Read the reference correctly
An RDA is intended to meet the needs of nearly all healthy people in a specified group. An Adequate Intake, or AI, is used when evidence is insufficient to establish an RDA. Neither is a deficiency-treatment prescription or an upper safety limit. The male and female categories below follow the source reference tables. [1][2]
Vitamins A, D, E and K
Vitamin A: 900 micrograms RAE for men and 700 micrograms RAE for women. Vitamin D: 15 micrograms, equivalent to 600 IU, for both. Vitamin E: 15 mg alpha-tocopherol for both. Vitamin K: an AI of 120 micrograms for men and 90 micrograms for women. [3][1][4][2]
RAE means retinol activity equivalents, which accounts for different vitamin A sources. Vitamin K’s reference covers the vitamin overall rather than assigning a separate K2 target. [3][1][4][2]
Thiamin, riboflavin, niacin and pantothenic acid
Thiamin, or B1: 1.2 mg for men and 1.1 mg for women. Riboflavin, or B2: 1.3 mg for men and 1.1 mg for women. Niacin, or B3: 16 mg NE for men and 14 mg NE for women. Pantothenic acid, or B5: an AI of 5 mg for both. [5][6][7][8]
NE means niacin equivalents; it includes niacin supplied directly and the contribution from tryptophan conversion. Do not interpret that total as a recommended dose of a high-strength niacin product. [5][6][7][8]
B6, biotin, folate and B12
For both men and women aged 19–50: B6 is 1.3 mg; biotin, or B7, has an AI of 30 micrograms; folate is 400 micrograms DFE; and B12 is 2.4 micrograms. DFE means dietary folate equivalents and accounts for differences in absorption between food folate and folic acid. [9][10][11][12]
After age 50, the B6 RDA increases to 1.7 mg for men and 1.5 mg for women. Pregnancy and breastfeeding have their own reference values; use the relevant life-stage guidance rather than extending this adult list. [9][10][11][12]
Vitamin C and later-life changes
Vitamin C is 90 mg for men and 75 mg for women; people who smoke need an additional 35 mg per day. Vitamin D remains 600 IU through age 70 and increases to 800 IU after 70. A food-label Daily Value can differ from an individual age-specific RDA, so percent Daily Value is not a personalized prescription. [13][1]
Add food and supplements before deciding there is a gap
Imagine food supplies 60 mg vitamin C and a supplement supplies 30 mg. Total intake is 90 mg. That arithmetic can inform a comparison with the appropriate reference, but it does not diagnose deficiency, measure absorption or mean another 90 mg supplement is required. [13][14]
| Source | Amount |
|---|---|
| Food | 60 mg |
| Supplement | 30 mg |
| Total | 90 mg |
Sources for this article
- Vitamin D - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product. - Vitamin K - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product. - Vitamin A and Carotenoids - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product. - Vitamin E - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product. - Thiamin - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product. - Riboflavin - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product. - Niacin - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product. - Pantothenic Acid - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product. - Vitamin B6 - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product. - Biotin - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product. - Folate - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product. - Vitamin B12 - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product. - Vitamin C - Health Professional Fact Sheet
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product. - Dietary Supplements: What You Need to Know
Source consulted: 2026-09-20. This is a reference resource, not a claim that we conducted the studies or tested a product.