Frequently Asked Questions

Store lyophilized peptides desiccated at −20 °C or below, protected from light and moisture — in this state most are stable for years. Once reconstituted, aliquot and freeze to avoid repeated freeze–thaw cycles.

They indicate the amino-acid residue range of the parent protein the peptide corresponds to. For example, (7-26) is the fragment spanning residues 7 through 26.

We routinely synthesize peptides up to 112 amino acids, including difficult sequences with multiple disulfide bridges. Send us your sequence for a feasibility assessment.

No. Peptides ship as a lyophilized powder in small quantities, so the material may be a thin film or barely visible at the bottom of the vial. Briefly centrifuge the vial before opening, then reconstitute as directed.

The public catalog groups currently available research materials by product family. If the required sequence is not listed, submit the sequence, scale, modification and specification for a feasibility review.

Custom synthesis typically starts at a few milligrams, with scale ranging from mg to kg. The minimum depends on sequence length and required purity — contact us for a quote.

Yes. We offer fluorescent, biotin, colorimetric, radioactive, and stable-isotope labeling of both custom and catalog peptides.

Extraction removes proteins and matrix components that interfere with assays, concentrating the target peptide to improve sensitivity and reproducibility.

Typically an appropriate anticoagulant, a peptidase inhibitor (e.g. aprotinin), and a solid-phase extraction column. Each EIA/RIA kit protocol specifies the recommended extraction materials for that analyte.

Collect with the recommended anticoagulant and inhibitors, separate promptly, and store at −20 °C (or −80 °C for long-term). Avoid repeated freeze–thaw cycles.

Frozen at −20 °C to −80 °C, most peptide analytes are stable for several months. For best results, assay as soon as practical.

The document set varies by product, lot and project. Request the applicable specification, available analytical records and any safety or handling documents before accepting a quotation.

Purity targets and analytical methods vary by product and project. Request the current specification and lot-specific result where available; an HPLC area result is not the same as peptide mass fraction.

Methods and release criteria vary by material and intended project. The written specification and available lot records should identify the applicable tests, methods, acceptance limits and measured results.

Example or lot-specific documents may be requested. Availability of documents or physical evaluation quantities is confirmed for the selected product before quotation.

Do not assume equivalence across lots. Compare the applicable specification and lot-specific results, and request change-control or traceability information where it is relevant to the project.

MOQ varies by product. Most peptides start from 5 mg for evaluation. Bulk orders range from grams to kilograms. Contact us for product-specific MOQ.

Current availability, the dispatch estimate, carrier options and destination-specific transit estimates are confirmed before quotation. Customs, import clearance and carrier timing cannot be guaranteed.

Temperature-controlled packaging with cold packs where required. Peptides are shipped lyophilized and are stable at ambient temperature for the duration of transit.

Bank transfer (T/T), PayPal, Western Union, and major credit cards. For large orders we can discuss payment terms and letter of credit arrangements.

Store lyophilized peptides at −20 °C, protected from light and moisture. After reconstitution, aliquot and freeze to avoid repeated freeze–thaw cycles.

I-125 labeled tracers are supplied at a defined activity (µCi) referenced to a calibration date on the vial. See the datasheet for the exact value.

I-125 has a half-life of approximately 59.4 days.

Store at 2–8 °C behind appropriate shielding, following your institution's radiation-safety procedures. Do not freeze unless specified.

Use A = A₀ × (1/2)^(t / 59.4 days), where A₀ is the activity at the calibration date and t is the number of days elapsed.

The dispatch estimate for a catalog or custom peptide is confirmed after the selected material, scale, specification and current availability have been reviewed.

Labeling feasibility and lead time depend on the requested label, incorporation position, scale and analytical requirements; the estimate is confirmed during technical review.

Current availability and the dispatch estimate for a selected kit are confirmed before quotation.

Custom-synthesis lead time is quoted after feasibility review because sequence length, modifications, scale, purification and analytical requirements can materially change the schedule.

Current availability and the dispatch estimate are confirmed for the selected product before quotation.

NHD supplies pharmaceutical companies, research institutions, cosmetic manufacturers, biotech firms and CROs. Products are for research, development and manufacturing use — not for direct human use.

Account approval requires business verification. Products are supplied for research, development and manufacturing use only.