- For Indians
| Group | Particulars | Body weight (kg) | * *RDA (mg/day) |
| Infants | 0-6 months | 5.4 | 0.2 |
| 6-12 months | 8.6 | 0.2 | |
| Children | 1-3 years | 12.2 | 0.2-1.0 |
| 4-6 years | 19.0 | 0.2-1.0 | |
| 7-9 years | 26.9 | 0.2-1.0 | |
| Boys | 10-12 years | 35.4 | 0.2-1.0 |
| 13-15 years | 47.8 | 0.2-1.0 | |
| 16-18 years | 57.1 | 0.2-1.0 | |
| Girls | 10-12 years | 31.5 | 0.2-1.0 |
| 13-15 years | 46.7 | 0.2-1.0 | |
| 16-18 years | 49.9 | 0.2-1.0 | |
| Man | Sedentary work | 60 | 1 |
| Moderate work | 60 | 1 | |
| Heavy work | 60 | 1 | |
| Woman | Sedentary work | 50 | 1 |
| Moderate work | 50 | 1 | |
| Heavy work | 50 | 1 | |
| Pregnant | 50 | 1 | |
| Lactation-0-6 months | 50 | 1.5 | |
| Lactation-6-12 months | 50 | 1.5 |
· For U.S. residents
| Age | * *RDA (mg/day) |
| Infants | |
| 0-6 months | 0.4* |
| 7-12 months | 0.5* |
| Children | |
| 1-3 years | 0.9 |
| 4-8 years | 1.2 |
| Males | |
| 9-13 years | 1.8 |
| 14-18 years | 2.4 |
| 19-30 years | 2.4 |
| 31-50 years | 2.4 |
| 51-70 years | 2.4 |
| > 70 years | 2.4 |
| Females | |
| 9-13 years | 1.8 |
| 14-18 years | 2.4 |
| 19-30 years | 2.4 |
| 31-50 years | 2.4 |
| 51-70 years | 2.4 |
| > 70 years | 2.4 |
| Pregnancy | 2.6 |
| Lactation | 2.8 |
*AI, adequate intake values. * *R.D.A (Recommended Dietary Allowance)
Those people who are older than 50 years should take foods fortified with B12 or a supplement containing it as the absorption of this vitamin decreases by this age