Table 6  Concentrations of metabolites in human urine as measured by GC-MS.
Compounds  Observed Concentration(µM/mM creatinine)  Literature Values(µM/mM creatinine)
2,4-Dihydroxybutanoic acid  1.0 (0.3–1.8)  2.0±2.0
2-Ethylhydracrylic acid  2.1 (1.3–2.9)  NA**
2-Furoylglycine  3.6 (0.7–5.8)  9.95 (2.0–18.66)
2-Hydroxy-2-methylbutyric acid  0.8 (0.4–1.5)  2.8±1.5
2-Methyl-3-hydroxybutyric acid  4.0 (1.3–6.2)  5.5 (0.0–11.0)
3,4-Dihydroxybenzeneacetic acid  0.9 (0.6–1.3)  1.16±0.50
3,4-Dihydroxybutanoic acid  42.2 (21.9–56.1)  34.9 (12.5–57.2)
3-Aminoisobutanoic acid  25.8 (1.4–155.6)  2.91–116.43
3-Hydroxyhippuric acid  6.1 (4.1–7.8)  2.5 (0.2–5.0)
3-Hydroxyisobutyric acid  29.0 (11.8–59.8)  17.5 (2.0–33.0)
3-Hydroxyisovaleric acid  7.4 (4.1–17.2)  8.5±3.2
3-Hydroxymethylglutaric acid  3.2 (1.1–5.2)  3 (0–10)
3-Hydroxyphenylacetic acid  5.6 (1.4–15.0)  6.1±4.1
3-Hydroxysebacic acid  2.9 (1.7–3.8)  NA**
3-Methyladipic acid  2.1 (0.9–5.6)  2.9 (0.7–10.5)
3-Methylglutaconic acid  6.2 (2.8–8.3)  4.5 (0.0–9.0)
4-Deoxythreonic acid  18.2 (5.6–23.9)  25±10
4-Hydroxybenzoic acid  2.4 (1.3–3.6)  1.8±1.8
4-Hydroxyphenyllactic acid  2.8 (2.6–3.0)  1.1 (0.2–2.6)
5-Hydroxyhexanoic acid  2.7 (0.8–5.7)  3.5 (0.0–7.0)
5-Hydroxyindoleacetic acid  2.9 (0.4–5.8)  2.4±0.40
Adipic acid  3.0 (1.0–12.9)  5.1 (0.8–35.0)
Alpha-Hydroxyisobutyric acid  2.9 (1.3–4.6)  3.8
Azelaic acid  1.9 (1.2–3.2)  4.8 (1.3–15.0)
Benzoic acid  3.6 (1.4–7.5)  4.2 (1.9–6.5)
Cholenic acid  0.015 (0.004–0.030)  NA**
Cis/Trans-Aconitic acid  15.3 (5.2–21.8)  NA**
Citraconic acid  1.6 (0.9–2.1)  2.2
Creatinine*  12,246±8,369  10,090±310
Deoxycholic acid  0.055 (0.050–0.060)  NA**
D-Galactose  3.3 (1.3–8.5)  4.4 (0.0–31.0)
D-Glucose  35.6 (10.3–56.7)  31.12
D-Xylitol  2.3 (0.9–8.2)  3.50±2. 37
D-Xylulose  19.7 (6.4–32.6)  NA**
Ethylmalonic acid  2.4 (0.9–4.0)  2.0 (0.5–3.9)
Gluconic acid  13.3 (8.2–26.4)  NA**
Glutaric acid  1.4 (0.5–2.3 )  1.3 (0.6–2.6)
Glyceric acid  14.4 (7.8–28.8)  4.5 (0.0–9.0)
Glycine  75.7 (21–205)  151 (233–248)
Glycolic acid  39.4 (2.9–78.1)  35 (18–55)
Hippuric acid  217 (28–610)  257 (20–770)
Homovanillic acid  4.3 (0.9–8.9)  4.9±3.4
HPHPA  4.2 (0.9–15.3)  0.55–54.93
Hydroxypropionic acid  8.1 (3.1–11.8)  6.5 (3.0–10.0)
Indoleacetic acid  2.6 (0.6–5.4)  2.0±1.0
Indolelactic acid  0.9  0.460 (0.098–0.980)
Isocitric acid  56.8 (19.4–119.1)  58 (36–84)
Kynurenic acid  2.6 (0.9–4.1)  1.34±0.30
L-Arabinose  8.8 (0.8–19.4)  8.75 (6.12–11.84)
L-Asparagine  9.5 (3.0–26.0)  10.0 (4.6–16.3)
Levulinic acid  1.7 (0.6–2.5)  1.28 (0.33–2.75)
Lithocholic acid  0.16 (0.10–0.20)  NA**
L-Lactic acid  7.1 (0.9–16.4)  12.3±6.2
L-Ornithine  5.3 (2.0–8.8)  5.0 (2.0–8.0)
L-Phenylalanine  7.8 (5.0–11.3)  4.50±1.15
L-Serine  19.0 (10.4–35.8)  26.0±10.0
L-Tyrosine  15.1 (6.1–23.2)  8.8±4.5
L-Valine  5.5 (2.7–9.8)  3.0±1.0
Malonic acid  2.3 (1.2–3.1)  1 (0–2)
m-Chlorobenzoic acid  0.7  NA**
Methylmalonic acid  1.3 (0.5–2.1)  1.6 (0.0–3.6)
Methylsuccinic acid  4.7 (1.1–6.2)  2.3 (0.8–10.8)
Myoinositol  12.6 (5.1–15.3)  18.8±2.9
o-Hydroxyphenylacetic acid  2.9 (1.4–3.7)  7.71±3.65
Oxalic acid  8.2 (3.9–14.0)  1.11–33.34
Oxoglutaric acid  3.4 (1.4–12.5)  2.98 (0.42–18.30)
Palmitic acid  6.7 (2.6–24.3)  11 (6–23)
Phosphoric acid  784 (425–1170)  1000–4900
p-Hydroxyphenylacetic acid  6.0 (2.4–9.7)  9.68
Pimelic acid  1.9 (0.5–3.5)  NA**
Pseudouridine  29.8 (21.8–47.3)  26.02±4.62
Pyroglutamic acid  18.6 (4.5–24.9)  28.8 (3.4–54.2)
Pyruvic acid  2.1 (1.0–3.7)  2.13 (0.54–8.67)
Quinolinic acid  3.9 (0.9–15.1)  2.5±1.1
Scyllitol  3.6 (1.9–6.9)  NA
Sorbitol  3.9 (1.9–5.1)  3.50±2.24
Stearic acid  3.9 (2.3–7.7)  2.9 (1.6–6.6)
Suberic acid  1.2 (0.5–1.9)  0.5 (0.0–2.9)
Succinic acid  6.2 (2.5–13.5)  5.6±3.8
Sumiki’s acid  1.6  NA**
Threonic acid  14.8 (8.6–36.1)  10.0±7.0
Trans-Ferulic acid  1  36.3±11.2
Uric acid  186 (93–329)  188 (79–296)
Ursodeoxycholic acid  0.022 (0.013–0.030)  NA**
Vanillylmandelic acid  1.6 (0.6–2.8)  1.2±0.5
*  Concentration of metabolite (Mean ± SD) is expressed by µM. HPHPA: 3-(3-hydroxyphenyl)-3-hydroxypropanoic acid; NA: not available; NA**: not available for healthy adults.