Minimize the Regumate Mess

30 AUG 2018, updated 18 Nov 2025

The following “Tip of the Day” is provided to assist you with horse and farm management.  It is an original idea developed by and/or used by Leslie Raulin.  This tip is available to you at your own risk.  Leslie Raulin does not make any claims or warranties, nor does she have any financial interest in any products that may be mentioned.

My horse Aviani (Annie) was a perfect adult amateur dressage horse, as long as she was on altrenogest (Regumate, OvaMed, Altren), a hormone that is administered daily to prevent equine estrous.  It is an oily liquid that is top-dressed over feed one time daily.  It is usually not used in the winter when a horse is anestrous. In this TOD, I use the term “Regumate”; however, it applies to all the brand names of altrenogest.

Without Regumate, Annie was a dangerous raging lunatic when she was in season.  I knew this when I bought her and, other than the expense (as of November 2025, $150 for Regumate, Ovamed; $130 for Altren; all per liter, which lasts a few months), I was ok with its use.  However, I was not prepared for the mess.  The bottle has a very short cap so the medication leaks all over the bottle.  Since altrenogest can affect humans, gloves are therefore necessary when administering it.  I tried the dispensing gun but had the same problem; in fact, it was worse.  I resorted to using a 20cc leur lock syringe and a lot of gloves.  A few years ago, I set out to minimize the mess.  The answer is simple – GLUE applied to the bottle cap!

Seal-All 2oz. Adhesive and Sealant.

This is the best glue I have found as it works with oily substances and plastics.  It is available in many stores.  I purchased it at Home Depot.  According to their web site:

Seal-All is the adhesive mechanics and hobbyists trust for all their automotive and garage repairs. It adheres with superior strength to most substrates and resists gasoline, oil, paint thinner, and solvents. Seal-All does not require mixing or heating and will not become brittle.

  • High strength multi-purpose adhesive that seals, bonds and insulates
  • Clear, waterproof and paintable
  • Temperature resistant-remains tough even in extreme temperatures
  • E-Z flow formula sets in 2-3 minutes

The cost is $5.00 – $7.00 per 2oz tube (Nov 2025).

The Regumate bottle arrives with a regular cap, a seal on the bottle, and a cap designed to work with a luer lock syringe.

Remove the regular cap and carefully remove the seal.  I use a knife to pierce the seal then peel the seal off with the knife.

Apply the glue along the threads on the inside of the cap designed for use with a luer lock syringe.  Ensure that some glue is on all the threads without using too much glue (experience leads to perfection!).

Screw the luer lock cap onto the bottle.

Although the glue package says it sets in 2-3 minutes, I let it set over night.

Depending on the dose in ml required for your horse (determine this with your veterinarian), purchase 10ml or 20ml luer lock syringes without needles.  I purchase syringes without needles in bulk via Amazon.com or Valley Vet.

The syringes can be used multiple times. Change to a new syringe when it becomes necessary to pull hard on the plunger.

Before each use, carefully screw the syringe into the bottle.

Tip the bottle so the syringe is down, and pull the plunger on the syringe to draw up the volume needed for your horse. 

Sometimes a small amount of Regumate leaks out from the syringe onto the cap when the syringe is removed from the bottle.  I wipe this with tissue or toilet paper and throw it away.

Slowly dispense the Regumate over your horse’s meal. 

I let it soak in for a few minutes then shake the meal to distribute the Regumate.

This is how I store the Regumate bottle and syringe. Note the paper towel at the bottom of the bucket to collect any spillage. If you are in a public barn, it is recommended to store the Regumate, etc. in a safe place with a warning sign on the bucket.

With this glue method, I no longer need to use gloves when dispensing Regumate as it does not leak all over the bottle.  You may still want to use gloves, particularly if your are a female of reproductive age and/or a hormone-sensitive cancer.

PS – I purchase Regumate via Valley Vet.  My equine veterinarian establishes a prescription with them, usually with refills for a year, so I just reorder from Valley Vet when I need another bottle.  This is convenient and is less expensive.

Enjoy!