Generics Versus Brand-Name Drugs

Are generic drugs as good as their brand-name rivals? Hopefully yes, as millions of people rely on generics to make medicines affordable. Is the claimed superiority of brand-name drugs just advertising, or is there a real difference?


An awful lot of people with diabetes are taking generic drugs. Most people take metformin, not Glucophage. (Generic names usually don’t have a capital letter, while brand names typically are capitalized.) Many take glipizide, a generic sulfonylurea drug, while few take Glucotrol, its brand-name version. Are there any differences in effectiveness?

Under federal law, generic drugs must be chemically identical to the FDA-approved brand-name drug. According to Melissa Stopler MD, generic drugs “are copies of brand-name drugs that have exactly the same dosage, intended use, effects, side effects…risks, safety, and strength as the original drug.”

So they ought to act the same in our bodies. Usually they do, but some people think there may be significant differences between generics and brand names. How could that be if the ingredients are the same?

All the active ingredients could be the same, but the inactive ingredients could make a big difference. According to “Examples of inactive ingredients include binding materials (which may be excipients), dyes, preservatives, and flavoring agents.” “Excipients” are bulking agents and fillers that give pills their size.

Those don’t sound like they could affect a drug much, except maybe if you’re allergic. But not all inactive ingredients are always inactive. According to Wikipedia, excipients can serve in various ways to strengthen or weaken a drug’s effects. These powders might “facilitate drug absorption or solubility.” They might slow down or speed up a drug’s passage through your system.

It’s not only excipients that can make a difference. gives the example of alcohol as “an ingredient that may be active or inactive based on the specific formulation of the medication.”

I never thought about this until my neurologist (a specialist in the nervous system) told me that over-the-counter generic melatonin pills don’t work. They’re not even real melatonin, he says. He wanted to give me a prescription, which would have cost ten times more than the generic. It’s funny, though. The OTC melatonin seems to work fine for me.

The different versions of drugs really are different. An eye-opening article in Fortune magazine explains that a drug patent

reveals the components of a drug, but it doesn’t explain how to make the drug. In reality, manufacturing a generic requires reverse engineering, and the result is an approximation rather than a duplicate of the original.

As a result of these differences, generics may get into the blood faster or slower and last longer or not as long. You can see how this would make a difference in a drug that, say, lowered blood glucose. This can be especially true with time-release medicines. The rate of release can vary greatly.

How important is this to you in practice? Do you trust generic drugs completely? I tend to, because the price advantage of generics is hard to ignore. But if they’re not as good or not safe, you would have to think twice about using them. On the other hand, some generic formulations seem to absorb better than the brand names and might be even more effective.

What do you think? Have you noticed a difference when you take a generic drug? What about when your pharmacy switches from one company’s generics to another? Are there any specific drugs you have found work better in their brand-name versions?

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  • Susan

    AS long as they leave my Novolog and my Lantus alone, I will try the generic of which most of mine are at this time. But don’t start with my injections. Right now it looks like if I stay with current insurance they will be wanting me to change meter, strips, etc.
    Anyone know anything about TrueTest meters and / or strips??

  • Redneck Angel

    A few years ago I had to have an open reduction one on my ankles. The incision developed a infection (not surprising on a older adult w/a 40+ years history of diabetes). I took several different antibiotics over a 8 month period before it cleared up. Except for the last 2 antibiotics I took which were new 1st generation, they were all generics. In this time period, I once filled one of them at a different pharmacy because it was more convient to get there. When I refilled it at my regular pharmacy it was obviously a different company’s formulation of the same generic–it looked different enough that I asked the Pharmacist if it was ‘right’–& after taking it a few days my stomach got so sore, & I so sick, that I had to stop. I complained to my Dr. & he changed the prescription–no more sickness (that’s when we changed to a non-generic, patented drug). When I mentioned it to the Pharmacist, he asked me if I knew which company the other formulation was from. He said he’s switch companies.
    This isn’t the 1st doctor who’s told me that all generics are NOT equal…. Just the 1st time it was so obvious.

  • Laurie Kutrich

    I can’t speak to specific diabetic drugs, but my daughter had an allergic reaction to generic Immitrex. After it happened a second time she switched to the patented product with no side effects. Fortunately her insurance would cover the medication. My husband isn’t so fortunate. His insurance refuses to pay for Lexepro, insisting that he can use Celexa in it’s place. Celexa isn’t even a generic form of Lexepro. The side effects and inffectiveness of the Celexa for my husband means we are now paying $600 out of pocket for Lexepro (a medication that had a $30 co pay 1 year ago). The reason we have so many medications is that we are not all the same! As consumers we must stand up for what works best for us and not the insurance companies.

