Happy Tuesday!
I just dropped a brand new deep dive video over on Spotify. This one is all about Dihexa.
I genuinely think Dihexa is one of the most underappreciated compounds in the cognitive enhancement space right now.
If you've been following me for a while, you know I'm not really a nootropics guy.
When you're hormonally optimized and running peptides, you get a lot of cognitive function as a byproduct. I don't need to push the gas pedal too often.
But Dihexa is different.
It sits in this perfect middle ground for me. Strong enough that I actually feel it working. Not so strong that I lose my personality or start feeling like a robot. I like operating as a human being with empathy and social awareness, and some nootropics can strip that away.
In today’s email, I will break down what I covered in the video.
Dihexa
Dihexa is a synthetic peptide developed over two decades at Washington State University. It was derived from angiotensin IV.
What makes it special is that it promotes synaptogenesis, meaning it helps your brain form brand new synaptic connections between neurons.
How It Works in the Brain
Dihexa binds to hepatocyte growth factor (HGF). That binding helps HGF dimerize. Once that happens, it activates the c-Met receptor tyrosine kinase on the surface of your neurons. This initiates downstream signaling via the PI3K/AKT pathway and the MAPK/ERK cascade.
The end result is synaptogenesis.
New synaptic connections form in your hippocampus and other brain regions responsible for learning and memory.
It also crosses the blood-brain barrier when taken orally. Most neurotrophic factors can't do that. Dihexa can, thanks to its engineered lipophilicity and small molecular size.
One more interesting detail. The half-life is around 12 to 13 days. That's extraordinarily long. It means you get a cumulative effect when dosing regularly. It also means you probably don't need to take it every single day.
Studies
A 2021 study out of China Pharmaceutical University confirmed that oral Dihexa improved spatial learning in APP/PS1 mice.
It increased neuronal cell counts, elevated synaptophysin expression, and reduced neuroinflammation. Specifically, it decreased IL-1β and TNF-α while increasing the anti-inflammatory cytokine IL-10.
Then there's a 2025 study from Rowan University. Dihexa dose-dependently improved working memory after repeated mild traumatic brain injury.
As someone who played football and has had multiple concussions, the TBI angle is near and dear to me. This is where I think Dihexa has some real untapped potential.
Dosing and How I Use It
Let me share what I covered in the video about dosing. Keep in mind this is based on community experience and the underground nootropic space.
Oral capsules are the most common route. The typical range is 5 to 40 mg. Personally, 10 mg is the sweet spot. At 5 mg, I notice something subtle. At 10 mg, I get a solid cognitive bump without being pushed too far.
For subcutaneous injection, I'd stay around 1 to 3 mg 2-3 times per week. Injection is 100% bioavailable, compared with roughly 38% for oral administration.
I like to take the oral capsules three times per week, or sometimes just on days when I know I need to be locked in for deep work.
Given the long half-life, you really don't need daily dosing. Two to three times per week gives you solid benefit without unnecessary accumulation.
For cycling, I recommend 8 to 12 weeks on, then two to four weeks off. And on your off days, consider taking alpha-GPC to help replenish neurotransmitters. That's a great support compound for any nootropic protocol.
Final Thoughts
Here's my honest take on Dihexa.
Every time I take it, I get a noticeable effect. The cognitive clarity and focus are tangible. Not overwhelming. Not personality-altering. Just a clean bump in processing power when I need it.
Will we ever have extensive clinical data on Dihexa itself? Probably not. No pharmaceutical company is going to invest hundreds of millions to take a simple peptide through FDA approval when they can't patent it. The economics don't work.
For age-related cognitive decline, I think Dihexa could be genuinely helpful. For TBI recovery, I'd absolutely include it alongside Cerebrolysin, BPC-157, and TB-500.
For healthy folks who want a cognitive edge without the heavy push of something like Modafinil, it's a great fit.
Start low. Work your way up. Cycle responsibly. Don't be the person who jumps to 40 mg a day because someone on the internet told you to.
Thank you for your support of my work!
Best,
Hunter Williams
P.S. You can get Dihexa from the following places:
Further Reading