Does Semax increase cortisol?

No. Despite being derived from ACTH (adrenocorticotropic hormone), Semax does not stimulate adrenal cortisol production. The specific ACTH fragment used in Semax (positions 4-10) lacks the N-terminal amino acid sequence (positions 1-3) required for MC2R activation on adrenal cells. Semax retains the neurotrophic effects of ACTH while completely lacking its steroidogenic (cortisol-stimulating) activity.

How quickly does Semax work?

Semax's acute cognitive effects (improved attention, focus, mental clarity) are typically reported within 15-30 minutes of intranasal administration. However, the neurotrophic effects — BDNF and NGF upregulation, neuroplasticity enhancement — likely require sustained use over days to weeks to fully develop. Russian prescribing guidelines recommend treatment courses of 10-14 days, suggesting optimal benefits develop with sustained use.

Can I use Semax and Selank together?

The Semax-Selank combination is popular in the nootropic community and has a theoretical rationale — Semax primarily enhances cognition via BDNF/NGF pathways while Selank primarily reduces anxiety via GABA modulation. However, there is very limited published data on the combination. If combining, conservative dosing of both and physician awareness would be advisable.

What is the difference between Semax, N-Acetyl Semax, and NA-Semax Amidate?

Standard Semax is the original approved formulation. N-Acetyl Semax (NA-Semax) has an acetyl group added to the N-terminus, reportedly enhancing potency and stability. NA-Semax Amidate adds both acetylation and amidation, claimed to further increase stability and duration. However, N-Acetyl Semax and NA-Semax Amidate have significantly less published clinical data than standard Semax. Most research supporting Semax's effects used the standard formulation.

Is Semax legal in the United States?

Semax is not FDA-approved for any indication in the United States but is not a controlled substance. It is available as a research chemical through peptide vendors. The legal framework is similar to other research peptides — purchasing for research purposes is legal, but it is not approved for human therapeutic use. Regulatory status could change.

Does Semax cause tolerance?

No tolerance has been reported in clinical data or post-marketing surveillance. However, Russian prescribing guidelines recommend course-based treatment (10-14 days on, with breaks) rather than continuous indefinite use. Whether this reflects a genuine concern about efficacy diminishing over time or is simply a conservative prescribing convention is not clear from the available literature.

Can Semax help with ADHD?

Semax's effects on attention, dopamine modulation, and BDNF expression are mechanistically relevant to ADHD. Some individuals with ADHD in the nootropic community report subjective benefit. However, Semax has not been studied in ADHD-diagnosed populations through controlled clinical trials, and it cannot be recommended as an ADHD treatment based on current evidence. Anyone considering Semax for ADHD symptoms should discuss this with their physician.

Vendor Rankings

Independent rankings of peptide vendors based on aggregated lab data, COA transparency, community sentiment, and verified pricing. We publish everything — including the failures.

0+ samples tracked 27 vendors ranked 15 peptides tracked

All BPC-157 Tirzepatide Semaglutide CJC-1295 Ipamorelin GHK-Cu Retatrutide Tesamorelin

AGreat

B+Very Good

BGood

COkay

DPoor

EBad

FFraud

Semax Rankings

HUMAN TRIALS

0 samples across 27 vendors · Updated weekly from independent lab testing

#	Vendor	Avg score	Purity range	Tests	Verified $/mg	Grade	Profile
Grade F — Fraud
1	Anlv Biotechnology	—	—	0	—	F	review →
2	Peptaion	—	—	0	—	F	review →
3	PeptideCraft	—	—	0	—	F	review →
4	Shanghai Leader Peptide Biotechnology	—	—	0	—	F	review →
5	Tianjin Ruiwang New Material Technology Co	—	—	0	—	F	review →
6	VertexBio	—	—	0	—	F	review →
7	Vital Living Bio	—	—	0	—	F	review →
8	Welon Peptide Solutions	—	—	0	—	F	review →
9	Xingtai Lesda Technology	—	—	0	—	F	review →
10	Zen Peptides	—	—	0	—	F	review →
11	ZePeptide	—	—	0	—	F	review →
12	Zhengzhou Lan Yun Cosmetic Trading	—	—	0	—	F	review →
13	LP Peptide	—	—	0	—	F	review →
14	NutriPeptix	—	—	0	—	F	review →
15	Lipeptides	—	—	0	—	F	review →
16	Bulk Peptide Supply	—	—	0	—	F	review →
17	Bulk Peptide Wholesale	—	—	0	—	F	review →
18	Coffee and Peppers	—	—	0	—	F	review →
19	Dankang BioHealth	—	—	0	—	F	review →
20	Grewo Peptide	—	—	0	—	F	review →
21	Guangzhou Jeep Biotechnology JEEP	—	—	0	—	F	review →
22	Heman Peptide HM	—	—	0	—	F	review →
23	Hot Girl Biohacking	—	—	0	—	F	review →
24	Huatai Peptide	—	—	0	—	F	review →
25	Ion Peptide	—	—	0	—	F	review →
26	LiliPeptide	—	—	0	—	F	review →
27	Zhejiang Peptites Biotech ZPC	—	—	0	—	F	review →

Verified $/mg = list price ÷ (avg tested qty / labeled qty). Vendors below the cutoff omitted from view.