Tips to Give Metformin


Hi, my 19 year old 10-hand pony was diagnosed with seasonal IR. The lab report said November - March. I want to get him started on Metformin and have the coffee grinder and can powder it but I'm having trouble getting him to accept it. What has worked for you all? If you use a syringe, what type works and where did you get it? Thank you! 
Heidi M. in Colorado 2022

Bobbie Day

Hello Heidi and welcome to the group!
I will be sending along your welcome message which we ask that you read and keep handy for any future questions you may have.
To answer your question, we have many members giving metformin, I'm sure you will get many great suggestions, but it's recommended to give with milk of magnesia, as described here:
Metformin 08.08.20 FINAL (
You can also do a search in our messages since this is a popular topic. 
Let us know if you have any additional questions.


Welcome to the group! 

The ECIR Group provides the best, most up to date information on Cushing's (PPID) and Equine Metabolic Syndrome (EMS)/Insulin Resistance (IR). Please explore our website where you'll find tons of great information that will help you to quickly understand the main things you need to know to start helping your horse. Also open any of the links below (in blue font) for more information/instructions that will save you time.

Have you started your Case History? If you haven't done so yet, please join our case history sub-group. We appreciate you following the uploading instructions so your folder is properly set up with the documents inside. Go to this CH message with info on how to use various devices and forms. If you have any trouble, just post a message to let us know where you are stuck.

Orienting information, such as how the different ECIR sections relate to each other, message etiquettewhat goes where and many how-to pages are in the Wiki. There is also an FAQs on our website that will help answer the most common and important questions new members have. 

Below is a general summary of our DDT/E philosophy which is short for Diagnosis, Diet, Trim and Exercise.


DIAGNOSIS: There are two conditions dealt with here: Cushings (PPID) and Equine Metabolic Syndrome (EMS)/Insulin Resistance (IR). These are two separate issues that share some overlapping symptoms. An equine may be either PPID or EMS/IR, neither or both. While increasing age is the greatest risk factor for developing PPID, IR can appear at any age and may have a genetic component. Blood work is used for diagnosis as well as monitoring the level of control of each.

PPID is diagnosed using the Endogenous ACTH test, while EMS/IR is diagnosed by testing non-fasting insulin and glucose.

The fat-derived hormone leptin is also usually abnormally elevated in insulin resistance but because there are many other things which can lower or increase leptin ECIR is not recommending routine testing for this hormone. Leptin is the hormone that says "stop eating".

In Europe, adiponectin is tested instead of leptin. Adiponectin helps regulate glucose and fat burning, and maintain insulin sensitivity. Low levels are associated with EMS. It has come to be preferred over leptin because it is not influenced by things like weight or exercise, and also because it was the only factor other than insulin levels that predicted laminitis risk

*Before calling your vet to draw blood for tests, we suggest saving time and wasted money by reading these details and then sharing them with your vet so that everyone is on the same page regarding correct testing and protocols.

*Please remember to request copies of the results of all the tests done rather than just relying on verbal information. Your vet should be able to email these to you. If you have previous test results, please include those as well. All should go in your CH, but if you are having any trouble with the CH, just post in the messages for now. 

Treatment: EMS is a metabolic type - not a disease - that is managed with a low sugar+starch diet and exercise (as able). The super-efficient easy keeper type breeds such as minis, ponies, Morgans, Arabs, Rockies are some of the classic examples. PPID is a progressive disease that is treated with the medication pergolide. Some, but not all, individuals may experience a temporary loss of appetite, lethargy and/or depression when first starting the medication. To avoid this "pergolide veil" (scroll down for side effects), we recommend weaning onto the drug slowly and the use of the product APF. The best long term results are seen when the ACTH is maintained in the middle of the normal range at all times, including during the annual seasonal rise. To accomplish this, the amount of medication may need to increase over time. Neither condition is ever "cured", only properly controlled for the remainder of the equine's life. If your partner is both PPID and IR then both medication and diet management will be needed. 

DIET: Almost all commercial feeds are not suitable - no matter what it says on the bag. Please see the International Safe Feeds List for the safest suggestions.

