Version 2.5 of the HMDB represents an evolution in the richness and depth of the data available in the HMDB. In addition, it includes several enhancements and refinements to the search and visualization tools available on the website. The following table provides a summary of the major changes and enhancements in version 2.5.
| Database feature/content status | HMDB Version 1.0 | HMDB Version 2.0 | HMDB Version 2.5 |
|---|---|---|---|
| Number of metabolites | 2180 | 6826 | 7982 |
| Number of unique metabolite synonyms | 27700 | 43882 | 69287 |
| Number of compounds with disease links | 862 | 1002 | 1064 |
| Number of compounds with biofluid or tissue concentration data | 883 | 4413 | 4857 |
| Number of compounds with urine concentration data | 231 | 472 | 782 |
| Number of compounds with serum concentration data | 174 | 3976 | 4418 |
| Number of compounds with cerebrospinal fluid concentration data | 47 | 360 | 363 |
| Number of compounds with experimental reference 13C NMR spectra | 380 | 784 | 899 |
| Number of compounds with experimental reference 1H NMR spectra | 385 | 792 | 905 |
| Number of compounds with reference MS-MS spectra | 390 | 799 | 2654 |
| Number of compounds with reference GC-MS spectra | 0 | 279 | 318 |
| Number of human-specific pathway maps | 26 | 58 | 71 |
| Number of compounds in the Human Metabolome Library (HML) | 607 | 920 | 1016 |
| Number of HMDB data fields | 91 | 102 | 111 |
| Pathway search/browse capability | No | Yes | Enhanced |
| Disease search/browse capability | No | Yes | Enhanced |
| Chemical class search/browse capability | No | Yes | Enhanced |
| Chemical substructure search capability | No | Yes | Enhanced |
| Biofluid search/sort tools | No | Yes | Enhanced |
| Advanced (multipeak or multicompound) NMR search | No | Yes | Enhanced |
| Advanced (multipeak or multicompound) MS-MS search | No | Yes | Enhanced |
| Advanced (retention index or MS peak) GC-MS search | No | Yes | Enhanced |