  • Wayne Carr

    Taking generics, for the most part has seems to be as effective as brand names for me. However, this is not true for the generic of Cardizem LA because I have an alergic reaction to the generic as I break out with a rash.

  • keypal


    TrueTest is a good brand.

    I really like Accu-chek products (& customer service) – Aviva Plus and Nano – these meters/supplies are also covered on most insurances. Currently, they are offering a free Nano meter:

    I would encourage you to check with your insurance about coverage on this brand as well.

  • wm tiep

    When the insurance switched me to generic warfarin for Coumadin my reading varied over a large range. After demanding [D.A.W.] & getting back on Coumadin my I.N.R. have been in tight range. Some name drugs work differently than generic.

  • Erik

    I’m a Type 1 Diabetic who also has hypothyroidism. For my hpothyroidism I started taking generic levothyroxin. I was on it for several months without issue and then I experienced what I thought were minor symptoms of a heart attack. (Excessive pounding of the heart and numbness in the left arm). All turned out to be OK with the heart, but I was given the theory by the ER Doctor that I might be experiencing some side effects from my thyroid medication. And I’ve heard from others that they experienced similar sypmtoms with the generic drug perhaps due to less than stellar consistency from the manufacturer. So, I switched to brand name Synthroid and didn’t have further issues, so I thought I had a clear case of generic being not as good as name brand. However, fast forward a couple years and my symptoms came back (again the heart checked out fine and they’ve since gone away). So, now I’m starting to wonder if it has absolutely nothing to do with the med and might just be a thyroid issue in general or just an inexpliecable medical experience, and perhaps I’ve been wasting an extra $20 per month for the brand name. I wonder if there has been any clinical studies that show a marked difference from generic to name brand?

  • ellen

    I was taken glucavance 5/500 for years and was just switched by the doctor to metaformin for the diabetes I find that the glucavance lowers the sugar better than the metaformin I was switched being my sugars levels were out of control and in the high 200’s Now its under 200 around 150-194 with the metaformin if I take a glucavance with the metaformin the sugar levels are from 100-150 my take on it is that the name brands work better I’m also taken junevia and victoza with the metaformin

  • Joe

    “Some people believe…” is a far cry from established scientific research, and even educated people sometimes have unfounded prejudices. If my doctor told me that my OTC preparation (that worked fine for me) was a fraud, I would want to see a study or two proving it. Anecdotes are nice, but controlled research tells a more complete story.

    As for prescriptions, if the name brand and generic have the same chemical composition then you’re looking at the unusual possibility that some filler or binder might be different and some users might be sensitive to some component. I can’t see that being much more of a risk in generics as opposed to name brands. Some people might be sensitive to either. Once again, greater suspicion falls on the generic due to the prejudice that “if it’s cheaper, it must be somehow inferior.”

    Bottom line: Generics and name brands may very well not be 100% identical. Does that mean generics are automatically more suspect? Not in the least.

  • Karen Hull

    Every time our Humana insurance demands we change from the brand written by the doctor we end up with a crisis where all systems get out of whack. It takes four to six weeks to overcome the ill effects and each time it has been pinpointed to the variances with the generics being ten to thirty five percentage points off from the name brand, even though they are marked the same dosage. It has been a nightmare and I do not like being told by insurance companies what I can and cannot take, when it is my life they are playing with to save themselves a little money. One’s life should not be the chip they use to gamble with when it is a human being, and not a paper with numbers on it.

  • Dave

    Keypal,I too use an Accu-chek meter. For backup I use a Walmart Prime meter which retails for $14.00 or so. Strips for this meter run $9.00/fifty,a $60 cost reduction from my Accu-chek strips which are $69 @ Costco. On a typical reading of 180 the meters will be maybe 2pts different. Pretty darn close.

  • ML Shannon

    Finally someone has the courage to print this. I constantly fight with Blue Cross about prescriptions. They require that I try generic. I do. Then either I get a really pretty rash or my throat swells. On rare occasion nothing happens and the drug does nothing either. Why do companies like Blue Cross not acknow. this problem with generic. All for the almighty buck. So I can pay top dollar for insurance policy thru work and pay top dollar for all prescriptions. Can not get discount or free as I work. Great American dream. Easier to drop dead.

  • Rani

    As far as I have seen (and personally experienced), generic drugs work just as well as the brand names. Plus they are cheaper than the brand name drugs. I would prefer to use generic drugs for all ailments, not just for Diabetes.

