NAD+ injections vs. supplements: what the evidence actually shows

What did @andresthedietitian actually say?

The creator, a registered dietitian, argues that NMN and NR supplements are merely precursors requiring conversion inside the body, with only "20 to 30%" absorption. Injections, he claims, deliver NAD+ directly with "up to 90% plus absorption" and faster onset. He personally uses IVRX, says he has a prescription, and reports noticeably better energy and focus within "the first few days." His wife has also supposedly noticed the difference. He recommends injections specifically for people over 35 who are trying to optimize recovery, and links to the supplier in his bio. The hashtags #ivypartner and #ivyaffiliate signal a paid or affiliate relationship, which is worth keeping in mind when evaluating the enthusiasm here.

Does the science back this up?

Partially, but the specific absorption numbers he cites are not well-supported in peer-reviewed literature, and some of the framing oversimplifies a genuinely complicated area of research.

On the precursor point, he is broadly correct. NMN and NR are not NAD+ themselves. They enter cells through distinct transporters and get converted via enzymatic pathways. Yoshino et al. (2021, Science) confirmed that orally administered NMN raises blood NAD+ metabolite levels in humans, but the degree of conversion varies considerably between individuals and tissues. The "20 to 30%" bioavailability figure he quotes for oral NMN or NR is not sourced to any specific study in the video, and published estimates range more widely than that range suggests.

On the injection side, intravenous NAD+ does bypass gut absorption entirely, so the pharmacokinetic logic is sound in principle. But "90% plus absorption" for subcutaneous NAD+ injections, which is what IVRX appears to sell, is a marketing-adjacent claim. There is no robust clinical trial in a peer-reviewed journal establishing that specific figure for subcutaneous delivery. Clement et al. (2019, npj Aging) examined NAD+ metabolism but did not establish subcutaneous bioavailability benchmarks.

What did they get wrong (or right)?

He got the basic biochemistry directionally right. Oral precursors do require conversion, and injection-based delivery does sidestep gut absorption. Those are fair points. Where he went wrong is in presenting exact, confident percentages, "20 to 30%" and "90% plus," without citing any source. Those numbers appear to come from brand marketing rather than clinical data.

His personal anecdote, better energy within "the first few days" and his wife noticing a change, is not evidence of anything beyond placebo response or natural variation. Subjective energy improvements over six weeks, while on an affiliate-sponsored product, tell us almost nothing scientifically. To his credit, he does not claim NAD+ injections treat any specific disease, and he acknowledges that pills "can work too." He also discloses the prescription and the affiliate relationship via hashtags, even if that disclosure is buried.

What is missing entirely: any discussion of cost, the absence of long-term safety data for repeated NAD+ injections, or the fact that NAD+ given intravenously degrades rapidly in blood and its downstream effects at the cellular level are still being studied.

What should you actually know?

NAD+ research is legitimately interesting, but it is still early. The strongest human data exists for oral NR and NMN raising NAD+ levels in blood, not for hard clinical outcomes like disease reversal or measurable longevity extension in humans. Rajman et al. (2018, Cell Metabolism) reviewed the preclinical and early human evidence and described the field as promising but pre-conclusive.

Subcutaneous NAD+ injections are not FDA-approved as a drug for any indication. They are compounded products, meaning quality, sterility, and dosing consistency depend entirely on the compounding pharmacy. That does not make them automatically unsafe, but it is a meaningful caveat that a dietitian with an affiliate link has a financial reason not to mention.

If you are considering any injectable NAD+ product, the conversation belongs with a licensed prescribing clinician who has no financial stake in the outcome, not primarily with a TikTok review. The prescription he mentions is a reasonable starting point, but it should be paired with an honest risk-benefit discussion, not a link in a bio.