No hay is "safe" until proven so by chemical analysis. The diet that works for IR is:

  • low carb (less than 10% sugar+starch)
  • low fat (4% or less) 
  • mineral balanced  

We use grass hay, tested to be under 10% ESC + starch, with minerals added to balance the excesses and deficiencies in the hay, plus salt, and to replace the fragile ingredients that are lost when grass is cured into hay, we add ground flax seed and Vitamin E. This diet is crucial for an EMS/IR horse, but also supports the delicate immune system of a PPID horse. 

*Until you can get your hay tested and balanced we recommend that you soak your hay and use the emergency diet (scroll down for it).  The emergency diet is not intended for long term use, but addresses some of the most common major deficiencies. Testing your hay and getting the minerals balanced to its excesses and deficiencies is the best way to feed any equine (look under the Hay Balancing file if you want professional help balancing). If you absolutely cannot test your hay and balance the minerals to it, or would like to use a "stop gap" product until you get your hay balanced, here's a list of "acceptable" ration balancers

There is a lot of helpful information in the start here folder so it is important you read all the documents found there. The emergency diet involves soaking your untested hay for an hour in cold water or 30 minutes in hot water. This removes up to 30% of the sugar content, but no starch. Starch is worse than sugar since it converts 100% to glucose while sugar only converts 50%, so starch causes a bigger insulin spike. Make sure you dump the soaking water where the equine(s) can't get to it. 

What you don't feed on the EMS/IR diet is every bit as, if not more important than, what you do feed! No grass. No grain. No sugary treats, including apples and carrots. No brown/red salt blocks which contain iron (and sometimes molasses) which interferes with mineral balancing, so white salt blocks only. 

No products containing molasses. No bagged feeds with a combined sugar and starch of over 10% or starch over about 4%, or fat over about 4%. Unfortunately, even bagged feeds that say they are designed for IR and/or PPID equines are usually too high in sugar, starch and/or fat. It’s really important to know the actual analysis and not be fooled by a name that says it is suitable for EMS/IR individuals.

We do not recommend feeding alfalfa hay to EMS/IR equines as it makes many of them laminitic. Although it tends to be low in sugar, many times the starch is higher and does not soak out. Additionally, protein and calcium are quite high, which can contribute to sore footedness and make mineral balancing very difficult.

TRIM: A proper trim is toes backed and heels lowered so that the hoof capsule closely hugs and supports the internal structures of the foot. Though important for all equines, it's essential for IR and/or PPID equines to have a proper trim in place since they are at increased risk for laminitis. After any potential triggers are removed from the diet, and in PPID individuals, the ACTH is under control, the realigning trim is often the missing link in getting a laminitic equine comfortable. In general, laminitic hooves require more frequent trim adjustments to maintain the proper alignment so we recommend the use of padded boots rather than fixed appliances (i.e. shoes, clogs), at least during the initial phases of treatment.

Sometimes subclinical laminitis can be misdiagnosed as arthritis, navicular, or a host of other problems as the animal attempts to compensate for sore feet. 

You are encouraged to make an album and post hoof pictures and any radiographs you might have so we can to look to see if you have an optimal trim in place. Read this section of the wiki for how to get a hoof evaluation, what photos are needed, and how to get the best hoof shots and radiographs.

EXERCISEThe best IR buster there is, but only if the equine is comfortable and non-laminitic. An individual that has had laminitis needs 6-9 months of correct realigning trims before any serious exercise can begin. Once the equine is moving around comfortably at liberty, hand walking can begin in long straight lines with no tight turns. Do not force a laminitic individual to move, or allow its other companions to do so. It will begin to move once the pain begins to subside. Resting its fragile feet is needed for healing to take place so if the animal wants to lay down, do not encourage it to get up. Place feed and water where it can be reached easily without having to move any more than necessary. Be extremely careful about movement while using NSAIDs (bute, banamine, previcox, etc.) as it masks pain and encourages more movement than these fragile feet are actually able to withstand. Additionally, NSAIDs (and icing) do not work on metabolic laminitis and long term NSAID use interferes with healing. Therefore, we recommend tapering off NSAIDs after the first week or so of use. If after a week's time your equine's comfort level has not increased, then the cause of the laminitis has not been removed and keeping up the NSAIDs isn't the answer - you need to address the underlying cause.


