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Can You Take NMN or NR with Warfarin? Drug Interaction Guide

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Key numbers

  • 250 mg/dayOral NMN dose in a 12-week trial of 30 healthy adults, which raised NAD+ with no obvious adverse effectsSource: pubmed.ncbi.nlm.nih.gov, as cited 2026-11-08
  • 900 mg/dayHighest NMN dose tested in an 80-adult, 60-day trial, where blood NAD+ rose mostSource: pubmed.ncbi.nlm.nih.gov, as cited 2026-11-08
  • 1,250 mgNMN dose in a four-week trial of 31 healthy adults, with no severe adverse eventsSource: pubmed.ncbi.nlm.nih.gov, as cited 2026-11-08
  • INR above 4.0INR level above which warfarin bleeding risk is higher, with no added benefit in most patientsSource: dailymed.nlm.nih.gov, as cited 2026-11-08

At a glance

  • Direct answer / Effect on INR unknown
  • Warfarin label / More frequent INR monitoring when other drugs, including botanicals, start or stop [1]
  • Label scope / No NMN- or NR-specific instruction [1]
  • NMN and NR status / Oral dietary supplements; neither is an FDA-approved drug [2]
  • Warfarin target INR / 2.5, range 2.0 to 3.0, for venous thromboembolism and non-valvular atrial fibrillation [1]
  • Warfarin bleeding warning / Boxed warning for major or fatal bleeding [1]

What is known about NMN, NR and warfarin?

NMN and NR are sold in the US as oral dietary supplements. Neither is an FDA-approved drug [2]. Warfarin is a prescription vitamin K antagonist with a boxed warning for major or fatal bleeding, and its label calls for regular INR monitoring in all treated patients [1].

We found no human study testing whether NMN or NR interacts with warfarin, so the direction and size of any INR effect are unknown. The label's instruction is general: more frequent INR monitoring when other drugs, including botanicals, are started or stopped [1].

What people on Reddit report

Accounts from people taking NMN while on warfarin, mostly from a single forum thread. They tracked INR, sometimes with a home testing kit, and their doctors' advice varied.

nacari0 · valvereplacement

My doctor says there shouldn't be any issue, but told me to carefully monitor INR.

The poster's doctor expected no problem but asked for careful INR checks while taking NMN.

Read the source discussion

nacari0 · valvereplacement

Nah it's hard to tell as many things can impact but doesn't feel like this has had any impact. But I've also approached it a bit more soft whereas others may use higher doses, I stuck with 300-500mg daily or every other day max

The poster felt no effect on INR but noted that many factors affect INR and that they used a low dose.

Read the source discussion

nacari0 · valvereplacement

Hi, its been going good, i dont have any sides. I do take 1 pill every second day tho, but as i get older i may up it to every day

The poster reports doing well on NMN with no side effects and taking it every other day.

Read the source discussion

Dr. Greger on why blindly taking NMN is not the best route to NAD

Dr. Greger argues that blindly overloading the body with NAD precursors such as NMN is not the best way to go, since the body keeps tissue levels in check and such supplements may have adverse effects. He calls them profit-making distractions and prefers natural approaches to boosting NAD, mainly exercise and reducing the oxidation and inflammation that drain it. On warfarin, he explains that the drug thins the blood by interfering with vitamin K, so a person taking it should keep vitamin K intake steady. In his view, the key is eating greens on a regular basis rather than suddenly binging on them.

Who is speaking?

Dr. Greger. Host of the NutritionFacts.org Live Q&A, as described on the channel Background

Episode notes and full video

What do human NMN and NR trials show?

Oral NMN and NR raise blood NAD+ in short trials [3][4][5]. In 30 healthy adults, NMN 250 mg/day for 12 weeks raised whole-blood NAD+ and caused no obvious adverse effects [3]. In 80 middle-aged adults, NMN 300, 600 or 900 mg/day for 60 days raised blood NAD+, highest at 600 and 900 mg, with no safety issues [4]. In a four-week trial of 31 healthy adults aged 20 to 65, NMN 1,250 mg once daily caused no severe adverse events or clinically relevant laboratory changes [6]. In a six-week trial of middle-aged and older adults, NR increased NAD+ metabolism [5]. These trials were short and small, so long-term safety is unknown.

What does the warfarin label say to watch for?

