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Medicines and supplements

Iron and dolutegravir

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

Ask your pharmacist or doctor before combining. The dolutegravir label says oral iron supplements, including multivitamins that contain iron, lower blood levels of the medicine. In the label's study, iron taken with dolutegravir on an empty stomach cut its exposure by more than half, while taken with a meal it did not.1

Key facts

  • The dolutegravir label lists oral calcium or iron supplements, including multivitamins that contain them, among products that lower dolutegravir levels.1
  • In the label's study, ferrous fumarate taken at the same time on an empty stomach lowered dolutegravir exposure by about 54%; taken with a meal, exposure was about the same as without iron.1
  • MedlinePlus lists iron supplements among the products that come with timing instructions for dolutegravir.2
  • NIH says iron is sold on its own and in many multivitamin and mineral supplements, so a product not labeled as iron may still contain it.3

Ask your pharmacist how far apart to take them

Oral iron supplements, including multivitamins with iron, lower blood levels of the medicine dolutegravir. Its label explains when they may be taken together with food and when they must be kept apart.1

On the medicine's label

What does the dolutegravir label say about iron?

MedlinePlus describes dolutegravir as a medicine taken with other medicines to lower the amount of HIV in the blood, and it tells people to report every vitamin and supplement they use. The label's interaction table says oral iron supplements, including multivitamins that contain iron, lower dolutegravir levels. It sets one instruction for taking both with food and a different one for taking them without food.1,2

The instruction for the fasting case keeps the two products apart by hours. This page does not give those hours, because the right plan depends on how you take your medicine and which products you use. Your pharmacist can confirm it.

How much does iron lower dolutegravir?

The label reports a single-dose study of 50 mg of dolutegravir with 324 mg of ferrous fumarate. Taken together on an empty stomach (11 participants), dolutegravir exposure fell to about 46% of its usual level, roughly 54% lower. Taken together with a meal (11 participants), exposure was about the same as without iron.1

Ferrous fumarate is one of the iron salts used in supplements, alongside ferrous sulfate and ferrous gluconate. The label's instruction also covers multivitamins that contain iron, and it sets no cutoff amount below which the advice stops applying.1,4

Where is iron found besides an iron supplement?

NIH says iron is available in many multivitamin and mineral supplements as well as in supplements that contain only iron. In its data, about 14% to 18% of Americans use a supplement that contains iron, from 6% of people aged 12 to 19 to 72% of pregnant women. Look for iron on the Supplement Facts panel of multivitamins and prenatal vitamins as well as products sold as iron.3,4

Do NIH's iron fact sheets mention dolutegravir?

No. NIH's iron fact sheets list medicines such as levothyroxine, levodopa and proton pump inhibitors but not dolutegravir, while its calcium fact sheets do name it. This page therefore rests on the dolutegravir label and MedlinePlus. Both are official sources, and the label is the more detailed of the two.3,4,5

What to ask your pharmacist about iron and dolutegravir

  • Do I take iron on its own, in a multivitamin or in a prenatal vitamin?
  • Do I take dolutegravir with a meal every time?
  • Did a clinician tell me to take iron, and does that person know I take dolutegravir?
  • Do I also take calcium, which the label groups with iron?

Questions people ask

Can you take iron with dolutegravir?

The label says oral iron supplements lower dolutegravir levels and gives separate instructions for taking them with food and without food. Ask your pharmacist which applies to your routine.1

Does iron lower dolutegravir levels?

In the label's study, ferrous fumarate taken together with dolutegravir on an empty stomach lowered dolutegravir exposure by about 54%, and with a meal the exposure was about the same.1

Does a multivitamin with iron count?

Yes, the label names multivitamins that contain calcium or iron. Check the Supplement Facts panel for iron and show it to your pharmacist.1

Should I stop my iron supplement while taking dolutegravir?

The sources checked do not tell people to stop iron. They describe an effect on dolutegravir levels and give instructions that depend on food. If you take iron for a reason, ask your prescriber before changing anything.1,2

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Sources

  1. Dolutegravir tablets and tablets for oral suspension: prescribing information (ViiV Healthcare). DailyMed, U.S. National Library of Medicine. Effective August 25, 2026. Opened 2026-10-07.
  2. MedlinePlus. Dolutegravir. U.S. National Library of Medicine. Last revised August 15, 2025. Opened 2026-10-11.
  3. Office of Dietary Supplements, National Institutes of Health. Iron: Fact Sheet for Consumers. Updated August 17, 2023. Opened 2026-10-07.
  4. Office of Dietary Supplements, National Institutes of Health. Iron: Fact Sheet for Health Professionals. Updated September 4, 2025. Opened 2026-10-07.
  5. Office of Dietary Supplements, National Institutes of Health. Calcium: Fact Sheet for Health Professionals. Updated June 22, 2026. Opened 2026-10-07.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.