There is lots more information in our files and archived messages and also on our website. It is a lot of information, so take some time to go over it and feel free to ask any questions. If you are feeling overwhelmed, don't worry, you will catch on, and we are always here to help you! Once you have your case history uploaded, we can help you help your equine partner even better.

For members outside North America, there are country specific folders in the files and many international lists in the wiki to help you find local resources.

If you have any technical difficulties, please let us know so we can help you. 


Bobbie and Maggie 
Desi (over the rainbow bridge 7/21) 
Utah, Nov 2018
ECIR Group Primary Response

Eleanor Kellon, VMD

Could you post the lab report in a case history please? There is no such thing as seasonal IR
Eleanor in PA 
EC Owner 2001
The first step to wisdom is "I don't know."

Sherry Morse

Hi Heidi,

There's no such thing as 'seasonal IR' - a horse is either IR or it is not.  IR is controlled through diet and exercise and if needed medication.  Using Metformin is only indicated if there's an emergency situation OR if diet and exercise (as possible) are not working. 

Once you get a case history started and can share the actual bloodwork report with us we'll better be able to advise you on next steps.


Hi, I have posted our case history file and the full bloodwork labs-- under Heidi and Romeo. It amazed my veterinarian that the lab wrote on it: "Evidence is mounting that insulin concentrations are affected by
season with higher concentrations detected in December, January, and February in the Northern hemisphere, suggesting a winter-associated exacerbation of ID." I'm very interested in your  thoughts on this as I had not found that anywhere before but it fits his profile. He is usually fine all summer long. 

My vet has prescribed Metformin to begin in late October to help when he usually has a bout of laminitis in December-March. I'm looking for ways to give that as I can't seem to get him to take it. 

I'm having trouble finding the older posts on this Groups website so if there are tips already shared that would be good to see, I'm glad for any pointers about how to use the system. I'll go on youtube to try to learn how to use this! 

Thanks for all, Heidi
Heidi M. in Colorado 2022

Maxine McArthur

Heidi, if you go to the Files section of this group, you’ll see a search box. Type in ‘Metformin’, and you’ll see a folder by the same name. Inside the folder is a document that tells you the basics about metformin use. 

You can also use the search box here in Messages. There have been several recent threads on metformin use. 

To learn more about navigating the group, please go to the Wiki—lots of instructions and a site map there. 
Maxine and Indy (PPID) and Dangles (PPID)

Canberra, Australia 2010
ECIR Primary Response


Nancy C

Hi Heidi

Here is the link to your CH

Would you please add it to your signature. Go here and scroll down to signature box. Once it is loaded, hit return to make teh link LIVE.  It will turn blue as you see here. Don't forget to hit save.

If you can find your way to the WIKI, you'll find lots of help in navigating this group.   Here is a recent post I put up to help folks search the archives and files, etc..

Good for you for keeping at it! Let us know if you get stuck.

I will be interested to hear what Dr Kellon has to say about Antech's report of seasonal insulin rise.
Nancy C in NH
ECIR Moderator 2003
ECIR Group Inc. President/Treasurer  2021-2022

Nancy C first response to the lab finding higher insulin in those months would be it is colder temperatures causing elevated readings.
Nancy C in NH
ECIR Moderator 2003
ECIR Group Inc. President/Treasurer  2021-2022


Thank you so much. I have attached my case history to my signature now. I'm learning! My vet was interested about the note from the lab talking about higher IR in the winter months and curious about how that aligns with when Romey has a laminits bout. 
Heidi M. in Colorado 2022 with the amazing Romeo, a 2004 model Shetland-type pony. 
Case history:

Sherry Morse

Hi Heidi,

It appears that Romeo is experiencing bouts of winter laminitis on a yearly basis.  Keeping his legs wrapped will help with this but you also need to get his insulin down as much as possible. You can read more at Winter Laminitis | Dr. K's Horse Sense (

Can you please rename your x-rays and photos following the guidelines here:

Can you also please add Romeo's breed, height weight, ideal weight and current weight info to your case history?  All of this is VERY important for us to know.  Metformin dosing is based on weight (30mg/kg 2x a day) and you should have a CURRENT insulin prior to starting the medication and then plan on retesting 7 - 10 days after starting to see if it's actually working for your pony.  If the last bloodwork you did was in February of 2022 (as indicated in your case history) you don't even know if he actually needs Metformin or not at this point.  