  • john mitchell

    I have been taking generic metformin and glyburide for over 10 years with no problems.Same with other blood pressure and cholesterol products.

  • Rusty

    I have had both good and bad experiences with generics. I have had type 1 diabetes for 48 years, since age 12. I have had issues with generic thyroid medicines and the Synthroid seems to be the only one that works as well for me. I also have found over the years that Novolin insulin does not absorb or react the same as the Lilly Humalog. My doctor told me to take the Humalog even though it costs me more but there is no doubt that it works better for me in the pump.

    If we trust the FDA to protect us then we all, as consumers, should beware.

  • Rammy

    My coworker isn’t allowed to take generic heart medications. Not sure which ones she’s on, but her Dr. said that generics are allowed up to a 30% variability on strength. So one pill could have 30% too much or too little medication in it.

    Her medications are so expensive, her medicare runs out by the end of September every year. At 74, she has to work all year long just to cover the out of pocket costs for those heart medications from Sept – Dec.

  • p j greten

    I have type 2 diabetes.. last march I was switched from novolog insulin to Humalog insulin for my mealtime coverage. it takes almost double the amount of Humalog to get the same results as did the original dosage of novolog, to cover the same meals. I brought this to the pharmacists attention, as well as my doctor… neither of them seemed concerned about it.. said the chemical makeup was the same…. I do not agree, but I follow my doctor’s orders.. thank you for the opportunity to share this information… keep up the good work…

  • Al Kurmas

    To: Susan
    RE: True Test strips/ meter

    I switched to these about 9 mo ago, and realized a significant savings. I got the meter free, along with a sampling of test strips. I compared these side-by-side with my old meter/strips
    (Bayer), and found the disparity insignificant (about 6%, plus or minus. I do this every time I switch meters, and found discrepancies in readings of 20% or more (i.e., between Bayer and Accu-Check, and other comparisons over the years), so I was very comfortable with the results. I do the comparison by taking one sample finger pick, and placing the sample on a strip from each brand in their meter, and I do this throughout the entire run of sample strips, usually 10, so I get a two-day record of results. I’m told this is not a true scientific sampling, but it’s the best I can come up with while standing in front of my bathroom sink.

  • BK CDE

    So many issues here. RE insulin, novolin and humalog are not anywhere near the same. Novolog and Humalog are usually considered interchangeable, but even then some people will notice some differences.

    For the 74 year old who hits the donut hose in September, Affordable Care Act is helping and will help even more in the future.

    I too had an experience with a generic antibiotic that made me ill with nausea about an hour after each dose. I got so I dreaded each dose. Decided it was the “fillers” as I had certainly taken that particular antibiotic before, it was just plain pen VK, usual first choice for strep and dental procedures.

    Each of us is different so you never know for any particular individual just what the effect will be until you try it I’m afraid.

  • Miguel A. Rodriguez

    I am 82 years old and not diabetic. But I take other medicines like Metoprolol and Hydrochloriazide, etc. How can I say the difference between generic and brand?

  • Lor

    I have been taking Synthroid for many years and I have been told by my doctor to never use a generic and he writes that on my perscription. I also do not like the fact that the insurance companies can dictate what medication I can take. I also used to take Humalog but my insurance company stopped covering it and I had to switch to Novalog which does not work as well for me and the doctor figured I had to use 33% more insulin to get the same result as the Humalog.

  • Karl Hockenbarger

    “As good as” – in my experience yes, “The same as” – absolutely not. I took antivert (meclozine, prescription strength Dramamine) for years. My first couple of prescriptions were for the brand name, antivert. My insurance company, of course wanted me to use the generic, and it cost me less than 20% as much as the brand name. But The first time I took the meclozine I could tell the difference. I felt like a zombie (dulled perception, slower reflexes, like a spectator watching life – instead of participating) when taking the generic, but not when taking the brand name. Both took care of my vertigo, but the generic had undesirable side effects. I have not had that same kind of experience with other drugs. My experience is to try the generic and if it works, great. If not advocate for yourself to get the name brand. It can make a real difference

  • Robert Abramson

    I turned in a prescription for a drug. I received a drug store plastic pill container with pills. I started taking the pills and my blood pressure began jumping up and down. When the time for the refill came due I was down to the last pill which I took. I went to the drug store and picked up my refill prescription. This time the pills were in the manufactures container. When I opened up the container I noticed that the pills were a different size and color. I called the manufacture and asked if the first pills or the second ones were generic. They advised me there was no generic and the container with their lable was the correct size and color. I started taking the new pills and my blood pressure went back to normal and I felt a whole lot better. I think the generic the pharmacy gave me must have been donkey dust from China.

