Study amounts / not a plan for you
NAD+ studies used set amounts, but they don't set your dose
Here are the amounts given to set research groups in NMN, NR, and IV tests. You will also see how long blood changed. None of these figures chooses a dose for you.
Each study amount belongs to its test group, not to you
Every figure below comes from a published study, not a care plan. When you see "NMN 250 mg/day," that is what one test group received. It doesn't say what suits you. The tests enrolled different people and ran for different lengths of time. Most chose NMN or NR because both supply material for NAD+. Very little swallowed NAD+ reaches the inside of cells. Use this page to see what researchers tested, not to choose your own dose.
NMN and NR tests used a wide range of amounts
Human tests gave NMN by mouth at 250–900 mg/day. The 250 mg/day amount appeared most often [1][9][10]. One test compared 300, 600, and 900 mg/day for 60 days; its authors called 600 mg/day the best of those tested [3]. Other work reached 1200 mg/day. NR, another form the body can use, often appeared at 250–1000 mg/day. One test compared 100/300/1000 mg/day for 8 weeks [4]. A heart-failure group received 1000 mg twice daily [7]. A Parkinson's disease safety test reached 3000 mg/day. Clinic reports describe about 250–1000 mg of IV NAD+ in one visit lasting hours. One blood test gave 3 micromoles, a tiny lab amount, each minute for 6 hours. Researchers also tested a vitamin form at 500 mg twice daily to help prevent skin cancer. None of these study figures chooses your dose.
NAD+ vs NMN: very little whole NAD+ reaches cells
For NAD+ vs NMN, ask what reaches a cell after you swallow the pill, since very little whole NAD+ gets through when taken by mouth [16]. NMN and NR are smaller, and the body can use them while making NAD+ [5]. Nearly every careful human test that raised the blood level used one of those two forms [3][4][9]. A plain NAD+ capsule only sounds similar. It has trouble reaching cells, so some experts doubt that it does much [16]. Study results for NMN or NR can't simply be claimed for whole NAD+, which matters when you read a bottle or discuss it with your doctor.
Pills have more human study than shots, sprays, or patches
Most careful human work used powder or pills taken by mouth. People swallowed NMN, NR, or a different vitamin form [3][4][9]. Some wellness clinics give NAD+ by IV, though that work is limited to small studies and reviews of past cases [17]. Pharmacies also mix shots placed beneath skin or into muscle. Good blood work on either shot is scarce. Read the injectable and IV NAD+ risks before you treat those forms like pills. Sellers offer more forms for the tongue, nose, or skin, with little strong proof. One vitamin cream helped some signs of skin age and dark spots [13]. Across all these choices, the swallowed forms have far more human study.
IV NAD+ left blood fast; pill changes lasted longer
How long a change lasts depends on the form. In one IV test, nearly all NAD+ had left plasma about two hours after the drip began [17]. Plasma is the clear liquid part of blood. The study didn't show whether your body used or discarded it. NMN and NR pills raised blood levels for days or weeks. Higher levels lasted through 8–12-week tests [4][9]. After people stopped NMN at 250 mg/day, the result returned to its old point by about week 16 [9]. One NR test measured how soon the body cleared the remains of NR. About half had gone after 8 hours [8]. Heat and damp harm NMN and NAD+. Mixed shot liquid needs cold storage away from light [16].
A study amount isn't a personal NAD+ dose
Studies used NMN 250–900 mg/day [1][3][9] and NR 100–3000 mg/day [4][7]. Each figure describes a group in a test. It can't select what you take. Your age, illnesses, and medicines all matter. Bring the study to your regular doctor, who can weigh it against your history and care.