Semax dosing — where I landed after 8 months of messing with 300 to 1000 mcg

S
Joined 2026
41 posts
3/5/2026 · 3191 views

Posting this because every Semax thread devolves into 'just try it' and nobody commits to a range. I'm 34M, desk job, ADHD-adjacent but no diagnosis, 8 months of intranasal Semax across three reconstitutions.

What I tried, in order:

  • 300 mcg AM only, 2 weeks — noticed basically nothing. Thought it was a dud vial.
  • 600 mcg AM only, 2 weeks — mild lift, verbal fluency a little better, no jitter.
  • 600 mcg AM + 300 mcg early afternoon, 3 weeks — this was the sweet spot for me. Clean focus for ~4-5 hours after each dose, no comedown.
  • 1000 mcg single AM dose, 1 week — felt overdosed. Slight pressure behind the eyes, too wired to nap, but also no better focus than 600. Backed off.
  • Now: 600 AM, 300 PM when needed (maybe 4 days a week).

Few things I didn't expect:

  1. Nasal spray accuracy matters more than the label mcg. I was almost certainly underdosing on my first vial because my atomizer was junk. Switched to a metered pump and the subjective effect jumped without changing dose.
  2. The effect is cumulative-ish for the first 4-5 days of a run, then steady-state.
  3. There is a mild tolerance curve. After ~3 weeks on 600 twice daily the effect dulls. 4 days off resets it for me.

Not a stim. Does not replace sleep. Does not replace caffeine (I still drink coffee). It's a focus floor, not a focus ceiling.

Curious where other people landed on dose and split.

Focus stack
  • Semax · 600 mcg · AM intranasal · intranasal
  • Selank · 250 mcg · as needed · intranasal

16 Replies

S
Joined 2026
34 posts
3/5/2026

This matches my experience almost exactly. 600 AM is the floor, anything under and I'm just making saline expensive. Second dose midday is where the day actually stays consistent.

N
Joined 2026
18 posts
3/6/2026

Question on the atomizer — which metered pump are you using? I'm convinced my 'nothing' runs were really 'most of it hit the back of my throat' runs.

S
Joined 2026
41 posts
3/7/2026

@noots_noop standard 100 uL metered nasal pump, nothing fancy. Key is that each pump is actually 100 uL not 'somewhere between 50 and 150.' Cheap atomizers are all over the place.

Focus stack
  • Semax · 600 mcg · AM intranasal · intranasal
  • Selank · 250 mcg · as needed · intranasal
P
Joined 2026
23 posts
3/7/2026

The tolerance piece is real. I run 5 on / 2 off and the Monday dose feels noticeably cleaner than the Friday one. 3 weeks straight would blunt it for me too.

H
Joined 2025
205 posts
hexaclinicContributor
3/7/2026

Good post. One thing I always flag on Semax threads: the 0.1% vs 1% concentration labeling is where people get mcg math wrong. A 0.1% 3mL bottle is 3mg total. A 'standard spray' of 100 uL from that is 100 mcg, not 1000 mcg. I've seen people convinced they were running 1000 mcg AM when they were running 100.

Q2 stack
  • CJC-1295 no DAC · 100 mcg · pre-bed · sub-Q
  • Ipamorelin · 200 mcg · pre-bed · sub-Q
  • BPC-157 · 500 mcg · 2x/day · sub-Q
W
Joined 2026
17 posts
3/8/2026

Saving this. First time I've seen someone actually lay out a dose ladder instead of saying 'start low.'

C
Joined 2026
23 posts
3/9/2026

Agreed on the pressure-behind-eyes feeling at 1mg. For me that's the tell that I've overshot. 600 is my ceiling and I don't chase past it.

S
Joined 2026
15 posts
3/9/2026

Curious if anyone stacks with tyrosine. I find Semax + 500mg L-tyrosine AM is noticeably better than either alone, but I have no idea if I'm fooling myself.

S
Joined 2026
115 posts
3/9/2026

Worth noting the human trials on Semax are mostly stroke / cognitive rehab populations at relatively high doses via professional intranasal delivery. Extrapolating to 'healthy desk worker wants focus at 300-600 mcg' is not nothing, but it's extrapolation. I use it too. Just calling it what it is.

S
Joined 2026
41 posts
3/11/2026

@stack_nerd I do the same. Whether it's real synergy or just 'two mild things stacked' I couldn't tell you, but I also don't feel compelled to A/B it anymore.

Focus stack
  • Semax · 600 mcg · AM intranasal · intranasal
  • Selank · 250 mcg · as needed · intranasal
D
Joined 2025
119 posts
dr_doubtRegular
3/12/2026

I'd push people to hold the dose constant and vary one other thing before assuming Semax is the lever. Sleep, caffeine timing, and first-meal timing move my subjective focus more than Semax does, and I actually like Semax.

S
Joined 2026
41 posts
3/13/2026

@late_bloomer_m it's intranasal so food doesn't really gate absorption the way oral does. I dose first thing, brew coffee, eat 20-30 min later. I wouldn't worry about it.

Focus stack
  • Semax · 600 mcg · AM intranasal · intranasal
  • Selank · 250 mcg · as needed · intranasal
L
Joined 2026
20 posts
3/13/2026

How long between the AM dose and breakfast? I read conflicting stuff about food blocking absorption.

C
Joined 2026
71 posts
3/14/2026

The 'focus floor, not focus ceiling' framing is the best one-line description of this class I've read.

R
Joined 2026
16 posts
11d ago

Followup a month later — tried the 600/300 split, and it's the first nootropic I've run that I can't tell is there while it's working but miss when I stop. That tracks with what you said.

P
Joined 2026
46 posts
10d ago

Good writeup. Adding one note for anyone newer: the 'sweet spot' dose is going to drift with your sleep. On 5 hours I basically can't feel 600 mcg. On 8 hours I barely need the afternoon dose. Sleep is the real substrate.

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