Warfarin can cause major or fatal bleeding; the label says to instruct patients to report signs and symptoms of bleeding [1]. Bleeding is more likely in the first month. Risk factors named in the label include an INR above 4.0, age 65 or older, prior gastrointestinal bleeding, hypertension, renal impairment and certain concomitant drugs [1]. An INR above 4.0 appears to give no added benefit in most patients and is linked to higher bleeding risk [1]. Keeping the INR in the therapeutic range does not remove the risk of bleeding [1].

Questions worth asking

Choose the questions you want to keep

Frequently asked questions

Does the warfarin label mention NMN or NR?
No. The label's instruction for botanicals and other drugs is general, and it gives no NMN- or NR-specific dose advice [1].
What doses were used in human trials?
These are doses studied, not recommended doses. NMN trials used 250 mg/day to 1,250 mg/day [3][4][6]. NR trials used 2,000 mg/day [8] and 3,000 mg/day [7].
What bleeding signs does the label say to report?
The label says to instruct patients to report signs and symptoms of bleeding. Warfarin carries a boxed warning for major or fatal bleeding [1].

What people actually ask

Can you take NMN when you're on blood thinners?

Not known. We found no human study testing NMN or NR with warfarin, so whether either changes INR or bleeding risk is unestablished. The warfarin label calls for more frequent INR monitoring when other drugs, including botanicals, are started or stopped.

Which supplements should be avoided when taking warfarin?

No specific supplements are named as ones to avoid. Warfarin's label says to monitor INR more often when other drugs, including botanicals, are started or stopped. It gives no NMN- or NR-specific instruction, and the effect of either on INR is unknown.

What medications should not be taken with NMN?

No medications are named to avoid with NMN. The warfarin label names certain concomitant drugs as a bleeding risk factor and says to monitor INR more often when other drugs start or stop. No study has tested NMN or NR with warfarin, so any interaction is unknown.

References

  1. U.S. National Library of Medicine, DailyMed. Jantoven (warfarin sodium) tablets, Upsher-Smith prescribing information. Jantoven (warfarin sodium) tablets, Upsher-Smith label
  2. Official web page. Official web page
  3. Okabe K, Yaku K, Uchida Y, Fukamizu Y, Sato T, Sakurai T, et al. Oral Administration of Nicotinamide Mononucleotide Is Safe and Efficiently Increases Blood Nicotinamide Adenine Dinucleotide Levels in Healthy Subjects. Front Nutr. 2022;9:868640. Oral Administration of Nicotinamide Mononucleotide Is Safe and Efficiently Increases Blood Nicotinamide Adenine Dinucleotide Levels in Healthy Subjects
  4. Yi L, Maier AB, Tao R, Lin Z, Vaidya A, Pendse S, et al. The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults: a randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial. Geroscience. 2023;45(1):29-43. The efficacy and safety of β-nicotinamide mononucleotide (NMN) supplementation in healthy middle-aged adults: a randomized, multicenter, double-blind, placebo-controlled, parallel-group, dose-dependent clinical trial
  5. Martens CR, Denman BA, Mazzo MR, Armstrong ML, Reisdorph N, McQueen MB, et al. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults. Nat Commun. 2018;9(1):1286. Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adults
  6. Fukamizu Y, Uchida Y, Shigekawa A, Sato T, Kosaka H, Sakurai T. Safety evaluation of β-nicotinamide mononucleotide oral administration in healthy adult men and women. Sci Rep. 2022;12(1):14442. Safety evaluation of β-nicotinamide mononucleotide oral administration in healthy adult men and women
  7. Berven H, Kverneng S, Sheard E, Søgnen M, Af Geijerstam SA, Haugarvoll K, et al. NR-SAFE: a randomized, double-blind safety trial of high dose nicotinamide riboside in Parkinson's disease. Nat Commun. 2023;14(1):7793. NR-SAFE: a randomized, double-blind safety trial of high dose nicotinamide riboside in Parkinson's disease
  8. Dollerup OL, Christensen B, Svart M, Schmidt MS, Sulek K, Ringgaard S, et al. A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men: safety, insulin-sensitivity, and lipid-mobilizing effects. Am J Clin Nutr. 2018;108(2):343-353. A randomized placebo-controlled clinical trial of nicotinamide riboside in obese men: safety, insulin-sensitivity, and lipid-mobilizing effects
  9. Reddit participants. Nicotinamide mononucleotide (NMN) supplement and warfarin (r/valvereplacement). Accessed 2026-11-10.
  10. NutritionFacts.org. Live Q&A: Answers on NMN, Calcium Sources, Pregnancy, and More. Accessed 2026-11-10.
Evidence overview for interactions nad nmn: Can You Take NMN or NR with Warfarin? Drug Interaction Guide