Read first if you’re using right now: naltrexone in its standard form is a full opioid antagonist. Taking it while 7-OH, kratom, buprenorphine, methadone, or any other opioid is still on your receptors causes immediate, severe precipitated withdrawal: covered in detail on the Normal-Dose Naltrexone page. Read that page’s safety section before considering naltrexone in any form.
Naltrexone is a mu-opioid receptor antagonist: it occupies the same receptors that opioids bind to, without activating them. It’s one of three FDA-approved medications for opioid use disorder, alongside buprenorphine (partial mu agonist) and methadone (full mu agonist), and the three are not formally ranked (ASAM 2020, SAMHSA TIP 63).
Three protocols use the same molecule at doses that span three orders of magnitude for three different purposes. Don’t mix them up.
The three protocols at a glance
| Protocol | Typical dose | Primary use | Evidence base | Where it fits in recovery |
|---|---|---|---|---|
| Normal dose, oral | 50 mg/day (after a 25 mg initial dose) | Sustained abstinence after detox; alcohol use disorder | FDA-approved; well-supported for AUD (COMBINE, Anton 2006); adherence-limited for OUD | After complete opioid clearance (7–14 days, varies by opioid) |
| Normal dose, Vivitrol injection | 380 mg IM gluteal every 4 weeks | Same as oral; monthly dosing solves adherence | FDA-approved; X:BOT 2018 found XR-NTX and bupe-nx equivalent once successfully started | After complete opioid clearance |
| Low dose (LDN) | 1–5 mg/day (most commonly 4.5 mg nightly) (Toljan & Vrooman 2018) | Off-label: chronic pain, autoimmune conditions, PAWS adjunct | Emerging, small trials in fibromyalgia, Crohn’s, MS; one RCT in opioid detox enhancement; no large RCTs | After acute withdrawal is over; not during active opioid use |
| Ultra-low dose (ULDN) | 1–100 μg/day | Investigational, adjunct to opioid agonists for tolerance/withdrawal modulation | Thin and dated; mechanism papers retracted in 2022; no FDA-approved product | Investigational; rarely standard of care |
The three are different tools for different problems. The normal-dose column is FDA-approved and the most clinically established. The LDN column is off-label but has a real (if limited) evidence base. The ULDN column is investigational, the mechanism literature has issues (see the ULDN page), and it is not a mainstream treatment.
When naltrexone is and isn’t generally considered
Generally considered:
- After complete opioid clearance, for relapse prevention — either oral (daily) or Vivitrol (monthly injection). The choice between formulations is usually about adherence vs. cost; the monthly injection removes daily decisions but is expensive and requires clinic visits.
- For alcohol use disorder, where the evidence base is stronger than for OUD specifically.
- Off-label, in low-dose (LDN) form, for ongoing post-acute symptoms once you’re past acute withdrawal and fully opioid-free.
Not generally considered (or not yet):
- During active opioid use, full-dose naltrexone causes immediate, severe precipitated withdrawal.
- During a buprenorphine (Suboxone) or methadone taper, same problem, with longer-acting consequences.
- As a substitute for a structured taper, naltrexone is a post-abstinence tool, not a quitting tool. For the four community-validated paths off 7-OH and synthetics, see Withdrawal Help.
- In ULDN form, as a routine recovery intervention, it’s investigational and the evidence base is thin.
For 7-OH and kratom synthetics specifically
There is almost no peer-reviewed clinical literature on naltrexone specifically for 7-OH or kratom dependence. Clinicians prescribing it for this population are extrapolating from the OUD and AUD evidence base. That extrapolation is reasonable, 7-OH is a mu-opioid agonist — but it should be named honestly.
The longer-acting kratom synthetics (MGM-15, MIT-A, pseudo) probably require longer abstinence windows before naltrexone initiation than the standard short-acting-opioid guidance suggests. A prescriber experienced with this population is more likely to err on the side of caution. See Telehealth Providers for the fact-checked comparison of options with kratom experience.
Where to read next
- Normal-Dose Naltrexone: oral and Vivitrol. The page with the unmissable precipitated withdrawal callout. Read first if you’re considering naltrexone at any dose.
- Low-Dose Naltrexone (LDN): for off-label use in PAWS and related post-acute symptoms, after you’re fully opioid-free.
- Ultra-Low-Dose Naltrexone (ULDN): the investigational tier. Honest framing about how thin the evidence is.
- Telehealth Providers: primarily for normal-dose naltrexone (FDA-approved and routinely prescribed by OUD telehealth). LDN and ULDN are mostly outside standard OUD telehealth, the LDN page points at the LDN Research Trust directory, and the ULDN page notes that pain-medicine and integrative-medicine clinicians are the realistic prescribers.