Metformin can bring insulin down but we recommend starting with diet and exercise.  

Is the current hay being fed being weighed or is that an estimate of how much he's eating per day?  Do you have the hay test results?  Have you changed anything since you had his insulin tested earlier this year?  Is he being exercised on a regular basis now?  

Knowing the answers to all these questions will help us help you and Romeo.

On Wednesday, September 14, 2022 at 04:44:31 PM EDT, HMel <heidi@...> wrote:

Thank you so much. I have attached my case history to my signature now. I'm learning! My vet was interested about the note from the lab talking about higher IR in the winter months and curious about how that aligns with when Romey has a laminits bout. 
Heidi M. in Colorado 2022 with the amazing Romeo, a 2004 model Shetland-type pony. 
Case history:


Thanks so much for your guidance. I updated the case file and changed the radiograph name. 

Romey is a Shetland-type pony, 18 years old. He is at a good weight –about 500-- with ribs showing just slightly. Not overweight. He is fed in a slow feeder with another horse in the same paddock. He gets one flake in the feeder twice a day. Not weighed as they do allow each other to share food at some times though the big horse chases him off mostly so he usually gets what I give him. Current hay was 7 NSC. New hay will come this weekend and tested at 9 NSC. Protein at 14 percent. It won't be started until December. Hay has not changed since early last June. Gets regular exercise. Is trimmed well and timely. 

My vet has recommended starting Metformin in November to help him through his usual bad wintertime. I will look into the 

Thank you! 

Heidi M. in Colorado 2022 with the amazing Romeo, a 2004 model Shetland-type pony. 
Case history:

Sherry Morse

Hi Heidi,

So a couple of things that jump out at me:

1 - do you have the actual hay test results?  Was the testing done via Wet Chem or NIR?  We don't look at NSC but ESC+starch so having those actual numbers would be very helpful.

2 - 14% protein is quite high - were nitrates checked on that hay to be sure they're not also high?  You would want to read this recent message and the links within it: High protein hays / how to choose ( as well as this one: Re: Hay-High Protein/Low Sugar (

3 - Without any disrespect to your vet this group has many more years of experience dealing with IR and winter laminitis.  Starting an equine on Metformin at a random point in time to try to stop something that we have not necessarily found to be related to high insulin levels is literally taking a shot in the dark that it will work.  At the very least you want to test insulin before starting and 7 - 10 days later to see if the medication is even working and if the temperature drops below 40 you need to get boots and wraps on the pony to keep his legs warm since he already has a history of winter laminitis. 

Kirsten Rasmussen

Hi Heidi,

What a sweet looking guy, I bet he's a great children's pony!

Cold weather does increase insulin, and in a horse with barely or poorly controlled EMS that can push them into acute laminitis.  We see this every January or February with new members joining at that time who have equines in the acute stage.  If cold weather is the cause of Romeo's hoof pain then it's likely his insulin is not well controlled year-round, but it's just colder temps in winter that push him over the edge.  You may want to test him in the summer to see how high his insulin in them, too.  Insulin above ~80uIU/mL is where acute laminitis start to show up (sub-clinical chronic laminitis occurs at much lower insulin levels though, and can cause smoldering chronic damage), although at what exact level acute pain sets in does vary individually.  You will know if high insulin is the problem by doing bloodwork when he's acute.  Then Metformin would be a second line of defense, after or in conjunction with necessary dietary changes.

However, what we call "winter laminitis" is neuropathic pain related to poor circulation to the hooves.  High insulin does not cause this pain, so it's actually not "laminitis".  Poor circulation can be caused by chronic laminitis that damages circulation over time, and warming the horse and it's extremities is the first line of treatment.  If insulin is also high, then dietary changes +/- pharmaceuticals are necessary, too. 

Since Romeo had high insulin in February, dietary changes (ie hay soaking) +/- meds are critical, but in case some of the pain is neuropathic we also advise warming as an equine can have both problems at the same time.

Kirsten and Shaku (IR + PPID) - 2019
Kitimat, BC, Canada
ECIR Group Moderator
Shaku's Case History
Shaku's Photo Album