DSIP vs P21
Which should you choose? Here's what you need to know.
The short answer
DSIP and P21 are both cognitive / neuro peptides, but they work differently. Delta Sleep-Inducing Peptide, a neuropeptide studied for its role in sleep regulation, stress response, and circadian rhythm modulation. Compare vendor pricing and availability below.
On 19 Sep 2026 Peptide Compare tracked 51 vendors selling DSIP, cheapest in stock $2.20 per mg at Step One, and 7 selling P21, cheapest $8.50 per mg at Soma Chems.
DSIP
Cognitive / NeuroDelta Sleep-Inducing Peptide, a neuropeptide studied for its role in sleep regulation, stress response, and circadian rhythm modulation.
P21
Cognitive / NeuroPrice & availability
Once you've decided which peptide fits your needs, here's how they compare on price and vendor options. Prices verified Sep 19, 2026.
DSIP
P21
$22.00
Starting from
$84.99
$9.39
Avg. price per mg
$47.57
51
Vendors selling it
7
45 options
In stock now
5 options
9.1/10
Top trust score
7.0/10
Ready to buy?
Our top-rated vendor for each, based on trust scores, purity testing, and price.
Some outbound links may earn us a commission. Vendors cannot pay to improve rankings.
Where does this data come from?
We re-check vendor prices continuously and score vendors on Finnrick blind-test results — samples bought anonymously and sent to a lab, not vendor claims. No vendor can pay to rank higher. See our full methodology.