Compare prices and buy peptides in the Immune & Anti-inflammatory category from every research peptide vendor, supplier and source we index. Updated daily.
Thymic peptides (Thymalin, Thymulin, Thymosin alpha-1), cathelicidins (LL-37), and alpha-MSH-derived fragments studied for immune modulation and inflammatory-pathway research.
The peptides grouped here act on immunity from opposite directions. The thymic peptides target adaptive immunity, principally T-cell maturation and differentiation, and come out of research on calf thymus extracts that ran in parallel in the United States and the Soviet Union. The second group acts on innate immunity, through direct antimicrobial activity and modulation of the local inflammatory response, with no thymic involvement at all.
Thymosin Alpha 1 is the best characterized member, a defined synthetic peptide first isolated from a calf thymus extract and marketed outside the United States as a licensed drug.
The Russian and Soviet thymic preparations occupy the same mechanistic space with far fewer randomized trials behind them. Thymalin is a polypeptide complex extracted from calf thymus rather than a single defined sequence. Thymogen is the dipeptide glutamyl-tryptophan, isolated from that complex as one of its active components. Thymulin, which comes from separate work on a thymic hormone found in serum, is a nonapeptide whose activity depends on a bound zinc ion.
One distinction matters when comparing prices across the group: thymosin alpha-1, thymogen and thymulin are defined sequences, while thymalin is an extract, a mixture of peptides rather than one molecule. A per-milligram figure on an extract is not measuring the same thing as a per-milligram figure on a single molecule.
LL-37 is the antimicrobial peptide released from human cathelicidin, and in laboratory studies it both permeabilizes bacterial membranes and recruits immune cells.
KPV is a fragment of alpha-melanocyte-stimulating hormone studied for anti-inflammatory activity in cell and rodent models, apparently without the melanocortin-receptor activity behind the parent hormone's pigmentation effect. Its full-length relative Melanotan I is catalogued under Skin and Cosmetic, where the melanocortin activity KPV lacks is the entire point of the product.
Nothing in this category holds an FDA approval. Two members changed status in the US compounding process in 2026. On April 15, 2026 the FDA announced the removal of twelve peptides, effective seven days later, from Category 2 of its interim policy on substances nominated for the Section 503A bulks list, the group it says may present significant safety risks. Their nominators had withdrawn the nominations, and both KPV and LL-37 were on that list.
KPV has since been heard by the Pharmacy Compounding Advisory Committee, which recommended adding it to the 503A bulks list, and LL-37 is on the slate for the committee's next meeting. Removal from Category 2 is not authorization, and the committee's vote is advisory, since the list changes only through notice-and-comment rulemaking. In October 2026 HHS issued a policy under which it does not intend to take enforcement action against pharmacies compounding KPV under set conditions until a final rule settles its listing, and our post on the HHS policy covers its terms.
Thymosin alpha-1's international approvals apply to the licensed Zadaxin product, not to research-grade powder. Material sold by the vendors indexed here is labeled for laboratory use only.
KPV turns up in four separate multi-peptide blends, which makes it easy to buy twice without noticing. It is a component of KLOW (GHK-Cu plus BPC-157 plus TB-500 plus KPV), the BPC-157 plus TB-500 plus KPV tri-blend, BPC-157 plus KPV, and GHK-Cu plus KPV, which some vendors label "Beauty Blend".
Thymosin alpha-1 appears as TA-1 or TA1 depending on the seller, and thymogen is sometimes spelled thymagen. PeptideScouter maps every one of these labels onto a single page per compound so that per-milligram prices stay comparable across vendors that use different naming.
All four came out of thymic-peptide research, but they are not variants of one molecule. Thymosin alpha-1 is a defined 28-amino-acid synthetic peptide, originally isolated from calf thymus fraction 5 and now sold internationally as the licensed drug Zadaxin. Thymalin is a polypeptide complex extracted from calf thymus, a mixture of peptides rather than a single sequence. Thymogen is the dipeptide glutamyl-tryptophan, isolated from that complex as one of its active components. Thymulin is a nonapeptide whose activity depends on a bound zinc ion. The practical consequence for price comparison is that a per-milligram figure on an extract like thymalin is not measuring the same thing as a per-milligram figure on a defined sequence.
Four blends tracked here include KPV. KLOW is GHK-Cu plus BPC-157 plus TB-500 plus KPV. The tri-blend sold as BPC-157 plus TB-500 plus KPV drops the copper component. BPC-157 plus KPV is the two-component version. GHK-Cu plus KPV is also sold under the name Beauty Blend. Because KPV also sells as a standalone peptide, it is easy to buy it twice by ordering a blend alongside the single compound without checking the blend composition.
No. In July 2026 the FDA Pharmacy Compounding Advisory Committee voted to recommend adding KPV to the Section 503A bulk drug substances list. The vote is advisory. It does not make KPV an approved drug, and it does not by itself authorize compounding, because the FDA changes the bulks list through notice-and-comment rulemaking and is not bound by the committee's recommendation.
Yes, outside the United States. Under the international nonproprietary name thymalfasin and the brand name Zadaxin, from SciClone Pharmaceuticals, thymosin alpha-1 is marketed for chronic hepatitis B in a number of countries. FDA stated in its November 2024 evaluation that it could not independently verify SciClone's claims about which countries approved it. The regulator records FDA cited are from Italy, India and Hong Kong, plus a monograph in Singapore's national drug formulary. It has never been approved by the FDA for any indication in the United States. Those approvals cover the licensed pharmaceutical product, while research-grade thymosin alpha-1 powder sold by the vendors indexed here is a different supply chain and is labeled for laboratory use only.
44 vendors tracked by PeptideScouter sell Immune & Anti-inflammatory peptides, across 155 listings covering 6 compounds. The widest Immune & Anti-inflammatory catalogs belong to Alpha Peptides (4 peptides), Biotech Compounds (4 peptides), Disguised Alpha (4 peptides). Prices are normalized to USD per milligram and refreshed daily.
Immune & Anti-inflammatory peptides indexed on PeptideScouter have a median price of $4.45/mg, ranging from $3.40/mg to $8.00/mg across the 6 peptides in the category. Pricing is normalized across vendors and refreshed daily.
Thymogen carries the lowest median price in the Immune & Anti-inflammatory category at $3.40/mg across 3 listings. Its cheapest in-stock listing is $3.25/mg at Platinum Lion Peptides. Per-milligram price varies widely between compounds in a category, so the cheapest per mg is not necessarily the cheapest vial or the right compound for a given experiment.
The most widely sold Immune & Anti-inflammatory peptides on PeptideScouter (by vendor count) are: KPV, Thymosin Alpha 1, LL-37, Thymalin, Thymogen. Each peptide page shows current pricing across every tracked vendor, normalized to USD per milligram.