  • john e. rubbo

    I cannot take metformin because of adverse gastrointestinal reactions which does not happen with Glucophage. I pay extra to get Glucophage.

    I know the FDA has a document which rates how close generics are to original medications because I used to check this document in the past. Unfortunately, I can’t recall the name of this document .

    John Rubbo

    • Erika Renee Sandman

      Hi John,

      I know this thread is super old, but by chance you get this and comment, do you remember how much the difference in price was between metformin and Glucophage? I am requesting to switch to Glucophage as well because I’ve heard people have less side effects than with the metformin, and metformin is just not the right drug for me.

  • Pharmacist Linda

    Please go to the FDA website and get accurate information. There cannot be a 35% variance between generic and Brand formulations. Generic manufacturers must submit data that shows that their products are bioequivalent to the name brands – same strengths and clinical results . ALL manufacturers are allowed a small percentage of variance (5-10% depending on critical clinical effect such as heart drugs)of their stated strengths. That means there can be as much as a 10% variance in different lots of the Brand manufacturers drugs. I find that physicians know the least about these issues. Ask your pharmacist.

  • Brendaq

    Hubby & I had a standing joke regarding our Lasix (generic version). He would come running down the hall heading for the bathroom and we’d joke that he got “a live one” out of the bottle today. We live with that one, cost being the deciding factor. But when the insurance company switched our GENERIC version of Vicodin, we had to complain. I noticed a difference immediately but did not say anything to my husband. About two weeks into the new version he started to complain about them not working. So I decided to do a little research. First off, were they really a different company? Most times we never check. This time, it was a different company. Pharmacist said we should be having a problem and no one was complaining — which I seriously doubt. Internet search revealed that the number of ingredients in the new, not-working brand contained 7 different ingredients. The working brand contained 5. Have you ever baked a cake from a box mix or from scratch? It’s pretty hard to screw up a box mix and end up with something inedible. Scratch cakes are a different story, the right ingredients added at the right time and beat for the right amount of time will give you a beautiful cake. Ignore the instructions and you’ve got a lump of stuff for the garbage pail. It took some doing to get our GP to change the medication order to DAW and a specific brand but he did it and the insurance plan pharmacy did comply. Many of our generic drugs are being made in India among other foreign nations where the controls are not always in place to assure the proper quality. That’s why they’re being made there, the labor is cheaper, they’re not as highly trained and there is little, if any, quality controls in place. Keep tabs on the brands that you are using and whether or not the drug is acting like it usually does or not as it should. If something is different, tell your doctor and have him change it to another brand and put DAW (Dispense as written) on your prescription.

  • joan

    Generics! I have allergies and so my pharmacists knows when not to fill a prescription for me in either a generic or brand name if it holds any of the ingredients I am allergic to! This is often difficult because as mentioned, not all that goes into either type of medications is easily found, at times.

    So, both generic and brand names drugs do at times not work well for me; usually give me a rash or upset digestion or in some way disturb my test results.

    I would hope that some day soon it will be much easier for the pharmacists, and the patient to know ALL the ingredients in any medication before it is filled!

  • Ellen

    I have no choice, I can only afford generic. No ins, and a year away from medicare.

  • H Molvang

    Comparison is more often than not on the
    the radar of newly diagnosed patients. They
    start out with metformin so have no way to know if their response to the drug could be improved.
    with the original version. Diarrhea is a real problem and often self treatment with Imodium becomes the drug of choice.HM

  • Marjorie Mattas

    I started having trouble with some generics about 2 years ago. I now find I can use only 1 manufacturer of Lisinopril. My pharmacist was the one to see that I had started with a different manufacturer. Now 2 years later I just got a different manufacturer of metformin and I am having eczema -like reaction on my skin. When I now start a new pill I get only 1 month supply to see if I am allergic and if alright with new drug then I have Dr do a 3 month supply and request the same manufacturer. It is a pain to do this but much less of a pain on my body.

  • Deanna

    The ‘Only’ difference I have had was with generic for Soma. There where times it would work and times it didn’t work. I could also tell at times when I was taking the drug, that I got ‘Stoned,’ and I wouldn’t drive. When I took the real drug Soma, I didn’t have that problem. I no longer take any muscle relaxers for my back, due to that problem and plus I can’t afford the Soma.

    I also take Levemir for my diabetes. I used to take pills that where generic, but they didn’t work like Levemir. My body is just fine from taking the injects.

    I’m on Medicare due to a permanent injury. With that being known, I can’t afford anything else but generic medications.

  • jim snell

    Intresting blog and opportunity to respond.

