Safety studies / pills aren't shots
NAD+ side effects were few with pills, but shots bring more risk
People in short pill tests had little trouble with NMN or NR. NAD+ shots aren't approved drugs. Germ waste put one shot product under the FDA's top recall.
Pill tests found few problems; shots add other risks
Short tests found few health problems among people assigned NMN or NR. Trouble was about as common with a placebo, which held no test drug [4][9]. Both pills give the body material for NAD+, while a needle brings a different risk because pharmacies mix these shots and few careful tests have checked them in people over time. The FDA used its strongest recall level, Class I, after one shot tested high for harmful waste from germs [18]. These facts pick no amount; they show why you and your doctor need separate safety questions for pills and shots.
Short pill tests found little trouble with NMN or NR
One fair test gave healthy adults NR at 100, 300, or 1000 mg/day for 8 weeks. Unwanted health problems occurred at much the same rate in the placebo group. No group showed flushing or a rise in bad LDL cholesterol [4]. A different group swallowed NMN at 250 mg/day for 12 weeks. No harm was seen, and their NAD+ blood reading returned to its old point after they stopped [9]. People with heart failure used 1000 mg twice daily for 21 days without new safety trouble [7]. Researchers reached 3000 mg/day in a Parkinson's disease safety test. Selected groups were watched for only a short or medium span. You can't turn that into a promise of safety for everyone or for many years.
NAD+ shots aren't approved and one product was recalled
A shot can place NAD+ beneath your skin or deliver it straight into a vein. This gets around the fact that very little swallowed NAD+ reaches cells. The shots still aren't FDA-approved drugs. Pharmacies mix them, while careful human tests remain scarce. In one small test, the plasma reading was nearly gone about two hours after the drip started [17]. If the drip goes in too fast, you may feel flushing, nausea, or pain in the chest or belly. The FDA pulled one shot through a Class I recall, its gravest kind, because the product might cause severe harm or death. Tests found too much harmful germ waste [18]. A pharmacy-mixed shot can be dirty or have the wrong strength. Keep that history in view when you weigh an unapproved shot.
The FDA and sellers disagree about how NMN may be sold
In the FDA's view, NMN no longer fits the dietary supplement group. Researchers had already received permission to study NMN as a possible drug [16]. The FDA reads the law to mean that earlier step can keep NMN out. Sellers disagree, so the sales rule remains unsettled. The dispute isn't proof that NMN harms people, and buyers aren't banned from having it. Sport rules don't bar NAD+ or NMN, but they don't prove either one is safe [19].
Labels may be wrong, and cancer effects aren't known
Supplement pills can differ in strength and cleanliness. Outside testing isn't always done, so the bottle may not match its label [16]. Cancer raises a separate question. Fast-growing cancer cells use NAD+, so more might help an old cancer grow. Lab work also suggests that NAD+ could slow cancer in other ways [16]. Human studies haven't shown which effect matters in a person. Tell your doctor about any past or present cancer before weighing a supplement. This page gives no amount or way to use one.
The main downside depends on the form of NAD+
Reviews haven't found proof that NAD+ products prevent disease or lengthen life [15]. NAD+ put into a vein has few careful tests. Pharmacy-mixed shots may also be dirty. Too much harmful germ waste put one NAD+ shot under a Class I recall from the FDA [18]. By contrast, short tests of NMN and NR found little trouble [4][9].
Daily pill studies were short, so they can't answer for years
A group swallowed NR at 100–1000 mg/day for 8 weeks. Unwanted health problems occurred about as often with the sugar pill [4]. Another group used NMN at 250 mg/day for 12 weeks and showed no warning signs [9]. Both daily tests ended soon. No one yet knows the effect of years of use, and no study figure becomes your personal amount.
An NAD injection puts NAD+ into a vein or under skin
A needle can send NAD+ through a vein, called IV, or place it beneath your skin. Pharmacies mix these products. They aren't FDA-approved drugs, and good tests are few. Quality has failed before: too much harmful germ waste forced one shot into a Class I recall [18].
Studies don't show a best time for an NAD+ shot
No careful test names a best time for the shot. Some clinics let a drip run for hours, but their custom doesn't prove a sound schedule. NAD+ also leaves plasma, the liquid around blood cells, quickly [17]. This page can't tell you an amount, a time, or an injection method.
No study record promises that NAD+ is safe
People in short NMN and NR tests had little trouble [4][9]. Sport rules don't bar either pill, but that isn't a safety finding [19]. A shot mixed in a pharmacy can carry germs. Harmful germ waste forced a Class I recall of one NAD+ shot [18]. None of this promises safety or picks an amount for you.
NAD+ drip symptoms ended when the drip ended in reports
Reports of fast NAD+ drips mention flushing, chest or belly pain, and nausea. The reported trouble stopped with the drip. Trials of the two swallowed starting parts found few health problems [4][9]. Once people stopped NMN, their blood reading returned to its old point within about 16 weeks [9]. If you have symptoms, your own doctor needs to hear about them.