting, or a workplace exposure assessment — repeating the test under similar conditions helps clarify directionality.

When Testing Is Especially Informative

Consider tiglylglycine when you’re exploring unexplained fatigue or recovery issues, evaluating possible mitochondrial stress, or mapping patterns alongside broader organic acids. It can add context during high‑exposure occupations in which mitochondrial stressors are plausible, during pregnancy when metabolic demands shift, or when monitoring known inborn errors of metabolism under clinical supervision. In the era of intense interest in metabolic health — from protein targets to GLP‑1 medications — TG offers a grounded, mechanistic window into how your energy pathways are actually handling their workload.

Interpreting Results Responsibly

Safety, Caveats, and Next Steps

Tiglylglycine is an internal metabolite, not a toxin you ingest. Still, it can rise in settings where mitochondria work harder or less efficiently. Some environmental and pharmaceutical exposures are known to affect mitochondrial enzymes, but their impact on TG specifically varies and evidence in everyday exposures is evolving. Use TG as one piece of a larger, evidence‑based puzzle. If your level is persistently elevated or climbs together with related markers, that’s a strong cue to review recent stressors, product and workplace exposures, diet and training loads, and to decide — with your clinician — whether additional testing is appropriate.