Is longevity medicine legit? what’s proven and what isn’t

Longevity medicine sits in an awkward place. The online clinics that sell it are, for the most part, legitimate businesses: licensed clinicians write the prescriptions and licensed pharmacies fill them. But the promise behind the products, that a shot, a spray or a pill will slow aging, isn’t backed by human trials. None of the treatments these clinics sell is FDA-approved to slow aging, and no human trial has shown that any of them extends lifespan.

So the useful question isn’t “is it legit?” but “what, exactly, is proven for the thing I’m being sold?” This guide answers that for the eight treatments online longevity clinics sell most, and sets out how to tell a careful clinic from a careless one.

What’s proven, treatment by treatment

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Where the evidence is strongest

Rapamycin has the best case. Started late in life, it extended mouse lifespan by 14% in females and 9% in males, measured at 90% mortality (Harrison 2009). In people, the PEARL trial ran 48 weeks and found 5 mg or 10 mg of compounded rapamycin once a week relatively safe, with lean-mass and pain improvements in women on 10 mg. It did not change visceral fat, its main outcome, and it didn’t measure lifespan. Read rapamycin for longevity for the detail.

Metformin has the longest safety record of any drug on the list, from decades of diabetes care. The longevity case is weaker than it sounds: a 2014 UK study suggested metformin users outlived healthy peers, and a 2022 Danish study of singletons and twins found the opposite. In older adults, it also blunted gains from exercise. See metformin for longevity.

Where it’s thin

NAD+ injections, the most heavily marketed product, have no controlled trial at all. The only direct human data are two small IV studies, one of which showed infused NAD+ was cleared from the blood for the first 2 hours (Grant 2019). Sermorelin’s trials are small and decades old: in 11 men aged 64 to 76, six weeks of nightly injections raised growth hormone release but didn’t change muscle, fat or IGF-1 (Vittone 1997); our sermorelin provider rankings compare the clinics that prescribe it. Low-dose naltrexone failed to beat placebo for fibromyalgia pain in a 12-month trial, and nobody has tested it for aging. Oral methylene blue has no aging trial, and in a 2023 study IV doses lowered brain blood flow and oxygen use in healthy volunteers.

Off-label and compounded aren’t the same thing

Clinics use both words, and they mean different things. An off-label drug is FDA-approved for something else: rapamycin for transplant patients, metformin for diabetes, naltrexone at 50 mg for addiction. A clinician may legally prescribe it for aging, and you get a product made to FDA standards, but nobody has shown it works for that purpose.

A compounded drug is prepared by a pharmacy for your prescription. NAD+, glutathione, sermorelin, low-dose naltrexone, oral methylene blue and MIC blends all reach you this way. Compounding is legal when the pharmacy follows the 503A rules, and NAD+ and glutathione are compounded under an interim FDA policy (Category 1 of its 503A list). But a compounded product hasn’t been through FDA review for safety, effectiveness or quality, so the pharmacy that makes it matters more.

The safety warnings that matter most

Three treatments carry an FDA boxed warning, the strongest kind:

• Rapamycin: immunosuppression. Increased susceptibility to infection and the possible development of lymphoma may result (label).
• Methylene blue: serotonin syndrome. It may cause serious or fatal serotonin syndrome with serotonergic drugs and opioids, so it shouldn’t be combined with SSRIs, SNRIs, MAOIs or opioids (label).
• Metformin: lactic acidosis, with higher risk in kidney impairment, age 65 or older, contrast imaging and heavy drinking (label).

Low-dose naltrexone blocks opioids, so it can bring on withdrawal and stop opioid pain relief from working. For the compounded products, the risk is different: the FDA doesn’t review compounded drugs for safety, effectiveness or quality before they reach you (FDA).

What makes a clinic legitimate

The clinics in our longevity rankings differ more in how carefully they work than in what they sell. These are the signs we look for, and score:

1. A licensed clinician reviews you first. Every clinic we list prescribes only after a US-licensed clinician reviews your history. The best include a video visit (Hone Health, Mochi Health) or lab monitoring where the drug calls for it (AgelessRx and Healthspan for rapamycin).
2. A named pharmacy. Most clinics say only “licensed pharmacies.” PepScribe publishes its three 503A pharmacies with NPI numbers.
3. A plain statement about compounding. The FDA has told telehealth companies not to imply that compounded drugs are FDA-approved or the same as approved drugs. A careful clinic says on the product page that the product is compounded and not FDA-approved.
4. The full price up front. As of October 2026, NAD+ injections cost $99 to $224 a month at the clinics that publish a monthly price, including Hone Health’s required membership, and Eden and Mochi Health bill a membership ($49 to $99 a month) on top of NAD+ prices they publish only per order or for the first month. Watch for first-month prices and per-vial prices with no supply length.
5. LegitScript certification. Several clinics we list carry it, including PepScribe, Eden, Hone Health, Luvo Health, Maximus, Strut Health and Valhalla Vitality.

How we rank the clinics

We’re paid by the providers we list, and only providers that pay us appear in our rankings. Scores and the order of each list come from our published rating method: value (30%), clinical care (25%), treatment options (20%), transparency (15%) and experience (10%), each scored from facts on the clinic’s own site. A clinic that adds a membership or shows only a first-month price scores lower on value; one that names its pharmacy and publishes refund terms scores higher on transparency. The details are on how we rate.

Red flags

• Claims that a product reverses aging, adds years to your life or is “proven” to slow aging.
• Peptides sold as lab chemicals without a prescription, or labeled not for people.
• Prices that hide a required membership or show only the first month.
• No way to reach a clinician after you start.
• Products a pharmacy can’t lawfully compound. In April 2026 the FDA moved BPC-157 off its list of substances that raise significant safety risks, after its nomination was withdrawn, but says that doesn’t make it eligible for compounding, and it hasn’t added it to the bulk list or to Category 1 as of October 2026. We don’t list any provider for it.

The bottom line

Longevity medicine is legitimate in the sense that licensed clinicians and pharmacies deliver it, and some of its drugs, rapamycin and metformin, are real medicines with long records. It is not legitimate to sell any of these treatments as proven to slow aging, because no human trial shows that. If you go ahead, treat it as an informed experiment: choose a clinic that reviews you properly, names its pharmacy, states its full price and tells you plainly what is compounded. Our longevity hub compares the clinics that meet that bar.