    My case was metformin. My liver depends on sufficient up to strength in blood from dose of metformin to cut off excess liver glucose release.

    Many generics worked fine but there are a few knotheads out there whereby I had to have my Docter increase the dose of that generic version to get liver compliance.

    And this is NOT A PERSONAL PREFERENCE issue as the classic rejoiner from the drugist class.

    Unfortunately some of the large mail order ( and I will say I appreciate their excellent cost saving health stratagies ) get locked on some of the cheapest generic variants that tend to be a precise pain in derrier.

    Otherwise like many of the responders I also depend on the cost saving opportunities of the generics.

  • Big T

    They have generic Viagra now in Europe. I’ll be glad when it comes here. $30 for a 100MG is outrageous!

  • Donmarie Desrosiers

    This article was very interesting. Now, what made me take pause, was the fact that you used Wikipedia as a source! Wikipedia is well known to NOT be a reliable source for any information. Information on it is mostly opinion, half-truths, and made up stuff. There probably is some legitimate info on it from writers very educated in their field, who rely on “evidence based” medicine, and don’t go off on some tangent of their own. Also, info on Wikipedia can be changed and altered by anyone. I would not trust or take to heart or quote as Gospel, anything derived from Wikipedia.

  • Mando Carr

    I used True meter and strips and was confident they were working correctly until my readings were not coinciding with my A1c. Turns out True meter was giving me a 20=30 point difference in the readings, sometimes over sometimes under the correct reading.

    On the advice of the manufacturer I tested the strips and the meter and all indicated it was working properly. I switch to a different make and model of monitor and all is well.

  • Bob Baker

    My concern comes from that fact that it is frowned upon for consumers to buy pharmacuticals from other countries even those drugs are manufactured in the U.S., but the major pharmacies (Walgreens, CVS, etc) dispense drugs manufactured in other countries to us. I worry more about that, some of those countries don’t like us, harbor terrorists and it would be a great way to harm U.S. citizens.

  • charlotte miller

    I have been using a lot of generic drugs because of my being in “the donut hole” and I can honestly say the generic drugs are a bit better than the name brand and not because of the price. My use of metformin well, I’ve been using it for ten years and my blood sugar is great, but that’s with diet and some walking.

  • Nancy Russell

    I had yet another negative experience. I have been taking Metformin for about 10 years. My pharmacy changed and unfortunately the supplier also changed. I had been taking Metformin by Solco and then the new pharmacy supplier became Teva. I was immediately experiencing GI difficulties and overall malaise. Fortunately I, with my NP, after having a colonoscopy and endoscopy- all negative- we discovered the manufacturer variable. I found another pharmacy who used Solco and have been back to baseline ever since.

  • Susan Milld

    Bad generic Candesartan for brand name Atacand. My mother had taken Atacand for over 10 years for blood pressure with no side effects and excellent control of bp. In January medicare force her insurance to generic. She has had repeated episodes of non-control with high bp suddenly in middle of the night. Two trips to ER due to dizziness etc. We tried the doctor letter route for emergency approval and were denied. At 90 years old I am scared now about damage to her heart which was good before this. She lives alone and it scares her. We also have had allergic reactions to other generics such as levothyroxine with corn starch being an inactive and now the one brand is recalled and we just started a new one and waiting to see if it will be safe and dependable. Ugh!!!

  • caroline

    I have a question: Does anyone notice a difference in using a brand name meter and test strips — I was using Accu Chek Aviva, or in using a generic, such as Walmart Prime, which I have switched to for financial reasons. Even on my insurance, the Accu Chek Aviva strips were close to $100 for a month’s supply. I am relying only on the Prime meter and strips. The Prime strips cost me $18 for a month’s supply. My blood sugars have been tightly controlled for over 7 years and my A1C’s range from 5.9 – 6.3. I haven’t had an A1C since I switched test strips, and hopefully when I do have one done, it will still be within this good range. Anyone try generic strips and if so, what are your thoughts?

  • Colonel

    lacks explanation of isomers and possible effect. generic for Prandin had negative effect for me.

  • Melinda Moses Jacobson

    I have tried Metformin several times over the past 15 years. I can not tolerate it at all. In a last attempt after reviewing some family medical history I asked to try Glucophage, the name brand. Night and day difference for me. I am doing awesome with absolutely no side effects. The metformin actually raised my blood sugar and also raised my A1C over 3 points. That is huge!!!! Once I quit taking the metformin my A1C came back down into safe range. I have to take the medication for Severe PCOS. I am so excited I trusted my gut and am having such positive results with the Glucophage. Hope this helps someone else who may be experiencing the same issues.