Dihexa

A small, stabilized fragment of angiotensin IV (PNB-0408) made at Washington State University to work by mouth and reach the brain. It was pitched as a synapse builder for dementia. It is sold only as a research chemical.

There is no tested human dose. The most cited range is 5 to 20 mg once a day, with new users near 5 mg and some going to 20 to 30 mg. Others space 10 to 20 mg one to three times a week. All of it comes from vendors and forums.

All three are used, plus nasal. Oral relies on rat data from papers now under question. Transdermal use means dissolving it in DMSO, which some skin cannot take. One user ranked sublingual weakest and nasal strongest, but called nasal DMSO painful and not recommended.

It does not dissolve in bacteriostatic water. Users dissolve it in DMSO, and injection-grade DMSO is hard to find, so most people with 10 mg vials end up using it on the skin or under the tongue.

In rats, 12.68 days after an IV dose, from a paper now under an expression of concern. No one has measured it in people. The related drug fosgonimeton's active metabolite cleared in about 1.5 hours in humans, and some users read that as Dihexa's human half-life, which is disputed.

Partly. In April 2025 the journal retracted the two papers that tied Dihexa to HGF and c-Met. A Washington State University committee had already found that one of their co-authors altered images in papers from that period. The 2013 paper behind the oral, brain-penetrant claims has carried an expression of concern since 2021. An independent 2021 mouse study did report memory benefits.

That line comes from one cell-culture spine assay comparing picomolar Dihexa with nanomolar BDNF, in a paper now under an expression of concern. It says nothing about strength in a living brain.

No study shows it does. The worry is mechanistic: HGF and c-Met drive cell growth and are overactive in some cancers, so boosting them is a theoretical risk. A patent says short safety studies found no tumor induction; Wikipedia flags that claim as unsourced.

Rats got 0.05 to 0.5 mg/kg by injection or 1.25 to 2 mg/kg by mouth before maze tests, and aged rats got 2 mg/kg a day orally.

Not of Dihexa. ClinicalTrials.gov lists none. Fosgonimeton, a related injectable from the same program, was tested in 88 people in Phase 1 and then failed its Phase 2/3 Alzheimer's trial in 2024.

No. Dihexa acetate sat on FDA's Category 2 compounding safety-risk list until its nominators withdrew it, and FDA says it has no human exposure data. It is not in any category on FDA's current 503A list.

Yes, at all times. WADA's 2026 List does not name Dihexa, but section S2.3 bans "growth factors and growth factor modulators" and names hepatocyte growth factor (HGF). Dihexa is sold as an HGF/c-Met potentiator, which puts it in that class. If it fell outside S2.3, the S0 class for substances with no human therapeutic approval would still cover it.

Headache in the first days is the most common, then brain fog or sleepiness, irritability or anxiety, skin burning or rash from DMSO and a garlic-like DMSO smell. Many report no effect at all, sometimes blamed on fake product.

No human timeline exists. Some users feel it within days; several who used high transdermal doses felt nothing at first and reported improvement 2 to 5 weeks later.

Powder: room temperature or fridge, away from light, or -20 C long term. DMSO solutions: fridge, within about 14 days per one guide. Premixed liquids: 4 C, not frozen.