Frequently Asked Questions

Find all the answers here.

VetIMMUNE® PI is a patented blend of bioactive polyprenyls from American mulberry. Using advanced technology, it delivers physiologically relevant quantities of these essential natural signaling molecules for
proper organism growth and functioning.

Innate immune response is necessary to keep the organism healthy.

Innate immunity is the body's first line of defense, consisting of rapid, genetically pre-coded cellular responses to threats. Innate immunity is universal and naturally occurs in all organisms; it is also broad-range and does not require activation by vaccines. This universal immune response relies on functional white blood cells of specific types: neutrophils, monocytes, macrophages, and dendritic cells that "devour" agents and control the inflammatory process, gamma-delta-T-cells that mount a quick response, and other cells. Innate immunity is mediated by cytokines, including antiviral proteins like interferons.

Polyprenyls in VetIMMUNE® PI have been found to upregulate cytokine expression in human cell cultures. Most notably, healthy cats receiving VetIMMUNE® PI show upregulation of interferons in their blood leukocytes. This supports VetIMMUNE® PI's enhancement of non-specific, innate immunity, which helps build robust immune responses.

Studies by Harvard University researchers have demonstrated that polyprenyls act as stop signals in support of normal inflammatory response and also have antioxidative effects. Other research suggests that polyprenyls may help the proper functioning of the liver.

We are proud to say that VetIMMUNE® PI is an All-American product made from American mulberry by Sass & Sass, Inc., a Tennessee company.

VetIMMUNE® PI is made by a dedicated team of experts, and all critical operations and quality control are done manually to ensure the highest product quality.

We do not have any reports of side effects from using VetIMMUNE® PI with medicines or supplements.

That depends on your pet's weight.

The Small Cat & Dog Up to 16 lbs. formulation (blue cap, 2 mg/ml) is the best fit for immunity support of smaller cats and dogs.

The Large Cat & Dog 17 lbs. and Up formulation (green cap, 4 mg/ml) is designed for immunity support in larger cats and dogs.

VetIMMUNE® PI is a boutique product and is packaged more securely than required for an oral supplement. To give, pop off the plastic top (do not remove the aluminum seal) and stick the provided adaptor through the grey rubber in the opening. Attach the supplied syringe and draw the appropriate amount. To protect bottle contents, do not return excess product back into the bottle, so draw carefully. Detach the syringe and either give VetIMMUNE® PI by mouth or add it to a small amount of food.

You can watch an instructional video here.


VetIMMUNE® PI is tasteless but has a slight smell that some animals, even cats, find pleasant, but most animals are indifferent. Very few cats find the smell unpleasant, in which case give VetIMMUNE® PI during mealtime.

After opening or if you plan on using VetIMMUNE® PI later than 30 days, it should be stored in the dark in the refrigerator.

VetIMMUNE® PI MUST NOT BE FROZEN because it may fall out of the solution!

The expiration date is printed on the right side of the label. After the expiration date, the concentration may decrease, but
VetIMMUNE® PI does not become toxic or harmful.  It is also easy to tell if any degradation has occurred due to improper storage: look at the vial content against bright light - opalescence and turbidity are signs of degradation. The substance is there, but its delivery may be altered. Degradation does not make VetIMMUNE® PI toxic - it makes VetIMMUNE® PI less concentrated or delivered less efficiently.

VetIMMUNE® PI is probably the best-studied health supplement, described in many scientific papers by US and international researchers from major universities. It has been used worldwide in cats, dogs, and ferrets for two decades.

The studies have consistently reported the safety and benefits of VetIMMUNE® PI for support of innate immunity, maintaining a normal inflammatory response, and healthy homeostasis, normalizing homeostasis, and support of overall health in animals of all ages, including during long-term use.

For technical information, you may refer to the following publications and share those with your veterinarian:

Legendre & Bartges, 2009

Legendre et al., 2017

Legendre et al, 2017

Cerna et al., 2022

Addie et al., 2022

Cerna et al., 2024

VetImmune LLC (vetimmune.com) is the only distributor of VetIMMUNE® PI for the US and countries outside of the EU. Please contact us at orders@vetimmune.com to place an international order.

For EU orders, VetIMMUNE® PI is registered and available from Panda Plus s.r.o., in the Czech Republic. (www.pandaplus.cz/index.php/kontakty).

Unless you need VetIMMUNE® PI urgently and let us know, we will ship using the cheapest available method: USPS or FedEx.

In the wintertime, we will use FedEx Express Saver to ship to our customers during freezing temperatures because
VetIMMUNE® PI must not be frozen.

We are doing our best to ship all orders on the day they are received. However, we have cutoff times due to local pickup schedules. We will be able to send on the same day if we have your complete order by:

3 PM ET if you requested shipping by FedEx Ground (available May-October only)
4 PM ET if you requested shipping by FedEx Express services or USPS.

We do not ship on Saturdays, Sundays, or major public holidays. All orders received after the cutoff on days off will be processed on the next business day.

No. VetIMMUNE® PI is stable at temperatures above freezing and would not spoil even at elevated temperatures. However, we would not recommend leaving it outside for prolonged periods.

Very likely, it will. VetIMMUNE® PI is unstable at lower temperatures; it should never be frozen. In some areas, we will not
allow signature waivers in the wintertime to ensure that the product does not spoil while waiting outside. Freezing breaks fine micelles in the solution, and VetIMMUNE® PI may precipitate. It will remain safe, but its delivery to the organs may be affected.

If the animal’s condition worsens or does not improve, stop product use and consult your veterinarian. Safe use in pregnant animals or animals intended for breeding has not been proven. If the veterinarian confirms that the adverse event is due to the supplement, you need to file a report with the manufacturer:
info@sassandsass.com

Yes, we accept returns within 5 days from purchase as long as the bottle has not been opened and is returned along with the original packaging. We will reimburse you for the cost of the bottle but can not reimburse you for the cost of shipping or returning it.