Synthetic ACTH-derived heptapeptide; investigational nootropic

Semax

aka ACTH(4-7)-Pro-Gly-Pro · ACTH(4-10) analogue

Evidence grade
Grade C: Preliminary human data
for nootropic / cognitive enhancement
User score everyone · n = 61
US FDA Not approved checked 2026-11-13
WADA 2026 Not named no clearance either · checked 2026-11-13
EU No data · checked 2026-11-13

Goals: Cognition & mood Compare with another peptide →

User reports

approximate — combined from two independent Reddit reads

Men 45–60

0 men aged 45–60

No reports in this group yet.

All men

1 man

small sample · n = 1

Outcome negative 1 of 1

Side effects hair shedding 1 of 1

Why stopped side effects 1 of 1

Stopped 1 of 1 Used with other compounds 0 of 1

Everyone

61 people

  • Positive: 29 of 61 (48%)
  • Mixed: 18 of 61 (30%)
  • Negative: 4 of 61 (7%)
  • No effect: 5 of 61 (8%)
  • Unclear: 5 of 61 (8%)
Benefits reported of 61
Benefits reported (n = 61)
ItemReports
Focus / cognition31 of 61 (51%)
Mood / anxiety13 of 61 (21%)
Other7 of 61 (11%)
Energy5 of 61 (8%)
Sleep2 of 61 (3%)
Hair1 of 61 (2%)
Less appetite1 of 61 (2%)
Side effects reported of 61
Side effects reported (n = 61)
ItemReports
Other5 of 61 (8%)
Fatigue4 of 61 (7%)
Heart rate up4 of 61 (7%)
Low mood4 of 61 (7%)
Anxiety3 of 61 (5%)
Headache3 of 61 (5%)
Hair shedding2 of 61 (3%)
Insomnia2 of 61 (3%)
Why people stopped of 61
Why people stopped (n = 61)
ItemReports
Side effects4 of 61 (7%)
No effect2 of 61 (3%)
Cost1 of 61 (2%)

Stopped 6 of 61 (10%) Used with other compounds 13 of 61 (21%)

User reports are anecdata, not evidence: self-selected, unverified, often combined with other compounds.

In their words

  • “Semax was game changer for brain fog”

  • “nice uplift and clarity”

  • “been on it 5 days and felt nothing”

  • “I will continue to do injectable semax for the foreseeable future as it has increased my mental clarity, active recall, and reduced brain fog.”

  • “Semax is the only thing that's worked for me for anxiety, low mood, and anhedonia.”

  • “Hi my friend, I'm a male, it was definitely related to Semax because it was two large patches, nothing like male pattern baldness.”

  • “Didn't do shit for my depression, brain fog or ADHD. Useless. I stopped using it after a week cause it made me extremely angry”

Read summaries and method notes

Read 1. No man aged 45–60 and no explicitly male poster in five fully read threads. Of 23 users, positives were focus, mental clarity, motivation and brain-fog relief; several noticed nothing. Mixed: transient stimulation, raised heart rate, headaches, post-dose tiredness or low mood; some found benefits faded with repeated use. Onset 10–60 minutes; courses of weeks. Nasal and SubQ both represented; potency/delivery consistency was a recurring doubt.

Read 2. No man aged 45–60 (a "mid 50s" user did not state sex). One man reported a negative outcome: two large reversible patches of hair shedding that resolved 2–3 months after stopping. Everyone (n=38, 12 threads): 20 positive, 13 mixed, 4 negative — cognition/focus (22), mood/anxiety (10), energy (5). Intranasal acts in 10–20 minutes, SubQ in 30–60 and smoother; full effects peak at 1–6 weeks. Side effects: overstimulation or vision/sensory changes (5), low mood/irritability (3), anxiety (3), headaches at higher doses, fatigue, hair shedding, insomnia, raised heart rate (2 each). Warnings: fast tolerance with sprays, contamination of multi-use sprays, agitation with stimulants.

Note 1. No qualifying male age reports. Several reports involved Selank or other nootropics. Nasal delivery/potency was a recurring confound. Adamax was not counted.

Note 2. Five seed threads could not be opened. The 'mid 50s' user did not state sex and is in everyone only. Two promotional comments were excluded.

Each read counted people independently. Overlap between the two reads is estimated from shared threads and removed; counts are approximate. How we count.

Summary

Synthetic ACTH-derived peptide with preclinical neurobiological findings and preliminary human evidence; reliable cognitive-enhancement benefit is unestablished. Human research includes intranasal use; subcutaneous safety is not established.

Proposed mechanism

  • Dopamine/serotonin modulation, BDNF expression, cerebral blood flow and neuroprotection are proposed or preclinical effects, not established healthy-person cognitive benefits.
  • Rat hippocampal BDNF/TrkB findings require human outcome confirmation. Animal study.

Safety

  • Hospitalization report involving eye pain/burning; causality unestablished
  • Potential bleeding and immunogenicity concerns
  • Human pharmacokinetics and subcutaneous safety not established

From labels, regulators and trials. No signal in small studies ≠ safe.

Evidence C nootropic / cognitive enhancement

C stands. A 24-person imaging study and a 110-person stroke-rehabilitation comparison with unclear allocation. Its Russian registration is treated the same way as thymalin's and DSIP's: no adequately reported controlled trial behind it, so no lift to B.

Human trials · 2

  1. PMID 302257152018Placebo-controlled exploratory fMRI study; randomization not established 24 people

    Healthy adults

    Changed default-mode-network topography; clinical cognitive benefit not measured. Source

  2. PMID 297989832018Comparative study; allocation/blinding unspecified in abstract 110 people

    Stroke rehabilitation

    Higher plasma BDNF and more favorable Barthel-index recovery reported with Semax. Source

Bar length = trial size on a log scale.

Dose ranges

Reported ranges from labels and studies, with context. Not a recommendation.

  • clinical trial
    1.2 mg intranasally once (imaging study) Source
  • clinical trial
    6 mg/day for two 10-day courses separated by 20 days; route unspecified in abstract Source

Editorial ratings EDITORIAL

Editors’ judgement, 0–5. Opinion, not data; separate from grade and user score.

  • Safety 4.5 out of 5
  • Sleep 3 out of 5
  • Recovery 3 out of 5
  • Cognitive 5 out of 5

Sources

  1. pubmed.ncbi.nlm.nih.gov/30225715/
  2. pubmed.ncbi.nlm.nih.gov/29798983/
  3. hhs.gov/sites/default/files/hhs-503a-peptide-enforcement-discretion-policy-appendix-b.pdf
  4. wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf
  5. ema.europa.eu/en/medicines
  6. fda.gov/media/193774/download
  7. fda.gov/advisory-committees/advisory-committee-calendar/july-23-24-2026-meeting-pharmacy-c
  8. fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-pres
  9. fda.gov/media/193348/download
  10. federalregister.gov/documents/2026/10/30/2026-22192/enforcement-discretion-policy-regardin
  11. pubmed.ncbi.nlm.nih.gov/30225715/?dopt=Abstract
  12. pubmed.ncbi.nlm.nih.gov/16996037/

Reddit threads read · 17

1 further source on commercial or non-primary hosts not listed.

Research checked 2026-11-13.